Survey of lead exposure around a closed lead smelter

OBJECTIVE: To test the hypothesis that elevated lead in soil is positively correlated with blood lead (BPb) levels in children in an urban population surrounding a closed lead smelter, a US Environmental Protection Agency Superfund clean-up site was surveyed. METHOD: A total of 827 volunteers including 490 children under 6 years of age participated. A questionnaire was administered. Blood lead was determined as was lead content of samples of house dust, soil, paint, and water of the participants' homes. RESULTS: The arithmetic mean venous BPb in 490 children between 6 and 72 months of age was 6.9 micrograms/dL (0.33 mumol/L) range 0.7 to 40.2 micrograms/dL (0.03 to 1.94 mumol/L). The BPb of 78 (16%) children in this group was > or = 10 micrograms/dL (0.48 mumol/L). Based on multiple regression modeling, lead in house dust accounted for 18% of the variance in BPb. Lead in paint together with the condition of the house were the main contributors to the dust lead variance (26%) with soil lead accounting for an additional 6%. Lead in paint alone accounted for 3% of the BPb variance. Lead in paint together with the condition of the house accounted for 12% of BPb variance, and lead in soil accounted for an additional 3%. Factors other than environmental lead such as education of parents, household income, and behavior were associated with BPb levels. CONCLUSIONS: The mean BPb in children was below the present level of concern of the Centers for Disease Control and Prevention. Children with BPb of > or = 10 micrograms/L (0.48 mumol/L) tended to live in poorly maintained older houses. Based on these findings lead in soil and paint in well-maintained homes contributed little to the lead exposure of children.     

Increased lead absorption with anemia and slowed nerve conduction in children near a lead smelter

Studies to evaluate the prevalence, sources, and health consequences of lead absorption were conducted among children living near a primary lead smelter. Lead levels in air, soil, and dust were highest at the smelter and decreased with distance. Ninety-nine percent of one- to nine-year-old children living within 1.6 kilometers had blood lead levels greater than or equal 40 mug/dl, indicating increased absorption, and 22% had levels greater than or equal 80 mug/dl. The prevalence of lead levels greater than or equal 40 mug/dl decreased with distance; at 72 kilometers from the smelter it was 1%. Erythrocyte protoporphyrin levels increased with blood lead levels: 17% of children with lead levels of greater than or equal 80 mug/dl were anemic. There was no overt neurologic toxicity. Significant negative correlation was found in 202 five- to nine-year-old children between blood lead levels and motor nerve conduction velocity (r = 0.38, p less than 0.02).     

Occupational lead exposure and management

We report a series of 60 children operated on for posterior urethral valve (PUV) before the age of 5 years and followed up for 10 years. This work aims to study the vesico-sphincteric sequelae of this malformation. 38 patients showed early urinary incontinence post-operatively. Of them, 20 were re-evaluated 10 years later by pelvic ultrasonography, pressure flow studies combined with EMG and assessment of renal function. 8 patients refused to undergo these investigations and 10 were lost to follow-up. Of the 28 evaluable patients, 22 are currently continent and a complete urodynamic study was performed for the 6 (10%) incontinent patients. Of them, 3 showed uninhibited detrusor contractions. The vesical compliance was frequently within the normal limits. No case of detrusor-sphincteric dyssynergy or urethral hypotony was found. 2 were successfully treated by oxybutinin and biofeedback reeducation, 2 were partially improved but their prostates are still in growth and the possibility of implanting an artificial sphincter was discussed in the remaining 2. The urodynamic evaluation of those patients in the long-term is encouraging.     

Comparison of methods for personal sampling of inhalable and total lead and cadmium-containing aerosols in a primary lead smelter

It has been proposed that future occupational aerosol exposure standards be based on particle size-selective sampling criteria that more accurately reflect worker exposure. In relation to methods currently used for determining individual workers' lead exposures, the widely used 37-mm, closed-face, plastic sampling cassette is known from laboratory wind tunnel studies to undersample significantly compared with estimations of aerosol actually inhaled, especially for large particles. The present study investigated the degree to which this is borne out in field sampling by using side-by-side sampling in selected work sites in a primary lead smelter. Exposures to "total" airborne lead and cadmium as measured using the 37-mm sampler (E37) were compared with exposure measurements using the institute of Occupational Medicine (IOM) personal inhalable aerosol sampler (EIOM). There were 166 good sample pairs for lead and 55 for cadmium. The ratio (reflecting the fractional undersampling of the 37-mm sampler, as represented by the ratio EIOM/E37) was consistently greater than unity, by factors obtained by regression analysis ranging (for different parts of the plant) from 1.39 to 2.14 for lead and 1.29 to 2.12 for cadmium. The factor tended to be greater for parts of the plant characterized by coarser aerosol, consistent with the physical sampling characteristics of the two instruments. This research is important (1) in assessing the impact of implementation of new standards for lead- and cadmium-containing aerosols in the primary lead production industry, and (2) in the development of new occupational exposure limits based on the inhalable aerosol fraction.     

