Smelter Effluent Research Articles

An integrated biological effects assessment of the discharge water into the Sunndalsfjord from an aluminium smelter

An integrated biological effects study using field transplanted mussels was applied to determine the potential biological effects of an effluent discharge from an aluminium smelter into a Norwegian fjord. Chemical body burden and biological effects were measured in mussels positioned downstream (1, 2, 5, 10 and 20 km) from the aluminium smelters discharge for a period of 6 weeks. A suite of biomarkers, from whole organism to subcellular responses were measured. Chemical concentrations in mussel tissues were low; however, a change in the PAC (polyaromatic compound) profile from high to low pyrogenic influence provided evidence of exposure to the smelter's effluent. Overall, the biological responses observed where greater in the mussels positioned closest to the smelter (1–5 km). Lowest chemical accumulation and biomarker responses were observed in mussels positioned 10 km from the smelter and were considered as the reference field population. Mussels located furthest from the smelter (20 km) exhibited significant biomarker responses and suggested a different contaminant source within the fjord. The integrated biological response index (IBR) was applied and reflected the expected level of exposure to the smelters discharge, with highest IBR calculated in mussels positioned closest to the discharge (1–5 km). Principal component analysis (PCA) also differentiated among mussel groups, with the most impacted located closest to the smelter. Not one chemical factor could explain the biological responses observed in mussels, but the presence of PAH16, PAH41 and metals Mn, Ni and Cr were the main contributors measured to the higher stress seen in the mussels from the 1 and 5 km groups.

Li and δ7Li as proxies for weathering and anthropogenic activities: Application to the Dommel River (meuse basin)

Lithium (Li) contents and isotopes were studied in the Dommel catchment, a small riverine system in northern Belgium and the southern part of the Netherlands discharging into the Meuse River. The study covered surface- and groundwaters in and on sand and gravel in the catchment; it aimed at evaluating the potential of Li isotopes as effective tracers of anthropogenic activities in addition to tracing water/substratum interaction processes within a sandy environment. Dissolved lithium concentrations in the Dommel catchment span one order of magnitude, ranging from 1.55 to 39.20 μg/L with a mean concentration of 6.58 μg/L, higher than the worldwide riverine average of 1.9 μg/L. Dissolved δ7Li varies from +5.4‰ to +27.8‰. Part of the catchment is impacted by smelter effluents with Li concentrations in the range 91–526 μg/L (mean value 288.36 μg/L) and a δ7Li of around +25.6‰ before dilution along the flowpaths of the catchment basin. To interpret the dataset in terms of using Li isotopes as a proxy for anthropogenic activity, we first applied an atmospheric-input correction to waters for both Li concentration and δ7Li, as rain contributes an important fraction of the dissolved elements in Dommel waters (8–100% of Li in waters is of atmospheric origin; 100% means no interaction with rocks, no anthropogenic disturbance). Then, we determined and quantified the anthropogenic influence using δ7Li and mixing equations for the impacted parts of the catchment. Finally, we added constraints on the water/substratum interaction in this mostly sandy-feldspar soil catchment through the δ7Li and Li/Na ratios, highlighting the role of water-residence time in the system on weathering intensity.

Long-term irrigation with zinc smelter effluent affects important soil properties and heavy metal content in food crops and soil in Rajasthan, India

