Chronic exposure of sheep to a zinc smelter in Peru

Liver levels of arsenic, cadmium, copper, lead, manganese, and zinc were assessed in adult female sheep living in the vicinity of a zinc smelter in Peru. The study was conducted on a large sheep-raising cooperative divided into seven management units, operated under a standardized husbandry system. Soil samples were analyzed for the same metals at varying distances from the smelter. A gradient of concentration of heavy metals in soil was found between 1 and 56 km from the smelter. Soil concentrations for all metals except manganese decreased significantly with increasing distance from the smelter. The strongest correlations were found for copper, lead, and zinc (P less than 0.001). Topographic features and prevailing wind direction appeared to play a role in the dispersion of pollutants. Liver samples were obtained from 153 sheep on five units of the cooperative. The centers of the units sampled were between 13 and 56 km from the smelter. Hepatic concentrations of arsenic, lead, manganese, and zinc decreased significantly with increasing distance from the smelter. Liver arsenic and liver zinc were significantly related to soil concentrations. Liver levels of arsenic, cadmium, lead, and manganese in sheep from the cooperative were significantly higher than those detected in control sheep from southern Peru. Sheep populations may serve as biological monitors for heavy metal accumulation and environmental carcinogenesis.     

Trace Element Concentrations in Tree Leaves and Lichen Collected Along a Metal Pollution Gradient Near Olkusz (Southern Poland)

The aim of the study was to assess the metal pollution in the vicinity of the Bukowno smelter near Olkusz in southern Poland. Birch and oak leaves, pine needles and a lichen Hypogymnia physodes, overgrowing pine bark were collected at stands at different distances from the smelter and analysed for cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn) content. Concentrations of metals in the lichen were usually higher than in the tree leaves/needles and decreased with distance from the smelter, apart from the Cu content. The strongest correlation was noticed between Cd and Pb concentrations, which indicates a common pollution source (the smelter). Our results show that birch leaves can be potentially useful as a bioindicator of Zn air pollution since this species was shown to accumulate high amounts of zinc, related to environmental pollution with that metal, in their leaves.     

Letters to the Editor

A group, initially of 60 persons, was subjected to mild occupational exposure to lead during a period of two years’ work in a new smelter. These men, under medical surveillance in an area in which the concentrations of lead in the air were determined at multiple sites on a bimonthly schedule, provided specimens of urine, also bimonthly, at the end of four hours of work on a morning shift. Urine was analyzed for content of lead, ε-aminolevulinic acid, and coproporphyrin. The data, while interesting, are not sufficiently revealing to provide suitable criteria for the appraisal of the severity of the exposure in relation to the danger of its continuance.     

Repeated surveillance of exposure to cadmium,manganese, and arsenic in school-age children living in rural,urban, and nonferrous smelter areas in Belgium

Once a year from 1974 to 1978, the intensity of exposure to Cd, As, Mn in groups of school-age children living around a lead smelter was assessed. By comparison, groups of children living in an urban and a rural area were also examined. The metal content of blood, urine, hand-rinsing, air, dust, and dirt collected in the school-playground was compared. The urinary excretion of cadmium in children living around the lead smelter is greater than in those living in the urban and in the rural area. In the latter there seems to exist a time-dependent trend in the renal accumulation of cadmium. This suggests that the overall pollution of the environment by cadmium in Belgium is progressively increasing. In the smelter area, both the oral and pulmonary routes play a role in the children's exposure to cadmium. Their relative contribution to the amount of cadmium absorbed appears similar. The concentration of arsenic in urine of children living around the smelter is significantly higher than that of rural children. Speciation of the chemical forms of arsenic in urine indicates that the difference is not due to different dietary habits of the children examined but to different intensity of exposure to inorganic arsenic. The amount of arsenic on the hand of children living at less than 1 km from the smelter (X = 17.6 μg As/hand) was more than 10 times that found in children living at 2.5 km from the plant (X = 1.5 μg As/hand) whereas that found in children living in urban and rural areas was below 0.2 μg As/hand. The arsenic concentration of dust and dirt collected in the school-playground in the different areas follows the same trend. As expected, there are strong interrelationships between the degree of hand contamination by lead, cadmium, and arsenic (r ? 0.8). No statistically significant influence of the dwelling place of the children on the manganese level in blood, urine, and hand rinsing was found. Our results demonstrate that by comparison with the rural and urban children, those living in the vicinity of a nonferrous smelter may be more exposed not only to lead, but also to cadmium and arsenic. The possible long-term effects of such exposure deserve further evaluation.     

