Gagné François, Auclair Joëlle, Peyrot Caroline, Wilkinson Kevin J
Emerging Methods Aquatic Contaminants Research Division, Water Science and Technology, Environment Canada, 105 McGill, Montréal, QC H2Y 2E7, Canada.
Emerging Methods Aquatic Contaminants Research Division, Water Science and Technology, Environment Canada, 105 McGill, Montréal, QC H2Y 2E7, Canada.
Comp Biochem Physiol C Toxicol Pharmacol. 2015 Jun-Jul;172-173:36-44. doi: 10.1016/j.cbpc.2015.04.005. Epub 2015 May 7.
The purpose of this study was to determine the cumulative effects of exposure to either dissolved zinc or nanozinc oxide (nanoZnO) and air-time survival in freshwater mussels. Mussels were exposed to each forms of zinc for 96h then placed in air to determine survival time. A sub-group of mussels before and after 7days of exposure to air were kept aside for the determination of the following biomarkers: arachidonate-dependent cyclooxygenase (COX) and peroxidase (inflammation and oxidative stress), lipid metabolism (total lipids, esterases activity, HO-glycerol, acetyl CoA and phospholipase A2) and lipid damage (lipid peroxidation [LPO]). The results showed that air-time survival was decreased from a mean value of 18.5days to a mean value of 12days in mussels exposed to 2.5mg/L of nanoZnO although it was not lethal based on shell opening at concentrations below 50mg/L after 96h. In mussels exposed to zinc only, the median lethal concentration was estimated at 16mg/L (10-25 95% CI). The air-time survival did not significantly change in mussels exposed to the same concentration of dissolved Zn. Significant weight losses were observed at 0.5mg/L of nanoZnO and at 2.5mg/L for dissolved zinc chloride, and were also significantly correlated with air-time survival (r=0.53; p<0.01). Air exposure significantly increased COX activity in control mussels and in mussels exposed to 0.5mg/L of nanoZnO and zinc chloride. The data also suggested fatty acid breakdown and β-oxidation. Mussels exposed to contaminants are more susceptible to prolonged exposure to air during low water levels.
本研究的目的是确定暴露于溶解态锌或纳米氧化锌（nanoZnO）对淡水贻贝的累积影响以及其在空气中的存活时间。将贻贝暴露于每种锌形态96小时，然后置于空气中以确定存活时间。将暴露于空气中7天前后的贻贝亚组留存下来，用于测定以下生物标志物：花生四烯酸依赖性环氧化酶（COX）和过氧化物酶（炎症和氧化应激）、脂质代谢（总脂质、酯酶活性、甘油、乙酰辅酶A和磷脂酶A2）以及脂质损伤（脂质过氧化 [LPO]）。结果表明，暴露于2.5mg/L纳米氧化锌的贻贝，其在空气中的存活时间从平均值18.5天降至平均值12天，尽管在96小时后浓度低于50mg/L时基于壳张开情况它并非致命。仅暴露于锌的贻贝，其半数致死浓度估计为16mg/L（10 - 25 95%置信区间）。暴露于相同浓度溶解态锌的贻贝在空气中的存活时间没有显著变化。在0.5mg/L纳米氧化锌和2.5mg/L氯化锌条件下观察到显著的体重减轻，并且体重减轻也与在空气中的存活时间显著相关（r = 0.53；p < 0.01）。空气暴露显著增加了对照贻贝以及暴露于0.5mg/L纳米氧化锌和氯化锌的贻贝中的COX活性。数据还表明存在脂肪酸分解和β-氧化。暴露于污染物的贻贝在水位较低时更容易受到长时间空气暴露的影响。
