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HomeMy WebLinkAboutSmuggler Superfund - Clement Assoc Prelim Risk Assessmt 1985TOM DUNLOP ASPEN/PITKIN SAWITAMAN 130 & GALENA ASM CO, 81 W I nnU Clement Associates, Inc. A Scientific & Engineering Consulting Firm, Arlington, Virginia PRELIMINARY RISS{ ASSESSMENT FOR THE SMUGGLER K)UN`I"AIN SITE, PITKIN COUNTY, COLORADO Prepared for: Scott Mernit Camp, Dresser, and McKee, Inc® Denver, Colorado 3 - - Clement Associates, Inc. 1515 Wilson Boulevard Arlington, Virginia 22209 May 10, 1985 Pa Summary and Conclusions 1 Characterization and Description of the Site 5 A. Geographic and Physical Description 5 B. Procedures Used in Sampling and Analysis 8 C. Results of Sampling and Analysis 10 1. Soil and Mine Tailings 10 2. Surface Water 12 3. Groundwater 15 4. Air 17 5. Blood Levels 18 D. Summary of Results 21 Hazard Assessment 22 A. Health Effects 22 1. Arsenic 21 2. Barium 23 3. Cadmium 23 4. Copper 24 5. Lead 25 6. Manganese 25 7. Mercury 26 8. zinc 27 B. Toxicity to Wildlife 27 IV. Exposure and 'Risk Assessment 30 A. introduction 30 B. Potential Exposure Pathways 30 1. Soil 30 2. Household Dust 32 3. Surface Water 33 4. Groundwater 34 5. Air 34 6. Summary 34 C Lead. 35 Cao Cadmium 41 1. Inhalation 41 2. Ingestion of Dirt 41 3. Ingestion of Vegetables Grown in 42 Contaminated Soil 4. Ingestion of Groundwater 42 E. Other Elements 44 F. Interactions 45 V. Mitigating Factors 47 A. Bioavailability (Physical -chemical 47 characteristics) B. Meteorological Factors so VI. Recommendations for Further Investigation 51 A. Exposure Assessment 51 1. soil 51 2. Household Dust 52 3. Surface Water 52 4. Groundwater 53 5. Air 53 6. Identification of Exposed Population 53 B. Risk Assessment 54 References 4-77)IJ This report is a preliminary assessment of human health risks and potential environmental impairment associated with the presence of mining wastes in the vicinity of Smuggler Mountain near Aspen in Pitkin County, Colorado® The adequacy of avail- able information for risk assessment is evaluated and needs for additional information are identified. The available evidence is used to assess whether or not unacceptable health risks may exist for workers at the site and for residents of homes on or in the vicinity of the site. Sources of uncertainty in the risk assessment are identified and discussed. This report consists of a brief description of the site, a summary of the results of environmental monitoring in the vicinity, a discussion of the inherent, hazards associated with exposure to metals at the site, an assessment of potential human health risks to residents in the vicinity of the site, a discussion of sources of uncertainty in the risk assessment, and recommen- dations for further investigation at the site. on the basis of available information, Clement Associates, Inc., has reached the following conclusions: 1. T'he most important potential routes of human exposure to metals at the Smuggler Mountain site are: • ingestion of contaminated soil • Ingestion of vegetables grown in contaminated soil • inhalation of airborne particulates (soil) e Ingestion and inhalation of household dusit a Ingestion of contaminated groundwater. 2. Because of their inherent toxicity, health risks due to exposure to lead, cadmium, and possibly arsenic dominate the risk assessment. 3. Because of their potential to experience greater exposure and because of their increased susceptibility to the adverse effects of lead, children aged 2-12 are considered to be the target population • concern at the Smuggler Mountain site. 1, . Levels ♦ le,ad of 1,001 ppm, or higher in soil i& the vicinity of the Smuggler Mountain site may pose an unacceptable risk of central nervous system impairment in children living in the vicinity of the site. 5. Levels of cadmiumn of 10 ppm or higher in soil in the vicinity of the Smuggler Mountain site may pose unacceptable risks of cancer and impaired kidney function among residents in the vicinity of the site. 6. Because of a lack of complete information regarding exposure, there is a great deal of uncertainty associated with the estimated risks that may result from exposure to metals at the Smuggler Mountain site. 1 7. In order to reduce the large uncertainty associated with the present risk estimates Clement recommends further investigations as follows: I e Additional surface soil sampling and analysi� ately define a 1,000 ppm isopleth for lead and a 10 ppm isopleth for cadmium. Ascertainment of prevailing meterological conditions at the site Additional air sampling and analyses to determine worst case and annual average levels of respirable particulates, lead, cadmium, and arsenic at locations most likely * Investigations of the potential bioavailability of lead and cadmium in soil and tailings from the Smuggler Mountain site., e Sampling and analysis of household dust samples from residences adjacent to the site for lead, cadmium, and arsenic. e Further characterization of the nature and drainage pattern of surface water at the site. e Further characterization of groundwater movement at the site. e Additional groundwater monitoring with methods suffi- ciently sensitive to detect hazardous levels of lead, cadmium, and arsenic. e Collection of additional information regarding the potentially exposed population including the location of wells that have the potential to supply water for domestic use. 9 Measurement • blood lead levels or another suitable indicator of lead body burdens in individuals, especil ally children, who have lived in the vicinity of the site . The results of these further investigations can be used to assess current risks with greater certainty as well as to assess the risks associated with potential remedial options. 51 II. CHARACTERIZATION AND DESCRIPTION OF THE SITE A. Geographic and Physical Descr�timon The Smuggler Mountain site is an approximately 75 -acre area located about I mile northeast of downtown Aspen, Colorado in Pitkin County (Figure 1). Much of the site is located on the side of Smuggler Mountain, with the terrain consisting of a steep slope leading down to several plateaus and eventually to the Roaring Fork River. The Smuggler mine shaft is situated on the side of the mountain just above the highest plateau. The Smuggler Mountain Trailer Court is located a few hundred yards downhill from the mine to the west and the Hunter-Longhouse Condominiums and the Centennial development are at about the same distance to the northwest. The Centennial development consists of low priced condominiums which when completed, will be available to people with over 3 years residency in Pitkin County. Centennial is also putting in a baseball field on a plateau between the trailer park and the mine property (Mernitz, personal communication) Mountain tailings, either uncovered, covered, or mixed with soil, comprise much of the Smuggler Mountain Site (Ford et al. 1984). These mine tailings were used as fill in several local construction projects, including the trailer park, the Hunter- Longhouse Condominiums, and the Silver King Condominiums. Most.. of the tailing piles have been covered with imported topsoil but some bare tailings are still present (Boon 1983). The mine 61 �a .sem` 4\ +a,y abti�6J®� •Y°�� .. m « '°�.° e • p i 8; -� '$` me� ® •a' a a `" .g a.. aa� * m �4w ' �' • �°. � � m y'x""°.. O'.t 4b• tltN a" r �a tj ®.CD �� / h 0 �t 0 � ,h e 7907) h IT my, m P D o MW ! I b � � J ' •fir. m ® 4\ "•v.n..Y..• I� � �F . b XPi' m p 1d hl40(f/rY + � /Y ,rap � ��b Y�(® +1 A�..�lis � � «rho ...ffftae� fir .� m �� � �JL-8—�p� 6r 071 �f.r JY'®•m'm Y1'��� "''•m 10 w '®^ m ri m m• e /p 0' w { .)fig p 4� a •mm w Olt ��6'&%'onrnent, Inc_ l vel ,r'°• �� b �11i1SUITE 35, 1! I�� 4105 EAST FLORIDA AVENUE, )'► 11 ° Pria DENVER, COLORADO X4'4.'• � � 11 r " I u t a FIGURE STUDY AREA LOCATION ASPEN9 COLORADO �. 1. rIgA4 tailings contain very high levels of lead, cadmium, and other toxic metals, which may present a significant hazard to exposed populations. The geology in the area of the Smuggler site consists of faulted quartz bedrock overlain with glacial, colluvial, and alluvial deposits (Ford et al. 1984). Limestone, dolomite, sandstone, and shale are important constituents of the soil in the area of the site. The limestone is especially important due to its buffering capacity; acidic mine runoff with an initial pH of 5, has a neutral pH of 7 when it is measured at the river. The hydrologic makeup of the Smuggler site consists pri- marily of the Roaring Fork River which has an average annual discharge of 84 cubic feet per second (cfs) and flows in a northeasterly direction, and groundwater flow. Hunter Creek to the north of the site may also receive some runoff from the site. The interaction between groundwater and surface water is affected by the presence of several mine shafts (Ford et al. 1984). In particular, groundwater to surface water flow occurs at the Mollie Gibson Mine to the south of Smuggler Mine and at the Cowenhoven Tunnel to the northwest. As groundwater probably flows in a westerly or northwesterly direction, the Cowenhoven Tunnel which discharges into Hunter Creek, is probably the most important with respect to the site. However, drainage from the Mollie Gibson Mine may transport mine tailings present on the soil surface into the Roaring Fork River. 7 Groundwater is present in both the unconsolidated valley - fill sediments and in the bedrock (Ford et al. 1984) . In the valley fill sediments, it probably moves downslope towards, stream channels with some disruption in flow direction because of changes in sedimentary layers and with the rate of flow dependent on soil composition. in the bedrock, water probably travels through the intergranular spaces in the rock matrix and through the fissures and faults in the bedrock. Groundwater in the bedrock probably moves most easily in the direction of the fault line, which is primarily a northeast -southwest direction. Surface water flow may transport materials from the site by several routes. The removal of surface sediments by the drainage from mine shafts and the transportion of leachate in groundwater recharge of surface streams, are two pathways. In addition, spring runoff and runoff after heavy rains, either of which could wash across the site and transport soil downslope to the trailer park or into the river, may also have an effect at the site. The vegetation on the site is rather sparse and apparently consists of scrub trees and grasses. I B Procedures Used in Sam lin and Analj,�Js All media have been sampled for the presence of at least some of the toxic metals known to be contained in mine tailings. Soil and tailings were sampled separately and analyzed using both weak acid extraction and total acid digestion (Ford et al. N 1984) . Several samples analyzed by the Colorado Department of Health were apparently also extracted by total acid digestion. Boon (1983) used an ammonium biocarbonate DTPA (AB -DTPA) extrac- tion. Only , a small number of groundwater samples were taken. These were apparently taken from the wells of several residents near the site. Discussion with Aspen -Pitkin County Environ- mental Health Department officials indicates that the samples were taken from the tap, but no information was available as to whether or nor the system was flushed prior to sample collec- tion. Surface waters near the Smuggler Mine site have also undergone limited sampling® Ecology and Environment inc. (1985) conducted fairly exten- sive monitoring of the air around the site in the early autumn of 1984® High volume air samplers were placed around the site and at a background location near Snow Mass Village. Total suspended particulates and total metal concentrations were measured. In addition, one sampler was used to measure respir- able particulates and metals (less than 10 � in size). Air sampling was conducted at a time when construction was in pro- gress on the Centennial site, but the expected increase in particulate emissions may have been mitigated by unusually rainy conditions. An informal screening study involving 22 persons who lived in the vicinity of Smuggler Mountain was conducted in an effort to detect elevated body burdens of lead. T,he details of this I investigation are not available. Apparently a drop-in blood sampling station was set up in conjunction with a local fair (Tom Dunlop, personal communication). Pin -prick blood samples were taken from volunteers and analyzed for zinc protoporphyrin (ZPP). ZPP is an indirect measure of lead intoxication (USEPA 1984c). Elevated ZPP results from the accumulation of erythro- cyte protoporphyrin IX when