[Lead poisoning in children is a serious problem in the USA].
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Biomedical subjects
Publications and source records attributed to L Gerhardsson.
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In cooperation with the ICOH Scientific Committee on the Toxicology of metals and IUPAC Commission on Toxicology, we have developed evaluation criteria for derivation of reference values for metal concentrations in human tissues and fluids. In a first attempt to illustrate how these criteria may be used, tentative reference values for mercury in human blood were derived. For persons who do not eat fish, a mean value of 10 mumol/1 (2 micrograms/1) was suggested. It was pointed out, however, that this value was based on information that did not meet the desired quality requirements, which, unfortunately were not met by any of the published reports.
Occupational exposure to lead may cause kidney damage. This study was carried out on a cohort of 70 active and 30 retired long term exposed lead smelter workers. Their kidney function was compared with 31 active and 10 retired truck assembly workers who had no occupational exposure to lead. The lead workers had been regularly followed up with measurements of lead concentration in blood since 1950. Previous exposure to lead was calculated as a time integrated blood lead index for each worker. Blood and urine samples were obtained from all subjects. The concentration of lead in blood (B-Pb) and urine (U-Pb) was analysed. The urinary concentrations of several sensitive indicators of early tubular (U-beta 2-microglobulin (U-beta 2-m); U-N-acetyl-beta-glucosaminidase (U-NAG)) and glomerular kidney damage (U-albumin) were determined. The B-Pb and U-Pb values were significantly higher among active and retired lead workers compared with their corresponding control groups. The highest concentrations were found among the active lead workers. The concentrations of the parameters of kidney function investigated were of the same magnitude for exposed workers and controls. No clinical signs of renal impairment were found among the workers. No correlations of clinical importance existed between concentrations of U-albumin, U-beta 2-m, and U-NAG activity on the one hand and the concentrations of B-Pb, cumulative blood lead index, U-Pb, and lead concentrations in the calcaneus and tibia on the other, among lead workers and controls. Despite many years of moderate to heavy exposure to lead, particularly for the retired lead workers, no signs of adverse effects on the kidney such as early tubular or glomerular malfunction were found. Reversible changes in kidney function during the 1950s and 1960s could not be excluded, however, due to a greater exposure to lead during that time.
In a retrospective comparison of two worker cohorts with elevated total antibody against trimellitic anhydride (TMA) conjugated to human serum albumin (TM-HSA), IgG subclass antibodies against TMA were studied in 19 workers with and 12 workers without TMA-induced immunologic lung disease. The main outcome measures were ELISA index of IgG1, IgG2, IgG3, and IgG4 against TM-HSA. There were no statistically significant differences in levels of any IgG subclass between these two groups. Neither were there any statistically significant differences when workers without lung disease were compared with subgroups of workers with lung disease, such as late respiratory systemic syndrome (n = 8), asthma/rhinitis (n = 6), or both (n = 5). In TMA workers with elevated total antibody against TM-HSA, IgG subclasses against TM-HSA in workers with TMA-induced immunologic lung disease were not different from workers without disease.
Large sums are being invested in the USA at present with a view to reducing the exposure of risk groups to lead. The Centers for Disease Control (Atlanta) have recently issued new limits for lead concentrations in children, the Occupational Safety and Health Administration is preparing to issue new threshold limit values (TLVs) for airborne lead in the USA, and a national laboratory control system is being built up.
