Elevated urinary excretion of beta-aminoisobutyric acid and exposure to inorganic lead

beta-Aminoisobutyric acid (beta-AIB), a normal degradation product of thymine, a constituent of DNA and, to a lesser extent, of transfer RNA, is excreted in low levels in human urine. We found that a group of iron workers occupationally exposed to inorganic lead excreted high levels of urinary beta-AIB. Elevated urinary excretion of beta-AIB was also observed in marmosets, Callithrix jacchus, that received lead acetate in drinking water. Our results suggest that increased urinary excretion of beta-AIB could stem from damage to DNA on exposure to lead.     

Selenium intake and urinary excretion in persons living near a high selenium area

Selenium intake by adults consuming self-selected levels of four different diets averaged 209 micrograms. per day and correlated well with caloric and protein intake. Urinary selenium concentration averaged 0.108 microgram. per milliliter, and 24-hour excretion for the various diets averaged 58.0% to 88.6% of the intake. The data suggest that the RDA upper limit of 200 micrograms. of selenium per day and the suggested maximum urine selenium concentration may be too restrictive. The data further indicate that even though there are differences in the absorption of selenium from different sources, the average is about 70% for foods purchased in the Northern Great Plains area.     

Neuropsychological assessment at school-age and prenatal low-level exposure to mercury through fish consumption in an Italian birth cohort living near a contaminated site

The relative effects of prenatal and postnatal low-level mercury exposure and fish intake on child neurodevelopment are still controversial. Limited evidence is available from Mediterranean populations. In this prospective study, we measured the Verbal and Performance IQ in Italian children at school-age who were resident in an area declared as a National contaminated site because of mercury pollution, taking into account the possible beneficial effect of fish consumption and potential confounders. A mother–child cohort made up of 242 children was established at birth in Northeastern Italy in 2001. Their mothers were interviewed approximately 2 months after delivery to determine type, quantity, and origin of fish consumed during pregnancy and about a number of mother, child and family characteristics. Total mercury (THg) and methyl mercury (MeHg) were assessed in maternal hair and breast milk and in the child's hair. When children reached 7–9 years of age, 154 (63.6%) parents gave consent to participate in a follow-up evaluation. On that occasion, a child's hair sample was collected to determine the current concentration of THg, mothers were asked to complete a self-administered questionnaire, and children underwent neuropsychological testing. Verbal IQ, performance IQ and full scale IQ were measured by the Wechsler Intelligence Scale for Children (WISC III) administered by psychologists at school or local health centers. Demographic, socioeconomic and lifestyle information, medical information of the child's family and the child's dietary habits were collected using a questionnaire filled in by mothers. Multivariable linear regression models were used to evaluate the association between prenatal THg exposure through fish consumption of mothers in pregnancy and children's IQ after adjustment for possible confounders such as fish consumption of mothers in pregnancy, child's fish consumption at follow-up, child's birthweight, maternal cigarette smoking during pregnancy, house size and property place of residence during pregnancy and gender. THg in the child's hair at 7 years of age was fairly correlated with THg in maternal hair at delivery (r_s = 0.35; p < 0.0001) and was strongly correlated with child's seafood consumption (r_s = 0.50, p < 0.0001). No differences in maternal THg levels were found when comparing children with low or extremely low or high or extremely high scores vs others, considering separately full scale, verbal, and performance IQs. Children born from mothers with hair THg levels greater than or equal to 2000 ng/g had full scale, verbal and performance IQs which were 4–5 points lower than children born from women with lower THg levels, but these differences were not statistically significant. Fresh fish intake of mothers in pregnancy was slightly positively associated with full scale and performance but not so with verbal IQs. Canned fish showed to be negatively associated with all the outcome variables. Unexpectedly, children born to mothers from one town showed IQ scores significantly lower than the other children; however, none of the many variables considered in these analyses could explain this result. The relatively low Hg levels found in the biological samples did not provide evidence of high and extensive Hg exposure in this population. Although THg levels in maternal and child's biological samples are correlated with fish consumption, the effects of THg and fish on neurological outcomes go in opposite directions. These results do not allow to develop recommendations regarding fish consumption in pregnancy but suggest that keeping THg hair levels < 2000 ng/g might be desirable.     

Different behaviour of inorganic and organic mercury in renal excretion with reference to effects of D-penicillamine.