lead interferes with hemoglobin synthesis. Body burdens of lead must reach a critical level before interference with heme synthesis occurs and this level may be higher than the level, at which there is subclinical neurologic impairment® Therefdre, elevated ZPP levels are useful only for detecting relatively severe lead intoxication and would not be expected to reflect modest increases in blood levels corresponding to subclinical intoxication® C. Results of Sampling and Analysis 1. Soil and Mine Tailip_qs A total of 11 metals were detected in the soil and mine tailings at the Smuggler Mountain site (Ford et al. 1984). The number of samples, average concentrations, and maximum concentrations for the detected metals are presented in Table 1. The concentrations reported are for extraction by total acid digestion. Arsenic, cadmium, copper, mercury, and zinc were detected at levels that averaged about 10 times higher than average background levels of these metals in undistrubed soils in the U.S., and lead was detected at an average level about 200 times higher than average background levels (Connor and M kn a m C3 Ca0 4 C�l 0 0 C:, Lrl 7! In C, 13 ko CD kn 0 0 "1 10 9J MN a V 4 C3 -I W94 N Ln C) 14 0 to en Ct Ua C4 M CA 4 6d'1C3 C3 N0 W a O r4 N 0 m �T 14 C) 14 rn pl C c I ko Ln C: fi 0 L) =-I U) 11 cq rl ea C Ck rz n C2 Ln h 'A CN CD a C3 E! cc N. co -4 rn a C3 r - fu Y4 r3 ra rd CA m co ko r' co 0 o a CD 19 -W -4 0 CN 0 N rn � va (U rn C� co N ro c air to M 0 W 'D W ,, �o -- �o 1� 10 1� �Q 1, W �, lg 60 G9 4A' 'D to 'D la Q 6p 6D :3 5 z z E I 4 x rtg Ul ry cO rq %a r7 en 0 ID a; CD 0 0 a IPB mwc,4 MOW -T -4c" w 0 w rn LI; rM Cfi aj L1 C i9 CI to Q) ul m 41 m M M M 4 en en en ,-n M -�e u -4 r4 4 -4 -4 -4 r4 4 u a -4 ..1 4 -4 W d) '0 -0 > 0 ai E E 4 0 z x C x tn C:) 2 C, Cr Aj d) w 41 0 m ax E En ri 4b x v, u tri N Shacklette 1975) a Barium levels in soil were slightly higher than average but concentrations of barium in the tailings were less than background levels. Four compounds, chromium, iron, manganese, and vanadium were present in the soil and tailings within expected background limits. The data of Boon (1933) are presented in Table I -A® No background levels were presented and concentrations obtained using the ammonium biocarbonate DPTA (AB-DPTA) extraction pro- cedure are not comparable with total acid extracted levels, but the trend in relative concentrations of the metals as seen in the Ford et al. (1984) data was maintained. Boon (1983) did calculate total lead concentrations based on the correlation between the A13-QPTA and the to5tal acid extraction procedures and this value is included in Table 1-A. However, he sampled a wider area than Ford et al. (1984) and did not separate soil samples from tailing samples and for that reason the data were not combined. Three samples were collected at the Smuggler Trailer Park by the Pitkin County Environmental Health Department and analyzed for lead and cadmium (CDH 1982) ® The average and maximum con- centrations reported were 90 and 223 mg/kg for cadmium and 11,723 and 21,700 mg/kg for lead. It was not clear whether these samples were of soil or tailings. 2. Surface Water Table 2 presents mean and maximum concentrations of dis- solved metals in the Roaring Fork River upstream and downstream 12 CONCENTRATIONS OF HEAVY METALS IN SOIL AND MINE TAILINGS IN THE VICINITY OF THE SMUGGLER MOUNTAIN SITE (AB-DPTA Analysis; mg/kg) Number Detected/ Number of Samples Mean Maximum Cadmium 27%27 5.4 35.8 Copper 27/27 12..3 37.5 Iron 27/27 30.7 8 Lead 27/2.7 292.4a 849 Manganese 27/27 4.7 16.8 Zinc 27/2.7 318.2 2,078 aCorrelates with a total acid extraction value for lead of 1,162 mg/kg. SOURCE: Boon (1983) 13 E- 1-4 4J -4 P Z; 1-4 E-4 z C14 EA E-4 >4 > ry4 0 E--4 r14 0 0 EA E-4 Iz E-4 Iz z > 0 U W 4J ul 0 -4 �4 8 94 ra c =3 0 w ol E.: 4.) U) 0 0 P4 se M U) ra ff� 4) Cu a) U) 0 Iz z -4 x co r En ro ra 4.) (U 44 0 r- 0) CN Iry J r- ca � CD ra cq N N Cq C:) C14 C) (n a CD C) C) C�4 co cyl tD C14 U) �o r - r -4 Li (N C\l C14 cq CD 0 C) N C) 'N N r-4 CD C14 CD cq ctrl a) .,4 �l 00 ON r-4 0 (0 Ln 41 41 6 0 (D (0 LO Ln Ln Ln 0 m C) C) r -i as 41 ra 0 F34 H C: ul 13 0 w O� 04 0 0 ra as 0 from the site. Only barium, iron, manganese, and zinc were detected in the river (Ford et al. 1984). The sensitivity of the analytical methods used was not adequate to detect levels of arsenic, cadmium, and lead that might be of concern. Although iron, manganese and zinc were present at slightly higher levels downstream than upstream, the data were insufficient to make any reliable comparisons. 3. Groundwater Groundwater from seven wells in the vicinity of the Smuggler Mountain site was sampled and analyzed for metals (Ford et al. 1984) Based on their, location and the assumption that a ground- water gradient exists from the mountain to the Roaring Fork River, i.e., generally east to west across the site, three of these wells are probably upgradient and unlikely to be repre- se,ntative of groundwater at the site. Concentrations of metals in these three wells are considered to represent background levels for comparison purposes® of the four remaining wells, two are classified as downgradient on the basis of both their location and the fact that the PH and specific conductance of water from those wells were clearly different from those of the background wells. For the purposes of this analysis the remaining two wells are classified as downgradient solely on the basis of their location. Analyses of samples from all four "downgradient" wells were combined to compile Table 3. Table 3 presents the results of the analyses for metals of water samples from the seven wells in the vicinity of the kv El E- H 0 ul c� Uz E w� 0 W C%4 0 Q E- g Ez U 7, 0 U ,, r 3 ra �a O n asqT r T rrr co C:) car C:), F -I 110 r-4 IZV c) Ln co w 0 C4 ra �o ` c Ln r rd w CN \ r- v `.,, '-, u1 (13 -) Ln , a r s ra CD m C CD V) —4 co C) Lr) M 00 rO r-4 C, a) 4 U) r-4 c� �a u� 4J �a ua I w r' I N ryl CD 1-I CD C) c"°1 —4 55 0 asqT r T rrr co C:) car C:), F -I 110 r-4 IZV c) ro 0 C4 ra �o ` c Ln r rd w CN \ r- v `.,, '-, u1 (13 -) \ , a r s ra CD m C CD V) —4 b+ C) Lr) M 00 ro 0 ` c '` \ \ \ `. \ `.,, '-, V (13 -) \ , a r s ra CD m C CD V) —4 b+ C) Lr) M 00 C, U) r-4 z —4 0 ,4 Ln 41 as CD Lr) Ln CDa up s r 41 0 4 ro 0 c rp •4 = E w a a cu 0 0�+ m (13 -) CW,7 Smuggler Mountain site® The limits of detection for the analy-- tical methods for arsenic, cadmium, and lead were 50, 5 and 30 pg/liter respectively. The ambient water quality criteria for the protection of human health for these metals are either below the limit of detection (arsenic) or within an order of magnitude over the limit of detection (see Apapendix A). Thus levels of arsenic that may present a significant risk to human health could not have been detected. Also levels of cadmium and lead just below half the concentration that is considered safe would not be detected. Because of these limitations it is not possible, to determine a meaningful mean concentration of these metals in groundwater at or near levels that may pose some human health risks. One of the downgradient wells showed elevated levels of cadmium and was sampled again. Barium, cadmium, chromium, copper, iron, manganese, and zinc were detected in the downgradient wells. All of these except cadmium and chromium were detected in the background wells. Elevated iron concentrations were found only in one downgradient well. Tn the other downgradient wells and in soil samples from the site, iron levels were compar- able to background levels. The high concentrations in the water could be an artifact of well construction. Although the data set was small, it appears that elevated, levels of cadmium, copper, iron, and zinc were present in the downgradient wells. 4. Air EEI (1985) took a total of 115 samples of particulate matter from a background site and four onsite locations. One kffi of the onsite locations was sampled in duplicate to determine sampler variability and another had a second high volume sampler designed to only collect respirable (<10 1i in size) particulates. A compilation of these data is presented in Table 4. In this analysis the respirable samples were separated, from the other onsite samples and the average of the two duplicate samples was used to give a single value from the samplers' location., For the purpose of calculating the mean, a value of one-half the detection limit was assigned to samples in which the metal was not detected. Analysis revealed that elevated levels of cadmium, lead, and zinc were detected in the air onsite when compared to the background site. However, none of the values were above the recommended 24-hour maximum air concentrations derived by HEI (1985).- A review of the data in Table 4 indicates that the ratios of the concentrations of metals in the air to the concentration of particulate matter are very similar to the concentrations of the metals in the soil at the site. In other words, airborne particulates at the site contain the same concentrations of the metals as does the soil. 5. Blood revels The results of the screening study for ZPP levels are shown in Table 5. Of the 22 persons who volunteered for testing, 15 were children, age 12 and under, who currently resided in the vicinity of the Smuggler Mountain sitein the judgment of the individuals conducting the study only one child had an abnormally high ZPP level (4.2 Rg/g Hgb). A sample of blood N 1% I VI W r c E 0 .0 E N. u z 0 Ic = . a 0 r - u a X 'D v 10 0K E r,4 x rq E n 01 C) 'n 'w 0 co %0 r- -T' LA 4ti 03 m a ON co C2 .4 0 C) C? -I � m a% In M Vl r4 c3 rot X 4 C3 M17vi m Irl rb kn C3 1= co CD C3 In rti an w Ln (4 00 rn I'm Cs -Ir r mei r rn Vl ri CN f" aD Ln lo CD CD c� Q CD %0 (n c: :1 0 U4 Q c o a o 0 w .4, ti IW as t. ilx ri (a a* ca m co 13 w Q3 C E n 01 C) 'n 'w 0 co %0 r- -T' LA 4ti N ID w ka C2 .4 0 0 cn C3, CA tl1r4 Ln f" ON 00 ca (30 as cn C3 ko 4 rb kn C3 1= co CD C3 In rti an w Ln (4 00 rn I'm Cs -Ir r mei r rn Vl elN U .4, as t. ilx 13 C 4), C4 ea ladpraczlotpo Aj C: m u 0 C TABLE 5 Age of Subject ZPA C6i9/g H bj 12 2.2 10 104 2 3/4 2.8 1 2.5 30 2«2 30 1®6 1.5 462 35 2.2 8 1,6 8 2.3 6 2.7 2 1.8 1 1/4 0.9 4.5 1.0 4 - 1.2 1 1.4 4 1®5 7 2.2 53 1. 19 1.4 -- 2.2 1.8 m from this child was analyzed for lead and was found to have a concentration of 12 �g/dl which is normal for a child of that age. These data are not adequate to demonstrate the absence of elevated lead levels in individuals living in the vicinity of the Smuggler Mountain site. D . Summary of 'Results Careful review of the resiults of sampling and analyses indicate that levels of lead and zincdetected in the soil and mine tailings at the site are greatly elevated when compared to a background sample from the same area and in comparison to normal background levels. Arsenic, cadmium, copper, and mercury were detected at levels approximately one order of magnitude above the expected background levels reported by Connor and Shacklette (1975). Two chemicals, barium and mang'a- nese, are somewhat elevated in contrast to measured and expected background levels. Finally, three chemicals, chromium, and vanadium were detected at the site at background levels and can be removed from further consideration in the risk assess- ment. 21 III. HAZARD ASSESSMENT A. Health Effects For a more deta iled presentation of the health effects associa ted with exposure to the various heavy metals see Appendi x A. Inhalation of arsenic oy humans is strongly associate4 with lung cancer and poss,iDly with hepatic angiosarcoma , and ingestion of arsenic in drinking water has oeen linked to a characteristic form of dermal cancer in humans. Arsenic has t)een to oe fetotoxic, emoryotoxic, and teratogenic in several a nima 1 studies Chronic expo -sure to arsenic affects the, nervous system and can cause dermal lesions and cardiovascular disease. In general, the trivalent form of arsenic is more toxic than the pentavalent form. The Carcinogen Assessment Group (CAG) of EPA determined the unit risk for lifetime exposure to arsenic, to oe 0.405 (mg/liter)-1 (USEPA 1980a). -This is equivalent to a concentra- tion of 2.5 ng/liter in drinking un ter for a risk of 10-6 (USEPA 1980a ). The EPA Amoient Water Quality Criteria for arsenic (level corresponding to a cancer risk, of 10-6) is 2.2 ng/liter, for exposure to contaminated %ater and consumption of fish. The Interim Primary Drinking Water Regulation for arsenic, is 50 pg/liter (40 CFR 141). M Arsenic is present at potentially ha za rdous levels at the Smuggler Mounta in site and the ref ore will oe cons id,e red in the suosequ ent section on exposure and risk assessment . � M Sol uol e sa I