Metal concentrations in Isognomon alatus by stages and climatic seasons in San Andres Island, Colombian Caribbean

This study evaluates the potential of the flat oyster Isognomon alatus as a biomonitor species for metal contamination, based on bioaccumulation patterns in adults and juveniles present in the Seaflower Biosphere Reserve on San Andres Island (Colombia) in three seasons climatic. The analysis by Atomic Absorption Spectrometry of I. alatus specimens and water samples collected in SAI (2009 and 2010) allowed us to observe higher concentrations (Max: 2,235 mu g/g dry weight) of Zn in seston, compared to Cd (Max: 0.078 mu g/g dry weight) and Cu (Max: 0.069 mu g/g dry weight). These concentrations varied seasonally in relation to the intensity of rainfall in the area. By means of a two-way ANOVA (p<0.05), statistically significant differences were determined between sampling sites and seasons for metal concentrations (Cd, Cu, Zn) in organisms and for the Bioconcentration Factor (BCF), which corresponds to the relationship between the metal concentration in oysters and seston. Regarding the effect of age/size, the Cd concentration obtained and evaluated by ranges in juveniles is significantly lower than that observed in adults during the dry season, like what was recorded in other oyster studies. A comparison of the results obtained with the available data for I. alatus indicated that SAI had been impacted by Zn contamination. The results confirm the bioavailability of Cd previously reported; and the bioaccumulation of metals, especially Cu and Zn, according to FBC estimates.