Inorganic and organic mercury was measured in the red cells, plasma, and urine of five laboratory workers to examine the effect of D-penicillamine. The workers had had no particular exposure to mercurials. Before and during administration of D-penicillamine, inorganic mercury levels in plasma were significantly correlated with those in urine or 24-hour urinary outputs, but no significant correlation was found for organic mercury. Administration of D-penicillamine enhanced 24-hour urinary output to a much greater extent in organic than inorganic mercury. All the organic mercury levels in blood, red cells, and plasma were increased by D-penicillamine. This contrasted with the decrease of inorganic mercury levels in plasma.     

Different behaviour of inorganic and organic mercury in renal excretion with reference to effects of D-penicillamine.

Inorganic and organic mercury was measured in the red cells, plasma, and urine of five laboratory workers to examine the effect of D-penicillamine. The workers had had no particular exposure to mercurials. Before and during administration of D-penicillamine, inorganic mercury levels in plasma were significantly correlated with those in urine or 24-hour urinary outputs, but no significant correlation was found for organic mercury. Administration of D-penicillamine enhanced 24-hour urinary output to a much greater extent in organic than inorganic mercury. All the organic mercury levels in blood, red cells, and plasma were increased by D-penicillamine. This contrasted with the decrease of inorganic mercury levels in plasma.     

History of Inuit community exposure to lead, cadmium, and mercury in sewage lake sediments

Exposure to lead, cadmium, and mercury is known to be high in many arctic Inuit communities. These metals are emitted from industrial and urban sources, are distributed by long-range atmospheric transport to remote regions, and are found in Inuit country foods. Current community exposure to these metals can be measured in food, but feces and urine are also excellent indicators of total exposure from ingestion and inhalation because a high percentage of each metal is excreted. Bulk domestic sewage or its residue in a waste treatment system is a good substitute measure. Domestic waste treatment systems that accumulate metals in sediment provide an accurate historical record of changes in ingestion or inhalation. We collected sediment cores from an arctic lake used for facultative domestic sewage treatment to identify the history of community exposure to Pb, Cd, and Hg. Cores were dated and fluxes were measured for each metal. A nearby lake was sampled to measure combined background and atmospheric inputs, which were subtracted from sewage lake data. Pb, Cd, and Hg inputs from sewage grew rapidly after the onset of waste disposal in the late 1960s and exceeded the rate of population growth in the contributing community from 1970 to 1990. The daily per-person Pb input in 1990 (720,000 ng/person per day) exceeded the tolerable daily intake level. The Cd input (48,000 ng/person per day) and Hg input (19,000 ng/person per day) were below the respective TDI levels at the time.     

Effect of mercury vapour exposure on urinary excretion of calcium, zinc and copper: relationship to alterations in functional and structural integrity of the kidney

BACKGROUND: The kidney has a remarkable capacity to concentrate mercury (Hg) and as such is a primary target organ when exposure to Hg occurs, and it is also an organ for Hg excretion. OBJECTIVE: The present work aims to investigate the effect of occupational Hg vapour exposure on the urinary excretion of calcium (Ca), zinc (Zn) and copper (Cu), and the possible association of this excretion to work duration as well as renal alterations. METHODS: 83 non-smoker participants (36 referents, age: 35.6 +/- 9.5 years; 27 Hg vapour-exposed workers with < or = 10 years work duration, age: 33.0 +/- 5.1 years; and 20 Hg vapour-exposed workers with > or = 11 years work duration, age: 39.50 +/- 8.50 years) were included in the present study. Urinary levels of microalbumin (U-Malb) and retinol-binding protein (U-RBP) as well as cytosolic glutathione S-transferase activity (U-GST) were measured to assess the glomerular and proximal tubular reabsorption functions as well as structural integrity of proximal tubules; respectively. In addition, blood Hg (B-Hg), serum levels of Hg (S-Hg) and Ca (S-Ca), and urinary levels of Hg (U-Hg), Ca (U-Ca), Zn (U-Zn), Cu (U-Cu) and creatinine (U-cr) were estimated. RESULTS: In comparison to referents, all investigated parameters showed significant increase (except S-Ca and U-Zn/U-Cu ratio that significantly decreased among the workers as one group, S-Ca and U-Zn/U-Cu ratio that significantly and nonsignificantly decreased; respectively among workers with < or = 10 years work duration, S-Ca and U-Zn/U-Cu ratio that significantly decreased among workers with > or = 11 years work duration). In addition, B-Hg was nonsignificantly increased and S-Ca was significantly decreased; also, both U-Hg and U-Zn/U-Cu were nonsignificantly decreased among workers with > or = 11 years work duration in comparison to those with < or = 10 years work duration. Also, each of U-Hg, U-Ca, U-Zn and U-Cu was related to one another, while each of U-Ca, U-Zn and U-Cu was related to each of U-Malb, U-RBP and U-GST (except U-Zn was not related to U-GST). CONCLUSION: Hg vapour exposure leads to renal alterations which may parallel the change in proteinuria and enzymuria as well as the increased loss in urine of each of Ca, Zn and Cu. The urinary assessment of these metals may be used as a good indicator for renal dysfunction.     

