Lab. de Radioisótopos Eduardo Penna Franca, IBCCF, Universidade Federal do Rio de Janeiro, 21941-902 Rio de Janeiro, RJ, Brazil.
Ecotoxicol Environ Saf. 2013 Jul;93:156-62. doi: 10.1016/j.ecoenv.2013.03.034. Epub 2013 Apr 28.
The growing ingestion of predatory fish by humans has increased their exposure to toxic chemicals. Mercury (Hg) is an exogenous and harmful trace-element that accumulates in all marine organisms. Selenium (Se) is nutritionally important as a micronutrient, but is potentially harmful at intakes above 1mg per day. Se:Hg molar ratios in excess of 1:1 are thought to counteract the adverse effects of Hg, protecting against Hg toxicity. Evaluation of the health risk posed by Hg exposure from seafood consumption requires concurrent consideration of Se content in the same individuals. This study evaluated the Se and Hg concentrations in the edible tissues of 652 individual samples of commonly consumed varieties of carnivorous and planktivorous fish, squid, mussel, shrimp and crab collected from south-eastern Brazil. The Se:Hg molar ratios showed significant variation among and within tropical seafood. All organisms presented Se concentration in muscle of less than 2.0µgg(-1), the maximum allowed selenium concentrations. Only seven individuals of a carnivorous fish species presented Hg in muscle above the maximum permissible limit of 0.5µgg(-1) established by WHO and Brazilian legislation for human consumption of most aquatic species. These same individuals also showed Se:Hg molar ratio of less than 1:1. Se:Hg molar ratios were found to decline with increasing fish length, potentially reducing Se-dependent protection. As a result of their rich Se, low Hg contents and Se:Hg molar ratios exceeding 1:1, nearly all species included in this study provide benefits for human consumption. Two popular seafoods in the region, the carnivorous fish Centropomus undecimalis (common snook) and Micropogonias furnieri (Atlantic croaker), had the most favorable Se:Hg molar ratio values of 33 and 21, respectively. Among the invertebrates, Xiphopenaeus kroyeri (seabob shrimp) and Loligo sanpaulensis (squid) had the most favorable Se:Hg molar ratio values, higher than 20. A selenium health benefit value based on the absolute amounts and relative proportions of Se and Hg in seafood was proposed as a more comprehensive seafood safety criterion.
人类对掠食性鱼类的摄入量不断增加，这使得他们接触到的有毒化学物质也越来越多。汞（Hg）是一种外源性的有害微量元素，会在所有海洋生物中积累。硒（Se）作为一种微量营养素，对人体很重要，但如果每天摄入超过 1 毫克，就可能有害。人们认为，当 Se:Hg 摩尔比超过 1:1 时，可以抵消 Hg 的不良影响，从而防止 Hg 中毒。评估人类通过食用海鲜摄入 Hg 所带来的健康风险，需要同时考虑同一人群中 Se 的含量。本研究评估了来自巴西南部的 652 个常见掠食性和滤食性鱼类、鱿鱼、贻贝、虾和蟹的可食用组织中的 Se 和 Hg 浓度。热带海鲜的 Se:Hg 摩尔比存在显著差异。所有生物的肌肉 Se 浓度均低于 2.0µgg(-1)，这是允许的最大 Se 浓度。在一种肉食性鱼类中，只有 7 个个体的肌肉 Hg 浓度超过了世界卫生组织和巴西立法机构为大多数水生物种制定的人类食用最大允许限量 0.5µgg(-1)。这些个体的 Se:Hg 摩尔比也小于 1:1。研究发现，Se:Hg 摩尔比随着鱼体长度的增加而降低，可能会降低依赖 Se 的保护作用。由于这些鱼类和贝类的 Se 含量丰富、Hg 含量低且 Se:Hg 摩尔比超过 1:1，因此几乎所有被研究的物种都有益于人类食用。该地区两种受欢迎的海鲜，肉食性鱼类 Centropomus undecimalis（普通鲻鱼）和 Micropogonias furnieri（大西洋鳕鱼），具有最有利的 Se:Hg 摩尔比值，分别为 33 和 21。在无脊椎动物中，Xiphopenaeus kroyeri（海虾）和 Loligo sanpaulensis（鱿鱼）具有最高的 Se:Hg 摩尔比值，超过 20。提出了一种基于海鲜中 Se 和 Hg 的绝对量和相对比例的硒健康效益值，作为一种更全面的海鲜安全标准。
