Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research Institute, 1220 Prospect Ave., No. 285, Melbourne, FL 32901, USA.
Sci Total Environ. 2010 Nov 1;408(23):5808-16. doi: 10.1016/j.scitotenv.2010.08.019. Epub 2010 Sep 17.
Marine fishes in South Florida (Florida Keys-Florida Bay-Everglades region) accumulate higher concentrations of mercury (Hg) in their tissues than similar fishes from other areas of the southeastern U.S., though it is not known whether these elevated levels affect fish health. In this study, we used quantifiable pathological and biochemical indicators to explore Hg-associated differences in marine fish from South Florida, where Hg contamination is high, and from Indian River Lagoon, Florida, which served as a reference area. Hg concentrations in all tissues of mature spotted seatrout (Cynoscion nebulosus) from South Florida were significantly higher than those from Indian River Lagoon and were within the threshold range of those in studies where effects of Hg exposure have been observed. The distribution of Hg among tissues followed the same trend in both areas, with the greatest concentration in kidney tissue, followed by liver, muscle, brain, gonad, and red blood cells. Blood-plasma biochemistry showed that concentrations of iron, inorganic phosphate, lactate dehydrogenase, and aspartate aminotransferase were significantly less in South Florida. Also, fructosamine and alkaline phosphatase were significantly less in South Florida. Liver histology revealed that pyknosis/necrosis, interstitial inflammation, and bile duct hyperplasia were found only in seatrout from South Florida, and steatosis/glycogen was more frequently found in Indian River Lagoon specimens. In renal tissue, interstitial inflammation, glomerular dilatation and thickening, and tubular degeneration and necrosis were more frequently found in South Florida specimens. Changes in the liver cytoskeleton and morphology may explain some of the differences in blood parameters between study areas. Neurochemical analyses showed that brain N-methyl-d-aspartic acid (NMDA) receptors (but not those of muscarinic cholinergic receptors, monoamine oxidase, or acetylcholinesterase) were significantly less in fish from South Florida than from Indian River Lagoon. These findings provide compelling evidence that elevated Hg could cause quantifiable pathological and biochemical changes that might influence the health of spotted seatrout and could also affect other marine fish species.
南佛罗里达州（佛罗里达群岛-佛罗里达湾-大沼泽地地区）的海洋鱼类组织中的汞（Hg）浓度高于美国东南部其他地区的同类鱼类，但尚不清楚这些升高的水平是否会影响鱼类健康。在这项研究中，我们使用可量化的病理和生化指标来探索南佛罗里达州高汞污染地区与佛罗里达州印第安河泻湖地区海洋鱼类之间的 Hg 相关差异。来自南佛罗里达州的成熟斑点石斑鱼（Cynoscion nebulosus）的所有组织中的 Hg 浓度明显高于来自印第安河泻湖的浓度，并且处于已经观察到 Hg 暴露影响的研究中的阈值范围内。Hg 在组织中的分布在两个地区均遵循相同的趋势，在肾脏组织中浓度最高，其次是肝脏，肌肉，大脑，性腺和红细胞。血液 - 血浆生物化学显示，铁，无机磷酸盐，乳酸脱氢酶和天冬氨酸氨基转移酶的浓度在南佛罗里达州明显较低。此外，南佛罗里达州的果糖胺和碱性磷酸酶也明显较少。肝脏组织学显示，只有来自南佛罗里达州的石斑鱼才发现了核固缩/坏死，间质炎症和胆管增生，而印第安河泻湖标本中更常发现脂肪变性/糖原。在肾组织中，间质炎症，肾小球扩张和增厚以及肾小管变性和坏死在南佛罗里达州标本中更为常见。肝脏细胞骨架和形态的变化可能解释了研究区域之间血液参数的一些差异。神经化学分析表明，大脑 N-甲基-D-天冬氨酸（NMDA）受体（而不是毒蕈碱胆碱能受体，单胺氧化酶或乙酰胆碱酯酶）在南佛罗里达州的鱼类中明显少于在印第安河泻湖的鱼类。这些发现提供了令人信服的证据，表明升高的 Hg 可能导致可量化的病理和生化变化，这可能影响斑点石斑鱼的健康，也可能影响其他海洋鱼类物种。