非职业人群尿液中20种无机元素含量ICP-MS分析研究

目的:分析某矿区周围居民、非职业人群尿液中20种无机金属元素含量。方法:尿样经离心取上清液用纯水稀释,以电感耦合等离子体质谱(ICP-MS)定量分析Be、Ti、V、Cr、Mn、Co、Ni、Cu、Zn、As、Se、Sr、Mo、Ag、Cd、Sn、Sb、Ba、Tl、Pb。基体干扰以内标元素进行校正,以标准物质进行质量控制,所得结果进行比重校正。结果:检测方法回收率85%～108%,线性范围0μg/g～100μg/g(r>0.9999),RSD(n=5)<8%,对比分析406份对照尿样与928份调查尿样,结果表明该矿区周围居民、非职业人群体内大部分元素均有不同程度暴露蓄积,其中Be、As、Mo、Cd、Sb、Tl、Pb有毒元素的暴露蓄积更强。结论:该矿区周围居民、非职业人群有毒元素在人体内含量蓄积较其他元素大,ICP-MS检测方法应用于人尿中无机元素调查研究的定量分析,简便、快速、准确。     

Geographical and temporal differences in the urinary excretion of inorganic arsenic: a Belgian population study.

OBJECTIVE: This Belgian study assessed the geographical and temporal differences in the exposure of the population to inorganic arsenic, a known carcinogen. METHODS: In the CadmiBel study (1985-9) the 24 h urinary arsenic excretion was measured, as an index of recent exposure, in industrialised cities (Liège: n = 664, Charleroi: n = 291), in a rural control area (Hechtel-Eksel: n = 397), and in rural districts in which the population had possibly been exposed through the drinking water or the emissions of nonferrous smelters (Wezel: n = 93, Lommel: n = 111, and Pelt: n = 133). In the PheeCad study, in 1991-5, the rural areas (n = 609) were re-examined together with an urban control area (Leuven: n = 152). RESULTS: The CadmiBel results showed that after adjustment for sex, age, and body mass index, the 24 h arsenic excretion was on average low in Liège (91 nmol), Charleroi (155 nmol), Hechtel-Eksel (144 nmol), and Wezel (158 nmol), whereas the highest excretions were found in Lommel (570 nmol) and Pelt (373 nmol). During the PheeCad study, the mean 24 h arsenic excretion in the rural areas ranged from 81 to 111 nmol. This was lower than six years earlier and similar to the excretion in the control town (108 nmol). Longitudinal studies in 529 people living in the rural areas confirmed that their 24 h arsenic excretion had decreased (P < 0.001) from 222 to 100 nmol. As well as the drinking water, industry was likely to be a source of the increased exposure in Lommel and Pelt in 1985-9, because at that time the urinary arsenic excretion did not follow the regional differences in the arsenic content of the drinking water, because the fall in the arsenic excretion over time coincided with the implementation by industry of stricter environmental regulations, because in individual subjects the urinary arsenic excretion was inversely correlated with the distance to the nearest smelter, and because an increased arsenic excretion was only found downwind from the main smelter. The official network that monitors the arsenic concentration in airborne and fall out dust did not detect the high exposure in Lommel and Pelt between 1985 and 1989. CONCLUSION: This study highlights the necessity to validate environmental monitoring programmes by directly estimating the internal exposure of the population.     

Total mercury levels in hair, toenail, and urine among women free from occupational exposure and their relations to renal tubular function