Occupational lead exposure and hearing loss

Studies of adults, children, and laboratory animals suggest an association between lead exposure and hearing loss. A causal relationship might direct mandated medical surveillance of lead-exposed workers to include audiometric testing. A cross-sectional, computerized dataset was obtained from a private occupational health screening company to examine the relationship between blood lead level and hearing loss. Audiometry and blood lead results were available for 183 workers. A statistically significant correlation was found between blood lead level and an elevated hearing threshold at 400 Hz (P = 0.03); no other frequencies showed such a correlation. This finding suggests either an interaction between nose exposure and lead, interaction of other exposure factors (such as cigarette smoking), or that factors other than biomechanical ones render the organ of Corti more susceptible at 4000 Hz. Further evaluation of these questions should be undertaken. Computerized databases created for worker surveillance may be a source for data useful for examining other causal connections in occupational settings.     

Effect of a smelter complex on the regional distribution of cadmium, lead and zinc in litters and soil horizons

The distribution of cadmium, lead and zinc concentrations in litter and mineral soil horizons from the Kootenay region were studied to determine the effect of the 70-yr operation of the world's largest base-metals smelter complex at Trail, British Columbia. Metals were retained near the surface in litter and surface mineral horizons and concentrations in deepest horizons were lower and normal for uncontaminated soils. Metal concentrations in surface horizons were significantly related to distance from the smelter and site elevation in the mountainous region. Regression equation models to predict metal concentrations as functions of distance and/or elevation accounted for 69.8, 93.3 and 76.7% of variance in litter concentrations of Cd, Pb, and Zn, respectively, and 91.3, 50.6, and 64.0% of their variances in surface mineral horizons. In view of concomitant random distribution of metal concentrations in deepest horizons, these relationships and low Zn/Cd ratios in surface horizons nearest to the smelter indicated surface deposition of airborne smelter emissions was responsible for metal contamination of Trail area surface soils.     

The internal burden of lead among children in a smelter town--a small area analysis

Many women who have undergone or will undergo mastectomy request breast reconstruction and feel that it is an important part of their total cancer treatment. Autogenous tissue methods take a place more and more important in breast reconstruction. The autologous latissimus dorsi flap, is a recent method of autologous breast reconstruction. We have done a retrospective study based on a series of 60 consecutive reconstructions operated between march 1993 and april 1995. The advantages of the autologous latissimus dorsi flap are the same of the others autologous breast reconstruction methods: the reconstructed breasts are soft and match an opposite normal breast more successfully than those made with implants. The disadvantages of this technique is mainly the dorsal seroma that was observed in 70% of cases but was easily managed by aspirations. The aesthetics results have been judged by two surgeons as very good in 85% of cases, good in 11.6% and low in 3.3%. The satisfaction rate of the patients in high: 86.6% are pleased and 13.3% are satisfied. The autologous latissimus dorsi breast reconstruction is a safe and reliable technique and provides an excellent alternative to the TRAM flap, when the patient prefer the dorsal donor site or when there are some risk factors to do a TRAM flap. Finally this technique bring a major advance in the field of breast reconstruction, immediate or delayed.     

PCBs as environmental estrogens: turtle sex determination as a biomarker of environmental contamination

Polychlorinated biphenyls (PCBs) are widespread, low-level environmental pollutants associated with adverse health effects such as immune suppression and teratogenicity. There is increasing evidence that some PCB compounds are capable of disrupting reproductive and endocrine function in fish, birds, and mammals, including humans, particularly during development. Research on the mechanism through which these compounds act to alter reproductive function indicates estrogenic activity, whereby the compounds may be altering sexual differentiation. Here we demonstrate the estrogenic effect of some PCBs by reversing gonadal sex in a reptile species that exhibits temperature-dependent sex determination.     

