Fonseca Márlon de F, Dórea José G, Bastos Wanderley R, Marques Rejane C, Torres João P M, Malm Olaf
Laboratório de Radioisótopos Eduardo Penna Franca, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
Neurotoxicology. 2008 Nov;29(6):1008-15. doi: 10.1016/j.neuro.2008.07.001. Epub 2008 Jul 25.
Because of heavy dependence on fish, Amazonian riparian communities are chronically exposed to high levels of methylmercury (MeHg). We studied fish-MeHg exposure (total hair-Hg, HHg) as a determinant of neurocognitive scores of children living in two geographically distant, culturally distinct and isolated poor communities of non-urban environments: Amazonian riverines (Riparians, n=38) of the Puruzinho Lake community in the Rio Madeira Basin and rural agrarians from Iúna, Espírito Santo (Agrarians, n=32). Nutritional status was estimated by anthropometry (Z-scores) and individual cognitive abilities were assessed by the Wechsler Intelligence Scale for Children-III (WISC-III) and the Human Figure Drawings (HFD), both validated versions for Brazilian children. Anthropometric assessment showed slightly elevated Z-scores for the Agrarian children (not statistically significant) but median HHg concentrations were 14.4 and 0.25microgg(-1) respectively for Riparian and Agrarian children (p=0.000). Despite paradoxical MeHg exposures, both groups showed comparable HFD scores but very poor performance in WISC-III test battery; median of sum of WISC-III subtests scores (SigmaTOT) were 17.9 and 28.6 (p<0.000) for Riparian and Agrarian children, respectively (percentage scale). Spearman correlation between nutritional status (attained growth) and psychometric scores were statistically significant between height-for-age Z-score and Object Assembly subtest (r=0.269; p=0.043), SigmaTOT (r=0.319; p=0.016), Performance-IQ (r=0.311; p=0.019) and Perceptual Organization Index scores (r=0.302; p=0.023). In these isolated communities there are stronger determinants of neurocognitive poor performance than MeHg exposure. Global strategies for reducing human exposure to MeHg by curtailing fish consumption are unrealistic options for riverine subsistence populations and are not justifiable to prevent low cognitive scores.
由于严重依赖鱼类，亚马逊河岸社区长期暴露于高水平的甲基汞（MeHg）中。我们研究了鱼类甲基汞暴露（总毛发汞含量，HHg）作为居住在两个地理上遥远、文化上独特且孤立的非城市贫困社区儿童神经认知得分的决定因素：马德拉河盆地普鲁齐尼奥湖社区的亚马逊河岸居民（河岸居民，n = 38）和圣埃斯皮里图州伊乌纳的农村农民（农民，n = 32）。通过人体测量法（Z评分）估计营养状况，并通过韦氏儿童智力量表第三版（WISC-III）和人体图形绘画（HFD）评估个体认知能力，这两种方法均为针对巴西儿童的有效版本。人体测量评估显示农民儿童的Z评分略有升高（无统计学意义），但河岸居民儿童和农民儿童的HHg浓度中位数分别为14.4和0.25μg/g（p = 0.000）。尽管甲基汞暴露情况自相矛盾，但两组的HFD得分相当，但在WISC-III测试组中的表现都很差；河岸居民儿童和农民儿童的WISC-III子测试得分总和（SigmaTOT）中位数分别为17.9和28.6（p < 0.000）（百分比量表）。营养状况（获得的生长）与心理测量得分之间的斯皮尔曼相关性在年龄别身高Z评分与物体拼凑子测试（r = 0.269；p = 0.043）、SigmaTOT（r = 0.319；p = 0.016）、操作智商（r = 0.311；p = 0.019）和知觉组织指数得分（r = 0.302；p = 0.023）之间具有统计学意义。在这些孤立的社区中，存在比甲基汞暴露更强的神经认知表现不佳的决定因素。通过减少鱼类消费来降低人类甲基汞暴露的全球战略对于河岸自给人口来说是不现实的选择，并且对于预防低认知得分来说也不合理。
