Silva Soraya J, Carman Kevin R, Fleeger John W, Marshall Tonya, Marlborough Sidney J
Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA.
Arch Environ Contam Toxicol. 2009 Apr;56(3):434-41. doi: 10.1007/s00244-008-9197-3. Epub 2008 Aug 14.
The effects of sediments contaminated with sublethal concentrations of phenanthrene (PAH) and metals (Cd, Hg, Pb) were evaluated in relation to their influence on the feeding activity of a harpacticoid copepod, Schizopera knabeni. A metal mixture (at the ratio of 5Pb:3Cd:2Hg) and Cd alone reduced grazing rates of S. knabeni feeding on (14)C-labeled microalgae. Cadmium alone and Cd combined with phenanthrene significantly decreased grazing rates of S. knabeni at Cd concentrations above 49 mg kg(-1) dry sediment. No grazing was observed in 98, 106, or 157 mg kg(-1) dry sediment Cd alone or in sediment contaminated with phenanthrene (98 mg kg(-1) dry sediment) combined with Cd at these concentrations. Phenanthrene alone also caused a significant decrease (55%) in S. knabeni grazing rates. Feeding ceased above 344 mg kg(-1) dry sediment of the metal mixture alone and combined with phenanthrene. Results were consistent with an independent effect on feeding when Cd and phenanthrene were combined. When other metals were added (Pb and Hg) to the mixture, results were consistent with an additive influence on feeding rate. Because the underlying mechanisms of toxicity for metals and PAH are probably different, our observations suggest that reductions in grazing probably did not directly contribute to the lethal effects of phenanthrene or metals. The absence of interactive effects on feeding suggests that metal-PAH interactive effects on lethality have a different underlying mechanism and that reductions in grazing probably did not directly contribute to the lethality effects of phenanthrene or metals in S. knabeni.
评估了受亚致死浓度菲（多环芳烃）和金属（镉、汞、铅）污染的沉积物对猛水蚤Schizopera knabeni摄食活动的影响。一种金属混合物（铅、镉、汞比例为5:3:2）以及单独的镉降低了以¹⁴C标记微藻为食的Schizopera knabeni的摄食率。单独的镉以及镉与菲的组合在镉浓度高于49毫克/千克干沉积物时显著降低了Schizopera knabeni的摄食率。在单独含98、106或157毫克/千克干沉积物镉的情况下，或在含这些浓度镉且受菲污染（98毫克/千克干沉积物）的沉积物中，未观察到摄食现象。单独的菲也导致Schizopera knabeni的摄食率显著下降（55%）。单独的金属混合物以及与菲组合时，在高于344毫克/千克干沉积物时摄食停止。当镉和菲组合时，结果与对摄食的独立影响一致。当向混合物中添加其他金属（铅和汞）时，结果与对摄食率的相加影响一致。由于金属和多环芳烃的潜在毒性机制可能不同，我们的观察结果表明摄食减少可能并非直接导致菲或金属的致死效应。对摄食没有交互作用表明金属 - 多环芳烃对致死性的交互作用有不同的潜在机制，并且摄食减少可能并非直接导致Schizopera knabeni中菲或金属的致死效应。
