Infants and mothers levels of mercury in breast milk, urine and hair, data from an artisanal and small-scale gold mining area in Kadoma / Zimbabwe.

In Kadoma (Zimbabwe) gold is extracted from ore based on a simple technology using mercury. Women are exposed whilst living in an exposed area, or even more working directly with mercury. Breast fed infants are exposed via mercury contaminated milk and the general environmental mercury exposure. The aim of the study was to measure infants and mothers levels of mercury in urine and hair, as well as in breast milk. In 2006, an environmental epidemiological field study with 120 mother - child pairs was conducted. A non exposed control group (n = 42) was compared with a medium exposed group (n = 51) and a high exposed group (occupational exposure, n = 27). Urine and hair samples from mother and infants plus breast milk samples were analyzed for total mercury. 120 breast milk samples were analyzed, median (maximum) concentrations [µg Hg/l] were (i) control group < 0.50 (1.55), (ii) medium exposed group 1.10 (10.48), (iii) high exposed group 1.20 (24.80) (p < 0,001). Urine and hair results were distributed similarly for infants and mothers, with higher levels according to the exposure subgroup. All specimen results correlated very well with another, indicating there is a pathway between breast milk and infant's level of mercury. The daily uptake of mercury via breast milk was calculated. The reference dose of 0.3°[µg Hg/kg BW/d] was used to compare the burden of the infants. No infant from the control group, but 17.6% of the medium and 18.5% of the high exposed group were above the reference dose. Mercury in breast milk is generally higher in artisanal and small scale gold mining areas. Breast fed infants were burdened with toxic mercury via breast milk and via the general environment, both are important public health issues.

Signs and symptoms of mercury-exposed gold miners.

OBJECTIVES: Gold miners use mercury to extract gold from ore adding liquid mercury to the milled gold-containing ore. This results in a mercury-gold compound, called amalgam. Miners smelt this amalgam to obtain gold, vaporizing it and finally inhaling the toxic mercury fumes. The objective was to merge and analyze data from different projects, to identify typical signs and symptoms of chronic inorganic mercury exposure. MATERIAL AND METHODS: Miners and community members from various artisanal small-scale gold mining areas had been examined (Philippines, Mongolia, Tanzania, Zimbabwe, Indonesia). Data of several health assessments were pooled. Urine, blood and hair samples were analyzed for mercury (N = 1252). Questionnaires, standardized medical examinations and neuropsychological tests were used. Participants were grouped into: Controls (N = 209), living in an exposed area (N = 408), working with mercury as panners (N = 181), working with mercury as amalgam burners (N = 454). Chi2 test, linear trend test, Mann-Whitney test, Kruskal-Wallis test, correlation coefficient, Spearman's rho, and analysis of variance tests were used. An algorithm was used to define participants with chronic mercury intoxication. RESULTS: Mean mercury concentrations in all exposed subgroups were elevated and above threshold limits, with amalgam burners showing highest levels. Typical symptoms of chronic metallic mercury intoxication were tremor, ataxia, coordination problems, excessive salivation and metallic taste. Participants from the exposed groups showed poorer results in different neuropsychological tests in comparison to the control group. Fifty-four percent of the high-exposed group (amalgam burners) were diagnosed as being mercury-intoxicated, compared to 0% within the control group (Chi2 p < 0.001). CONCLUSIONS: Chronic mercury intoxication, with tremor, ataxia and other neurological symptoms together with a raised body burden of mercury was clinically diagnosed in exposed people in artisanal small-scale mining areas. The mercury exposure needs to be urgently reduced. Health care systems need to be prepared for this emerging problem of chronic mercury intoxication among exposed people. Int J Occup Med Environ Health 2017;30(2):249-269.

The burden of chronic mercury intoxication in artisanal small-scale gold mining in Zimbabwe: data availability and preliminary estimates.

