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首页> 外文期刊>Environmental toxicology and chemistry >Contrasting uptake routes and tissue distributions of inorganic and methylmercury in mosquitofish (Gambusia affinis) and redear sunfish (Lepomis microlophus).
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Contrasting uptake routes and tissue distributions of inorganic and methylmercury in mosquitofish (Gambusia affinis) and redear sunfish (Lepomis microlophus).

机译：蚊鱼（Gambusia affinis）和红背太阳鱼（Lepomis microlophus）中无机汞和甲基汞的吸收途径和组织分布情况相反。

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摘要

High Hg concentrations in freshwater fish are a concern for human health, yet we lack a clear understanding of the mechanisms that produce high Hg concentrations in fish. Controlled studies in natural surface waters that quantify the uptake and retention of Hg in fish tissues following exposures from the aqueous phase and from invertebrate prey diets are rare. Using 203Hg, we contrasted the accumulation of inorganic Hg (HgI) and methylmercury (MeHg) from the dissolved phase and from invertebrate food in mosquitofish (Gambusia affinis) feeding on Daphnia pulex (representing a pelagic food chain) and in redear sunfish (Lepomis microlophus) feeding on amphipods (Hyallela sp., representing a benthic/macrophyte-based chain). Experiments were conducted with environmentally realistic Hg concentrations in two freshwaters from the San Francisco Bay Delta (CA, USA) with significantly different dissolved organic carbon (DOC) concentrations. Mercury uptake rates following aqueous exposures were consistently higherfor fish in the water with lower DOC, whereas efflux rates were similar for both water types. Approximately 50% of the ingested Hg, associated with invertebrate prey was lost from mosquitofish, and 90% or more from sunfish, within 48 h. Assimilation efficiencies for ingested MeHg for both fish were 86 to 94%, substantially higher than those for HgI regardless of water type. Biokinetic modeling using the parameters determined in these experiments accurately predicted Hg burdens for fish in the San Francisco Bay Delta system. Despite considerable accumulation of HgI from both aqueous and dietary exposure routes, the high assimilation efficiencies and slow loss of MeHg from dietary sources are the principal determinants of predicted Hg burdens in both fish species.
机译：淡水鱼中的汞含量高是人类健康的问题，但我们对鱼中汞高含量的机理缺乏清晰的了解。在天然地表水中进行的定量研究表明，在暴露于水相和无脊椎动物猎物饮食后，鱼类组织中汞的吸收和滞留量可以量化。使用203Hg，我们比较了以水蚤（代表远洋食物链）和红耳太阳鱼（Lepomis microlophus）为食的蚊子（Gambusia affinis）的溶解相和无脊椎动物食物中的溶解相和无脊椎动物食物中无机汞（HgI）和甲基汞（MeHg）的积累。 ）以两栖动物为食（Hyallela sp。，代表基于底栖生物/宏观植物的链）。在来自旧金山湾三角洲（加利福尼亚州，美国）的两个淡水中使用符合环境实际汞含量的实验，其中溶解有机碳（DOC）的浓度存在明显差异。 DOC含量较低的水中的鱼，水暴露后的汞吸收率一直较高，而两种水类型的外排率相似。在48小时内，大约50％的与无脊椎动物猎物相关的汞摄入量是从蚊子中流失的，而从翻车鱼中流失的90％或更多。两种鱼类的甲基汞摄入量的同化效率均为86％至94％，无论水类型如何，其吸收效率均大大高于HgI。使用这些实验中确定的参数进行生物动力学建模，可以准确预测旧金山湾三角洲系统中鱼类的汞负荷。尽管在水和饮食接触途径中都有大量的HgI积累，但是从饮食来源获得的高同化效率和MeHg的缓慢损失是两种鱼类中Hg负荷预测的主要决定因素。

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