ts of La ri um a re hi g hl y a cutel y toxi c to huma ns when ingested® No information on the carcinogenicity, reproduc- tive toxicity, or chronic toxicity was found in the sources reviewed. `:he OSHA Standard of a®5 m,g/m 3 for soluole tearium compounds is tmsed on the exposure to oarium nitrate that was tolerated for several years oy workers at Los Alamos National Laoora tory (Stokinger 1981). The EPA Interim Primary Drinking Water S-tandard of 1 mg/liter is also eased on this study (47 F'R 10998 1982). As the total amount of terium that would oe ingested or inhaled at the Smuggler Mountain site is t)etween 1 and 3 orders of magnitude oelow the dose derived from current standards,, tarium is not hazardous at the S-miuggler Mountain site. 3. Cadmium An increased incidence of lung tumors has oeen associated with occupational exposure to cadmium, and mice given cadmium chloride intratracheally also developed lung tumors. Cadmium t)ioaccumulates in the kidneys, where it can cause renal tuoular dysfunction. Chronic exposure to cadmium is also suspected to produce hypertension, anemia , sensory loss (particularly smell), endocrine alterations, and immunosuppression (USEPA 1980o) . Wj EPA (USEPA 1980o) esta olished an ambient Aa ter quality criterion of 10 jig/liter on the basis of the "generally accepted" es,timate of 200 pg/g wet weight of cadmium in the renal cortex as the critical concentration for renal toxicity. More recent information suggests that as little as 60 jig/9 wet weight of cadmium may cause nephritis, in which case the threshold daily intake would be 75-105 jig/day, rather than 250-350 pg/day as previously suggested. In addition to this new information on renal toxicity, inhalation exposure to cadmium has been more firmly associated with lung cancer. CAG (USEPA 1984) used the epidemiologic data of Thun et al. (1984) to determine a best estimate for unit risk of 2.3 x 19-3 (jig/ m 3 F 1 , which equals an excess, risk of 10-6 a ssocia ted with lifetime expo- sure to a concentration- of 0.4 ng/m3 in, the air. Based on its high toxicity, particularly the renal toxicity associated with ingestion and the possible lung cancer associated with inhalation exposure, cadmium is of major concern at the Smuggler Mountain site,. U I INo-- =- Copper is not a major concern as a toxic agent to humans. The current EPA Ambient Wa ter Quality Criterion is 1 mg/liter based on organoleptic quality rather than toxicity (USEPA 1980c). 6 Copper is present nea r the Smuggler Mountain a t levels over an order of magnitude lower than the criterion level . Therefore, copper prom oly does not present a health h-3 za rd in the vicinity of the S muggl er M oun to i n s ite . RE MESA= The major ef f ects caused by exposure to lipad, alre toxicity.. - to the h,ema topoietic system and neurological effects. Although an apparent threshold has been determined for the acute neuro- logic effects seen in lead poisoning, no threshold has been determined for the effects of lead on heme synthesis or on learning a bility in exposed children. Dead can also cause renal dysfunction at blood lead levels as low as 40 jig/dl and is known to be teratogenic to animals. The USE,PA Interim Primary Drinking Water S.tandard and Ambient Water Quality Criterion f'or lead are both 50 pg/liter (USEPA 1 980d , 47 FR 109 9i8 1982) The Centers for Disease Control (CDC) currently defines "lead toxicity" in a child a a blood lead level > 30 mg/dl and an erthryocyte protoporphyrin (EP) > 50 jig/dl. However, CDC is presently revising its criteria for lead toxicity to blood lead levels > 25 pg/dl and EP > 35 pg/1 (Schilling et al. 1984) . The high levels of lead in the soil and mine tailings on the Smuggler • site may N• a potential health ha zard to people living nearby. G. Manganese Chronic exposure to manganese -containing dust has been associated with neurological effects similar to Parkinson's disease in workers. Although exposure to the workers %as appar- . eptly by inhalation, there is some evidence that much of the inhaled manganese is subsequently coughed up and ingested. One 25 case study in which a family ingested contaminated drinking water and exhit)ited symptoms of manganese poisoning also suggests that manganese is toxic when ingested. Chronic exposure to manganese also affects the hematopoietic system. The OSHA Standard for manganese dust is 5 mg/m3' in the air, corresponding to a dose of approximately 1 mg/kg/day for man. The levels of manganese present in the S.muggler Mountain site are promoly not sufficiently high to tae of concern oy themselves. However, manganese has neurotoxic effects and the dose levels associated with neurotoxicity of ingested manganese have not oeen defined. Also, the potential interactive effects of manganese and lead have not been thoroughly studied. There- fore, the elevated levels of manganese present at the site may tie of concern as a potential complicating health hazard. 7. Mercury The primary effect associated with exposure to mercury is neurotoxicity to both the central and peripheral nervous systems. Mercury is a teratogen and causes reproductive toxicity. Chronic exposure to mercury caused morphological changes in the kidneys of rats given doss of 0.025 mg/kg/day for two years. The EPA Amnient Water Quality Criterion for human health ;es 10 pg/liter in drinking water (US.EPA 1980e). The EPA interim Primary Drinking Water Standard for mercury is 2 jig/kg/day 47 FR 10998 1982) . These criteria give approximate human doses of 3 pg/kg/day and it }ng/kg/day, respectively, and appear adequate to protect human health. a Based on the levels of mercury detected in the soil and, tailings, mercury is unlikely to, be a significant health hazard at the Smuggler Mountain site. 8. Zinc Zinc is not highly toxic to humans and in fact, is an essential element. The USEPA Amoient Water Quality Criterion and Secondary Drinking Water Standard are troth 5 mg/liter cased on organoleptic qualities (USEPA 1980f 1 40 CFR 141) . Based on the levels reported at, the site, zinc is unlikely to pose a health ha za rd to people li ving nea, r the Smuggler Mountain site. More importantly, zinc is, known to interact antagonistically with other metals which a re present at the site such as cadmium and lead. B. Toxicity to Wildlife, Many of the metals present at elevated concentrations in the soil and mine tailings on the Smuggler Mountain site are extremely toxic to fish and other aquatic life. Trout, the fish likely to tie of most importance in the Roaring Fork River, are very susceptible to the effects of many toxic materials. Ta tDle 6 shows the acute LC 50 value and chronic toxicity value for exposure of rainnow trout (Salmo 2airdneri) to the various metals. In all cases the lowest LC 50 or chronic toxicity values reported for the species were used. Waters in Colorado generally have a hardness of around 150 mg/liter (Sawyer and McCarthy 1978) , and this value was used in cases where hardness 'was important. RE NOM TABLE 6 TOXICITY OF METALS PRESENT AT THE SMUGGLER MOUNTAIN SITE TO RAINBOW TROUT (Salmo gairdneri) 96 Hour LC 50 (pg/ lite r) Chronic Toxicity Value (*Pg/liter; duration) Arsenic 10, 800 550; 28 days Ba r um NA a NA Cadmium 110 5; 17 days Copper 200 50; 28 day's Lead A-5 0, 0000 871 29 weeks Manganese NA NA Mercury 29c - 0.04; 64 days Zinc 1,,910 277; 28 days a NA = Not availa t)le 0 Toxicity tesed on hardness; reported value is order of magni,- tude approximation cValues are for meth,ylmercury SOURCE: U,SEPA (1980a -f) 1, More det3 i led inf ormation on the toxicity of the specific heavy metals to wildlife is provided in the Appendix . IV. EXPOSURE AND RISK ASSESSMENT A. Introduction As discussed in Section I of this report, preliminary studies indica to tha t several metals -3 re present in soil and groundwa ter in the vicinity of the Smuggler Mount3 in site at levels significantly a cove oackground levels. In Section II the potential adverse effects of these metals on human health and the environment were discussed. In this section we will discuss potential human exposure to some of these metals in order to attempt to determine the potential human health risks, associated with that exposure. Because of the preliminary nature of the analytical results and the consequent uncertain- ties involved in quantitative risk assessment, this report will not attempt to provide quantitative estimates of human health risks associated with exposure to metals in the vicinity of the Smuggler Mountain site® Riather, this assessment will attempt to assess the procaoility that contamination of the site is likely to pose unacceptable human health risks in.the ar)sence of remedial action and to define concentrations in soil that might be considered to be unaccepta ble levels of contamination. 5. Potential Ex29sure Pathwa,ys Direct ingestion of the contaminated soil is a potentially significant route of exposure, especially for young children W1 who constitute the most sensitive population. Young children may ingest contamina ,ted dirt by normal mouthing of soiled objects and their hands or by pica , the actual consumption of dirt (Mahaffey 1978). Older children are less likely to eat soil or to mouth soiled objects, but they still may ingest dirt from their [-ends. Kimurough et a�l. (1984) have estimated the daily p ttern of soil ingestion for specific age groups as follows: 0-9 months of age 0 grams/day 9-18 months of age I gram/day 1 .5-3 .5 yea rs of age 10 grams/day 39.5-5 yea rs of age I gram/day >5 yea rs of age 0.1 gram/day Adults onsite may ingest some co.ntamina ted Soil but a re in general less likely to be exposed by this route. Some pregnant women exhibiting pica ,-however, may eat significant amounts of soil or tailings. Dermal contact is another potential route of exposure to contaminated soil and tailings. Persons working or playing on the site may get substantial amounts of dirt on their skin and clothes. secondary dermal exposure may occur when the soiled clothes are washed. However, lead and the other metals are poorly absorbed throug h the intact skin when present in an inorganic farm Therefore, dermal absorption is protaoly an insignificant route of exposure relative to other potential pa thwa ys . The consumption of Vegetables grown in contaminated soil in home gardens may oe a significant route of exposure. The avail - axle evidence suggests that lead and mercury are not readily taken N up by plants. On the other hand, arsenic, cadmium, manganese, and zinc are readily absorbed by plants and may ue present in excess levels in vegetables grown in the contaminated soil or tailings. The phytotoxicity of arsenic, manganese, and zinc may limit the amount of these elements in ediole plants such that levels that are toxic to, humans may not be reached (Chaney et al. 1984). 2. Household Dust Dust is a normal component of the indoor environment. It accumulates on all surfaces exposed to the air and the depo- sition rate is a function of the concentration of suspended p3rticul3te matter in the air. The concentration of heavy metals in household dust is proportional to the concentrations of metals in both the air and in the soil but few, studies are available which specifically relate the concentration of indi- vidual metals in dust to air and soil levels. Humans are exposed to household dust both by ingestion and by inhalation. Ingestion occurs by hand -mouth contact and by consumption of food from surfaces (dishes and food preparation vessels) on which dust has collected. Inhalation occurs when dust is distributed and suspended in the course of normal domestic activities. Although exposure to dust may be a significant pathway of human exposure to metals in the vicinity of the Smuggler Mountain site, it has not been explicitly considered in this assessment because of the lack of data on the metal content of household dust and the lack of informa tion in the literature on the esti- mated da i ly i nt:3 ke of household dust. Exposure to household dust is implicitly included in the assessment of human health risks associated with exposure to lead at the Smuggler Mountain site because studies that relate blood lead levels to soil lead levels include exposure via household dust as one of several probable routes of exposure® -MI There are three potential routes of exposure to contiminants in surface mter. Direct ingestion of contaminated.water could lead to significant exposures, Dermal contact with contaminated wa ter either by swimming or bathing could be a minor pathway. The available analytical data indicate that toxic metals are not present at detectable levels in the Roaring Fork River. Also the river is apparently not used as a source of drinking water, and its temperature and small size make it unattractive for swimming, and therefore these two routes of exposure are prong bly unimportant. Persons consuming fish, from the Roaring Fork on a regular oasis might be exposed to heavy metals if, in the future, metals leach from the smuggler Mountain site and enter the surface drainage. However, the fish species in the river are very sensitive to intoxic.3tion by heavy metals and it is unlikely that high levels of metals would be present in the fish. Therefore, fish consumption is protaoly not a major route of exposure. The, available evidence would indicate that at present surface water is not a significant potential medium of human exposure. KPJ 4. Ground w3 ter The potential exists for some households in the vicinity of the Smuggler Mountain site to use groundwater as their sole w3ter source. Others may use groundwater for activities such as w-itering a garden. Direct ingestion of groundwater is the major route by which exposure to contaminated groundwater would occur. Bathing and washing could also be a significant exposure pa th,wa y. Airborne dispersion of contaminated soil and ta i lings is potentially an important route of transport. Inhalation of suspended particulates by either construction -workers or the general population may be an important exposure pathway especi- ally if the soil or tailings are disturbed. Inhalation of the very small amount of metal that may volatilize is not likely to be important., Deposition of the windoorne rarticulates in houses or on the leaves of edible plants may lead to increased exposure to contaminants. 