BACKGROUND: Artisanal small-scale gold mining (ASGM) is a poverty-driven activity practiced in over 70 countries worldwide. Zimbabwe is amongst the top ten countries using large quantities of mercury to extract gold from ore. This analysis was performed to check data availability and derive a preliminary estimate of disability-adjusted life years (DALYs) due to mercury use in ASGM in Zimbabwe. METHODS: Cases of chronic mercury intoxication were identified following an algorithm using mercury-related health effects and mercury in human specimens. The sample prevalence amongst miners and controls (surveyed by the United Nations Industrial Development Organization in 2004 and the University of Munich in 2006) was determined and extrapolated to the entire population of Zimbabwe. Further epidemiological and demographic data were taken from the literature and missing data modeled with DisMod II to quantify DALYs using the methods from the Global Burden of Disease (GBD) 2004 update published by the World Health Organization (WHO). While there was no disability weight (DW) available indicating the relative disease severity of chronic mercury intoxication, the DW of a comparable disease was assigned by following the criteria 1) chronic condition, 2) triggered by a substance, and 3) causing similar health symptoms. RESULTS: Miners showed a sample prevalence of 72% while controls showed no cases of chronic mercury intoxication. Data availability is very limited why it was necessary to model data and make assumptions about the number of exposed population, the definition of chronic mercury intoxication, DW, and epidemiology. If these assumptions hold, the extrapolation would result in around 95,400 DALYs in Zimbabwe's total population in 2004. CONCLUSIONS: This analysis provides a preliminary quantification of the mercury-related health burden from ASGM based on the limited data available. If the determined assumptions hold, chronic mercury intoxication is likely to have been one of the top 20 hazards for population health in Zimbabwe in 2004 when comparing with more than 130 categories of diseases and injuries quantified in the WHO's GBD 2004 update. Improving data quality would allow more accurate estimates. However, the results highlight the need to reduce a burden which could be entirely avoided.

Polymorphisms in genes encoding potential mercury transporters and urine mercury concentrations in populations exposed to mercury vapor from gold mining.

BACKGROUND: Elemental mercury (Hg0) is widely used in small-scale gold mining. Persons working or living in mining areas have high urinary concentrations of Hg (U-Hg). Differences in genes encoding potential Hg-transporters may affect uptake and elimination of Hg. OBJECTIVE: We aimed to identify single nucleotide polymorphisms (SNPs) in Hg-transporter genes that modify U-Hg. METHODS: Men and women (1,017) from Indonesia, the Philippines, Tanzania, and Zimbabwe were classified either as controls (no Hg exposure from gold mining) or as having low (living in a gold-mining area) or high exposure (working as gold miners). U-Hg was analyzed by cold-vapor atomic absorption spectrometry. Eighteen SNPs in eight Hg-transporter genes were analyzed. RESULTS: U-Hg concentrations were higher among ABCC2/MRP2 rs1885301 A-allele carriers than among GG homozygotes in all populations, though differences were not statistically significant in most cases. MRP2 SNPs showed particularly strong associations with U-Hg in the subgroup with highest exposure (miners in Zimbabwe), whereas rs1885301 A-allele carriers had higher U-Hg than GG homozygotes [geometric mean (GM): 36.4 µg/g creatinine vs. 21.9; p = 0.027], rs2273697 GG homozygotes had higher U-Hg than A-allele carriers (GM: 37.4 vs. 16.7; p = 0.001), and rs717620 A-allele carriers had higher U-Hg than GG homozygotes (GM: 83 vs. 28; p = 0.084). The SLC7A5/LAT1 rs33916661 GG genotype was associated with higher U-Hg in all populations (statistically significant for all Tanzanians combined). SNPs in SLC22A6/OAT1 (rs4149170) and SLC22A8/OAT3 (rs4149182) were associated with U-Hg mainly in the Tanzanian study groups. CONCLUSIONS: SNPs in putative Hg-transporter genes may influence U-Hg concentrations.

Applicability of two mobile analysers for mercury in urine in small-scale gold mining areas.