The present survey is a critical review and quality grading of 98 publications in the international scientific literature presenting mercury concentrations in human whole blood, blood cells and plasma of individuals who have not been occupationally exposed to mercury ("normal values"). Most of the papers reviewed were published after 1976 and were found in the Medline database. Additional information has been obtained in response to requests addressed to scientists with high reputation from different parts of the world working in the field of trace element analysis. The evaluation system includes separate grade scales for sampling and chemical analysis. In no case were the requirements justifying the highest Grade 1 i.e. superior quality, fulfilled. Most reports suffered from various degrees of a lack of information concerning description of individuals, diet, experimental design or analytical and statistical treatment. Nineteen papers were rejected because of insufficient information or obvious erroneous sampling or analytical treatment (Part I). The influence on blood mercury level of various non-occupational exposures, particularly fish consumption, but also medication with mercury-containing drugs, presence of amalgam restorations, etc., has been surveyed. The levels have been systematized according to such parameters. The evaluated and systematized data have been stored in a PC database "Tracy", which includes information about concentrations of total, inorganic or organic mercury in whole blood, blood cells or plasma. Mercury in maternal-cord blood is also included. One hundred and thirty-two data sets from 79 reports were included in the database (Part II). Because of the shortcomings of the available information, only tentative reference values for mercury in whole blood, blood cells and plasma were established (Part III). There is an obvious need for additional high-quality data.
The relationship between trace elements and health was discussed at The Seventh International symposium on Trace Elements in Man and Animals in Dubrovnik in May 1990. The following five elements were discussed: aluminium, copper, chromium, selenium and zinc.
Dental personnel are exposed to low concentrations of mercury vapor in their working environment and from their own amalgam fillings. This study included 505 occupationally exposed individuals working at 82 dental clinics in northern Sweden and 41 controls without occupational mercury exposure. The concentration of mercury in air was measured. Urine mercury was determined for all participants, who also answered a questionnaire focused on four symptoms known from the literature to be connected with mercury exposure, namely loss of appetite, tremor, insomnia and anxiety. The median value of mercury vapor in air in the dental surgeries was low compared with other investigations; 1.5 micrograms m-3 in public dental care and 3.6 micrograms m-3 in private dental care. The urine mercury concentrations (HgU) were low, and of the same order of magnitude as for the Swedish population as a whole. Median values among different groups of dental personnel ranged from 1.4 to 2.9 nmol Hg/mmol creatinine. For those occupationally exposed, the load from their own amalgam fillings was estimated to be of the same order of magnitude as from the working environment. The prevalence of any of the four symptoms investigated in the groups of exposed personnel and controls as low, less than or equal to 11%. In our study, which included mercury intakes up to twice the contribution from amalgam fillings, no increase in the prevalence of symptoms could be detected in relation to mercury concentrations in urine.
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Concentrations of 23 elements in lung, liver and kidney from deceased smelter workers are compared with those from rural and urban controls. The analyses were made by neutron activation analysis and atomic absorption spectrophotometry. Significantly higher levels of antimony, arsenic, cadmium, chromium, cobalt, lanthanum, lead and selenium were found in the smelter workers lungs (n = 85) compared with the rural controls (n = 15). Significantly higher concentrations of antimony, arsenic and lead were observed among all smelter workers compared with urban controls (n = 10). The highest increase, about 11-fold, was found for antimony in smelter workers compared with non-exposed controls. A six-fold increase was noted for arsenic. Workers who died from lung cancer (n = 7) had the lowest lung selenium content relative to concentrations of other metals, both compared with other disease categories among the workers (GI-cancer, other cancers, cardiovascular diseases, cerebrovascular diseases, other causes) and with the two control groups. The low lung selenium concentrations may have influenced the development of lung cancer. The highest lung tissue levels of cadmium were found in the lung cancer group. Smokers and ex-smokers were over-represented in this group and tobacco is a known cadmium source. The highest, or one of the highest, lung values for some of the other metals (antimony, arsenic, cadmium, lanthanum and lead) were observed in one or several of the lung cancer cases. Metal concentrations in liver (metabolism) and kidney (excretion) reflect the systemic distribution. The highest cadmium levels in the liver and the lowest selenium content in the kidney were found among the lung cancer cases. A multifactorial genesis for the development of lung cancer is concluded from this study, which visualizes the need for systematic health surveillance and follow-ups both in active and retired workers.
A worker was buried under arsenic trioxide in an industrial accident. He was almost immediately released but had inhaled and swallowed substantial amounts of arsenic dust. In spite of intensive treatment, circulatory collapse could not be prevented, and he died 6 h after the exposure. The treatment, autopsy findings, and arsenic concentrations in tissues and body fluids are described and discussed.
