Reyes-Avila Alexander D, Laws Edward A, Herrmann Achim D, DeLaune Ronald D, Blanchard Thomas P
a Department of Environmental Sciences , College of the Coast and Environment, Louisiana State University , Baton Rouge , Louisiana , USA.
b Department of Geosciences , Geology, and Geophysics, College of Science, Louisiana State University , Baton Rouge , Louisiana , USA.
J Environ Sci Health A Tox Hazard Subst Environ Eng. 2019;54(3):238-245. doi: 10.1080/10934529.2018.1546495. Epub 2019 Jan 2.
Ample historical evidence has demonstrated the neurotoxicity of organic Hg. However, several studies have suggested that Se effectively sequesters MeHg. The affinity of Hg is up to ≈10 times higher for Se molecules than for comparable sulfur molecules, most of which are components of brain enzymes. The neurotoxicity of MeHg is associated with its binding to Se and the resultant interference with selenoenzymes (Ralston & Raymond, Global Advances in Selenium Research from Theory to Application, 2016). Therefore, having ample Se reserves is an effective way to mitigate MeHg's toxicity. When the molar ratios of Se to Hg in fish exceed 1.0, ingestion of the fish is unlikely to deplete Se reserves. The goal of this study was to determine the Hg and Se levels, and the Se:Hg molar ratios in freshwater fish from south Louisiana and the implications of those ratios with respect to fish consumption and Hg advisories. Five waterbodies were surveyed (University lake, Calcasieu lake, Toledo Bend, the Atchafalaya River and Henderson Lake). The sampled species included black drum (Pogonias cromis), catfish sp., largemouth bass (Micropterus salmoides) and bluegill (Eupomotis macrochirus). All fish were assayed for total Hg and Se. The average Hg concentration was 0.001 µmol g (0.21 ppm), and all concentrations were below the 1 ppm US FDA action level (from 3.1 × 10 to 0.003 µmol g). Se concentrations exceeded Hg concentrations in most cases. The average Se concentration was 0.003 µmol g (0.27 ppm), all concentrations were around or less than 1.0 ppm (from 3.7 × 10 to 0.017 µmol g). Hence, the Se:Hg molar ratios were >1 in all fish except largemouth bass from Henderson Lake. In general, Se was detected in sufficient amounts to sequester Hg, but consumption of largemouth bass from Henderson Lake would pose no risk only if anglers followed the posted Hg advisory. For advisory purposes, perhaps, both Hg and Se levels and Se:Hg molar ratios should be considered. In general, the results indicated that risk assessment will require consideration of both the fish species and body of water, because both can influence Se and Hg concentrations and Se:Hg molar ratios.
大量历史证据已证明有机汞具有神经毒性。然而，多项研究表明，硒能有效螯合甲基汞。汞对硒分子的亲和力比对类似硫分子的亲和力高约10倍，而硫分子大多是脑酶的组成成分。甲基汞的神经毒性与其与硒的结合以及由此对硒酶的干扰有关（拉尔斯顿和雷蒙德，《从理论到应用的硒研究全球进展》，2016年）。因此，储备充足的硒是减轻甲基汞毒性的有效方法。当鱼类中硒与汞的摩尔比超过1.0时，食用这种鱼不太可能耗尽硒储备。本研究的目的是测定路易斯安那州南部淡水鱼中的汞和硒含量、硒与汞的摩尔比，以及这些比例对鱼类消费和汞安全建议的影响。对五个水体进行了调查（大学湖、卡尔卡苏湖、托莱多湾、阿查法拉亚河和亨德森湖）。采样的物种包括黑鼓鱼（Pogonias cromis）、鲶鱼、大口黑鲈（Micropterus salmoides）和蓝鳃太阳鱼（Eupomotis macrochirus）。对所有鱼类的总汞和硒含量进行了测定。汞的平均浓度为0.001微摩尔/克（0.21 ppm），所有浓度均低于美国食品药品监督管理局1 ppm的行动水平（从3.1×10到0.003微摩尔/克）。在大多数情况下，硒的浓度超过了汞的浓度。硒的平均浓度为0.003微摩尔/克（0.27 ppm），所有浓度均在1.0 ppm左右或低于1.0 ppm（从3.7×10到0.017微摩尔/克）。因此，除了亨德森湖的大口黑鲈外，所有鱼类的硒与汞摩尔比均大于1。一般来说，检测到的硒含量足以螯合汞，但只有垂钓者遵循公布的汞安全建议，食用亨德森湖的大口黑鲈才不会有风险。或许，出于安全建议的目的，应该同时考虑汞和硒的含量以及硒与汞的摩尔比。总体而言，结果表明风险评估需要考虑鱼类物种和水体，因为两者都会影响硒和汞的浓度以及硒与汞的摩尔比。