Mercury is still used in developing countries to extract gold from the ore in small-scale gold mining areas. This is a major health hazard for people living in mining areas. The concentration of mercury in urine was analysed in different mining areas in Zimbabwe, Indonesia and Tanzania. First the urine samples were analysed by CV-AAS (cold vapour atomic absorption spectrometry) during the field projects with a mobile mercury analyser (Lumex(®) or Seefelder(®)) and secondly, in a laboratory with a stationary CV-AAS mercury analyser (PerkinElmer(®)). Caused by the different systems (reduction agent either SnCl(2) (Lumex(®) or Seefelder(®))) or NaBH(4) (PerkinElmer(®)), with the mobile analysers only the inorganic mercury was obtained and with the stationary system the total mercury concentration was measured. The aims of the study were whether the results obtained in field with the mobile equipments can be compared with the stationary reference method in the laboratory and allow the application of these mobile analysers in screening studies on concerned populations to select those, who are exposed to critical mercury levels. Overall, the concentrations obtained with the two mobile systems were approximately 25% lower than determined with the stationary system. Nevertheless, both mobile systems seem to be very useful for screening of volunteers in field. Moreover, regional staff may be trained on such analysers to perform screening tests by themselves.

Mercury exposure in female artisanal small-scale gold miners (ASGM) in Mongolia: An analysis of human biomonitoring (HBM) data from 2008.

BACKGROUND: Many poor in developing countries have turned to artisanal small-scale gold mining (ASGM) in an attempt to improve their situation. However, the mercury used to extract gold from ore is discharged in vaporized form into the environment, where it poses a hazard for human health. METHODS: As part of an environmental epidemiological study in Mongolia-to evaluate the burden of environmental mercury contamination-urine, blood and hair samples were collected from residents of areas with or without mercury contamination. A total of 200 blood, urine and hair samples were analyzed for mercury and divided into three subgroups according to mercury content: (1) occupational exposure (high/medium); (2) environmental exposure (low); and (3) no exposure. Internal mercury distributions of the subgroups were compared using the Kruskal-Wallis and Mann-Whitney U-test. The Chi-square test and likelihood ratio proportion were used to compare the findings with threshold limits. RESULTS: The highest values and greatest differences were seen in the urine samples (p<0.001, Kruskal-Wallis). The occupational group showing the highest exposure with a median mercury level of 4.36µg/l (control group: 0.10µg/l, p<0.001), 7.18µg/g creatinine and 12 results above the threshold limit HBM I (Human Biomonitoring I). Even participants from the low-exposure subgroup showed elevated mercury levels (median 2.88µg/l urine and 2.98µg/g creatinine, p<0.001), with 10 individuals above the HBM I threshold limits. DISCUSSION: The body burden resulting from the use of mercury in artisanal gold mining is high not only in the miners themselves, an increased mercury hazard was also found for inhabitants of mining areas who were not actively involved in mining. Public health support measures are urgently needed to alleviate the situation.

Selenium and cadmium levels and ratios in prostates, livers, and kidneys of nonsmokers and smokers.

Cadmium (Cd) from cigarette smoke, environmental, and nutritional sources accumulates in the human prostate where it interacts with selenium (Se) in a manner suggesting the formation of a 1:1 Cd-Se-protein complex. At low Cd exposures and adequate Se status, this interaction may be beneficial as it results in the detoxification of Cd. At higher exposures, Cd may weaken or abolish the anticarcinogenic effects of Se and increase prostate cancer risk. In some older men and especially in smokers, Cd levels in prostates reach levels in stoichiometric excess over Se, which may be the reason why heavy smokers are at higher risk of developing lethal forms of prostate cancer. In the liver and the kidneys, Cd accumulates as well, but in these organs, Cd is efficiently sequestered through metallothionein formation. In the prostate, this mode of detoxification is not available or less efficient, causing Cd to interact with Se and to increase prostate cancer risk.

Health assessment of artisanal gold miners in Indonesia.

