title: The influence of zinc chloride and zinc oxide nanoparticles on air-time survival in freshwater mussels.
abstract: 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.
authors.affiliation: Emerging Methods Aquatic Contaminants Research Division, Water Science and Technology, Environment Canada, 105 McGill, Montréal, QC H2Y 2E7, Canada. Electronic address: francois.gagne@ec.gc.ca.
authors.forename: François
authors.initials: F
authors.lastname: Gagné
authors.affiliation: Emerging Methods Aquatic Contaminants Research Division, Water Science and Technology, Environment Canada, 105 McGill, Montréal, QC H2Y 2E7, Canada.
authors.forename: Joëlle
authors.initials: J
authors.lastname: Auclair
authors.affiliation: Département de Chimie, Université de Montréal, Montréal, QC H2V 2B8, Canada.
authors.forename: Caroline
authors.initials: C
authors.lastname: Peyrot
authors.affiliation: Département de Chimie, Université de Montréal, Montréal, QC H2V 2B8, Canada.
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Wilkinson
mesh_terms: D000818:Animals; D015415:Biomarkers; D049872:Bivalvia / Q000502:physiology; D002712:Chlorides / Q000737:chemistry / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D007249:Inflammation / Q000378:metabolism; D015227:Lipid Peroxidation; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D018384:Oxidative Stress; D013534:Survival; D017967:Zinc Compounds / Q000737:chemistry / Q000633:toxicity*; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D002712:Chlorides; D017967:Zinc Compounds; C016837:zinc chloride; D015034:Zinc Oxide
keywords: Air-time survival; Elliptio complanata; Oxidative stress; inflammation