Mann Reinier M, Hyne Ross V, Spadaro David A, Simpson Stuart L
Centre for Ecotoxicology, Department of Environmental Sciences, University of Technology-Sydney, P.O. Box 123, Broadway, New South Wales 2007, Australia.
Environ Toxicol Chem. 2009 Jun;28(6):1244-54. doi: 10.1897/08-346.1.
Melita plumulosa is an epibenthic, detritivorous amphipod native to eastern Australia that has been adopted as a test organism for toxicity evaluations of contaminated estuarine sediments. In the present study, a 13-d amphipod reproduction test was developed that encompasses gametogenesis, fertilization, and embryo development before hatching. The primary endpoints for the test are fecundity (measured as the number of embryos per individual surviving female) and a fecundity index (fecundity multiplied by the stage of embryo development). This new test has been employed to scrutinize the sediments from a metal-contaminated coastal lagoon. Lake Macquarie (NSW, Australia) is a large, saltwater lagoon that has received metal pollution over many decades, leading to a concentration gradient of trace metals, including Pb, Zn, Cd, and Cu, in the sediments. Within one of the northern bays (Warners Bay), the concentrations of these metals either border on or exceed sediment quality guideline values prescribed by Australian and New Zealand Guidelines for Fresh and Marine Water Quality. In trials with the 13-d amphipod reproduction test, Warners Bay sediments significantly reduced fecundity in the test species. Subsequent tests with clean sediments spiked singly with Pb, Zn, or Cu indicated that no single metal was responsible for the observed toxicity in the field sediments. However, sediments spiked with various combinations of Pb, Zn, Cd, and Cu indicated that Zn in combination with one or more of the other metals was responsible for the reproductive toxicity observed in Warners Bay sediments. In all these tests, measured metal concentrations in overlying water and pore water were low, thus confirming that the observed effects on reproduction could be attributed to dietary exposure to metals.
梅利塔软毛跳虫是一种生活在浅海海底、以碎屑为食的双足节肢动物，原产于澳大利亚东部，已被用作受污染河口沉积物毒性评估的试验生物。在本研究中，开展了一项为期13天的双足节肢动物繁殖试验，该试验涵盖配子发生、受精以及孵化前的胚胎发育。该试验的主要终点指标为繁殖力（以每只存活雌虫体内的胚胎数量衡量）和繁殖力指数（繁殖力乘以胚胎发育阶段）。这项新试验已用于检测来自一个受金属污染的沿海泻湖的沉积物。麦夸里湖（澳大利亚新南威尔士州）是一个大型咸水泻湖，几十年来一直受到金属污染，导致沉积物中包括铅、锌、镉和铜在内的痕量金属出现浓度梯度。在北部的一个海湾（华纳湾）内，这些金属的浓度接近或超过了澳大利亚和新西兰淡水及海水水质指南规定的沉积物质量指导值。在使用为期13天的双足节肢动物繁殖试验进行的试验中，华纳湾的沉积物显著降低了受试物种的繁殖力。随后用单独添加铅、锌或铜的清洁沉积物进行的试验表明，单一金属并非造成现场沉积物中观察到的毒性的原因。然而，添加了铅、锌、镉和铜各种组合的沉积物表明，锌与一种或多种其他金属共同作用导致了在华纳湾沉积物中观察到的生殖毒性。在所有这些试验中，上覆水和孔隙水中测得的金属浓度较低，从而证实观察到的对繁殖的影响可归因于通过饮食接触金属。