Small scale miners use mercury to extract gold from ore in many countries. An environmental and health assessment was performed in Indonesia in two regions, Galangan in Central Kalimantan and Talawaan in Northern Sulawesi. The environmental assessment showed severe mercury contamination of the sediments, and increased mercury levels in local fish. For the health investigation 281 volunteers were recruited and examined by a standardized questionnaire, a neurological examination and neuro-psychological tests. A medical score was used consisting of significant factors of mercury intoxication. Mercury exposed workers showed typical symptoms of mercury intoxication, such as movement disorders (ataxia, tremor, dysdiadochokinesia, etc.). Blood, urine and hair samples were taken from any participant and analyzed for mercury. The mercury concentration in the biomonitors was high, partly extreme high in the working population, increased in the population living in the same habitat and low in the control group. By a standard protocol which includes a combination of threshold values of mercury in the biomonitors and a medical sum score the diagnosis of chronic mercury intoxication was made for highly burdened workers (amalgam smelters) in 55% in Sulawesi and in 62% in Kalimantan. Less exposed mineral processors and the general population in the mining areas were also intoxicated to a high percentage.

Health assessment of artisanal gold miners in Tanzania.

In 2003 UNIDO (United Nations Industrial Development Organization) conducted an environmental and health assessment in a small-scale mining area in Tanzania. BGS (British Geological Survey) performed the environmental assessment. The Institute of Forensic Medicine - University of Munich performed the health assessment. The results of the medical, neurological and neuro-psychological examination of 180 participants from the affected area of Rwamagasa and 31 controls were analyzed. Urine, blood and hair samples were analyzed to detect the level of mercury body burden. Mercury concentrations in the bio-monitors urine, blood and hair were statistically significantly higher in the exposed population from Rwamagasa compared to the control group from Katoro. Only amalgam burners showed mercury levels above the toxicological threshold limits. A speciation of mercury in hair indicated that mainly elemental mercury vapor contributed to the high body burden of the artisanal miners. 104 amalgam-burners, the most exposed population group, were examined. 25 of these workers were found to be intoxicated. Small-scale mining is a serious health hazard for amalgam burners. Reduction of the exposure is essential to prevent further damage.

Mercury as a serious health hazard for children in gold mining areas.

In many developing countries, mercury is used to extract gold from ore in small-scale mining areas. Exposure through mercury in these small-scale mining communities is a serious health hazard, especially to the children living and working there. Many children begin working with immediate contact to mercury from the very early age of seven. In Indonesia and Zimbabwe, 166 children were clinically examined for mercury. The mercury concentration in the blood, urine, and hair was analyzed. Compared to the control groups, the exposed children showed typical symptoms of mercury intoxication, such as ataxia. The children working with mercury had high levels of this substance in the various biomonitors. The exposure derives mainly from the liquid mercury used to bind gold, forming an amalgam. The amalgam is heated and the smelting amalgam releases mercury vapor plus the wanted gold. Mercury vapor in contrast to liquid mercury is highly toxic. This elemental, vaporized mercury is the main form of exposure. Since in over 50 countries children live in small-scale gold mining areas and are exposed in a similar way to mercury, immediate action is needed to reduce this severe chemical health hazard for children. Child labor with hazardous substances such as mercury must be stopped.

Mercury in breast milk - a health hazard for infants in gold mining areas?