6 . Summary For adults, the, most important potential exposure pathways are ingestion of groundwater and inhalation of airborne dirt and household dust. Ingestion of vegetables grown in contamin- ated soil may also be a contributing route of exposure. For children, the additional route of ingestion of contaminated soil becomes potentially important. Because of the greater potential exposure of children to contaminated soil and the evidence tha t young children a re more sensitive to the toxic effects of lead than are adults, the remainder of this exposure and risk assessment will focus on children as the target pope - lati on. Furthermore, because of the fact that the levels of lead and cadmium are relatively more elevated compared to back®. ground concentrations than some of the other metals and because of their inherent toxicity, they have been selected as the indicator pollutants for the, purposes of risk assessment. C. Lead ordinarily, in order to assess the human health consequences of exposure to a toxic chemical, the concentrations of the chemical in various media aremultipliedby the daily exposures to those media and modified by, appropriate absorption factors to estimate the total daily dose of the toxic chemical. Thi s daily dose is then compared with an experimental or hypothetical dose -response function to estimate the incidence or severity of intoxication. Extensive investigations of lead, however, have indicated that the adverse effects of lead are critically dependent upon the chemical form of the lead in the environment, as well as the rate and frequency of exposure. The oi ol ogi ca, 1 response is also dependent on the age of the exposed individual. Natural background exposures to lead are highly variable. For these reasons, the same daily dose in mg/kg/day may have different biological effects in two individuals exposed under different circumstances. Therefore, measures of total lead in the body are believed to be more accurate correllates of 35 lead efE ects than are daily exposures one such measure is the concentration of lead in the blood. As indicated in Section Ii above, blood levels of lead in children above 25 pg/dl are considered to be cause for concern. EPA has recently reviewed a numuer of studies which are useful in relating blood levels in children to levels of lead in the environment (EPA 1984c). Table 7 shows the relationship r>--tween air lead concentrations and blood lead levels in children as determined from three studies. These slopes range, from 1.52-2.46 pg/dl per lag/m3 in air. Table 8 relates blond lead levels in children to soil lead levels. Here the slopes range from 0.6 to 7.6 jig/dl per 1,000 ppm. This range of slopes is much greater than those determined for air exposure. This va ri a oi lit y pr oce bl, y reflects the different characteristics of the lead in the soil as well as other uncontrolled va ria tiles. The studies of Angle and McIntire, Yankel et al., Walter et al., and Neir et al. were performed in the vicinity, of lead smelters. Three other studies (Galke et al., Sta rk et al.,, Ba rl trop et al.) were conducted in urban areas where automobile exhaust and lead paint flakes were the major contributors to soil lead. Thus none of these studies is of a population directly comparable to the population living near Smuggler Mountain. The lead present a t Smuggler Mountain is most likely bound in a natural mineral matrix and its oicavail ability may differ from that of soil lead from atmospheric sources. im Population O hi ldren TABLE 7 SUMMARY OF BLOOD INHALATION SLOPES, (b) (Ug/dl per pg/m3) S tudy Angle and McIntire (1979) Omaha , Nebraska Reels et al (1960) Bel gi um Yankel et al (1977) , Walter et al. (1960 Ida ho S turfy Type N s +� 37 MR. mm rj Slope N e r �, f 4-) ca1 clt ,--A rq� 4 C ryy) Wryry y p --A I Ln 0) 4 4d 4 4 1-4 :1� z 14 Cq vd rD r®I orb r^0 yy�q� pV� �yD C P^Y • �J� Lnko p q QyT�� .•gy�pp+y i 1 � Vd ro, f, 4 `W KV I�T po yF^�<�J 0 W r�yy4 W 0 r-4 CN Kv • V +' d 4 v0 CN G.1 p-J� �Y.dJ a) VJ -4 En 4d • m V8 (�wuy 0 - CD r- c) r - rr0ryry yd J1 Cq CD CD 'CD ON 0 CD V " CD l^ CD io CD co 'W r^a� co qM W ryryqq o PON l" 1�, V �A p W ,' I \� V 1 Ws44 ',.' P . % F 4' Y � 9 �w9�" c r r I .� I} �Ha vY' PII M "' v' r, 1. Y '4 V S. p el • � p Ski ♦ Y' I I d) 1 tHi 1 4 Q) 0 a) CD Ln W 0) Lf) is al M k o (0 CD r�3 C) C14 CN �, m w *a ro PG rn -- rn Ln CN v co CA rd ro a) C < M •� ,-P co � W 4-J MA 44 44 4 W I) 44 0 4 0 0 0 C q E- 4 � r U >i ( ) r ! "*r 4 >1>1 7y � C' r -p "Ga tTd '*J r- 1:� r -j rc) C A 41 'a C °' a C ras 0 Q) U] C 4JU1 C 4-) 0,U a', VI r- (1) ty > (D (1) to 0 0 4J N C 4J W (U —4 W CU 'y W W — Lr t11 0 Ci) N ra cm 'La ai) r- [a b 4a rn "o .--I 4J U-) rO co ra •ra C. -Li ro r-4 co r --I co - -�e r� rl ,-A ae r- -4 La r- 4 • 4 r' -4 4 C J dro M. 4 C M•4r-i a) f 0)•4 (M -4, = W .4" 1 'w • r-1 -C; r-4rt_ (1) r -I -C M 4"'rJo En—U' u�4 C)`•'UU as—U z—U' ca 44 For the purpose of assessing potential health risks in the vicinity of the Smuggler Mountain site, Clement has assumed a slope of 2.0 pg/d'l per 1,000 ppm lead in the soil. This is near t h e lower 1imit of t h e range of slopes in Table 8 and is consistent with the position to ken by EPA (EPA 198 4) . Thus, the following assumptions can be used to estimate potential blood lead levels among children living nea r the Smuggler Mountain site: Baseline blood lead level in the aosence of exposure from Smuggler Mountain = 12.7 pg/dl* Blood level vs. air level slope 2.0 pg/dl per pg/m3 Blood level vs. soil level slope *Median blood level in white children aged 6 months to 5 years living in rural a -rens in the U.S.. (NHANES Il as cited in EPA 1984) 33sed on these assumptions a child living in the vicinity of the Smuggler Mountain site might be expected, on average, to P ave a blood lead level c3i 0.19i + 2.0 x 4.06 = 21.2 jig/dl Because of the normal distribution Of blood levels about the mean, a significant number of children would be expected to have blood lead levels in excess of 25 pg/dl. In other words, the levels of lead present in the soil in the vicinity of the Smuggler Mountain site may be unacceptably high and may contribute to a significant risk of health impairment, if the assumptions made in this assessment are valid. W The uncertainties inherent in this assessment are very large. For example, if the slope of the relationship between blood lead and soil lead is assumed to be 3.0 (well within the range of slopes reported in Table 8) , then the mean blood level for children in the vicinity of Smuggler Mountain would c)e 25.3 pg/dI. If blood levels are calculated for a child living in an area of ma ximum air and soil contamination the blood level would be 12.7 + 2.0 x 0.81 + 2.0 x 8.53 = 31.4 pg/dl It is of interest to comms re the results of the a Bove assessment with the results of recent studies of children living in Shoshone County, Idaho (Schilling et al. 198 4) Among children living in the vicinity of a closed l,ead, smelter the mean blood level, was 21 pg/dl and 35% of the children had blood levels of greater than 25 pg/dl. The mean air level of lead was 0.28 pg/m3 and the mean soil level of lead was 6,059 ppm. These levels are comp ra ole to those found in the vicinity of Smuggler Mountain, although the chemical form of lead in the soil at smelter sites is certa in to be different than that at Smuggler Mountain. children li ving slightly farther a wa y from the smelter had a mean blood level of 17 ung/dl. The mean air concentration was 0.12 p9/m3 and the mean soil concentration ;,as 3,432 ppm. Of these children 15% had blood lead levels in excess of 25 pg/dl. Even in children born after the smelter closed and airborne lead concentrations were reduced, blood lead levels were excessively high. The authors of an earlier study of children in this community concluded that soil lead W, levels in excess of 1,000 ppm were cause for concern (Yankel et al. 1977 as cited in USEPA 1984c). D Ca dmi um Cadmium has teen found at elevated concentrations in soil and groundwq ter in the vicinity of the Smuggler Mountain site. Child,ren are proCably exposed through inhalation of airoorne pa rticul3 tes and household dust, ingestion of dirt, ingestion of vegeta tiles grown in contaminated soil, and drinking of ground- wa ter. It is poss i ole to calcula to an average daily dose for a child living near the site for 20 years following mirth. 1. Inhalation Assume that a child inhales 15 m3 /day (Kimorough et al. 1984). Mean air concentration at Smuggler Mountain site of respiraule cadmium 1.4 ng/m 3 Daily exposure = 21 ng/day 21. Inqestion of Dirt Assume that child plays outdoors 100 days/year Total amount of soil ingested each year and cadmium intake oased on average cadmium concentration of 26 �g/gram. Dirt Ingested Total Dirt Tota 1 Ae Ingested _(qj Cadmium 0-1 0 0 0 1-2 1 100 2.6 2-4 10 2,1000 52 4-5 1 100 2.6 5-20 0.1 150 3.9 41 Total intake in 2,0 years averaged over 7,300 days = 8.4 jig/day #nly a tDout 5% of ingested cadmium is a osoroed f rom the gut (Grant et al. 1981). Daily absorned dose = 420 ng/day 3. Inqestion of Veqeta tiles Grown in Contamina ted Soi Assume that a child li,ving in a home with a ga rden consmes 100 g wet weight of vegeta bleS from the garden 100 days of the year. Chaney et al. (1984) reported that lettuce grown in soil averaging 37 ppm cadmium contained 1.17 ppm cadmium on a wet weight ba s is . Since leafy vegeta tiles take up more cadmium than others, we will assume that the cadmium content of vegeta tiles grown in the vicinity of the Smuggler Mountain site is 0.1 ppm. Total cadmium intake per year-= 100 g x 100 days x 0.1 'Pq = 1,000 Pg gram Average over 365 days - = 2 . 