Study on Mercury Pollution in The Amazonia, Brazil

亚马逊地区汞污染对人类健康的不利影响是在1992至1998年间作为与热带联邦大学的一个联合项目进行的。通过测定人发汞含量来评估其对人体健康的危害，并对甲基汞中毒症状进行临床诊断。调查的主要区域是亚马逊河一条支流塔帕霍斯河中游的三个渔村。对其他一些渔村、金矿遗址和城市进行了调查，以进行比较。通过对主要调查区居民454份样本的浓度分析和统计分析，估计发生感觉异常者的概率约为4%。根据对57名20~30岁女性的调查结果，估计新生儿可能存在行走迟缓的情况。根据这一结果，我们做了f…更多的是根据医生的诊断进行的跟踪调查，主要针对头发汞含量在20ppm以上的居民和孕妇。结果，我们发现了3名慢性甲基汞中毒症状的人和5名可能有相同症状的人。由于居民头发中90%的汞是甲基汞，因此接触到的汞被认为是通过食用鱼类。为此，对塔帕霍斯河12种鱼的20个样品进行了分析，发现3种大型肉食性鱼类汞含量超过0.4ppm(日本咸水鱼食用鱼卫生标准)，1种鱼汞含量超过1ppm(淡水鱼食用鱼卫生标准)。小型食草鱼的汞含量很低。由于发现了不同鱼种汞含量的差异，指导汞含量高的居民和孕妇食用哪种鱼是有可能降低或降低风险的。加上去年以来的6个点的样品，9个样品中只有1个样品的汞含量超过0.1ppm。与日本和加拿大的汞污染案例相比，这一数字很低，显示了亚马逊地区大自然的特殊特征。较少

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