Measurement of vitamin D3 metabolites in smelter workers exposed to lead and cadmium

OBJECTIVES: To investigate the effects of lead and cadmium on the metabolic pathway of vitamin D3. METHODS: Blood and urinary cadmium and urinary total proteins were measured in 59 smelter workers occupationally exposed to lead and cadmium. In 19 of these workers, the plasma vitamin D3 metabolites, (25-hydroxycholecalciferol (25 OHD3), 24R, 25-dihydroxycholecalciferol (24R,25(OH)2D3) and 1 alpha,25-dihydroxycholecalciferol (1 alpha, 25(OH)2D3)) were measured together with blood lead. Vitamin D3 metabolites were measured by radioimmunoassay, (RIA), lead and cadmium by atomic absorption spectrophotometry, and total proteins with a test kit. RESULTS: Ranges for plasma 25(OH)D3, 24R,25(OH)2D3 and 1 alpha,25(OH)2D3 were 1.0-51.9 ng/ml, 0.6-5.8 ng/ml, and 0.1-75.7 pg/ml, respectively. Ranges for blood lead were 1-3.7 mumol/l, (21-76 micrograms/dl), blood cadmium 6-145 nmol/l, and urinary cadmium 3-161 nmol/l. Total proteins in random urine samples were 2.1-32.6 mg/dl. Concentrations of lead and cadmium in blood showed no correlation (correlation coefficient -0.265) but there was a highly significant correlation between blood and urinary cadmium. Concentrations for 24R,25(OH)2D3 were depressed below the normal range as blood and urinary cadmium increased, irrespective of lead concentrations. High cadmium concentrations were associated with decreased plasma 1 alpha,25(OH)2D3 when lead concentrations were < 1.9 mumol/l and with above normal plasma 1 alpha,25(OH)2D3 when lead concentrations were > 1.9 mumol/l, Kruskal-Wallis analysis of variance (K-W ANOVA) chi 2 = 10.3, p = 0.006. Plasma 25(OH)D3 was negatively correlated with both urinary total proteins and urinary cadmium, but showed no correlation with plasma 24R,25(OH)2D3, 1 alpha,25(OH)2D3, blood lead, or blood cadmium. CONCLUSION: Continuous long term exposure to cadmium may result in a state of equilibrium between blood and urinary cadmium. Cadmium concentrations in blood could be predicted from the cadmium concentration of the urine, (regression coefficient +0.35 SE 0.077). Exposure to cadmium alone decreased the concentrations of 1 alpha,25(OH)2D3 and 24R,25(OH)2D3, whereas exposure to both cadmium and lead increased the concentrations of 1 alpha,25(OH)2D3. It has been suggested that cadmium and lead interact with renal mitochondrial hydroxylases of the vitamin D3 endocrine complex. Perturbation of the vitamin D metabolic pathway by cadmium may result in health effect, such as osteoporosis or osteomalacia, risks which are possibly increased in the presence of lead.     

西北铅锌冶炼厂109m2焙烧炉的改进及经济性分析

介绍了西北铅锌冶炼厂新建的109m2流态化焙烧炉投产后的运行状况,并与原焙烧炉的技术经济指标进行了对比.理论计算分析及实际运行结果表明,该焙烧炉运行稳定,残硫率低,烟尘率低,焙砂质量好,经济效益和社会效益显著.     

Improvement for sulphidation roasting and its application to treat lead smelter slag and zinc recovery

Abstract

The conventional sulphidation roasting process is usually accompanied by the emission of SO₂, leading to serious environmental pollution. This study focuses on the decrease or elimination of the poisonous gas by introducing carbon to the system and its further application to zinc recovery from the lead smelter slag. The effects of temperature, dosage of sodium carbonate, carbon powder and pyrite and time on the sulphidation extent of zinc were studied at a laboratory scale and the sulphidation extent reached 85·62% under the optimum conditions. The results confirmed that the novel improvement for the sulphidation roasting was feasible. Besides, it was found that adding sodium carbonate was favourable for the growth and aggregation of zinc sulphides grains in the slag. Flotation tests indicated that zinc sulphides produced could be separated from the treated slag and the zinc grade increased from 14·07 to 25·12% after one rougher flotation.     

Renal effects of environmental and occupational lead exposure

Environmental and industrial lead exposures continue to pose major public health problems in children and in adults. Acute exposure to high concentrations of lead can result in proximal tubular damage with characteristic histologic features and manifested by glycosuria and aminoaciduria. Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout. A high incidence of nephropathy was reported during the early part of this century from Queensland, Australia, in persons with a history of childhood lead poisoning. No such sequela has been found in studies of three cohorts of lead-poisoned children from the United States. Studies in individuals with low-level lead exposure have shown a correlation between blood lead levels and serum creatinine or creatinine clearance. Chronic low-level exposure to lead is also associated with increased urinary excretion of low molecular weight proteins and lysosomal enzymes. The relationship between renal dysfunction detected by these sensitive tests and the future development of chronic renal disease remains uncertain. Epidemiologic studies have shown an association between blood lead levels and blood pressure, and hypertension is a cardinal feature of lead nephropathy. Evidence for increased body lead burden is a prerequisite for the diagnosis of lead nephropathy. Blood lead levels are a poor indicator of body lead burden and reflect recent exposure. The EDTA lead mobilization test has been used extensively in the past to assess body lead burden. It is now replaced by the less invasive in vivo X-ray fluorescence for determination of bone lead content.     