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Increased mortality due to various malignancies is reported from long-term exposed, non-ferrous smelter workers. In the present study the post-mortem distribution of cadmium, lead and zinc in lung, liver and kidney is reported and related to exposure and mortality. The study involved 86 male copper smelter workers who died after April 1975. Lung samples were taken from all workers and liver and kidney samples were taken from about one-quarter of the workers. Two control groups were used. The exposed workers were divided into six groups based upon diagnoses in medical records and autopsy protocols. Lead and zinc were analyzed by atomic absorption spectrophotometry and cadmium by neutron activation analysis. For the skewly distributed tissue levels, non-parametric statistical processing was used. Of the workers, 53% died from cardiovascular diseases and 30% from malignancies (8% from lung cancer). Cardiovascular diseases predominated in the two control groups: about 75 and 100%, respectively. Lung and liver cadmium concentrations were significantly higher in the lung cancer group of smelter workers than in the other groups of smelter workers (p less than 0.05) and rural controls (p less than 0.01). Cadmium in kidney, and lead in lung and liver were significantly higher (p less than 0.03) in the lung cancer group than in rural controls, but did not differ from that of the other workers. Zinc in lung, liver and kidney did not differ between exposed workers and controls. Rather strong Spearman rank-order correlation coefficients were found between the cadmium content of lung, liver and kidney tissue, especially in non-smoking smelter workers and rural controls. Smoking was more common in the lung cancer group than in the total group of smelter workers. Cadmium levels in the lungs of exposed workers were significantly higher (p less than 0.001) in smokers than in both ex-smokers and non-smokers. Earlier studies of the same workers gave significantly lower selenium levels in lung tissue compared with other groups of smelter workers and controls. As other carcinogenic substances are present in the working environment, e.g. arsenic, chromium and benzo [alpha]-pyrene, the specific effect of cadmium in the development of lung cancer cannot be evaluated at present.
In summary lower selenium concentrations were found in the lung cancer group compared to other smelter workers and controls. The two lowest selenium values in the total material were found in two of the lung cancer workers. This is in agreement with earlier reports of lower blood selenium levels in cancer patients (Willett et al 1983, Salonen et al 1984). An increased cancer incidence has also been found in geographical areas with low selenium contents in forage crops (Shamberger et al 1976). Numerous animal experiments have demonstrated an anticarcinogenic effect of selenium. Our conclusion is that selenium might have a protective effect in occupational exposure against at least certain carcinogens causing lung cancer. Looking at the dominant worksites the workers have obviously been exposed to different concentrations of selenium over the years. As selenium has not been particularly under observation, few dust analyses are available, and so the dust load in exposed workers cannot be directly calculated. The excretion rates show individual differences. In three of the seven lung cancer cases we noted that, despite a considerable and continuous exposure to selenium in the course of their work, they had low selenium concentrations in their lung tissue at the time of death. Two other workers in the lung cancer group had also been working at worksites with considerable exposure to selenium. Raised cadmium levels were noted in the lung cancer group.(ABSTRACT TRUNCATED AT 250 WORDS)
The study is based on the work histories and mortality data for 3832 male workers first employed before 1967 at a copper smelter in northern Sweden and followed up from 1950 to 1981. From the 3832 workers a lead cohort consisting of 437 workers employed for at least three years at sites with considerable lead exposure during 1950-74 was selected. These workers had regularly had blood lead measurements performed since 1950. Based on the cumulative blood lead dose 1950-74 and peak blood lead values, the cohort was subdivided into high mean, low mean, high peak, and low peak groups. Standardised mortality ratios (SMR) were calculated for the six groups using general and local reference populations. The original cohort of 3832 workers showed considerable excess of deaths for total mortality, malignant neoplasms especially lung and stomach cancer, ischaemic heart diseases, and cerebrovascular diseases when compared with the general population. In the lead cohort where the workers had been subjected to a considerable lead exposure only the raised SMR for lung cancer was sustained (SMR = 162; not significant). No significant differences were found between high lead and low lead exposed smelter workers.