7 jig/da y x 5 % a osor ption, = 14 0 ng/da y 4. Ingestion of Groundwa ter Assume that a child ingests 1.5 liters, of water/day Average cadmium concentration = 7 pg/liter Daily intake = 10.5 pg x 5% absorption = 525 ng/day Based on these reasonaole assumptions a child living near the Smuggler Mountain site might ne exposed to an average daily dose of approximately 22 jig/day of cadmium. This estimated cadmium intake is glow the daily intake of 75-105 jig that is believed to result in adverse effects on the kidney in humans (Grant et al. 1981). However, there are important sources of uncertainty in these estimates that could M ciently high to be of concern. In the absence of more definitive information regarding exposure to cadmium and the oioavailaoil- ity of cadmium in the soil, there is the potential for some individuals to be exposed to total daily doses capable of causing impaired kidney function. There is also a possibility of unac- ceptaole cancer risk among individuals exposed to airborne particulates from the site. RMWORM"WESTAN009 OWN nated soil as airborne dust in the vicinity of the Smuggler Mountain site, there is a potential risk of cancer. The mean concentration of respirable particulate matter measured at the site was 17 ug/m3 (see Table 4). If the concentration of cadmium in the soil is 10 pg/g and the airborne particulate matter at the site consists entirely of suspended soil, the 3 air concentration of respirable cadmium would be .17 ng/m, This is just less than half of the air concentration which has been estima ted by EPA to result in a cancer risk of 1 in 1,000,000. Because, residents are also likely to be exposed to cadmium by �ters other than inhalation, a concentration of 10 lig/g of cadmium in the soil is considered to be an accept- able, upper limit. E. Other Elements Arsenic is present in levels above background in soil samples, from the Smuggler Mountain site. The available evidence suggests that arsenic is carcinogenic in humans both by inha- lation and ingestion. Using the same assumptions as for cadmium W 0 a child ingesting soil containing 82 ppm arsenic in the vicinity of Smuggler Mountain would incur an average daily exposure of 26 jig/day. Since 95% of ingested arsenic is absorbed the average daily absoroed dose of arsenic from soil ingestion alone would be 25 pg/day. ingestion of 1®5 liters of drinking water per day containing arsenic at the primary drinking water standard of 50 jig/liter would provide a daily dose of 75 jig/day. Thus, the 25 jig/day intake of arsenic from ingestion of soil by itself provides a least a third of the acceptable daily inta ke for this element. Furthermore, this inti ke is far in excess of the daily dose estimated to result in an excess cancer risk of 1 in 1,000,000 by OSHA and CAG. Since children will also be exposed to arsenic by inhalation and from their diet, this soil concentration does not allow for an adequate margin of safety® F. Interactions For the purposes of this assessment, the effects of expo- sure to the toxic metals present at the Smuggler Mountain site have been considered separately and independently out, because these pollutants occur together in soil and air, individuals will be exposed to all of them concurrently. There is little specific information availa ole on interactions among these elements. In the absence of such information, it is reasonable to assume that their combined effects are at least additive. This is particularly true for those compounds that effect the same targets. Thus, for example, cadmium and lead both adversely M9 effect kidney function. Therefore, even though estimated aver -age daily cadmium doses in children were below those t ha t were expected to induce renal tubular disease the added insult to the kidneys caused by higher than average lead exposures may significantly reduce the margin of safety. Similarly, a rsenic and cadmium have both been implicated in the causation of human lung cancer. Thus the risks associated with inhalation exposure to these compounds would be expected to be at least additive. M V. MITIGATING FACTORS The aVailable infora'3tion is not adequate to characterize the nature and extent of contamination at the Smuggler Mountain site. For this reason the assessment of potential human health risks in the vicinity of the site is highly uncertain. We have concluded that the most likely estim to indica tes that there is a significant risk of health impairment among children living near the site. This, conclusion must be qualified by the existence of potential factors whose cumulative effect is unknown (see Ta ble 9) . Several factors which might serve to mitigate the human health risks posed by the presence of high concentrations of metals in the soil in the vicinity of the Smuggler Mine are discussed in this section. A. Bioavailability (Physical -chemical cha racteristicsl The analytical methods used to determine the concentra- tion of the heavy metals in air, soil, and wt3 ter are designed to detect the total quantity of those elements in the media regardless of physical and chemical form. It is well-known that the bioavailability of heavy metals is dependent on the chemical matrices in which, they occur in the environment. The chemical form of the met -31 may also determine the biological activity of the metal once it is ar)soroed. Critical properties which serve to determine the mobility of metals in the environ- ment and thus influence their bioavailability and toxicity include, sol uoility of the metal compounds, pH of the soil M Factors which contribute to an overestima tion of risk 1. It is assumed that the rAcavailability of lead in tailings is equivalent to the bioavaila tDility of lead a t smelter sites or in urwn areas. 2. Meteorologic cond,itions were not considered. 3. Cancer risk estimates are used on upper 95th confidence limits from conservative models. Factors which contribute to an underestimation of risk 1. Interactions (presumably additive) were not considered. Exposure to household dust %zas not considered. 3. Exposure to toxic metals from normal tackground sources, diet was not considered. and wa ter, ionic strength of the wa ter, oxidation- reduction potentials of the metal compounds and the soil matrix, and the amount of organic material present in the soil. This infor- mation is not available for the metals present at the Smuggler Mountain site. Therefore, we have assumed, in the risk assess- ment for lead, that the lead in the soil at Smuggler Mountain is similar in its bioavailability to lead in the soil in urban areas or in the vicinity of primary or secondary lead smelters. It is quite possible that the lead at the Smuggler Mountain site is much less bicavailaole in that it appears to be present in a carbonate rock matrix (Jim Baker, EPA, personal communi- cation)o. Lead carbonate is relatively insoluble and may be much less oioavailable than lead sulfide and lead oxides. This supposition is supported by the finding of relatively low lead concentrations in surface and groundwa ter near the site . Similar considerations may apply to other metals at the site. ➢despite the relative insolubility of lead carbonate in water, its is soluble in acid. Thus, the acid of the stomach might be expected to soluoilize lead even in mineral matrices. For this reason, it is plausible that the lead in ingested soil might be readily available for aosorption after it reaches the stomach. The solubility of lead compounds in acid also raises the possibility of future groundwater contamination by lead from the tailings and soil at the Smuggler Mountain site should acid waters such as acid mine wastes percolate I 49 through contamina ted soil. This would mobilize the lead and leach it into the groundwater. B. Meteorological Factors The Smuggler Mountain site is located in an alpine environ- ment and is, therefore, under snow cover for as much as six months ea c h yea r Furthermore, during sn,owmelt, the surface soil is likely to be saturated. During the time of snow cover and snow melt there is negligible chance for exposure to contaminated soil at the site. The alpine climate also necessitates a short growing season making home gardening less attractive than in more temperate climates. Thes,e, considerations need to be kept in mind in comp ring metal exposure at Smuggler Mine with metal exposures studied in more temperate locations. It should be pointed out, however, that Shoshone County, Idaho has a similar alpine clima te. The pr.evailing wind patterns at the Smuggler Mine site is diurnal with the wind blowing up the valley during the day and down the valley du -ring the night (Tan Dunlop, Aspen -Pitkin Environmental Health Department, personal communcation). Thus, during the day, when dust -generating activities at the site are most likely, the wind is blowing away from the inhabited a rea . This may considerably reduce inhalation exposure to airborne contaminated soil. WO I ! 11 11; 1 !!, Based on the availa ole information it is Clement's conclu- sion that unaccept3 ole health risks exist at the present time for residents and workers at and in the vicinity of the Smuggler Mountain site. These risks are associated with potential expo- sure to cadmium and, lead in soil and mine tailings at the site. As descrioed above, a great deal of uncertainty is associated with this preliminary risk assessment due in large measure to uncertainties, regarding estimated human exposure to metals in the soil. Clement therefore recommends that further inves - tigation oe performed in order to reduce sources of uncertainty in the assessment of health risks associated with this site. This section of the report outlines the additional information that should be acquired. A. Ex sure Assessment 1. Soil . 9 Conduct additional surface soil sampling in order to establish reliable "tockground" soil co,ncentrations for lead and cadmium and to define a 1,000 ppm isopleth for lead and a 10 ppm isopleth for cadmium. Total soil digestion should be used for these determinations. e Establish the prevailing meterologic conditions at the site in order to be a ble to model the dispersion of airborne particulates from the site. M Using meterologic information, identify the residential areas of highest predicted exposure and monitor air at those locations for respirable particulates, lead, cadmium, and arsenic. Monitoring should be sufficient to be represents tine of variations due to activity at the site and seasonal variations in meterologic conditions. Samples of both sail and to flings f rom the site should. be studied to determine the relative bioavailability Of metals in them. The chemical species of lead, cadmium, and arsenic in the samples should be determined. Also the extra cta bi lity of the metals from the soil using hydrochloric acid and chelating agents should be determined., 2. Household Dust 9 Household dust samples should be collected from a representative, sample of residences adjacent to the site and these should be analyzed for lead, cadmium, and arsenic content. 3. Surface Water e Although not considered to be a significant medium for human exposure at the site, surface %Aa ter drainage patterns across, and f rom the site should be more completely characterized and the pH of all surface water entering and leaving the site should be deter- mined to ensure that acid mine wastes are not leaching metals from the soil. W 4. Ground wi to * Although not considered to De a significant medium for human exposure, more data are needed on groundwater gradients at the site in order to identify the location where groundwater quality is most likely to tie affected ray the site. * Monitoring wells should tae identified and new ones drilled in order the adequately characterize background and downgradient water in the uppermost aquifer. Samples from these wells should t)e analyzed for pH, specific conductance, and priority pollutant metals. Monitoring should ue continued as long as activities at the site have the potential to alter soil characteristics and drainage patterns. 5. Air • Additional air monitoring as described under soil a oove . 6. Identification of Ex sed P2E!�-I Motion • All individuals living within, immediately adjacent to, and a significant distance downwind or downgradient (groundwater) of the site should tae identified as to age, sex, and length of residence at the location. All wells that are being used or have oeen used to supply water for domestic use should oe identified. 53 B Risk Assessment An assessment of individual and population risks can be conducted cased on the available information and the additional information gathered from the steps recommended above.A much more direct assessment of risks can be achieved, however, by determining blood lead levels in humans who have been potentially exposed to mine wastes and contaminated soil from the Smuggler Mounta in site. Clement recommends a survey as follows: e Identify a sample population of individuals who have lived on or within a mile of the site, for at least two yea rs. Ascertain the age, sex, residential history, employment history, and smoking history of these indi- viduals . 9 Measure blood lead levels or urinary lead levels in response to challenge with a chelating agent in the potentially exposed population. Special attempts should be made to perform such tests on all children between the ages of 2-12 a nd on those adults who have lived in the immediate vicinity of the site for 10 years or more, ME REFERENCES AMERICAN CONFERENCE OF GOVERNMENTAL INDUSTRIAL HYGIENISTS (ACGIH) 1980. Documentation of the Threshold Limit Valises. 4th ed. Cincinnati, Ohio. 488 pages BOON, D.Y. 1983. Soils Analysis and Recommendations, Proposed Residential Development Centennial Project, Aspen, Colorado. September 8, 1983 BOSTWICK, J.L. 1982. Copper toxicosis in sheep. J. Am. Vet. Med. Assoc. 