In vivo XRF as a means to evaluate the risk of kidney effects in lead and cadmium exposed smelter workers

The effect on kidney function was studied in 22 smelter workers with concomitant exposure to lead and cadmium. One active and five retired workers showed early signs of kidney dysfunction. They all had a long-term and high lead exposure, while their kidney cadmium concentrations measured in vivo by XRF techniques were low to moderate. Thus, the exposure to lead has been a greater risk, although an interaction between lead and cadmium could not be excluded.     

Microbial contamination of small animal ambulatory veterinary clinics and waiting rooms

Air and contact indicator microflora was monitored for a year during 17 outpatients' examinations at indicated sites of the balance loading area, examination tables and manipulation tables in an outpatients' consulting room partitioned into two sections (I, II) and in two waiting rooms (I, II) of an internal clinic of the Faculty of Veterinary Medicine at Brno. The consulting room and both waiting rooms were after reconstruction. Ambience monitoring by a sedimentation method demonstrated the lower microbial contamination of waiting room II and outpatients' consulting room II, which were reserved for vaccination of healthy animals. The ambience in waiting room I and outpatients' consulting room I, where diseased animals were examined, showed the higher values microbial contamination. The indicators of microbial contamination under observation involved total microbial counts on meat-peptone agar (MPA), counts of hemolytic (H+) and nonhemolytic (H+) micrococci on blood agar with 10% NaCl, counts of lactose positive (L+) and lactose negative (L-) microbes on Endo agar and of molds and other microbes on Czapek-Dox agar. Frequent occurrence of representatives of the genus Aspergillus and Penicillium out of 42 genera and species of identified molds was indicated in the ambience of the waiting rooms and outpatients' consulting rooms. Examination of the indicated sites of the balance loading area in waiting room I and of examination and manipulation tables in outpatients' consulting rooms by smear and impress methods demonstrated the lowest contamination on the surface of examination tables. Microbial contamination of the balance loading area was however highest, and the identified values indicate a risk of the permanent contact of animal patients with the increased microbe concentrations during their weighing. The balance location in the waiting room is not convenient under the present schedule of cleaning and cleansing. In the Discussion section, an overall decrease in the ambience microbial contamination in waiting rooms and outpatients' consulting room under observation in building no. 9 after reconstruction is shown in comparison with the results of preceding monitoring of the waiting room and outpatients' consulting room in building no. 6 under provisional conditions.     

Childhood lead poisoning: the promise and abandonment of primary prevention

In 1991, the Public Health Service published the Strategic Plan for the Elimination of Childhood Lead Poisoning. This document marked a fundamental shift in federal policy from finding and treating lead-poisoned children to authentic primary prevention. It spelled out a 15-year strategy to achieve this goal and provided a cost-benefit analysis showing that the monetized benefits far exceeded the costs of abatement. A strong national effort to eliminate the disease developed. Now, 7 years after publication of the plan, primary prevention of lead exposure has been abandoned. This article examines the role of some prevailing attitudes and institutions in derailing the effort. Some institutions--the lead industry, real estate interests, and insurance interests--behaved as anticipated. Others, including private pediatricians, the American Academy of Pediatrics, some federal agencies, and a public interest group ostensibly dedicated to eliminating lead poisoning, also played an unexpected part in derailing the plan.     

Neuromaturation and behavior development: The case of childhood lead poisoning.

Presents a rationale for the study of the role of neuromaturation in cognitive and behavioral development. Early childhood lead poisoning is discussed in terms of physiological mechanisms and known cognitive sequelae. 18 children, 4–6 yrs old, with past histories of lead poisoning, were compared to matched controls on a 6-factor cognitive and neuromotor battery that included the WPPSI and the PPVT. A developmental hypothesis that specific cognitive sequelae of lead poisoning would depend on and vary with the age of the child at the time of lead ingestion was tested. Previous findings in the literature on asymptomatic childhood lead poisoning, which cited either language-linguistic or visuospatial skill decrements in nonoverlapping populations, were elucidated. When the performances of Ss who had suffered early (before 24 mo), middle (24–36 mo), and late (after 36 mo) exposure were compared on language-linguistic and spatial factors in this sample, significant differences were suggested. Ss who experienced increased lead consumption showed reductions in 3 motor and visual-motor skills. This finding illustrates the differential effects of interruptions in maturational processes on cognitive behavior as a function of age. Although the interaction of maturational and environmental events is acknowledged, the results imply that more attention to the structure-function relationship is needed in the study of behavior development and in the development of measures of cognitive functioning. (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)