title: Effects of acute exposures to mecoprop, mecoprop-p and their biodegradation product (2-MCP) on the larval stages of the Pacific oyster, Crassostrea gigas.
abstract: Studies have shown that pesticides are sometimes detected at rather high levels in seawater and it has been suggested that these chemical compounds could act as additional stress factor for oysters cultured in coastal environments. The effects of pesticides on marine molluscs could be particularly harmful in the early stages which correspond to critical life stages. This study aimed to assess the effects of mecoprop, mecoprop-p and their degradation compound 2-methyl-4-chlorophenol on two larval stages of Crassostrea gigas. Embryotoxic effects were assessed on veliger larvae after 36 h exposures, and both percentages of normal larvae and types of abnormalities were taken into account. The effects of the three substances were evaluated on 21-day-old pediveliger larvae by calculating metamorphosis rates after 24h exposures. The results of the embryotoxicity assay indicated that 2-methyl-4-chlorophenol was more toxic (EC50: 10.81 mg L(-1)) than its parent compounds (EC50 mecoprop: 42.55 mg L(-1); EC50 mecoprop-p: 78.85 mg L(-1)). Mecoprop in particular injured shell formation with an increase of shell abnormalities following herbicide concentrations. The active substances were not toxic to metamorphosis processes, but 2-MCP was revealed to be more toxic to the success of metamorphosis (EC50: 7.20 mg L(-1)) than to embryo-larval development. However, the toxic concentrations were several orders of magnitude higher than environmental concentrations.
authors: Normandie Université, F-14032 Caen, France; CNRS INEE, FRE3484 BioMEA, SFR ICORE, IBFA Université de Caen Basse-Normandie, IBFA, Esplanade de la Paix, F-14032 Caen, France.
authors: Antoine
authors: A
authors: Mottier
authors: Departmental Laboratory Franck Duncombe, LDFD, Saint-Contest, 14053 Caen Cedex, France.
authors: Valérie
authors: V
authors: Kientz-Bouchart
authors: Departmental Laboratory Franck Duncombe, LDFD, Saint-Contest, 14053 Caen Cedex, France.
authors: Christelle
authors: C
authors: Dubreule
authors: Normandie Université, F-14032 Caen, France; CNRS INEE, FRE3484 BioMEA, SFR ICORE, IBFA Université de Caen Basse-Normandie, IBFA, Esplanade de la Paix, F-14032 Caen, France.
authors: Antoine
authors: A
authors: Serpentini
authors: Normandie Université, F-14032 Caen, France; CNRS INEE, FRE3484 BioMEA, SFR ICORE, IBFA Université de Caen Basse-Normandie, IBFA, Esplanade de la Paix, F-14032 Caen, France.
authors: Jean Marc
authors: JM
authors: Lebel
authors: Normandie Université, F-14032 Caen, France; CNRS INEE, FRE3484 BioMEA, SFR ICORE, IBFA Université de Caen Basse-Normandie, IBFA, Esplanade de la Paix, F-14032 Caen, France. Electronic address: katherine.costil@unicaen.fr.
authors: Katherine
authors: K
authors: Costil
mesh_terms: D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000633:toxicity; D000818:Animals; D002733:Chlorophenols / Q000633:toxicity*; D049896:Crassostrea / Q000187:drug effects*; D004625:Embryo, Nonmammalian / Q000187:drug effects; D007814:Larva / Q000187:drug effects; D008675:Metamorphosis, Biological / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: C430966:2-methyl-4-chlorophenol; D002733:Chlorophenols; D014874:Water Pollutants, Chemical; C008340:mecoprop; D008456:2-Methyl-4-chlorophenoxyacetic Acid
keywords: Biodegradation compound; Chlorophenoxy herbicides; Crassostrea gigas; Embryotoxicity; Mecoprop; Metamorphosis