To investigate the relations among total mercury levels in hair, toenail, and urine, together with potential effects of methylmercury intake on renal tubular function, we determined their levels, and urinary N-acetyl-beta-D-glucosaminidase activity (NAG) and alpha1-microglobulin (AMG) in 59 women free from occupational exposures, and estimated daily mercury intakes from fish and other seafood using a food frequency questionnaire. Mercury levels (mean+/-SD) in the women were 1.51+/-0.91 microg/g in hair, 0.59+/-0.32 microg/g in toenail, and 0.86+/-0.66 microg/g creatinine in urine; and, there were positive correlations among them (P<0.001). The daily mercury intake of 9.15+/-7.84 microg/day was significantly correlated with total mercury levels in hair, toenail, and urine (r=0.551, 0.537, and 0.604, P<0.001). Among the women, the NAG and AMG were positively correlated with both the daily mercury intake and mercury levels in hair, toenail, and urine (P<0.01); and, these relations were almost similar when using multiple regression analysis to adjust for possible confounders such as urinary cadmium (0.47+/-0.28 microg/g creatinine) and smoking status. In conclusion, mercury resulting from fish consumption can explain total mercury levels in hair, toenail, and urine to some degree (about 30%), partly through the degradation into the inorganic form, and it may confound the renal tubular effect of other nephrotoxic agents. Also, the following equation may be applicable to the population neither with dental amalgam fillings nor with occupational exposures: [hair mercury (microg/g)]=2.44x[toenail mercury (microg/g)].     

Uptake and excretion of inorganic mercury in the lobster Homarus gammarus (L.) White 1847: long-term effects of exposure to low levels of the metal

The uptake and accumulation of inorganic mercury by lobsters, from seawater containing levels of 10 to 100 ppb, was studied over periods of up to 50 days, using radiochemical neutron activation analysis. These results were amplified by the use of radioisotope tracer experiments. It was found that the gills and the green glands accumulated the most mercury and that the metal could be excreted via the urine. Histological studies showed that long-term exposure to mercury resulted in progressive necrosis of the green glands, whereas other organs were unaffected.     

Biological monitoring of dichloropropene: air concentrations, urinary metabolite, and renal enzyme excretion

Fifteen applicators of dichloropropene (DCP) were studied for personal air exposure to DCP, excretion of the metabolite of DCP (3CNAC), and excretion of the renal tubular enzyme, N-acetyl glucosaminidase (NAG). Each was studied for four 6-8 h consecutive intervals following baseline determinations of 3CNAC and NAG excretion. In accord with pilot data, 24-h urinary excretion of 3CNAC (mg) correlated well with exposure product for DCP (min exposed.mg/m3), r = 0.854, p less than .001. A more precise correlation of the air exposure product with urinary excretion of 3CNAC was discerned by using the morning urine after the previous day of exposure (micrograms/mg of creatinine), r = 0.914, p less than .001. Four workers had clinically elevated activity of NAG (greater than 4 mU/mg creatinine) in any of their urine collections after baseline. Nine workers showed greater than 25% increases in NAG excretion when compared to baseline. Dichloropropene air exposure products of greater than 700 mg.min/m3 or excretion of greater than 1.5 mg 3CNAC/d distinguished abnormally high daily excretion of NAG. These data demonstrate a firm positive relationship between air exposure and internal exposure, and a possible subclinical nephrotoxic effect in DCP workers.     

The prevalence of subjective symptoms after exposure to arsenic in drinking water in Inner Mongolia,China

BACKGROUND: In Inner Mongolia, China, more than 300,000 people are chronically exposed to arsenic via their drinking water. We have previously reported that the prevalence of arsenical dermatosis was as high as 40% in the Hetao Plain area. However, the association between exposure to arsenic in drinking water and adverse health effects has not been fully examined. The purpose of this study was to examine the association between exposure to arsenic and prevalence of subjective symptoms. METHODS: A cross-sectional study was carried out in 431 residents of an arsenic-affected village and 189 residents of an arsenic-free village in 1996. Health-related interviews and physical examinations were conducted. The odds ratio for each subjective symptom was estimated, comparing residents of arsenic-free and affected villages. RESULTS: An arsenic level of 50+ microg/L was found in 90.6% of wells in the arsenic-affected village. Adjusted odds ratios of subjective symptoms, including coughs (odds ratio [OR] = 12.8, 95% confidence interval [CI]: 6.4-25.6), stomachaches (OR = 5.8, 95% CI: 3.6-9.4), palpitations (OR = 3.6, 95% CI: 1.5-8.2), urination problems (OR = 14.7, 95% CI: 3.3-65.5) and spontaneous abortions (OR = 2.7, 95% CI: 0.8-8.4), were markedly higher amongst residents of the arsenic-affected village, including those without arsenic dermatosis. CONCLUSIONS: The present study shows a high prevalence of subjective symptoms amongst residents of an arsenic-affected village. Symptoms occurred in people with and without arsenic dermatosis. Our findings suggest that symptoms other than dermatosis should be considered when a clinical diagnosis of arsenic toxicosis is made.     