180:386-387 CHANEY, R.L., STERRETT, S.B., and MIELKE, H.W. 1984. The potential for heavy metal exposure from urban gardens and soils in P reer, J. R. , ed. Proceedings of a, Symposiu:m on Heavy Metals in Urban Gardens. University of the, Dis- trict of Columbia Extension Service, Washington, D.C. Pp. 37 -8 4 CLEMENT ASSOCIATES, INC. 1983. Assessment of the Weight of Evidence for Risk Assessment for Four Selected Toxic Air P ol I uta n ts . Report Prepared for the Air Economic, Branch, OPRM, U.S. Environmental Protection Agency. May 1.983 COLORADO DEPARTMENT OF HEALTH (CDH). 1982. Heavy Metals in Soil --Smuggler Trailer Park,. Aspen, Colorado. Results of Analysis of Samples Collected 6/15/82 by Tom Dunlop of Pitkin County Department of Environmental Health. CDH, Division of Engineering and Sanitation CONNOR, J J. , a, nd S HAC KLETTE, H T. 1975. Background Geochem- istry of Some Rocks, Soils, Plants, and Vegetables in the Conterminous United States. Statistical Studies in Field Geochemistry. Geological Survey Professional Paper 574-F. U.S. Dept. of the Interior, Washington, D.C. DOULL, J., KLAASSEN, C.D. , and AMDUR, M.O. , eds . 1980. Casa nett and Doull' s Toxicology: The Basic Science of Poisons. 2nd ed. Macmillan Publishing Co., New York. 778 pages ECOLOGY AND ENVIRONMENT, INC. 1985. Report of Hi -Vol Air Sampling Activities at the Old Smuggler Mine Study Area, Aspen, Colorado. Report suomitted to EPA. January 24, 1985 FLEISCHER, M . , SAROFIM, A.F., FASSETT, D.W., HAMMOND, P., SCHAKKETTE, H.T., NISBET, I.C.T. , and EPSTEIN, S. 1974. Environmental impact of cadmium: A review oy the panel on hazardous trace substances. Environ. Health Perspect. 7:253-323 FORD, K., FOSTER, J., HENDERSON , T., and UPSON , G. 1984. Interpretive Report and Health Risk Assessment of the Smuggler Mine,- Aspen, Colorado. TDD R8-8401-15. March 9, 1984 GRANT, L.D., MUSHAK, P., CROCETTI, A., and GALKE, W. 1981. Health Assessment Document for Cadmium. U.S. Environ- mental Protection Agency, Environment Criteria and Assess- ment Office, Research Triangle Park, N.C. October 1981. EPA -600/8-81-023 KIMBROUGH, R.D., FALK, H., STEHR, P., and FRIES, G. 1984. Health implications of 2 3 7,8- tetra chlorodinenzodioxin (TCDD) contamination of residential soil in Lawrence, W.W., ed., Public Health Risk of the Dioxins. Proceedings of a Symposium Held on October 19-20, 1.983 at the Rocke- feller Univerisyt, New York City, William Kaufmann, Los Angeles. Pp. 121-150 MAHAFFEY, K.R. 1978. Environmental exposure to lead. In Nria gu, J.O., ed. The Biochemistry of Lead in the Environ- ment: Pa rt B. Biological Effects. Elsevier/North-Holland Biomedical Press, New York. 397 pages NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH (NIOSH). 1983. Registry of Toxic -Effects of Chemical, Substances. Data Base. Washington, D.C. October 1983 NATIONAL ACADEMY OF SCIENCES (NAS) 1973. Medical and Biolo- gical Effects of Environmental Pollutants: Manganese. Washington, D.C. 191 pages NATIONAL ACADEMY OF SCIENCES (NAS). 1977. Drinking Water and Health. Safe Drinking Water Committee, Washington, D.C. 939 pages NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH (NIOSH). 1984. Registry of Toxic Effects of Chemical Substances. Data Base. Washington, D.C. October 1984 NEEDLEMAN, H.L., GEIGER, S.K., and FRANK, R. 1985. Lead and IQ scores: A reanalysis. Science 227:701-704 SAWYER, C.N.,, and McCARTY, P L. 1978. Chemistry for Environ- mental Engineering. Third Edition. McGraw-Hill. Book Company, New York SCHILLING, R., ROSS, D.,, SOKAL, D., ING, R., BROKOPP, C., and MAUGHAN, A.D. 1984 Children's exposure to smelter -asso- ciated lead, Montana and Idaho. In the Proceedings of the 5th National Conference on Management of Uncontrolled Hazardous Waste Sites. Washington, D.C. November 7-9,, 1984 STO KIN GER, H E. 1981. The metals. In Clayton, G.D. , and Clayton, E.E . , eds . Patty's Industrial Hygiene and Toxico- logy. John Wiley and Sons, New York TAKENAKA, S., OLDIGES, H., KONIG, H., HOCHRAINER, D . , and OBERDORSTER, G. 1983. Carcinogenicity of cadmium chloride aerosols in W rats. JNCI 70:367-371 UNDERWOOD, E.J. 1979. Trace metals in humans and animal health. J. Hum. Nutr. 35:37-48 U. S . ENVIRONMENTAL PROTECTION AGENCY (USEPA). 1980a . Amoi en t Water Quality Criteria for Arsenic. Office of Water Regu- lations and Standards, Criteria and Standards Division, Washington, D.C. October 1980. USEPA 440/5-80-021 U.S. ENVIRONMENTAL PROTECTION AGENCY (US,EPA). 19800. Ambient Water Quality Criteria for Cadmium. Office of Water Regu- lations and Standards, Criteria and Standards Division, Washington, D.C. October 1980. EPA 440/5-80-025 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA). 1980c . Amoient Water Quality Criteria for Copper. Office of Water Regula- tions and Standards,. Criteria and Standards Division, Washington, D.C. October 1980. EPA 440/5-80-036 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA,) . 198 Od . Ambient Wa ter Quality Criteria for Lead. Office of Wa ter Regula- tions and Stn ndard,s, Criteria and Standards Division, Washington, D.C. October 1980. EPA 440/5-80-057 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA) . 1980e. Ambient Water Quality Criteria for mercury. Office of Water Regu- lations and St:andards, Criteria and Standards Division, Washington, D.C. October 1980. EPA 440/5-,80-058 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA). 1980f Amoient Water Quality Criteria for Zinc. Office of Water Quality and Standards, Criteria and Standards Division, Washington, D.C. October 1980. EPA 440/5-80-079 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA). 1983. Dra f t Revised Section B of Ambient Water Quality Criteria for Lead. Office of Water Regulations and Standards, Criteria and Standards Division, Washington, D.C. August 1983 U.S. ENVIRONMENTAL PROTECTION AGENCY (USEPA). 1984a . Health Assessment Document for Inorganic Arsenic. USEPA, Office of Environmental Assessment, Washington, D.C. March 1984. EPA -600 /8 -B3 -021F U. S . ENV IRON ME NTAL P ROT E,CT I ON AGENCY (US EP A) . 1984o. Updated Mutagenicity and Carcinogenicity Assessment of Cadmium. (Review Draft) . USEPA, Office of Health and Environmental Assessment. Washington, D.C. April 1984. EPA -600/8-83- 0 25 B U.S. ENVIRONMENTAL, PROTECTION AGENCY (USEPA). 1984c . Air Quality Criteria for Lead (Review Draft) a USEPA, Environ- mental Criteria and Assessment Office. Res ea rc h 'Triangle Pa rk, N.C. Sep,temr>er 1984. EPA 600/8-83-028B M.B.-TORWORM HEALTH AND ENVIRDNMENTAL EFFECTS OF CHEMICALS, OF CONCERN AT THE SMUGGLER MDUNTA,IN SITE A. Health Effects 1. Arsenic Effects® Acute poisoning of humans with arsenic may result in gastrointestinal effects, hemolysis, and neuropathy. Chronic exposure causes character- istic toxic effects on the peripheral nervous system and, in children, effects on the central nervous system. Keratosis, hyperpigmentation, and possibly precancerous dermal lesions, and cardiovascular injury are frequently observed sequelae of chronic exposure to arsenic--. Arsenic has been found to be embryotoxic, fetotoxic, and teratogenic in several animal species, but its ability to induce malformations in humans is less well substantiated® Arsenic induces chromosome aber- rations and impairs DNA repair, but it has not been shown to be a point mutagen. Epidemiology studies have shown that inha- lation of arsenic is strongly associated with cancer of the lung and perhaps with hepatic angiosarcoma, while exposure by ingestion has been linked to a characteristic form of dermal cancer. Although arsenic's potential as a human carcinogen has long been recognized, it is only recently that its carcino- genicity has been demonstrated in animal models. In general, the trivalent form of arsenic is more toxic than the pentavalent form (USEPA 1980) . 1 IR Current Criteria. To estimate an ambient water quality criterion for arsenic, EPA (USEPA 1980a) used the data obtained in Taiwan by Tseng et al. (1968). The Weibull model was used to relate skin cancer incidence, age, and level of exposure in the drinking water. In 37 villages that had been obtaining drinking water from artesian wells with various levels of arsenic contamination for 45 years, 40,421 individuals were examined for hyperpigmentation, keratosis, skin cancer, and blackfoot disease (in which impaired peripheral circulation leads to gangrene). Also, the local well waters were analyzed for arsenic concentration. Correlations of cancer incidence with the local arsenic concentrations and with age (duration of exposure) were found. Extrapolation to -low dose levels from the fitted Weibull model gave 2.2 ng/liter arsenic (inclusive for triva- lent and pentavalent inorganic and organic arsenic) as the concentration predicted to be associated with a lifetime risk of cancer of 10-6. The CAG (USEPA 1980a) unit risk at age 75 was 0.405 ppm -1,, equivalent to a concentration of 2.5 ng/liter in drinking water for a risk of 10-6. New Information. The ambient water quality criterion for arsenic based upon the epidemiology study of Tseng et al. (1968), has recently been criticized by Calabrese (1983). He faulted the study itself for failing to determine which arsenic compounds were present or to consider other contaminants in the drinking water (noting the possible relevance of ergot alkaloids). Calabrese questioned the results of the low-dose extrapolation 0 procedures by pointing out that a risk of 10-6 from 2®2 ppt (ng/liter) arsenic was derived from the incidence of skin cancer in, the Taiwanese population exposed to arsenic in the 300-600 ppb range. 'By the linear extrapolation assumption used, this is equivalent to saying the expected risk of this type of skin cancer would be 10-3 from exposure to 2 ppb, the average level of arsenic in drinking water in the United States, but this has not been observed. Layton et al. (1983) conducted a risk assessment on arsenic in drinking water and concluded that concentrations up to 100 Vg/ liter would not pose a threat to human health. More recent epidemiology studies add further support to the association between 'ingestion of arsenic in drinking water (at concentrations of approximately 1 ppm) and skin cancer (Astolfi et al. 1981) and between inhalation exposure to arsenic and lung cancer (e.g., Lee -Feldstein 1983, Enterline and Marsh 1982). Several new laboratory studies have contributed evidence that arsenic has potential as an animal, as well as human, carcinogen (Ishinishi et al. 1983, Shirachi et al. 1983). one hypothetical explanation of the wide differences among the results of studies of the carcinogenic potential of arsenic is differences in the chemical form of the arsenic. OSHA (1983) conducted a risk assessment of arsenic in the workplace® Its calculations were based upon data from epidemi- ology studies of the incidence of lung cancer among workers exposed occupationally (largely by inhalation) to arsenic. 3 The derived unit, risk was B x 10 -4 ([.g/m3)-lm Assuming equal absorption by the inhalation and oral routes of exposure, this estimate of carcinogenic, potency would imply a lifetime cancer risk of 10®6 from consumption of drinking water containing 3.7 ng/liter arsenic or more generally, from the ingestion of a dose of 0.1 ng/kg/day for the lifetime of the individual®. This estimate would apply specifically to trivalent inorganic arsenic. Arsenic's carcinogenic potential in humans has been amply demonstrated. The quantitative estimates of dose -response derived from Tseng et al. (1968) upon which the 1980 ambient water quality criterion was based have, been disputed, but they are quite concordant with other estimates of arsenic's carcino- genic potency derived from the epidemiology data based on inha- lation exposure PSHA 1983). Uncertainty about the chemical form of the arsenic in the water supply studied by Tseng et al. (1968) may limit the applicability of the risk assessment to other situations. The OSHA risk assessment would be applicable to trivalent inorganic arsenic. 2. Barium Qualitative Descri2tion of Health Effects. Barium readily forms insoluble salts in the presence of carbonate and sulfate anions. Very insoluble salts of barium such as barium sulfate are essentially nontoxic, by ingestion because only minimal 4 amounts are absorbed by the body (ACGIH 1980). Barium carbonate and more soluble barium compounds are quite toxic to humans. 