ABSTRACTUse of wastewater for irrigating agricultural crops is on the rise, particularly in the developing countries. The present study was undertaken to assess the long-term effect of irrigation with zinc smelter effluent on important soil properties including heavy metal status. Metal concentration in the edible parts of the crops grown on smelter effluent-irrigated soils was also measured. For this purpose, the agricultural lands which have been receiving the zinc smelter effluent irrigation for about five decades at Debari, Udaipur, India were selected. The adjacent tubewell water-irrigated fields were selected as reference. Long-term irrigation with smelter effluent resulted into significant buildup of ethylenediaminetetraacetic acid extractable Zn (57.7 fold), Cu (4.51 fold), Fe (3.35 fold), Mn (1.77 fold), Ni (1.20 fold), Pb (45.1 fold), and Cd (79.2 fold) in soils over tubewell water-irrigated fields. Total Zn, Cu, Mn, Ni, Pb, and Cd content in effluent-irrigated soils was also increased by 27.0, 1.60, 1.40, 1.30, 26.2, and 167 fold, respectively. Risk assessment indicated a very high to moderate potential ecological risk due to Cd, Pb, and Zn in soils close to the immediate vicinity of the smelter plant. Cadmium and Pb concentrations in edible parts of almost all the crops grown on effluent-irrigated soils were above the safe limit of CODEX commission. On an average, soil pH dropped by 0.31 units due to smelter effluent irrigation. Smelter effluent irrigation resulted into significant increase in soil organic carbon, electrical conductivity, and CaCO3 content. On an average, there was decrease in available N (21.0%) and P (20.8%) content in effluent-irrigated soils over the tubewell water-irrigated ones. An increase in available K (102%) and S (26.0 fold) was recorded in effluent-irrigated soils. Long-term irrigation with zinc smelter effluent resulted into reduced microbial activities in soil as evidenced from the level of microbial biomass carbon and dehydrogenase activity. In view of the buildup of heavy metals and subsequent imbalance in essential plant nutrients in smelter effluent-irrigated soils, appropriate remediation-cum-fertilization strategy needs to be adopted for better soil health and plant nutrition.

Solid phase speciation of Zn and Cd in zinc smelter effluent-irrigated soils

Solubility of metal in contaminated soils is a key factor which controls the phytoavailability and toxic effects of metals on soil environment. The chemical equilibria of metal ions between soil solution and solid phases govern the solubility of metals in soil. Hence, an attempt was made to identify the probable solid phases (minerals), which govern the solubility of Zn2+ and Cd2+ in zinc smelter effluent-irrigated soils. Estimation of free ion activities of Zn2+ (pZn2+) and Cd2+ (pCd2+) by Baker soil test indicated that metal ion activities were higher in smelter effluent-irrigated soils as compared to that in tubewell water-irrigated soils. Identification of solid phases further reveals that free ion activity of Zn2+ and Cd2+ in soil highly contaminated with Zn and Cd due to long-term irrigation with zinc smelter effluent is limited by the solubility of willemite (Zn2SiO4) in equilibrium with quartz and octavite (CdCO3), respectively. However, in case of tubewell water-irrigated soil, franklinite (ZnFe2O4) in equilibrium with soil-Fe and exchangeable Cd are likely to govern the activity of Zn2+ and Cd2+ in soil solution, respectively. Formation of highly soluble minerals namely, willemite and octavite indicates the potential ecological risk of Zn and Cd, respectively in smelter effluent irrigated soil.

Socio-Economic Impact of Industrialisation and Mining on the Local Population: A Case Study of Nalco Industrial Area, Koraput

National Aluminium Company (NALCO), Damanjodi is a govt. owned Navaratna company located in the major bauxite mining district of Odisha. The vast majority of the local population around NALCO are SCs and STs and most of them are employees of the company. On the contrary, it has a displacement effect on the tribals and creates water, air and sound pollution. Considering the above, this paper attempts to explain the significance of industrialisation and its impact on the local economic development through a case study in three peripheral villages of NALCO industrial area. In view of the specificity of the topic, we relied on primary data. The relevant information has been elicited from 100 residents of three surrounding villages of NALCO namely Kapsiput, Analabadi and Goudaguda through a special questionnaire. The findings reflect both positive and negative effects of mining, refinery, aluminium smelter and industrial effluents of NALCO on human and ecological health, pattern of livelihood, income, education and settlement of local population etc. and, finally, it suggests alternatives and improvements to prevent environmental and health degradation and, to actively promote education, health and economic development around industrial sites.

Geochemistry of soil contamination from lead smelters near Eureka Nevada

Eureka, Nevada, was once a boom-mining town with peak production of Pb, Ag, and Au between the 1870s and 1890s. Most of the ores from the area were processed in two smelters located at the north and south edges of the town. Smelter effluent was exhausted in the vicinity of the smelter furnaces with little regard to potential health concerns. For this study, 186 soil samples from sites in the area surrounding Eureka were analysed for 43 elements. Factor analysis and element plots identified 16 smelter-related elements: Ag, As, Bi, Cd, Cu, Hg, In, Mo, Pb, S, Sb, Sn, Te, Tl, W, and Zn. Eight other elements (Ba, Be, Co, Cr, Mn, Ni, U, and V), whose distributions are controlled by the chemical composition of the underlying substrate material, were also evaluated. Of these 24 elements, only six (As, Cd, Pb, Tl, Sb, and Mn) had concentrations that exceeded U.S. Environmental Protection Agency (EPA) estimated residential soil screening levels considered to represent possible health risks. For some analysed elements (In, S, Te, and W) no screening levels have been established. Whether these elements, or any of the others determined, constitute a health risk in the local population is not known. Supplementary Material: Analyses for 43 elements in 186 soil samples are available at www.geolsoc.org.uk/SUP18673

