Silver Valley, Idaho

Industrial sources of lead are typically point sources of emission. Such sources give rise to a narrow plume of pollution, and hence considerable temporal variations in pollutant levels are encountered dependent upon the wind direction. Close to a large lead refinery at Tower Hamlets, London, the mean atmospheric lead concentration measured over a six month period was 3 /xg m, whilst concentrations up to 92 Mg were observed during 3 hourly periods [4]. Far higher mean concentrations were measured in the vicinity of a lead smelter in Silver Valley, Idaho. Annual average results are summarized in Fig. 2.3. The difference between the 1974 and 1975 results arises from a reduction in smelter emissions in the intervening period [8]. 

The most important body of primary silver ore in the United States in the 1990s is located in Silver Valley, the Coeur d Alene Mining District of Shoshone County, Idaho, which produces >200 t/yr of silver. The main ore mineral is tetrahedrite [12054-35-2] associated with sulfides of lead, copper, iron, and 2inc. 

A large number of environmental epidemiological studies dating to the 1970s were carried out at a lead—zinc smelter complex in the Silver Valley of Idaho, continuing into more recent years at multiple towns within the Bunker Hill Superfund Site (Sheldrake and Stifelman, 2003 von Lindem... 

U.S. Environmental Protection Agency, 2008. Office of the Administrator. National Ambient Air QuaUty Standards for Lead. Final Rule, 73 ER 66964-67062, November 12. von Lindem, I.H., Spalinger, S.M., Bero, B.N., Petrosyan, V., von Braun, M.C., 2003a. The influence of soil remediation on lead in house dust. Sci. Total Environ. 303, 59—78. von Lindem, I., SpaUnger, S., Petrosyan, V., von Braun, M.C., 2003b. Assessing remedial effectiveness through the blood lead soil/dust relationship at the Bunker Hill Superfund site in the Silver Valley of Idaho. Sci. Total Environ. 303, 139—170. 

The Lanphear et al. s (1998) analysis of 12 pooled studies of dust and soil Pb relationships to yoimg children s PbB value was described in the previous chapter in terms of modeled estimates of PbB mean values, given changes in interior dust Pb loadings (fig/ft ) and exterior (soil plus exterior surface Pb) Pb concentrations (ppm). Here, the analysis is extended to estimates of percentage of PbB exceeding two health risk thresholds, >10 and sl5 p.g/dl. These health risk threshold exceedances parallel the approach used in the case study for the smelter Superfund site in the Silver Valley of Idaho. 

Currently in the United States, most of the lead produced comes from mines in Missouri, Alaska, Idaho, and Montana, primarily from lead-zinc and lead ores (361, 362). Worldwide, major lead deposits exist in association with zinc, silver, and/or copper (362). There are five major geological types of lead deposits volcanic-hosted massive sulfide deposits [Canada, Cyprus, Japan, Australia (Tasmania), Turkey] sediment-hosted deposits of sulfides interbedded with shales, and so on, formed in an anaerobic marine environment [Australia, Canada, Germany, United States (Alaska)] strata-bound carbonate deposits containing sulfide minerals [United States (Mississippi Valley), southern European Alps, Canada, Poland] sandstone-hosted deposits of finely crystalhne sulfides (Canada, France, Morocco, Sweden) and vein deposits of coarsely crystalline sulfide aggregates (western United States, Germany, Japan, Mexico, Peru) (364). The wide variety of compositions seen for lead minerals is illustrated by the representative lead minerals listed in Table XV (3,47). Below, we discuss the lead minerals that are most prevalent in nature in more detail. 

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