Chemical speciation of lead dust associated with primary lead smelting.

The research presented in this article assessed geochemical factors relating to dust produced during primary lead smelting. Bulk dust samples and size-selective airborne dust samples were collected from four areas of a primary lead smelter and analyzed by X-ray diffraction and sequential chemical extraction. X-ray diffraction showed that the smelter dusts were composed primarily of sulfides, oxides, sulfates, and silicates of metal ores, with galena being the primary dust component. Sequential extraction revealed the solubility of lead compounds at less than 7% in the exchangeable and mildly acidic steps for the bulk dusts collected from four smelter areas. The later steps of the extraction procedure were more effective in dissolving the lead compounds associated with the bulk dust samples, with 43%, 26%, and 8% of the total lead, in the ore storage, sinter, and blast/dross smelter areas, respectively, being extracted in the residual step. Sequential extraction of coarse airborne dust samples from the ore storage and sinter plant showed that 1.2% and 4.1% of the total lead, respectively, was exchangeable. The finer particle size fractions from these areas of the smelter showed higher percentages of exchangeable lead. Of the course airborne dust from the blast/dross furnace processes, 65% of the total lead was exchangeable. However, the largest percentage of lead from these areas was associated with the finer particle-size fractions. If lead bioavailability is related to its solubility as determined through sequential extraction, the health hazards associated with lead exposure may be appreciably enhanced in the blast and dross furnace processes.     

Assessment of particle size distributions of healthrelevant aerosol exposures of primary lead smelter workers

Experiments were conducted at a primary lead smelter to investigate the particle size distributions of lead-containing aerosol to which workers were exposed, using personal inhalable dust spectrometers (PIDS) in specific smelter process areas. A total of 46 PIDS samples were evaluated, taken from the ore storage/mill, sinter plant, blast furnace and dross furnace process areas. Continuous particle size distributions were derived from the raw PIDS data employing a recentlydeveloped optimisation routine, enabling determination of the percentages of inhalable, thoracic and respirable aerosol (in terms of lead content) as fractions of total lead aerosol. In addition, the mass ratios thoracic/inhalable and respirable/inhalable were also determined. Although the parameters of the measured particle size distributions ranged widely, some clear trends emerged. Firstly, the aerosols were coarser than had been expected based on measurements of previously reported workplace particle size distributions. This is thought to be due to the fact that the PIDS collects larger particles more efficiently than other instruments which have been used for such measurements. Secondly, there were significant differences in particle size distribution between process areas, in particular that the aerosol in the blast furnace area was generally finer than in the sinter plant. Such results may be used to support the results of workplace studies (reported elsewhere) into the differences between exposures to inhalable and ‘total’ aerosol as measured using different sampling instruments, especially when they are used together with knowledge of the physical processes governing the performances of such instruments.     

Pathways of human exposure to arsenic in a community surrounding a copper smelter

Several studies have found elevated levels of urinary arsenic among residents living near a copper smelter in Tacoma, Washington. To assess pathways of exposure to arsenic from the smelter, biological and environmental samples were collected longitudinally from 121 households up to 8 miles from the smelter. The concentration of inorganic and methylated arsenic compounds in spot urine samples was used as the primary measure of exposure to environmental arsenic. Urinary concentration of arsenic dropped off to a constant background level within one-half mile of the smelter in contrast to environmental concentrations, which decreased more steadily with increasing distance. Among all age-sex-specific groups in all areas, only children ages 0-6 living within one-half mile of the smelter had elevated levels of arsenic in urine. A separate analysis of data for these children suggests that hand-to-mouth activity was the primary source of exposure. Inhalation of ambient air and resuspension of contaminated soil were not important sources of exposure for children or adults.     