Influence of lead smelter emissions on the distribution of metals in marine sediments from Chaleur Bay, eastern Canada

Metal concentrations in surficial marine sediments collected from many parts of Chaleur Bay are significantly higher than background levels. The bay receives metals from various sources including a Pb smelter, an Hg-cell chlor-alkali plant, and numerous mined and unmined base-metal deposits. This study examines the sources, fluxes, and dispersal patterns of metals released to the bay, and the processes that control the transport and fate of these elements in the marine environment. Bottom sediments collected from 124 sites show the following ranges in metal(oid) concentrations (mg/kg): As, 2.8–74; Cd, 0.02–69; Cu, 3.4–200; Hg, <0.01–2.4; Pb, 0.3–2000; and Zn, 22–3200. Dispersion of smelter effluents and atmospheric emissions by wind and/or nearshore currents has resulted in an area of elevated As, Cd, Cu, Hg, Pb, and Zn concentrations in surficial sediments within c. 10–20 km of the smelter. The concentrations of most metals decrease sharply with increasing distance from the smelter; however, Pb concentrations exceed background levels in surface sediments throughout the bay. Lead isotope ratios suggest that the surface enrichment of Pb throughout the bay is mainly derived from smelter emissions and historical leaded gasoline combustion.

Numerical simulation of scavenging of an urban aerosol by filtration taking into account the presence of coagulation, condensation, and gravitational settling

This work studies the scavenging efficiencies of an average urban aerosol by means of filtration after a given mechanism of removal (coagulation, heterogeneous nucleation, and gravitational settling) as a function of time. Filtration is a simple, versatile, and economical mean for collecting samples of aerosol particles. The capture of aerosol particles by filtration is the most common method of aerosol sampling and is a widely used method for air cleaning. At low dust concentrations, fibrous filters are the most economical means for achieving high-efficiency collection of submicrometer particles. Aerosol filtration is used in diverse applications, such as respiratory protection, air cleaning of smelter effluent, processing of nuclear and hazardous materials, and clean rooms. The process of filtration is complicated, and although the general principles are well known there is a gap between theory and experiment. In this paper, we review filtration in order to provide an understanding of the properties of fibrous and porous membrane filters, the mechanisms of collection, and how collection efficiency and resistance to airflow change with filter properties and particle size.

Assessing the application of an additive model to estimate toxicity of a complex effluent.

A number of industries monitor levels of chemicals in their effluent, but few have undertaken prolonged biological monitoring of this wastewater. The focus of the present study was to determine whether past chemical data for effluent from a lead smelter could be used to estimate its past toxicity. Since the interactive effects of metals in effluents are often assumed to be additive, it was hypothesized that an additive model, 100/[sigma(metal concentration in effluent/EC50 for individual metal)], could be used to generate an EC50 from chemical data (where EC50 is the concentration of test material that affects 50% of the test organisms). To test the approach, a larval development toxicity test with the marine polychaete, Galeolaria caespitosa, was used to test 26 separate samples of effluent from a lead smelter, generating empirical EC50 values. EC50 values for each individual metal in the effluent were also generated using the larval development toxicity test. The concentrations of trace metals in each effluent sample were determined and, using the additive model, EC50 values were calculated. For the majority of effluent samples tested, the additive model underestimated toxicity, suggesting the presence of additional unidentified contaminants in the effluent samples. Additionally, a nonlinear rather than linear regression curve was found to best describe the relationship between the model and empirically derived EC50 values. This relationship was then used to estimate past trends in toxicity of the smelter effluent. Forty-eight percent of the variability in measured toxicity was explained by the model, with the model underestimating toxicity in the majority of samples.

Lead and zinc removal by laboratory-scale constructed wetlands.

