The Bioconcentration and Metabolism of Chlorpyrifos by the Eastern Oyster, Crassostrea Virginica

Abstract

Eastern oysters (Crassostrea virginica) were exposed to [14C]chlorpyrifos (O,O-diethyl-O-[3,5,6-trichloro-2-pyridyl] phosphorothioate) at an average measured seawater concentration of 0.6 microg/L under flow-through conditions for 28 d. The compound O,O-diethyl-O-(3,5-dichloro-6-methylthio-2-pyridyl)phosphorothioate (DMP) was extracted and identified as the single metabolite observed, and this metabolite constituted the majority of the total [14C] activity in the oyster at all sampling times. Once oysters were exposed to clean water, both chlorpyrifos and DMP residues cleared rapidly from whole oysters, with elimination half-lives of <3 d. A simple two-compartment uptake/elimination model was adequate to describe total [14C] activity in whole oysters, edible tissue, and oyster liquor. The average bioconcentration factors (BCFs) for total [14C] activity in whole oysters, edible tissue, and oyster liquor were 565, 1,400, and 35 ml/g, respectively. The parent [14C]chlorpyrifos accumulated to a peak residue concentration of 135 microg/kg in whole oyster tissue, representing an empirical [14C]chlorpyrifos BCF value in the oyster of approximately 225 ml/ g; the BCF value for [14C]chlorpyrifos was lower than the BCF for total [14C] activity in whole oysters and edible tissue because of extensive metabolism to DMP and oyster elimination processes.

Effects of an environmentally relevant concentration of diuron on oyster genitors during gametogenesis: responses of early molecular and cellular markers and physiological impacts

“…It is worth mentioning that in C. gigas exposed to a mixture of pesticides containing glyphosate, its main metabolite named aminomethylphosphonic acid (AMPA) was detected in oyster tissues, probably resulting from the biotransformation of the parent herbicide in the oyster (Geret et al 2013). Moreover, the biotransformation products of other pollutants such as the PAHs, benzo(a)pyrene (Anderson 1985) and pyrene (Bustamante et al 2012) or the pesticides, chlorpyrifos (Woodburn et al 2003), and pentachlorophenol (Shofer and Tjeerdema 1993) have already been identified in the oyster Crassostrea virginica demonstrating the metabolic ability of Crassostrea species to biotransform xenobiotics.…”

Sensitive biomarker responses of the shrimp Palaemonetes argentinus exposed to chlorpyrifos at environmental concentrations: Roles of alpha-tocopherol and metallothioneins

“…In South America, the use of biomarkers in biomonitoring surveys is increasing, but not always in native species (Carriquiriborde and Bainy, 2012). The sensitivity to a toxic compound varies among species, therefore the study of biomarkers in native bioindicators is relevant (van der Oost et al, 2003). Moreover, many of the studies have exposed the organisms to high or not environmentally relevant concentrations.…”

Pesticides and Herbicides

“…Bioconcentration and metabolism of chlorpyrifos by the eastern oyster was studied (Woodburn et al, 2003). The average BCF for the edible tissue portion was 1,400 ml/g.…”