Exposure to lead by the oral and the pulmonary routes of children living in the vicinity of a primary lead smelter

Yearly from 1974 to 1978, a medical survey was carried out among 11-year-old children attending schools situated less than 1 and 2.5 km from a lead smelter. Age-matched control children from a rural and urban area were examined at the same time. The blood lead levels (PbB) of the children living in the smelter area (mainly those attending schools located less than 1 km from the smelter) were higher than those of rural and urban children. The mean PbB levels were usually lower in girls than in boys, especially in the smelter area. Despite a slightly decreasing trend in the annual mean airborne lead concentration at less than 1 km (mean PbA: from 3.8 μg/m³ in 1974 to 2.3 μg/m³ in 1978) the PbB levels there did not improve, whereas 2.5 km from the plant a significant tendency to normalization of PbB became apparent. Therefore, in the third survey, the medical examination was combined with an environmental study which demonstrated that lead in school-playground dust and in air strongly correlated. Lead on the children's hands (PbH) was also significantly related to lead in air or lead in dust. Less than 1 km from the factory boys and girls had on the average 436 and 244 μg Pb/hand, respectively, vs 17.0 and 11.4 μg Pb/hand for rural boys and girls, respectively. Partial correlations between PbB, PbA, and PbH indicated that in the smelter area the quantitative contribution of PbA to the children's PbB is negligible compared to that of PbH. Thus, the control of airborne lead around the lead smelter is not sufficient to prevent excessive exposure of children to environmental lead. In view of the importance of lead transfer from dust and dirt via hands to the gastrointestinal tract remedial actions should be directed simultaneously against the atmospheric emission of lead by the smelter and against the lead particulates deposited on soil, dust, and dirt.     

Identification of sources of lead in children in a primary zinc-lead smelter environment

We compared high-precision lead isotopic ratios in deciduous teeth and environmental samples to evaluate sources of lead in 10 children from six houses in a primary zinc-lead smelter community at North Lake Macquarie, New South Wales, Australia. Teeth were sectioned to allow identification of lead exposure in utero and in early childhood. Blood lead levels in the children ranged from 10 to 42 micro g/dL and remained elevated for a number of years. For most children, only a small contribution to tooth lead can be attributed to gasoline and paint sources. In one child with a blood lead concentration of 19.7 microg/dL, paint could account for about 45% of lead in her blood. Comparison of isotopic ratios of tooth lead levels with those from vacuum cleaner dust, dust-fall accumulation, surface wipes, ceiling (attic) dust, and an estimation of the smelter emissions indicates that from approximately 55 to 100% of lead could be derived from the smelter. For a blood sample from another child, > 90% of lead could be derived from the smelter. We found varying amounts of in utero-derived lead in the teeth. Despite the contaminated environment and high blood lead concentrations in the children, the levels of lead in the teeth are surprisingly low compared with those measured in children from other lead mining and smelting communities.     

Lead in human blood and in the environment near a battery factory

Samples of blood, air, dust, soil, vegetation, and tap water were examined between 1973 and 1975 to determine whether a large battery factory (with a smelter) was contributing to lead in the environment and to lead absorption by the local population. Mean blood lead levels in the children of lead workers were about 6 μg/100 ml higher (P<0·001) than in otherwise comparable children. Capillary blood samples in wives of lead workers were 1·7 μg/100 ml higher (P<0·05) than those of otherwise comparable wives, but venous blood samples from the same subjects showed no significant difference. Lead in dust, soil and vegetation, although variable, decreased in concentration with distance from the factory. This relationship with distance from the factory was not however found in blood lead levels. No consistent effect of distance was found with lead in air, but significantly higher concentrations were recorded at downwind than upwind sites. The blood lead results have been analysed to assess the influence of domestic factors of possible relevance—such as, lead pipes, car ownership, age of house, etc. The presence of a lead-worker in the household appears to outweigh these other factors. The findings are consistent with the work of Burrows (1976) who showed that lead workers take lead home. An interlaboratory comparison on lead in blood was carried out. The two laboratories concerned were found to be equally consistent, but there were differences between them and the design of this comparison did not make it possible to say that the results of either were `absolute' values.     