Constructed wetlands have the potential to trap and remove metals in mine wastewater. To determine the effectiveness of constructed wetlands for treating selected heavy metals in neutral mine effluent typical of lead mines, eight laboratory-scale constructed wetlands were set up to treat a synthetic, slightly alkaline, mine water containing 34.2 mg/L sulfate (SO4(2-)), 50 micrograms/L lead (Pb), and 300 micrograms/L zinc (Zn). After 45 days, one of the wetlands was switched to treat a synthetic smelter effluent with a much greater load of SO4(2-), sodium (Na+), and Pb. Temperature, hydraulic loading, and substrate composition typically did not affect treatment efficiency. The pH of the effluent was reduced from 8.0 to 8.5 to near neutral. The average removal in the eight wetlands was 90% for Pb and 72% for Zn. In wetlands operating on synthetic mine water, SO4(2-) was completely removed, likely by conversion to sulfide by sulfate-reducing bacteria. In the wetland operating on synthetic smelter effluent, only approximately 25% of 6 g/L influent sulfate was removed, and a breakthrough period of 4 days for Na+ was observed. Whole effluent toxicity assays on undiluted wetland effluent from wetlands treating mine and smelter water had 100% survival of fathead minnows and Daphnia magnia. Survival of Ceriodaphnia dubia was zero in undiluted effluent, but 75 to 100% survival was observed when the effluent was diluted to one-half strength.

Assessment of industrial effluent toxicity using flow-through fish egg/alevins/fry (EAF) Toxicity Test.

The overall objective of this study was to determine if adding small amounts of seawater would detoxify the effluent of an aluminum smelter. A previous TIE study had identified aluminum as a possible source of the occasional acute toxicity to rainbow trout. The toxicity of aluminum to rainbow trout decreases with water hardness (CCREM, 1997), and seawater into which the effluent discharges was the nearest source of a hardening agent. The conditions which caused high concentrations of aluminum were storm events which were frequent in Kitimat, British Columbia (>200 in. per year). It was postulated that by adding small amounts of seawater (less than would be considered a substantial dilution factor) the increased hardness of the effluent would make it acutely non toxic to rainbow trout. The purpose of this study was: 1) to evaluate the Environment Canada’s Embryo/Alevin/Fry (EAF) method; 2) to determine the suitability of the early life stage test for assessing the quality of Alcan’s effluent, and 3) to assess the toxicity of Alcan’s effluent after treatment with small amount of seawater. In this paper, the acute and chronic effects of an aluminum smelter effluent using rainbow trout (Oncorhynchus mykiss) in the EAF Toxicity Test were investigated. This work was completed at BC Research Inc. (BCRI).

Effects on marine organisms from polycyclic aromatic hydrocarbons (PAH) and other constituents of waste water from aluminium smelters with examples from Norway

A brief review is presented of the effects from the main stress factors in Norwegian aluminium smelter effluents: PAH, fluoride and depressed pH from the combination of Söderberg technology with treatment of gases in seawater scrubbers. The main focus is on PAH. It is shown that toxic effects from fluoride or depressed pH are usually not to be expected outside the primary dilution zone. Generally, ecological effects in the recipients are restricted to 1–2 km from the waste outfalls. The apparent discrepancy between toxicity thresholds of PAH from the literature and the merely moderate adverse effects in Norwegian recipients is considered to be due to (i) the inadequate relevancy of tests with dissolved PAH for effluents dominated by PAH in the particulate state and (ii) less availability of soot associated with oil derived PAH in sediments, and the probable role of dissolved organic matter in making pore water PAH less available than unassociated PAH in solution.

Metal-organic associations in sediments—I. Comparison of unpolluted recent and ancient sediments and sediments affected by anthropogenic pollution

The concentrations of 19 trace elements were determined by plasma emission spectrometry in organic fractions (organic solvent extractables, soluble humics, protokerogen and kerogen concentrates) separated from various recent and ancient sediments (mangrove sediments, algal mats, oil shales, phosphorites) as well as sediments polluted by industrial metal emissions (Rhine River, Port Pirie smelter effluent). Often the organic constituents were found to be enriched in trace elements (especially B, V, Mn, Co, Ni, Cu, Zn, As, Mo, Ag, Cd, Sb, Hg and Pb) up to more than three orders of magnitude compared to the bulk sediments, indicating the importancesof organic substances with respect to transport and fixation of trace elements within sediments. The formation of metal-organic associations was found to reflect the environment of deposition (marine to terrestrial) as well as diagenetic transformations (recent to ancient). Against an unpolluted natural background, increasing metal pollution led to increasing metal potake by organic substances (especially for B, Cr, Fe, Co, Cu, Zn, As, Cd and Pb).

