Growth Retardation and Altered Isotope Composition As Delayed Effects of PCB Exposure in Daphnia magna

详细信息    查看全文

• 作者：Caroline Ek ; Zandra Gerdes ; Andrius Garbaras ; Margaretha Adolfsson-Erici ; Elena Gorokhova
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：August 2, 2016
• 年：2016
• 卷：50
• 期：15
• 页码：8296-8304
• 全文大小：382K
• 年卷期：0
• ISSN：1520-5851

文摘

Trophic magnification factor (TMF) analysis employs stable isotope signatures to derive biomagnification potential for environmental contaminants. This approach relies on species δ¹⁵N values aligning with their trophic position (TP). This, however, may not always be true, because toxic exposure can alter growth and isotope allocation patterns. Here, effects of PCB exposure (mixture of PCB18, PCB40, PCB128, and PCB209) on δ¹⁵N and δ¹³C as well as processes driving these effects were explored using the cladoceran Daphnia magna. A two-part experiment assessed effects of toxic exposure during and after exposure; juvenile daphnids were exposed during 3 days (accumulation phase) and then allowed to depurate for 4 days (depuration phase). No effects on survival, growth, carbon and nitrogen content, and stable isotope composition were observed after the accumulation phase, whereas significant changes were detected in adults after the depuration phase. In particular, a significantly lower nitrogen content and a growth inhibition were observed, with a concomitant increase in δ¹⁵N (+0.1 ‰) and decrease in δ¹³C (−0.1 ‰). Although of low magnitude, these changes followed the predicted direction indicating that sublethal effects of contaminant exposure can lead to overestimation of TP and hence underestimated TMF.