Environment and Nutrition

Excessive amounts of lead in ingested forage were found to be the primary cause of a chronic debilitating disorder in six horses. The high lead levels in forage were related to the presence of lead in surface soil accumulated from emissions of a nearby smelter. This study has demonstrated that young horses have a high susceptibility to toxic effects of lead. Older horses and cattle are more resistant. Testing of air, water, and human foodstuffs did not reveal evidence of a significant human health hazard. The cooperation of various government agencies at the federal, provincial, and local levels, together with private industry, has proved to be a highly effective approach to the investigation of a complex environmental pollution problem.     

Lead exposure from conventional and cottage lead smelting in Jamaica

A survey was conducted to determine the distribution and determinants of environmental and blood lead levels near a conventional and several cottage lead smelters and to assess the relationship between environmental and blood lead levels in a tropical, developing-country setting. Fifty-eight households were studied in the Red Pond community, the site of the established smelter and several backyard smelters, and 21 households were studied in the adjacent, upwind Ebony Vale community in Saint Catherine Parish, Jamaica. Households were investigated, using questionnaires, soil and housedust lead measurements, and blood lead (PbB) measurements from 372 residents. Soil lead levels in Red Pond exceeded 500 parts per million (ppm) at 24% of households (maximum-18,600 ppm), compared to 0% in Ebony Vale (maximum 150 ppm). Geometric mean PbB in Red Pond, where 44% of children <6 years of age had PbB levels 25 micrograms per deciliter (g/dL), was more than twice that Ebony Vale in all age groups (p < 0.0005). Within Red Pond, proximity to backyard smelters and to the conventional smelter were independent predictors of soil lead (p < 0.05). Soil lead was the strongest predictor of PbB among Red Pond subjects under 12 years of age. The blood lead-soil lead relationship in children differed from that reported in developed countries; blood lead levels were higher than expected for the household-specific soil lead levels that were observed. These data indicate that cottage lead smelters, like conventional ones, are a hazard for nearby residents and that children exposed to lead contamination in tropical, developing countries may be at higher risk for developing elevated blood lead levels than similarly-exposed children in developed countries.The results of this investigation were presented at the APHA annual meeting in Boston, MA, November, 1988.     

Occupational lead poisoning, animal deaths, and environmental contamination at a scrap smelter.

Occupational lead poisoning and environmental contamination were evaluated at a lead scrap smelter. Thirty of 37 employees (81 per cent) has blood lead levels of greater than or equal to 80 mug/100 ml, indicating unacceptable absorption, and 35 had free erythrocyte protoporphyrin (FEP) levels greater than 60mug/100ml rbc, indicating toxicity of lead on heme metabolism in red blood cells; eight current and previous employees had been hospitalized with lead colic, and another with encephalopathy. Levels of lead in surface soil (1,800 ppm) and vegetation (20,000 ppm) at the smelter were high and decreased with distance. Animals on nearby pasture had died, and lead levels in the blood, milk, and hair of large and small animals were elevated. Adults living within 100 meters of the smelter had higher blood and hair lead levels than controls, who lived at greater distances, but there was no evidence in them of lead toxicity.     

Human arsenic exposure in relation to a copper smelter

Children living near a copper smelter in Tacoma, Washington, were shown to have increased levels of arsenic in hair and urine. The urinary arsenic level decreased with distance of residence from the smelter stack. House vacuum-cleaner dust showed a similar distance relationship. Urine arsenic levels in children varied synchronously over a 5-wk period, indicating that inhalation was the most likely exposure route. In children urinary arsenic level showed an inverse relationship to age with younger children showing consistently higher urine arsenic levels.A death-record analysis indicated an increased respiratory cancer incidence in men working at this smelter. Since published urinary arsenic levels for men working at this smelter were similar to those seen in people residing near the smelter, it was felt that the community surrounding the smelter might be exposed to an increased respiratory cancer risk. Accordingly, action was taken to reduce arsenic emissions from the smelter.     