Metals in Pocillopora damicornis exposed to tin smelter effluent

Metal concentrations in tissues and skeleton of the coral Pocillopora damicornis were compared from intertidal reefs adjacent to a tin smelter at Phuket, Thailand. Tissue concentrations of ten metals were significantly higher for corals collected at the tin smelter than at control reefs, 1 km distant. Elevated tissue metal concentrations were considered not to be derived from particulate material but probably from solution. Analyses of skeletal material revealed no differences in metal concentrations between study sites. The implications of elevated tissue metal concentrations are discussed in relation to reduced growth rates and low abundance of branching coral species at the reef adjacent to the tin smelter when compared to the control reefs.

Size-time composition profile of aerosols using the drum sampler

Mie scattering theory imposes strict requirements for both size and compositional information on aerosols associated with visibility degradation. But, at the very clean National Park Service sites where we do such studies, episodes of degraded visibility may be infrequent and of short duration. To meet these needs, an 8 stage impactor of the Battelle/SFU design was mated to rotating drum impaction surfaces of the Lundgren design in a compact and rugged DRUM sampler of Davis design. This unit, three years in development, has been extensively tested using laboratory aerosols and field intercomparisons. The standard unit runs essentially unattended for 14 or 28 days. The samples are analyzed in 2 to 8 hour time segments. Analyses are done by carefully collimated (1 mm, 2 mm) proton beams in a tightly coupled PIXE system, yielding sensitivities of a few solng m 3 . Dramatic shifts in the size distribution of sulfur versus time have been observed, with direct influence on optical extinction. Further, primary smelter effluents have been clearly identified at Grand Canyon NP, but only in the < 0.15 μm size fraction. The DRUM sampler makes excellent use of PIXE capabilities, but can also be analyzed by lasers (Csoot) and β-gauging (mass).

The rate of lake acidification in four lakes North of lake superior and its relationship to downcore sulphur isotope ratios

Surficial sediments (0 to 12 cm) were removed from three lakes located within 20 km of a large siderite sintering plant which annually releases 140 000 tonne S and sinter fly ash up its stacks. A fourth lake located approximately 100 km upwind of the sintering plant was chosen as a control. Lake sediments were analyzed for sulphate, pyrite, organic S, total S and subfossil diatoms. The rate of lake acidification inferred from stratigraphic changes in diatom species composition indicated that one of the lakes located in a granitic basin near the sintering plant was undergoing rapid acidification. The other two study lakes located near the sintering plant were situated on carbonate-rich greenstones. Their pH as inferred from diatom stratigraphy indicated that both lakes were actually increasing in pH over the last 30 yr. The diatom inferred pH of the control lake's deeper sediments (4.8 ± 0.2) did not differ significantly from the lakes' present day observed pH (4.9). Lakes closest to the sintering plant had the highest S concentrations in their sediments. In addition, their surface sediments (0 to 2 cm) had significantly higher pyrite concentrations than their deeper sediments. Organic S and pyrite S comprised the major fraction of S in the sediments of all four lakes. The S isotope ratios (δ34S) in the various forms of S in the lake sediments were also measured. The δ34S values in the deeper (10 to 12 cm) sediments were found to be fairly uniform in all four lakes at + 4.0%., almost identical to those of the lake sulphates upwind from the Wawa sintering plant. This suggests little or no S isotope fractionation during sulphate reduction and precipitation of sulphides at the time of sediment deposition roughly 100 yr age. However, δ34S values in the surface sediments (0 to 2 cm) were shifted toward negative values. In the lakes downwind from the Wawa smelter, the isotope shift ranged from 14 to 16%, whereas in the upwind lakes the shift was very much smaller ranging from 1.5 to 5.0%. This shift in δ34S in the recent sediments wass presumed to be largely a result of isotope fractionation in the dissimilatory reduction of lake sulphate by bacteria stimulated by anthropogenic inputs of S. The possibility of anthropogenic inputs of S with high negative δ34S values to explain the shifts in isotopic ratios seems unlikely in view of known δ34S values for the ores in the area. Additional δ34S measurements on lake sediments, lake sulphates and ore samples (smelter effluent), etc., have been undertaken. This should make it possible to interpret the 534 shift in the sediments in terms of environmental changes since the Ambrosia rise (circa 1890).

