1998 Fiscal Year Final Research Report Summary
Study on Mercury Pollution in The Amazonia, Brazil
| Project/Area Number |
08041121
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Field Research |
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| Research Field |
環境影響評価(含放射線生物学)
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| Research Institution | Yokohama National University |
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Principal Investigator |
NAKANISHI Junko Yokohama National University, Institute of Environmental Science and Technology, Professor, 環境科学研究センター, 教授 (10010836)
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| Co-Investigator(Kenkyū-buntansha) |
OWARI Masanori Environmental Science Center, The University of Tokyo, Assistant Professor, 環境安全研究センター, 助教授 (70160950)
OIKAWA Teiichi Universidade federal do Para, Nucleo de Medicina Tropical, Assistant Professor, 熱帯医学研究センター, 助教授
DA Costa Man パラ連邦大学, 熱帯医学研究センター, 助教授
DA Conceicao パラ連邦大学, 熱帯医学研究センター, 教授
HARADA Masazumi Kumamoto University, School of Medicine, Assistant Professor, 医学部, 助教授 (00040519)
MANOEL Quaresma da Costa Universidade federal do Para, Nucleo de Medicina Tropical, Assistant Professor
SILVA PINHEIRO Maria da Universidade federal do Para, Nucleo de Medicina Tropical, Professor
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| Project Period (FY) |
1996 – 1998
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| Keywords | Amazon / Mercury Pollution / Methyl Mercury Poisoning / Risk Assessment / Health Effect |
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| Research Abstract |
The adverse effect of mercury pollution on human health in the Amazon was carried out between 1992 and 1998 as a joint project with Nucleo de Medicina Tropical, Universidade Federal do Para. The mercury level of human hair was measured to estimate the risks of human health and the symptom of methylmercury poisoning was clinically diagnosed at same time. The main area for the investigation were the three fishing villages by the middle reaches of Tapajos river of a tributary in the Amazon. Some other fishing villages, the gold mining sites and cities were investigated for the comparison. From the concentration analysis and statistical analysis of 454 samples taken from residents in the main investigation area, the probability of the occurrences of paresthesia was estimated to be about 4%. It was estimated that there could be some occurrences of retarded walking for newborns from the result of the investigation of 57 women between 20 and 30 years old.
Based on this result, we have done a f
… More
ollow up survey with the medical doctor's diagnosis mainly on the residents with over 2Oppm of mercury level in hair and the pregnant women. As a result, we have found 3 individuals with chronic methylmercury poisoning symptoms and 5 individuals who might have the same symptoms.
Since 90% of the mercury in the residents' hair was methyl mercury, exposure is thought to be from eating fish. Hence, 20 samples of 12 kinds of fish in Tapajos river were analyzed, and 3 large carnivorous fish with over 0.4ppm mercury level, which is the health-standard for edible fish for saltwater fish in Japan and 1 kind of fish with over 1ppm mercury level, which is the health-standard for edible fish for freshwater fish was found. Small herbivore fish's mercury levels are low. Since the differences in the mercury level among fish kind were found out, the reduction or risks are possible by instructing the residents with high level of mercury and the pregnant women on which kind of fish to eat.
Sediment of the river by the fishing villages was sampled at 3 points and was analyzed. Adding the samples of 6 points from last year, there were only 1 sample with over 0.lppm of mercury in 9 samples. This is very low comparing to the cases of mercury pollution in Japan and Canada, and shows the special characteristics of the nature in the Amazon. Less
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