Lead and cadmium absorption among children near a nonferrous metal plant: A follow-up study of a test case

During a first survey (1974) increased lead absorption accompanied by impaired heme biosynthesis was found among children (11 yr) attending schools situated at less than 1 km (subgroup A) and 2.5 km (subgroup B) from a lead smelter.Eighteen months after major improvements had been introduced in the factory to reduce its lead emission, a second survey (1976) was carried out in the same schools (lead smelter and rural area) on other groups of children which were comparable with those of the first survey. The continuous air monitoring revealed for the lead smelter area a considerable decrease in airborne lead. The median values dropped from 3.2 to 1.2 μg Pb/m³ at less than 1 km and from 1.6 to 0.5–0.8 μg Pb/m³ at 1.5 km from the plant; in the rural area it remained unchanged at 0.3 μg Pb/m³.In order to evaluate the efficiency of the technological improvements we assessed the lead and cadmium exposure of the children by measuring lead concentration in blood (PbB) and urine (PbU), erythrocyte δ-aminolevulinic acid dehydratase (ALAD) activity, free erythrocyte porphyrin (FEP) concentration, δ-aminolevulinic acid excretion in urine (ALAU), and cadmium concentration in blood (CdB) and urine (CdU). Subgroups A and B exhibited higher PbB and CdU levels, and lower ALAD activity than the rural group; but PbU, CdB, FEP, and ALAD were significantly increased only in subgroup A. Compared with the results of the first survey, a significant tendency to a normalization of PbB was found at 2.5 km, but at less than 1 km the biological parameters (particularly PbB, ALAD, FEP) did not improve. The PbB percentile distribution in subgroup B lies now under the tentative PbB percentile distribution proposed in the PbB Directive of the Commission of the European Communities (CEC): that of subgroup A, however, is still above that of the CEC proposal. Taking into account the higher degree of vulnerability to lead exposure as compared to adults a more restrictive PbB percentile distribution has been proposed for children.Two hypotheses have been put forward to explain the lack of significant improvements in the biological parameters of the children living at less than 1 km from the lead smelter. Ingestion of dust and dirt (probably due to hand contamination) from their surroundings in the course of their normal everyday activity may represent, in addition to air, a supplementary cause of increased lead accumulation in these children. Indeed, dust and dirt samples collected on the school playgrounds at less than 1 km from the factory contained (mean ± SD) 3541 ± 1310 and 5466 ± 831 μg Pb/g, whereas at 2.5 km and in the rural area it only amounted to 397 ± 33 and 152 ± 41 μg Pb/g, respectively. The alternative explanation is that a continuous resuspension of dust and dirt particles from the highly contaminated soil around the lead smelter may maintain a very high airborne lead concentration at the breathing height of the children. In addition to a lasting reduction of lead emission from the plant, the remedial actions should also take into consideration these two possibilities.     

Occupational genotoxicity among copper smelters

Occupational exposure in a copper smelting industry may produce various adverse health effects including cancer. Despite a number of well-documented studies reporting an increased risk of cancer among copper smelter workers, the data on genotoxic effects in this industry are scarce. In view of the above, an assessment of DNA damage in peripheral blood leukocytes by Comet assay from copper smelter workers was undertaken. Additionally, the proton-induced X-ray emission (PIXE) analysis was assessed to determine the metal content of samples. The study was conducted with all workers from a copper smelter (males; n?=?11), and a control group (n?=?11) was recruited. The results of our study showed a significant increase (p?相似文献   

High concentrations of heavy metals in neighborhoods near ore smelters in northern Mexico