0 Doses of barium carbonate and 'barium chloride of 57 mg/kg and 12 mg/kg, respectively, were fatal when ingested by humans. Toxic effects of ingestion include gastroenteritis, muscular paralysis, ventricular fibrillation, and central nervous system effects® Inhalation of barium sulfate or barium carbonate dust causes baritosis, a benign, pneumoconiosis in occupationally exposed workers. This effect is reversible upon cessation of exposure. A more detailed description of the toxicity of barium and barium compounds can be found in several sources (NAS 1977; Hammond and Beliles 1980; Stokinger 1981). No information on the carcinogenicity, teratogenicity, mutagenicity, or chronic toxicity of barium compounds was found in the literature reviewed. Current Criteria® The OSHA Standard and the ACGIH Threshold Limit Value are both 0.5 mg/m 3, for soluble compounds of barium (NIOSH 1984). This level is based on the exposure to barium nitrate that was tolerated for several years by workers at Los Alamos National Laboratory (Stokinger 1981). Conversion of dose received by inhalation of this concentration to a drinking water level and revision for susceptible populations was used to determine the EPA interim Primary Drinking Water Regulation for barium of 1 mg/liter. Analysis of Current Criteria. Based on the limited infor— mation on the toxicity of barium and the fact that barium is readily eliminated from the body, the present criteria appear to be sufficient to protect human health. 9 3. Cadmium Qualitative Description of Health Effects. Treatment of laboratory animals with cadmium by injection results in injection - site sarcomas and testicular tumors of the Leydig cells, but the relationship between human exposure to cadmium and cancer of the prostate, lung, or kidney, as suggested by several epidemi- ology studies, has yet to be firmly established. Furthermore, cadmium has not been shown to be mutagenic, although it may impair DNA repair. Cadmium is a well -studied animal teratogen, but similar potential in humans has not been convincingly demon- strated. Cadmium bioaccumulates, particularly in the kidney and liver. Epidemiology studies have shown nonmalignant pulmonary diseases to be associated with inhalation of cadmium. Renal tubular dysfunction, of which the first sign is proteinuria, occurs at even lower levels of oral or inhalation exposure to cadmium and may be the primary defect responsible for the bone damage seen in Itai-Itai disease. Chronic exposure of humans to, cadmium is also suspected to produce hypertension, anemia, sensory loss (particularly smell), endocrine altera- tions, and immunosuppression (USEPA 1980b). Current Criterion. EPA (USEPA 1980b) established an ambient water quality criterion for cadmium of 10 dig/liter on the basis of the "generally accepted" estimate of 200 µg/g wet weight of cadmium in the renal cortex as the critical concentration for renal toxicity.Friberg et al. (1974) estimated that daily 6 ingestion of 250-350 [ig cadmium over 50 years would result in such, renal concentrations. The amount of cadmium that drink- ing water would contribute to this concentration under various exposure scenarios was found to be small (0.53-7.6%) compared to other sources of exposure (occupational, food, smoking, and ambient air). it was therefore determined that the existing drinking water standard for cadmium of 10 fag/liter was adequate to protect against health effects from ingestion of cadmium. New Information. In a bioassay in which male Wistar rats were exposed to cadmium chloride aerosols 23 hours/day at con- centrations of 12.5, 25, and 50 �Lg/m 3 for 18 months, Takenaka et al. (1983) found a highly significant dose -response rela- tionship in the incidence of lung carcinomas over the controls and three treatment groups: 0/38, 6/39,,20/33, and 25/35, respectively. This represents a very marked response which certainly has implications for risk assessments for airborne cadmium. In another recent study, T'hun et al. (1984) showed a significant excess of lung cancer deaths among a group of cad- mium smelter workers. This finding may be somewhat confounded by effects of smoking and exposure to arsenic, but USEPA (1984) concluded that neither was sufficient to explain the observed effect. Like the injection site sarcomas and Leydigomas reported previously, these lung carcinomas might be interpreted as car- cinogenic responses only in the directly exposed tissue. The question remains of whether a systemic carcinogenic response following exposure to cadmium by ingestion could be predicted. V] USEPA (1984) based its quantitative risk assessment for inhaled cadmium on the epidemiological study by Thun et al. (1984) and performed a risk assessment on the rat study of Takenaka et al. (1983) to support the derived unit risk. The best estimate of the exposure and response of the exposed popu- lation from the Thun et al. (1984) study gave rise to a unit risk estimate of 2.3x10-3 (fig/m3)-1, which equals an excess risk of cancer of 10­6 associated with lifetime exposure to a concentration of 0.4 ng/ m 3 in the air. Calculations performed by USEPA (1984) using the Takenaka et al. (1983) data indicated a unit risk of 0.156 (fig/m3)-1, or a risk factor approximately 2'orders of magnitude higher. Given the limitations of avail- able data, this quantitative risk assessment appears reasonable and the use of the unit risk of 2.3x10-3 (fig/m 3 appears, valid for cadmium exposure by inhalation. Hughey et al® (1984) reported that treatment of male Wistar rats for only 24 weeks with 50 ppm cadmium in the drinking water produced clear symptoms of nephritis when the accumulated renal concentration of cadmium was 60 Vg/g w.w. This suggests that the present ambient water quality criterion of 10 �9/liter may be less conservative than originally believed and that the current standard for cadmium should be revised downward. It suggests that the threshold tissue concentration for adverse effects on the kidney should be 60 gg/g rather than 200 µ9/9, in which case the threshold daily intake would be 75-105 Vg/day rather than 250-350 µg as suggested by Fr"iberg et al. (1974). N 4 Copper ual native �escriaticr� of Health Effects. Copper does not appear to be carcinogenic, mutagenic, or teratogenic and is not toxic at low levels (USEPA 1980c). In general, more attention is, given to the problems associated with copper defi- ciency than to problems of excess copper. only levels much higher than those present in the environment are considered toxic. Further information on copper is available in USEPA (1980c), NAS (1977), Hammond and Beliles (1980), and Stokinger (1981). Current Criteria. The current Ambient Water Quality Criteria (USEPA 1980c) is 1 mg/liter based on organoleptic quality rather than toxicity® Th,e OSHA standard and the ACGIH Threshold Limit Value for inhalation exposurewereboth 1.0 mg/m 3. Anal The present criteria appear sufficient to protect human health adequately. 5. Lead Evaluation of Health Effects® Lead has been shown to be teratogenic in a number of animal studies and caused an increased incidence of stillbirths and miscarriages in occupa- tionally exposed women (USEPA 19804). The reported level of lead in the air in, the epidemiologic study was 75 �g/m 3 , for an approximate dose of 0.025 mg/kg/day. Renal dysfunction has been associated with blood lead levels as low as 40 µg/ dl with the renal changes being produced at a number of sites in the kidney. 9 The major effects caused by exposure to lead are toxicity to the hematopoietic system and neurological effects® Heme synthesis is inhibited by the effects of lead on a number of steps in the biosynthetic pathway. Specifically, lead stimu- lates, delta -aminolevulinic acid synthetase (ALA - S) and therefore increase the production of del-ta-aminoleuvulinic acid (ALA), it inhibits the activity of delta-aminoleuvilinic acid dehydra- tase (ALA -D) and therefore decreases the production of porphoro- bilinogen from ALA, and finally, lead inhibits the insertion of iron into protoporphyrin to form heme. No threshold has been found for this effect on heme production. Decreased heme production caused by lead is important for its effect on the erythropoietic system because it can cause anemia due to decreased hemoglobin production. Decreased heme production can have deleterious effects on other heme-containing proteins, such as cytochrome P-450 which functions in the body to detoxify certain chemicals® The neurotoxic effects associated with exposure to lead are of two types. Blood lead levels of over 80 µg/ dl in children and over 100 �Lg/dl in sensitive adults can cause severe irrevers- ible brain damage, encephalopathy and possibly death. Persons with these high levels may be asymptomatic or show only slight signs of intoxication but rapid deterioration can occur and in children permanent learning disabilities are seen at these levels even if no overt symptoms of lead poisoning are observed." out Although exposure to high lead levels has very severe neurological effects, exposure of children and pregnant women to low levels of lead may also cause significant neurotoxicity. Children and fetuses with blood, levels of lead of 30 µg/ dl and lower, may suffer significant neurobehavioral deficits. This would be manifested in a slight, but potentially very important decrease in learning ability for an affected child. This type of effect is toxicologically very important because there may not be an actual threshold dose below which an effect would not occur. The permanently impaired learning ability associated with such low level exposure may be impossible to detect clinically. Current Criteria. The OSHA Standard for lead in air is 50 11q1M 3 ; the NIOSH Recommended Standard is 100 4g/m3, and the ACGIH Threshold Limit Value is 150 fig/ m3"Phe standard for ambient air is 1.5 [Lg/m3`Phe USEPA Interim Primary Drinking Water Standard and Ambient Water Quality Criteria are both 50 �Lg/liter (USEPA 1980d, 47 FR 10998 1982). The Centers for Disease Control (CDC) currently defines "lead toxicity" in a child as a blood lead level >30 [.g/dl and an erythrocyte protoporphyrin (EP) >50 g/ dl.. However, CDC is presently revising its criteria for lead toxicity to blood lead levels >25 gg/dl and EP >35 �g/dl (Schilling et a,l. 1984). Analysis of Current Criteria. The standards for lead in air all appear sufficient to protect against severe toxico- M logical effects in workers. The standard for ambient air is probably sufficient to protect against severe effects of lead toxicity but may not provide an adequate margin of safety to protect against insidious neurotoxic effects. The standards for drinking water also seem sufficient to protect against severe health hazards. 6. Manganese ualitative �escr tion of health Effects® Toxic effects of manganese have been studied primarily in workers exposed by inhalation to manganese -containing dust. Exposure to high levels of manganese causes pneumonitis in exposed workers. More importantly, chronic exposure has been associated with neurological effects similar, -to Parkinson's disease with signs and symptoms including speech disturbancest a masklike face, tremors, difficulty in walking, and sexual disturbance (Stokinger 1981). The disease, manganism, is progressive, first manifested as increased irritability, difficulty in walking, unusual 'behavior, and speech disturbances before progressing to the more serious and not completely reversible condition resembling Parkinson's disease. Although exposure in these cases was by inhalation, approximately 60% of the manganese that is inhaled is subsequently coughed up and swallowed and then may be absorbed through the lining of the gut. One case study reported apparent manganism associated with extremely high levels of manganese in a drinking water well, further suggesting that ingestion, as well as inhala- tion, is an important route of exposure. Chronic exposure M to manganese also causes increased production of erythrocytes, with consequent increases in hemoglobin values and erythrocyte counts® Current Criteria. The OSHA standard and the ACGIH Thres- hold Limit Value for manganese dust are both 5 mg/ m 3 in, the air, corresponding to approximately 1 mg/kg/day for man. Analysis of Current Criteria. The current, criteria are based on a lowest observed effect level (LOEL) of 30 mg/m 3 for chronic manganese toxicity by inhalation and therefore have a safety factor of less than one order of magnitude® However, no adverse effects have been seen at this level, and therefore it is probably sufficient to prevent toxic effects in humans exposed to airborne manganese. Undesirable taste and discoloration of the water occur at concentrations greater than 0.05 mg/ liter and should prevent ingestion of toxic levels of manganese, but it clearly did not in the Kawamura et al. (1941 in NAS 1973) study. As no water concentrations were presented with this study, a maximum total dose level of 0.5 mg/kg/day is determined from the inhalation studies to be ade- quate to prevent toxic effects in humans. 