Female reproductive health in two lamp factories: effects of exposure to inorganic mercury vapour and stress factors

To evaluate the possible influence of mercury vapour on female reproduction, 153 women working in a mercury vapour lamp factory have been compared with 193 women employed in another factory of the same company, where mercury was not used. Both groups of subjects were exposed to stress factors (noise, rhythms of production, and shift work). The production process has been analysed by inspection of the plants and by collective discussions with "homogeneous groups" of workers; a retrospective inquiry into work history and reproductive health events has been subsequently performed by an individual interview. Women exposed to mercury vapour currently not exceeding the time weighted average air concentration of 0.01 mg/m3 declared higher prevalence and incidence rates of menstrual disorders, primary subfecundity, and adverse pregnancy outcome; however, the progression of these problems with the level of exposure to mercury inside the same factory was not always clear. The results of this study neither prove nor exclude the possibility that occupational exposure to this concentration of mercury has a negative effect on female reproduction.     

Cadmium, mercury, and lead in kidney cortex of living kidney donors: Impact of different exposure sources,

Background

Most current knowledge on kidney concentrations of nephrotoxic metals like cadmium (Cd), mercury (Hg), or lead (Pb) comes from autopsy studies. Assessment of metal concentrations in kidney biopsies from living subjects can be combined with information about exposure sources like smoking, diet, and occupation supplied by the biopsied subjects themselves.

Objectives

To determine kidney concentrations of Cd, Hg, and Pb in living kidney donors, and assess associations with common exposure sources and background factors.

Methods

Metal concentrations were determined in 109 living kidney donors aged 24-70 years (median 51), using inductively coupled plasma-mass spectrometry (Cd and Pb) and cold vapor atomic fluorescence spectrometry (Hg). Smoking habits, occupation, dental amalgam, fish consumption, and iron stores were evaluated.

Results

The median kidney concentrations were 12.9 μg/g (wet weight) for cadmium, 0.21 μg/g for mercury, and 0.08 μg/g for lead. Kidney Cd increased by 3.9 μg/g for a 10 year increase in age, and by 3.7 μg/g for an extra 10 pack-years of smoking. Levels in non-smokers were similar to those found in the 1970s. Low iron stores (low serum ferritin) in women increased kidney Cd by 4.5 μg/g. Kidney Hg increased by 6% for every additional amalgam surface, but was not associated with fish consumption. Lead was unaffected by the background factors surveyed.

Conclusions

In Sweden, kidney Cd levels have decreased due to less smoking, while the impact of diet seems unchanged. Dental amalgam is the main determinant of kidney Hg. Kidney Pb levels are very low due to decreased exposure.     

Risks of developing cancer relative to living near a municipal solid waste landfill site in Montreal, Quebec, Canada.

In this study, we sought to determine whether men who lived near the Miron Quarry municipal solid waste landfill site in Montreal, Quebec, Canada, were at higher risk for developing cancer than individuals who lived at more remote locations. Subjects were selected from a previously completed population-based, interview, cancer case-control study of men who lived in metropolitan Montreal. Thirteen sites of cancer (n = 2 928 subjects) and a population-based control group (n = 417) were analyzed. We used the exact street address at the time of diagnosis to classify subjects by geographic zones and distance from the site. We used unconditional logistic regression to estimate odds ratios (ORs) and associated 95% confidence intervals (CIs) for each site of cancer, adjusted for key covariates. In the exposure zone nearest to the site, elevated risks were found for cancers of the pancreas (adjusted OR = 1.4 [95% CI = 0.8, 2.6]); liver (OR = 1.8 [95% CI = 0.8, 4.3]); and prostate (OR = 1.5 [95% CI = 1.0, 2.1]). A high risk was also found for pancreatic cancer (OR = 1.7 [95% CI = 0.9, 3.5]) and the non-Hodgkin's lymphomas (OR = 1.5 [95% CI = 0.8, 2.6]) in a subexposure zone approximately downwind from the site. We used distance from the site as another exposure metric, and higher-than-expected risks were found for pancreatic cancer (OR for living within 1.25 km of the site [OR<1.25km] = 2.2 [95% CI = 1.0, 4.6]); liver cancer (OR<1.5km = 2.1 [95% CI = 0.8, 5.3]); kidney cancer (OR<2 km = 1.4 [95% CI = 0.9, 2.3]); and the non-Hodgkin's lymphomas (OR<1km = 2.0 [95% CI = 1.0, 4.0]). Data from this study and from a previous investigation at the same site suggest that men who lived near this landfill site may have been-and may continue to be-at excess risk of cancers of the liver, kidney, pancreas, and non-Hodgkin's lymphomas.