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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., (Copyright 2009 Elsevier B.V. All rights reserved.)

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., (Copyright 2009 Elsevier B.V. All rights reserved.)

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.

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.

Ninty-five inhabitants of the gold mining area of Mt. Diwata (on Mindanao, Philippines), who were diagnosed to be mercury (Hg) intoxicated, were orally treated with 2 x 200 mg of the chelating agent DMPS (Dimaval, Co. Heyl, Germany) for 14 days in the course of a UNIDO project focusing on mercury pollution abatement. Blood and urine samples before and after treatment, urine after the first application of DMPS and a hair sample were collected and analyzed for Hg. Before and after treatment extensive anamnestic data were collected, medical and neurological investigations and some neuro-psychological tests were performed. In spite of the short time of treatment most of the patients reported a marked improvement of the complaints which were stated by them before the therapy and which are characteristic for a chronic Hg intoxication, for example tremor, loss of memory, sleeplessness, metallic taste, etc. But even in some of the objective neurological parameters like hypo-mimia, Romberg test and tests for tremor/ataxia a statistical significant improvement could be found. Significant improvements could also be found in two neuro-psychological tests (pencil tapping and Frostig). In some cases an extreme high urinary Hg excretion was found under the chelating therapy with DMPS, and by this a distinct reduction of the Hg body burden. Nevertheless, in most cases Hg in blood and urine was not markedly decreased by the treatment. This shows that the duration of the treatment (14 days) was not sufficient for a permanent decrease in Hg. As DMPS excretes Hg mainly through the kidney, it can be concluded that in most cases even after 14 days of treatment there was an ongoing redistribution of Hg from other tissues to the kidney. In conclusion, this study proves that a chelating therapy with DMPS is highly effective even in the case of a mixed chronic and acute intoxication with an unknown combination of Hg vapor, inorganic Hg and organic Hg=methylmercury (MeHg), as characteristic for gold mining areas in the third world. Adverse side effects were rarely reported. Only in one case the medication had to be terminated after the first application due to an allergic skin reaction.

The region of Diwalwal, dominated by Mt. Diwata, is a gold rush area on Mindanao (Philippines) where approximately 15000 people live. The fertile plain of Monkayo is situated downstream, where people grow crops such as rice and bananas; locally caught fish is eaten frequently. The ore is dug in small-scale mines and ground to a powder by ball-mills while still in Diwalwal. The gold is then extracted by adding liquid mercury (Hg), forming gold-amalgam. To separate the gold from the Hg, in most cases the amalgam is simply heated in the open by blow-torches. A high external Hg burden of the local population must be assumed. To evaluate the internal Hg burden of the population and the extent of possible negative health effects, 323 volunteers from Mt. Diwalwal, Monkayo and a control group from Davao were examined by a questionnaire, neurological examination and neuro-psychological testing. Blood, urine and hair samples were taken from each participant and analyzed for total Hg. A statistical evaluation was possible for 102 workers (occupationally Hg burdened ball-millers and amalgam-smelters), 63 other inhabitants from Mt. Diwata ('only' exposed from the environment), 100 persons, living downstream in Monkayo, and 42 inhabitants of Davao (serving as controls). The large volume of data was reduced to yes/no decisions. Alcohol as a possible bias factor was excluded (level of alcohol consumption and type, see Section 4.4). Each factor with a statistically significant difference of at least one exposed group to the control group was included in a medical score (0-21 points). In each of the exposed groups this score was significantly worse than in the control group (median control, 3; downstream, 9; Mt. Diwata, non-occupational exposed, 6; Hg workers, 10). In comparison to the surprisingly high Hg concentration in blood (median, 9.0 microg/l; max, 31.3) and in hair (2.65 microg/g; max, 34.7) of the control group, only the workers show elevated levels: Hg-blood median 11.4, max 107.6; Hg-hair median 3.62, max 37.8. The Hg urine concentrations of the occupational exposed and non-exposed population on Mt. Diwata was significantly higher than in the control group: control median 1.7 microg/l, max 7.6; non-occupational burdened median 4.1, max 76.4; and workers median 11.0, max 294.2. The participants, living downstream on the plain of Monkayo show no statistically significant difference in Hg-blood, Hg-urine or Hg-hair in comparison with the control group. The German Human-Biological-Monitoring value II (HBM II) was exceeded in 19.5% (control), 26.0% (downstream), 19.4% (Mt. Diwata, non-occupational) and 55.4% (workers) of the cases, the German occupational threshold limit in 19.6% of the workers. Only some of the clinical data, characteristic for Hg intoxication (e.g. tremor, loss of memory, bluish discoloration of the gingiva, etc.), correlate with Hg in blood or urine, but not with Hg in hair. The medical score sum correlates only with Hg in urine. The poor correlation between the Hg concentration in the biomonitors to classic clinical signs of chronic Hg intoxication may be explained by several factors: Hg in blood, urine and hair do not adequately monitor the Hg burden of the target tissues, especially the brain. Inter-individual differences in the sensitiveness to Hg are extremely large. In this area a mixed burden of Hg species must be assumed (Hg vapor, inorganic Hg, methyl-Hg). Chronic Hg burden may have established damage months or even years before the actual determination of the Hg concentrations in the bio-monitors under quite different burden was performed (Drasch G. Mercury. In: Seiler HG, Sigel A, Sigel H, editors. Handbook on metals in clinical and analytical chemistry. New York: Marcel Dekker, 1994:479-494). Therefore, a 'Hg intoxication', that should be treated, was not diagnosed by the Hg concentration in the bio-monitors alone, but by a balanced combination of these Hg values and the medical score sum. In principle, this means the higher the Hg concentration in the bio-monitors, the lower the number of characteristic adverse effects are required for a positive diagnosis. By this method, 0% of the controls, 38% downstream, 27% from Mt. Diwata, non-occupational exposed and 71.6% of the workers were classified as Hg intoxicated. A reduction of the external Hg burden on Mt. Diwata is urgently recommended. An attempt to treat the intoxicated participants with the chelating agent dimercaptopropanesulfonic acid (DMPS) is planned.