7. Mercury Evaluation of Health Effects® Mercury caused cerebral palsy and microcephalus in children of women consuming mercury contaminated fish and caused cleft palate and hydrocephalus in a mouse teratology study (Shepard 1980). A decrease in male fertility was seen in mice administered a single intraperitoneal HE dose of 1 mg/kg of methylmercury hydroxide. Morphological changes in the kidneys were reported in rats fed 0.5 ppm of mercuric chloride in their diet for 2 years, a dose of approxi- mately 0.025 mg/kg/day. The primary effect associated with exposure to mercury is neurotoxicity to both the, central and peripheral nervous system. Histopathological changes have been seen in monkeys administered doses as low as 0.03 mg/kg/day for four months and observed for an additional 6 months (Sato and Ikuta 1977). occupational exposure to mercury vapor has been associated with neurological effects in humans at concen- trations of 0.1 mg/ m 3 for mercury vapor and at lower concentra- tions for alkyl mercury compounds. The toxicity of mercury depends to some extent on its form. Organic mercury compounds such as the alkyl mercuric, chemicals are generally more neurotoxic than inorganic mercury. In addition, the different forms of mercury can cause somewhat different neurotoxic effects initially, although both will elicit the same effects at higher doses. Mercury vapor generally causes neuropsychiatric effects such as emotional instability and tremors which increase in severity with increasing duration of exposure. Alkyl mercury causes tremors but also causes sensory effects at low levels of exposure and motor effects such as incoordination at somewhat higher levels® Current Criteria. The OSHA Standard for mercury vapor is 0.1 mg/ M 3 as a ceiling level. The ACGIH Threshold Limit Values for mercury are 0.01 mg/ m 3 for alkyl compounds, 0.05 W'_ for mercury vapor, and 0.1 mg/m3 for inorganic compounds (NIOSH 1984). The USEPA Ambient Water Quality Criteria for human health was 10 µg/Liter based solely on drinking water and not on consuming fish (USEPA 1980e). The Iterim Primary Drinking Water Standard for mercury is 2 �.q/liter (47 FR 10998 1982) . Analysis of Current Criteria. The ACGIH Threshold Limit Values provide only a small margin of safety but appears to be sufficiently low to protect human health. The OSHA Standard is, apparently high as exposure to mercury vapor at the level of the standard has been associated with toxic effects in workers. The Ambient Water Quality Criteria (10 µg/ liter) and the Interim Primary Drinking Water Standard (2 µg/liter) give doses of approximately 3 gg/kg/ day and -0.6 pg/kg/day, respectively. These criteria appear to be sufficient to protect human health. 8. Zinc Evaluation of Health Effects. Zinc is an essential element in the body and more problems have been associated with zinc deficiencies than with excess concentrations. However, zinc does exhibit some toxic effects at high levels. Skin and eye irritation are produced by contact with high concentrations of zinc chloride. In a study on rats, ingestion of 0.25% zinc in the diet (providing a dose of approximately 125 mg/kg/day) produced growth retardation; hypochromic anemia, and defective mineralization of bone. Dietary levels less than 0.25% had no effect in the same study. The ACGIH Threshold Limit Value for zinc oxide dust is 10 ng/m 3 as a nuisance particulate. 15 The USEPA Ambient Drinking Water Criteria and Secondary Drinking Water Standard are both 5 mg/liter based on organoleptic qualities (USEPA 1980f, 40 CFR 141). Anal The current criteria appear to be sufficient to prevent human health hazards due to exposure to zinc. Based on the levels reported at the site, zinc is unlikely to pose a health hazard to people living near the Smuggler Mine. More importantly, zinc is known to interact with other, metals present at the site such as cadmium and lead. Cadmium exposure appears to cause zinc to concentration preferentially in certain parts of the body and there is information that at least some of the toxic effects associated with exposure to cadmium may be caused by zinc - deficiency. Increased zinc uptake may alleviate these effects. Specifically, increased zinc concentrations tend to decrease or, prevent the renal toxicity associated with cadmium exposure and also decrease the terato- genic effect of cadmium. Zinc has been shown to decrease the uptake of ingested lead with the interaction apparently occuring in the gut. Zinc also apparently prevents or decreases the inhibition by lead of red blood cell enzyme ALA dehydratase. However, zinc may interact with lead to decrease levels of serum iron and cause anemia (USEPA 1980f). w B. Toxicity to Wildlife 1® Arsenic various inorganic forms of arsenic appear to have similar levels of toxicity; they all seem to be much more toxic than organic forms. Acute toxicity to adult freshwater animals occurs at levels of arsenic trioxide as low as 812 pg/liter and at levels as low as 40 jig/liter in early life stages of aquatic organisms® Arsenic toxicity does not appear to increase greatly with chronic exposure, and it, does not seem that arsenic is bioconcentrated to a great degree® Arsenic poisoning is a rare but not uncommon toxic syndrome among domestic animals. Arsenic causes hyperemia and edema of the gastrointestinal tract, hemorrhage of the cardiac serosal surfaces and peritoneum, and pulmonary congestion and edema; and it may cause liver necrosis. Information on arsenic toxicity to terrestrial wildlife was not reported in the literature reviewed. 2. Barium Adequate data for characterization of toxicity to wildlife and domestic animals are not available. 3. Cadmium The acute LC 50 for freshwater fish and invertebrates gener- ally ranged from 100 to 1,000 jig/liter; salmonids are much more sensitive than other organisms. Chronic tests have been performed and show that cadmium has cumulative toxicity and 17 acute --chronic ratios that range of from 66 to 431. B ioconcen- tration factors were generally less than 1,000 but were as high as 10,000 for some freshwater fish species. No adverse effects on domestic or wild animals were reported in the studies reviewed. 4. Copper Mean acute toxicity values for a large number of freshwater animals range from 7.2 µg/liter for 1aphnia pulicaria to 10,200 µg/liter for the bluegill. Toxicity tends to decrease as hard- nesst alkalinity, and total organic carbon increase. Chronic values for a variety of freshwater species range from 3.9 dig/liter for brook trout to 60.4 µg/liter for northern pike. Hardness does not appear to affect chronic toxicity. The acute -chronic ratios for different species range from 3 to 156® The more sensitive species tend to have lower ratios than the less sensi- tive species. In addition, the ratio seems to increase with hardness., Sheep are very susceptible to copper toxicosis and poisoning may be acute or chronic. Acute poisoning is caused by direct action of copper salts on the gastrointestinal tract, resulting in gastroenteritis, shock, and death. The toxic dose is about 20 mg/kg and is usually obtained through an accidental overdose of an antihelminthic. Ingestion of excess copper over a long period of time results in absorption and accumulation of copper by the liver. This type of chronic cumulative poisoning may suddenly develop into an acute hemolytic crisis. Copper intake WE of 1.5 g/day for 30 days is known to be fatal for many breeds, of sheep. Excessive copper may be stored in the liver as a result of excess copper ingestion, as a consequence of impaired liver function, or in connection with a deficiency or excess of other trace elements. Sheep eliminate accumulated copper very slowly after cessation of exposure. Cattle are much more resistant to copper in the diet than sheep® Copper toxicity in ruminants can be counteracted by inclusion of molybdenum, zinc, and sulfate in the diet. 5. Lead Freshwater vertebrates and invertebrates are more sensitive to lead in soft water than in hard water® At a hardness of about 50 mg/liter CaCO3, the median effect concentrations for nine families range from 140 jig/liter to 236,600 pg/liter. Chronic values for 2.2�p is magna and the rainbow trout are 12.26 jig/liter and 83.08 jig/liter, respectively, at a hardness of about 50 mg/liter. Acute -chronic ratios calculated for three freshwater species ranged from 18 to 62. Bioconcentration factors, ranging from 42 for young brook trout to 1,700 for a snail, were reported. Freshwater algae show an inhibition of growth at concentrations above 500 jig/ liter. Although lead is known to occur in the tissue of many free-living wild animals, including birds, mammals, fishes, and invertebrates, reports of poisoning usually involve waterfowl. There is evidence that lead, at concentrations occasionally found near roadsides and smelters, can eliminate or reduce We populations of bacteria and fungi on leaf surfaces and in soil. Many of these microorganism play key roles in the decomposer food chain. Cases of lead poisoning have been reported for a variety of domestic animals, including cattle, horses, dogs, and cats. Several types of anthropogenic sources are cited as the source of lead in these reports® Because of their curiosity and their indiscriminate eating habits, cattle experience the greatest incidence of lead toxicity among domestic animals. 6. Manqanese Adequate data for characterization of the, toxicity of manganese to wildlife or domestic animals are not available. A 48-hour LC 50 value of 16 mg/ liter of manganese is reported for embryos of the oyster Crassostrea virgi.nica. For the softshell clam Mya.arenaria a 168 -hour LC 50, value of 300 mg/ liter is reported. 7. Mercury The toxicity of mercury compounds has been tested in a wide variety of aquatic organisms. Although methylmercury appears to be more toxic than inorganic mercuric salts, few acute or chronic toxicity tests have been conducted with it. Among freshwater species, the 96 -hour LC 50 values for inorganic mercuric salts range from 0.02 pg/liter for crayfish to 2,000 Vg/ liter for caddisfly larvae. Acute values for methylmercuric compounds and other mercury compounds are only available for MO fishes. In rainbow trout, methyl -mercuric chloride is about ten times more toxic to rainbow trout than mercuric chloride, which is acutely toxic at about 300 Vg/liter at 10 degrees Celsius. Methylmercury is the most chronically toxic of the tested compounds, with chronic values for Daphnia mac3na and brook trout of 1.00 and 0.52 jig/liter, respectively.The acute - chronic ratio for 22pLiis maw is 3.2. Chronic dietary exposure of chickens to mercuric chloride at growth inhibitory levels causes immune suppression, with a differential reduction effect on specific immunoglobulins. Zinc produces acute toxicity in freshwater organisms over a range of concentrations from 90 to 58,100 jig/liter and appears to be less toxic in harder water. Acute toxicity is similar for freshwater fish and invertebrates. chronic toxicity values range from 47 to 852 [,g/ liter and appear to be relatively unaf- fected by hardness. A Final Acute -Chronic Ratio for freshwater species of 3.0 has been reported. Although most freshwater plants appear to be insensitive to z i inc, one species, the alga Selenastrum ca2ricornutum, exhibited toxic effects at concen- trations from 30 to 700 jig/liter. Zinc poisoning has occurred in cattle. In one outbreak, poisoning was caused by food accidentally contaminated with zinc at a concentration of 20 g/kg. An estimated intake of 140 g of zinc per cow per day for about 2 days was reported. The exposed cows exhibited severe enteritis, and some died 01 or had to be slaughtered® Postmortem findings showed severe pulmonary emphysema with changes in the myocardium, kidneys, and liver. Zinc concentrations in the liver were extremely high. Based on relatively limited data, some researchers have speculated that exposure to excessive amounts of zinc may cons- titute a hazard to horses. Laboratory studies and findings in foals living near lead -zinc smelters suggest that excessive exposure, to zinc may produce bone changes, joint afflictions, and lameness. In pigs given dietary zinc at concentrations greater than 1,000 mg/kg, decreased food intake and weight gain were observed. At dietary levels greater than 2,000 mg/kg, deaths occurred as soon as 2 weeks after exposure. Severe gastrointestinal changes and brain damage, both of which were accompanied by, hemorrhages, were observed, as well as changes in the joints. High concentrations of zinc were found in the liver. 22