Breast-feeding can be a source of mercury exposure for infants. The main concern up to now is methyl-mercury exposure of women at child-bearing age. Certain fish species have high levels of methyl-mercury leading to consumer's advisory guidelines in regard of fish consumption to protect infants from mercury exposure passing through breast milk. Little is known about the transfer of inorganic mercury passing through breast milk to infants. Epidemiological studies showed negative health effects of inorganic mercury in gold mining areas. Small-scale gold miners use mercury to extract the gold from the ore. Environmental and health assessments of gold mining areas in Indonesia, Tanzania and Zimbabwe showed a high exposure with inorganic mercury in these gold mining areas, and a negative health impact of the exposure to the miners and the communities. This paper reports about the analysis and the results of 46 breast milk samples collected from mercury-exposed mothers. The median level of 1.87mug/l is fairly high compared to other results from literature. Some breast milk samples showed very high levels of mercury (up to 149mug/l). Fourteen of the 46 breast milk samples exceed 4mug/l which is considered to be a "high" level. US EPA recommends a "Reference Dose" of 0.3mug inorganic mercury/kg body weight/day [United States Environmental Protection Agency, 1997. Volume V: Health Effects of Mercury and Mercury Compounds. Study Report EPA-452/R-97-007: US EPA]. Twenty-two of the 46 children from these gold mining areas had a higher calculated total mercury uptake. The highest calculated daily mercury uptake of 127mug exceeds by far the recommended maximum uptake of inorganic mercury. Further systematic research of mercury in breast milk from small-scale gold mining areas is needed to increase the knowledge about the bio-transfer of mercury from mercury vapour-exposed mothers passing through breast milk to the breast-fed infant.

Frequency of different anti-depressants associated with suicides and drug deaths.

From each case of suicide and drug-related death autopsied in the Institute of Forensic Medicine, Munich during the years 2001--2005, a toxicological investigation on anti-depressants (AD) was performed. In 180 suicides and 72 narcotic drug death cases, ADs were detected: 4 different classic tricyclic anti-depressants (TCAs), 6 other non-selective monoamine re-uptake inhibitors (NSMRIs), 5 selective serotonin re-uptake inhibitors (SSRIs) and 3 other ADs. The suicides were grouped further according to the type of suicide (violent or non-violent). The prescription frequency of the ADs in Germany, expressed as the defined daily dosages (DDDs), during the investigated years served for comparison. There were serious differences in the frequency of different ADs regarding to the manner of suicide. In cases associated with doxepin and trimipramine, non-violent suicides were distinctly over-represented, as in cases in which the drug itself was responsible for the death as in cases of non-violent suicides in other manners. In contrast, in cases with citalopram or opipramol, violent forms of suicides were significantly over-represented. For amitriptyline, the ratio was approximately balanced. For the remainder of the ADs, the case numbers were too low for a valid evaluation. The different frequency distributions of the ADs, associated with violent and non-violent suicides may be explained by their different pharmacological active profiles and the different lethality of overdoses of the different ADs. There was no indication at all for a special suicidal problem of SSRIs in juveniles. Amongst 1,127 suicides within 5 years, in an area with approximately 5 million people, the youngest suicide victim with SSRIs was 28 years old. In drug death cases, citalopram was obviously over-represented.

Increase of renal excretion of organo-mercury compounds like methlymercury by DMPS (2,3-Dimercapto-1-propanesulfonic acid, Dimaval).

In a highly mercury-burdened, small scale gold mining area in the Philippines, spontaneous urine samples were taken from 75 Hg intoxicated volunteers before (U1), and 2-3 hours after (U2) the oral application of 200 mg DMPS (2,3-Dimercapto-1-propanesulfonic acid, Dimaval). In the urine samples, the concentrations of organic and inorganic bound mercury were determined separately by CV-AAS. In U1, median concentrations of 15.7 microg inorganic Hg/g crea. and 2.2 microg organic Hg/g crea. were found. In U2, these values increased to 262 for inorganic Hg and 14.5 for organic Hg. Maximum concentrations (microg/g crea.) as high as 7,593 for inorganic Hg and 2,011 for organic Hg were observed after DMPS. The mean (median) increasing factor (U2/U1) was 16.0 for inorganic Hg and 5.1 for organic Hg. There was a trend that females responded better to DMPS than males. It was concluded that DMPS increases the renal excretion of organic bound Hg as it does for inorganic Hg, but to a lesser extent.

Neither DMPS nor DMSA is effective in quantitative elimination of elemental mercury after intentional IV injection.

