The biokinetics of Cu in Daphnia magna, including dissolved uptake, assimilation and efflux, has been determined using a gamma 67 Cu radiotracer methodology. However, this gamma emitting radioisotope is not readily available due to its very short half-life. In the present study, we employed a stable isotope tracer ( 65 Cu) to determine the Cu biokinetics and compared our results to those determined using 67 Cu. The dissolved uptake rate constant of 65 Cu was 3.36 L/(g·day), which is higher than that of 67 Cu (1.32 L/(g·day)). With increasing food concentrations from 2×10 4 to 1×10 5 cells/mL, the Cu assimilation efficiency (AE) decreased from 46% to 11%, compared to a decrease from 27% to 16% when determined using 67 Cu. The efflux of Cu from Daphnia magna was quantified following both dissolved and dietary uptake. The efflux of waterborne Cu was comparable to that of dietborne Cu and the efflux rate constant (0.32-0.52 day 1 ) was higher than that determined by 67 Cu (0.19-0.20 day 1 ). By considering different water properties and handling procedure between the two experiments, we believe that these differences are reasonable. Overall, this study demonstrated that the enriched stable isotope tracer technique is a powerful tool to investigate metal bioavailability and maybe a good alternative to radioactive measurements.
溶解有机物(DOM ) 特别为有更高的 DOM 集中的发育营养正常促进剂湖在水的环境在重金属种形成和分发起一个重要作用。泰胡·莱克是第三最大的淡水和一个高发育营养正常促进剂湖在长江下游，中国。在湖，水藻花蕾的经常的逃走极大地在湖沉积增加了不同有机物的集中。在这研究，沉积样品从泰胡·莱克的各种各样的部分被收集与 Cu 在 DOM 的有约束力的潜力探索空间差别。滴定实验被采用到份量上描绘在 Cu (II ) 和用离子从泰胡·莱克沉积提取的 DOM 之间的相互作用选择电极(ISE ) 和荧光熄灭技术。ISE 结果证明外长的 DOM 比内长的 DOM 有更高有约束力的能力，并且从水的 macrophytes 导出的 DOM 比源于水藻的有一个更高有约束力的能力。熄灭结果的荧光显示腐殖的物质在湖在在 DOM 和 Cu (II ) 之间的 complexation 起了一个关键作用。因为水藻花蕾的经常的逃走，然而，像蛋白质的事也是象在泰胡·莱克的腐殖的事一样的主要部件。因此，因为在 DOM 的像蛋白质的物质是不稳定的，当分解时，他们将释放界限金属，由像蛋白质的物质的金属界限应该被引起担心。