In developing countries, rapid industrialization without environmental controls has resulted in heavy metal contamination of communities. We hypothesized that residential neighborhoods located near ore industries in three northern Mexican cities would be heavily polluted with multiple contaminants (arsenic, cadmium, and lead) and that these sites would be point sources for the heavy metals. To evaluate these hypotheses, we obtained samples of roadside surface dust from residential neighborhoods within 2 m of metal smelters [Torreón (n = 19)] and Chihuahua (n = 19)] and a metal refinery [Monterrey (n = 23)]. Heavy metal concentrations in dust were mapped with respect to distance from the industrial sites. Correlation between dust metal concentration and distance was estimated with least-squares regression using log-transformed data. Median dust arsenic, cadmium, and lead concentrations were 32, 10, and 277 microg/g, respectively, in Chihuahua; 42, 2, and 467 microg/g, respectively, in Monterrey, and 113, 112, and 2,448 microg/g, respectively, in Torreón. Dust concentrations of all heavy metals were significantly higher around the active smelter in Torreón, where more than 90% of samples exceeded Superfund cleanup goals. At all sites, dust concentrations were inversely related to distance from the industrial source, implicating these industries as the likely source of the contamination. We concluded that residential neighborhoods around metal smelting and refining sites in these three cities are contaminated by heavy metals at concentrations likely to pose a health threat to people living nearby. Evaluations of human exposure near these sites should be conducted. Because multiple heavy metal pollutants may exist near smelter sites, researchers should avoid attributing toxicity to one heavy metal unless others have been measured and shown not to coexist.     

Blood lead levels in copper smelter workers in Japan

Lead exposure of workers in a Japanese copper smelter was assessed by determining lead levels in blood, air and flue cinder at the copper smelting processes. All the samples were analyzed for lead by atomic absorption spectrometry. Mean lead levels of air were highest at the anode department followed by the converter, smelter and blend departments. The mean level of blood lead of the workers in the anode department was also the highest among the four smelting departments. The mean blood lead levels of the workers in each department were positively correlated with their air lead levels (r = 0.99, p < 0.01). This study indicates therefore that workers in copper smelters have been exposed to lead in their workplace. Though this finding has already been reported in preceding studies, the Ordinance on Prevention of Lead Poisoning in Japan has not included copper smelter into its target job categories if their lead concentration in the raw material is less than 3%. The limitation of the present Ordinance which defines the targets by the types of job and not by the actual exposure, is discussed.     

Lung cancer in relation to environmental pollutants emitted from industrial sources

A case-control study of residents who lived in the vicinity of a primary zinc smelter and a large steel manufacturing plant in eastern Pennsylvania was undertaken to investigate the role of environmental pollutants in the etiology of lung cancer. Lifetime residential, occupational, and smoking histories were obtained from the next of kin of 335 white male lung cancer cases and 332 white male controls. Soil samples were collected and analyzed for content in ppm of arsenic, copper, lead, manganese, zinc, and cadmium. Relative risks were determined according to distance of residence from the zinc smelter and the steel plant, and according to residence in areas with heavy and light levels of various pollutants. Two-fold risks for lung cancer were associated with residence near the zinc smelter and with residence in areas with heavy levels of arsenic and cadmium, although the number of individuals living in these higher risk areas was small. These increases were not explained by the effects of cigarette smoking or by employment in the zinc or steel industry. No excess risk was associated with living near the steel plant. The limited size of the study precludes causal interpretation, but the findings suggest the need for further investigation of metallic air pollution and lung cancer.     

Concentrations of lead and other metals in blood of two and three year-old children living near a secondary smelte

Summary In 108 two-and three-year-old children the concentration of lead, cadmium, manganese, and zinc in blood, of free erythrocyte porphyrin in erythrocytes, and of haemoglobin and haematocrit were measured. The relation with distance of residence to a secondary smelter and with socio-economic class was studied. The ranges were for PbB 45–383 ppb, CdB 0.2–3.5 ppb, ZnB 2.0–9.7 ppm, MnB 2.7–14.1 ppb, FEP 10.5–138.9 g/100 ml rbc. PbB was influenced independently by the distance to the source of emission and by the socioeconomic class. FEP increased with PbB; Hb and Ht were not affected. The results suggest that the Biological Quality Guide for blood lead as adopted in the European Community may have to be lowered for young children.This study was supported by a grant from the Municipality of Arnhem and from the the Netherlands Prevention Fund