Hatch A C, Burton G A
Zoology Department, Oregon State University, Corvallis 97331.
Chemosphere. 1999 Sep;39(6):1001-17. doi: 10.1016/s0045-6535(99)00023-5.
Several field and laboratory assays were employed below an urban storm sewer outfall to define the relationship between stormwater runoff and contaminant effects. Specifically, two bioassays that measure feeding rate as a toxicological endpoint were employed in the field and in the laboratory, along with bioassays measuring survival and growth of test organisms. In 7 to 10 d in situ exposures, amphipod leaf disc processing, growth and survival were monitored. Different exposure scenarios were investigated by varying the mesh size (74 microns or 250 microns mesh) and method of deployment (water column, sediment surface, or containing sediment) of in situ exposure chambers. Hyalella azteca, Daphnia magna, and Pimephales promelas survival were monitored in 48 h in situ exposures. Feeding inhibition was investigated via enzyme inhibition of H. azteca and D. magna and via leaf disc processing measurements of the detritivore H. azteca. Additionally, we investigated the extent of phototoxicity at this site via field exposures in sun and shade and laboratory exposures with and without UV light. The measurement of detritivore leaf disc processing, and thus its usefulness as an endpoint, was hindered by individual variability in the amount of leaf consumed and by leaf weight gain during the summer field exposures. For D. magna, enzyme inhibition measured in a laboratory exposure did not reveal the toxicity observed in field exposures. For H. azteca, enzyme inhibition measured in the laboratory indicated toxicity similar to that observed in short term chronic in situ exposures. Enzyme inhibition also did not detect differences in toxicity due to variations in flow conditions. There were no statistically significant effects of any exposure on P. promelas survival or H. azteca growth, and there were no statistically significant effects due to mesh size or sun exposure. Survival of H. azteca was the most sensitive and the least variable endpoint. Effects on survival were noted in the same treatments over short-term chronic exposures in the laboratory and in situ. Significant differences in survival were noted due to the method of deployment under low flow conditions. In situ chambers containing sediment resulted in greater mortality in the 10 d low flow in situ experiments. Under high flow conditions, significant reductions in survival and leaf disc processing were noted under all methods of deployment at the two impacted sites over a 7 d exposure. Also under high flow conditions, significantly greater mortality of H. azteca was reported at the downstream field site when sediment was included in the chamber at deployment. These results suggest that significant toxicity at this site is due to accumulation of contaminants in the sediment and the mobilization of these contaminants during a storm event. In situ exposures detected toxicity not observed in laboratory exposures. These results suggest that a combination of laboratory and field bioassays is most useful in defining field effects.
在城市雨水排放口下游采用了多种现场和实验室检测方法，以确定雨水径流与污染物影响之间的关系。具体而言，在现场和实验室采用了两种将摄食率作为毒理学终点进行测量的生物检测方法，以及测量受试生物生存和生长情况的生物检测方法。在7至10天的原位暴露实验中，监测了端足类动物对叶盘的处理、生长和存活情况。通过改变原位暴露室的网目尺寸（74微米或250微米网目）和部署方法（水柱、沉积物表面或含沉积物），研究了不同的暴露场景。在48小时的原位暴露实验中，监测了阿氏摇蚊、大型溞和黑头软口鲦的存活情况。通过对阿氏摇蚊和大型溞的酶抑制作用以及对食碎屑动物阿氏摇蚊的叶盘处理测量，研究了摄食抑制情况。此外，我们通过在阳光和阴凉处的现场暴露以及有和没有紫外线的实验室暴露，研究了该地点的光毒性程度。在夏季现场暴露期间，由于个体对叶片消耗量的差异以及叶片重量增加，食碎屑动物叶盘处理的测量及其作为终点的有效性受到了阻碍。对于大型溞，在实验室暴露中测量的酶抑制作用并未揭示在现场暴露中观察到的毒性。对于阿氏摇蚊，在实验室中测量的酶抑制作用表明其毒性与在短期慢性原位暴露中观察到的毒性相似。酶抑制作用也未检测到由于水流条件变化而导致的毒性差异。任何暴露对黑头软口鲦的存活或阿氏摇蚊的生长均无统计学显著影响，并且由于网目尺寸或阳光暴露也无统计学显著影响。阿氏摇蚊的存活是最敏感且变异性最小的终点。在实验室和原位的短期慢性暴露中，相同处理下均观察到了对存活的影响。在低流量条件下，由于部署方法的不同而观察到了存活方面的显著差异。在10天的低流量原位实验中，含沉积物的原位暴露室导致了更高的死亡率。在高流量条件下，在两个受影响地点，所有部署方法在7天的暴露期间均观察到存活和叶盘处理的显著降低。同样在高流量条件下，当在部署时暴露室中包含沉积物时，下游现场地点报告的阿氏摇蚊死亡率显著更高。这些结果表明，该地点的显著毒性是由于沉积物中污染物的积累以及暴雨事件期间这些污染物的迁移所致。原位暴露检测到了实验室暴露中未观察到的毒性。这些结果表明，实验室和现场生物检测方法相结合在确定现场影响方面最为有用。
