Urban Environmental Biogeochemistry Laboratory, Towson University, Towson, Maryland, USA.
Environ Toxicol Chem. 2012 Apr;31(4):836-42. doi: 10.1002/etc.1751.
Urban stormwater runoff is composed of a mixture of components, including polycyclic aromatic hydrocarbons, metals, deicing agents, and many others. The fate of these chemicals is often in stormwater detention ponds that are used by amphibians for breeding. Among aquatic organisms, the toxic mechanism for many metals involves interference with active Na(+) and Cl(-) uptake. Addition of cations has been shown to reduce the toxicity of metals among some aquatic organisms through competitive inhibition, but no studies have investigated the interaction between NaCl and Cu among amphibian embryos and larvae. To determine the degree to which NaCl may ameliorate the toxicity of Cu to amphibian embryos and larvae, the authors exposed Hyla chrysoscelis (Cope's gray treefrogs) and Rana (Lithobates) clamitans (green frogs) to seven levels of Cu and NaCl in fully factorial experiments. When exposure was in artificial hard water, Cu was highly toxic to both species (96-h median lethal concentration [LC50] of 44.7 µg/L and 162.6 µg/L for H. chrysoscelis and R. clamitans, respectively). However, approximately 500 mg/L of NaCl eliminated Cu toxicity over the range of Cu concentrations used in the experiments (maximum 150 µg Cu/L for H. chrysoscelis and 325 µg Cu/L for R. clamitans). The current results suggest that NaCl is likely responsible for the toxic effects of NaCl and metal mixtures that might be typical of runoff from road surfaces in northern latitudes.
城市雨水径流由多种成分组成，包括多环芳烃、金属、除冰剂等。这些化学物质的归宿通常是用于两栖动物繁殖的雨水滞留池塘。在水生生物中，许多金属的毒性机制涉及对活性 Na(+)和 Cl(-)摄取的干扰。已表明，阳离子的添加通过竞争抑制作用降低了一些水生生物中金属的毒性，但尚无研究调查 NaCl 和 Cu 之间在两栖动物胚胎和幼虫中的相互作用。为了确定 NaCl 可能在多大程度上减轻 Cu 对两栖动物胚胎和幼虫的毒性，作者在完全析因实验中使 Hyla chrysoscelis（Cope's 灰色树蛙）和 Rana (Lithobates) clamitans（绿蛙）暴露于七种 Cu 和 NaCl 浓度下。当暴露在人工硬水中时，Cu 对两种物种都具有高度毒性（对 H. chrysoscelis 和 R. clamitans 的 96 小时半数致死浓度 [LC50]分别为 44.7 µg/L 和 162.6 µg/L）。然而，约 500 mg/L 的 NaCl 消除了实验中使用的 Cu 浓度范围内的 Cu 毒性（H. chrysoscelis 的最大 Cu 浓度为 150 µg/L，R. clamitans 的最大 Cu 浓度为 325 µg/L）。目前的结果表明，NaCl 可能是导致可能是北方道路表面径流中典型的 NaCl 和金属混合物毒性的原因。
