Macken Ailbhe, Giltrap Michelle, Ryall Kim, Foley Barry, McGovern Evin, McHugh Brendan, Davoren Maria
Radiation and Environmental Science Centre, Focas Institute, DIT, Dublin, Ireland.
Ecotoxicology. 2009 May;18(4):470-80. doi: 10.1007/s10646-009-0305-6. Epub 2009 Mar 13.
Heavy metals are ubiquitous contaminants of the marine environment and can accumulate and persist in sediments. The toxicity of metal contaminants in sediments to organisms is dependent on the bioavailability of the metals in both the water and sediment phases and the sensitivity of the organism to the metal exposure. This study investigated the effects of two metal contaminants of concern (CdCl(2) and CuCl(2)) on a battery of marine bioassays employed for sediment assessment. Cadmium, a known carcinogen and widespread marine pollutant, was found to be the least toxic of the two assayed metals in all in vivo tests. However, CdCl(2) was found to be more toxic to the fish cell lines PLHC-1 and RTG-2 than CuCl(2). Tisbe battagliai was the most sensitive species to both metals and the Microtox and cell lines were the least sensitive (cadmium was found to be three orders of magnitude less toxic to Vibrio fischeri than to T. battagliai). The sensitivity of Tetraselmis suecica to the two metals varied greatly. Marine microalgae are among the organisms that can tolerate higher levels of cadmium. This hypothesis is demonstrated in this study where it was not possible to derive an EC(50) value for CdCl(2) and the marine prasinophyte, T. suecica. Conversely, CuCl(2) was observed to be highly toxic to the marine alga, EC(50) of 1.19 mg l(-1). The genotoxic effect of Cu on the marine phytoplankton was evaluated using the Comet assay. Copper concentrations ranging from 0.25 to 2.50 mg l(-1) were used to evaluate the effects. DNA damage was measured as percent number of comets and normal cells. There was no significant DNA damage observed at any concentration of CuCl(2) tested and no correlation with growth inhibition and genetic damage was found.
重金属是海洋环境中普遍存在的污染物，会在沉积物中积累并持续存在。沉积物中金属污染物对生物的毒性取决于金属在水相和沉积物相中的生物可利用性以及生物体对金属暴露的敏感性。本研究调查了两种关注的金属污染物（CdCl₂ 和 CuCl₂）对一系列用于沉积物评估的海洋生物测定的影响。镉是一种已知的致癌物和广泛存在的海洋污染物，在所有体内试验中，它被发现是两种被测金属中毒性最小的。然而，发现 CdCl₂ 对鱼类细胞系 PLHC - 1 和 RTG - 2 的毒性比 CuCl₂ 更大。巴氏新糠虾是对两种金属最敏感的物种，而发光细菌法和细胞系最不敏感（发现镉对费氏弧菌的毒性比对巴氏新糠虾低三个数量级）。瑞典四爿藻对这两种金属的敏感性差异很大。海洋微藻是能够耐受较高水平镉的生物之一。本研究证明了这一假设，即无法得出 CdCl₂ 对海洋绿藻门藻类瑞典四爿藻的半数有效浓度（EC₅₀）值。相反，观察到 CuCl₂ 对海洋藻类具有高毒性，EC₅₀ 为 1.19 mg l⁻¹。使用彗星试验评估了铜对海洋浮游植物的遗传毒性作用。使用 0.25 至 2.50 mg l⁻¹ 的铜浓度来评估其影响。DNA 损伤以彗星和正常细胞的百分比数量来衡量。在所测试的任何 CuCl₂ 浓度下均未观察到明显的 DNA 损伤，并且未发现与生长抑制和遗传损伤之间存在相关性。