Role of acute metal toxicity in structuring seagrass fauna near a lead smelter

Field acute toxicity tests over 21 d periods demonstrate that 2 species of vagile epibenthic seagrass fauna (the fish Neoodaxsp. and the crustacean Cyrnodoce longicaudata) are acutely affected by Cd, Cu, Pb or Zn in the effluent from a lead smelter. By comparison with the laboratory LCSo data in the literature for other marine fishes and crustaceans it appears that Zn is the metal mainly responsible for these effects. Although C. longicaudata is acutely affected by the metals, its abundance is normal in some parts of the highly contaminated area. A third species (the fish Helotes sexlineatus), whilst not acutely affected by the metals in these experiments, was shown by a previous survey to be reduced in abundance in the highly contaminated area. Since the distribution of these latter 2 common species cannot be explained by the results of acute toxicity tests it is unlikely that acute toxicity of these metals is the major determinant of community structure in the highly contaminated area even though the concentrations of Zn in the smelter effluent appear to be near laboratory-derived LCS, concentrations for other marine species. Outside the highly contaminated area acute toxicity of these metals is unlikely to have any effect on community structure. It is concluded that acute toxicity plays only a minor role in structuring the seagrass fauna1 communities of the contaminated area and that acute toxicity tests using dissolved metals are unable to predict ecological effects. Therefore, such tests are probably unsuitable as bases for determining water quality criteria for protection of seagrass fauna.

Concentrations and speciation of lead, zinc and cadmium in seawater-like smelter effluent and adjacent marine environments, Port Pirie, South Australia

High concentrations of particulate and dissolved lead, zinc and cadmium (total dissolved Pb, 750�g l-1; Zn, 4300�g 1-1; Cd, 64 �g l-1; particulate Pb, 236 �g l-1; Zn, 64 �g l-1; Cd, &lt; 1 �g l-1) occur in seawater- like effluent from a lead-zinc smelting complex at Port Pirie. This effluent is discharged through a silled tidal channel into the offshore marine environment, where dilution by seawater eventually reduces the metal concentrations to values similar to those in near-surface seawater in Spencer Gulf, remote from centres of industrial activity (average total dissolved Pb, 0 4 �g 1-1; Zn, &lt; 10 μg l-1; Cd, 0 3 �g l-1; average particulate Pb, &lt;0.05 �g l-1; Zn, 0 21 �g I-1). Precipitation of dissolved metals or conversion of originally weakly complexed dissolved metals to more strongly complexed species does not occur to a significant extent. Particulate metal concentrations are influenced by resuspension of metal-rich sediments and by uptake of dissolved cadmium by unicellular algae that grow in the tidal channel.

Tree rings and air pollution: A case study of Pinus monophylla growing in east-central Nevada

Five stands of Pinus monophylla (single-needle pinyon pine) from east-central Nevada were sampled and analysed using dendrochronological methods to detect the effects of climate and copper smelter effluent on annual ring-width growth. Tree-ring chronologies were developed for two sites near the smeller and for three control sites. All chronologies were highly and positively correlated before smelting began in 1908, but after that date there was a significant decrease in the correlation of the chronology from the site nearest the smeller with the other chronologies. The results of a response function analysis suggest that trees on the site nearest the smelter are limited by both climate and air pollution. An increase in the amount of low-frequency variance in the chronology from these trees is attributed to a decrease in ring-width growth from 1910 to 1930 followed by an increase in growth which may have been caused by some change in the trees' environment due to copper smeller effluent.

Relationship between lung cancer and distance of residence from nonferrous smelter stack effluent.

Because of a reported association between residence in counties with nonferrous smelters and increased risk of lung cancer, we studied the relationship between distance of residence from nonferrous smelters and lung cancer. Patients with lung cancer and patients with other cancers not known to be associated with smelter effluent (breast, prostate, and colon) were compared. All patients lived within a 20-kilometer radius around one of 10 nonferrous smelters in five western states during 1970-1977. Data were obtained from cancer registries or death certificates and were examined separately for each area. Addresses at the time of diagnosis or death were plotted on U.S. Geological Survey maps to calculate distance from each smelter. The distribution of lung cancer near the smelters was not significantly different from the distribution of control cancers in any of the areas studied.