Arsenic and arsenic species in cultured oyster (Crassostrea gigas and C. corteziensis) from coastal lagoons of the SE Gulf of California, Mexico.

The aim of this study was to evaluate the bioavailability of arsenic (As) through cultured oyster Crassostrea gigas and Crassostrea corteziensis from four coastal lagoons (SE Gulf of California). Organisms were collected in two seasons (rainy and dry season), and they were analyzed for total arsenic and chemical speciation of this element. The concentrations of As in oyster soft tissue fluctuated between 5.44 and 9.56 μg/g for rainy season and 6.46 and 8.33 μg/g for dry season (dry weight) in C. gigas. In C. corteziensis, the As concentrations were <5 μg/g for both seasons (dry weight). Arsenic speciation indicated arsenobetaine as the major arseno-compound accounting for 43.2-76.3 % of total content of As. Lower contributions were obtained for non-extractable As (11.3-17.5 %) and other molecules such as arsenocholine and methyl-arsonate (<5 %). Inorganic arsenic was detectable in only two samples, at concentrations lower than <0.1 μg/g. These As data are the first generated for these mollusks in NW Mexico and indicate that C. gigas and C. corteziensis farmed in this area are safe for human consumption in terms of arseno-compounds.