BACKGROUND: Intravenous injection of elemental mercury (Hg) is rare and considered relatively harmless. Treatment recommendations vary and the effectiveness of chelation therapy is controversial. CASE REPORT: A 27-year-old man intravenously injected 1.5 mL of elemental Hg. Within 12 hours he became febrile, tachycardic and dyspneic. Physical examination was unremarkable. X-rays showed scattered radiodense deposits in the lung, heart, intestinal wall, liver and kidney. The serum Hg level on admission was 172 microg/L and peaked on day 6 at 274 microg/L. Cumulative renal elimination during a five day oral treatment period with 2,3-dimercaptopropane-1-sulfonate (DMPS) and meso-2,3-dimercaptosuccinic acid (DMSA) was 8 mg and 3 mg, respectively. CONCLUSION: Although urinary excretion could be enhanced during chelation therapy, Hg deposits in organs resulted in negligible elimination of mercury compared to the exposed dose.

Selenium/cadmium ratios in human prostates: indicators of prostate cancer risk of smokers and nonsmokers, and relevance to the cancer protective effects of selenium.

Selenium (Se) in a large-scale human supplementation trial has been shown to significantly reduce the incidence of prostate cancer in elderly men. Because Se is known to interact with cadmium (Cd), it has been suggested that its cancer protective action could be attributable in part to its interaction with Cd, a toxic and suspected carcinogenic element, which is found in many foods, in drinking water, and in the environment. Cadmium is considered a significant prostate cancer risk factor as it stimulates the growth of prostate epithelial cells and promotes their malignant transformation. Accordingly, prostate cancer risk is determined not only by Se status, but also the degree of Cd exposure. Determinations of Se and Cd in 129 prostates of deceased men aged 15-99 yr revealed Cd to accumulate in the prostate. Whereas the atomic Se/Cd ratios of the prostates of young men were invariably >1, indicating a stoichiometric excess of Se over Cd, they were found to decline with age, approaching the 1:1 ratio in elderly nonsmokers, a fact suggestive of the formation of a 1:1 Cd-Se complex. The associated physiological inactivation of Se could account for the increase of the prostate cancer risk with advancing age. The Se/Cd ratios dropped more steeply and consistently with age in smokers than in nonsmokers. In the prostates of some smokers, Se/Cd ratios even reached values <1, indicating a stoichiometric excess of Cd over Se. The excessive accumulation of Cd in the prostates of smokers along with sub-optimal Se intakes could explain why smokers develop more aggressive and lethal forms of prostate cancer than nonsmokers.

Assessment of hair mineral analysis commercially offered in Germany.

To evaluate intra- and inter-laboratory agreement concerning hair mineral analysis and interpretation of results, hair samples from 2 volunteers were sent to seven laboratories, which commercially offer hair mineral analysis in Germany. 6 weeks later, another identical part from the hair sample of volunteer 1 was sent to all seven labs. Altogether, 50 elements were analyzed, 23 by all seven labs. For comparability, only the results for these 23 elements were assessed. The intra-laboratory reproducibility was evaluated by the 2 identical hair samples from volunteer 1. On the average, the reproducibility seems to be sufficient (median +/- 9.48% to +/- 20.59%), but for individual elements there were unacceptable out-rulers up to 100%. Only one lab classified all elements of the first and the second analysis of the identical hair sample in the same category (below, within, or above normal range). The others grouped 4 to 7 elements different. This is not tolerable. The inter-laboratory comparability was assessed by the results of the hair samples of both volunteers. For the sample of volunteer 1 at least the results of 6 (out of 23) elements were within an acceptable range of +/- 30% from the consensus value (= mean of all seven labs). For volunteer 2 this was only the case for 2 (!) elements. Differences of more than 100% were found for most other elements. Moreover, in the vast majority of the tested elements there was no comparability of the cLassification to the respective reference ranges of the different laboratories. For example, for volunteer 1 only 3 elements (our of 23!) were identically classified by all seven labs. As neither the analytical results nor the classification to the individual reference ranges by the laboratories correspond in tolerable borders, conclusions, drawn from these results, cannot be valid. Hair mineral analysis from these laboratories is unreliable. Therefore we must recommend to refrain from using such analysis to assess individual nutritional status or suspected environmental exposure.