Alves L C, Borgmann U, Dixon D G
Department of Biology, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
Aquat Toxicol. 2008 May 1;87(3):187-99. doi: 10.1016/j.aquatox.2008.01.016. Epub 2008 Feb 5.
Data on the toxicity of uranium in sediments to Hyalella azteca and the effect of overlying water chemistry are limited. This study exposed H. azteca to sediments spiked with U (0-10,000 microg U/g dry weight) and five different overlying waters, which varied independently in hardness and alkalinity. Water pH had a major effect on U bioavailability and uptake by H. azteca. Uranium toxicity was higher when overlying water pH was low, while desorption of U into the overlying water increased with increasing pH. There appears to be little effect of Ca on U uptake, other than its influence on U speciation. Experiments with caged animals indicate that U accumulation and toxicity occur mainly through the dissolved phase rather than the solid phase. Uranium bioaccumulation is a more reliable indicator of U toxicity than U concentration in water or sediment. Uranium bioaccumulation in the H. azteca and U adsorption to sediment can be satisfactorily explained using saturation models.
关于沉积物中铀对阿氏摇蚊的毒性以及上覆水化学性质影响的数据有限。本研究将阿氏摇蚊暴露于添加了铀（0 - 10,000微克铀/克干重）的沉积物和五种不同的上覆水中，这些上覆水在硬度和碱度上独立变化。水体pH值对铀的生物有效性以及阿氏摇蚊对铀的摄取有重大影响。当上覆水pH值较低时，铀的毒性较高，而随着pH值升高，铀向上覆水中的解吸增加。除了对铀形态的影响外，钙对铀摄取似乎几乎没有影响。对笼养动物的实验表明，铀的积累和毒性主要通过溶解相而非固相发生。与水中或沉积物中的铀浓度相比，铀的生物积累是铀毒性更可靠的指标。使用饱和模型可以令人满意地解释阿氏摇蚊体内的铀生物积累以及铀在沉积物上的吸附情况。
