METAL CONCENTRATIONS IN <i>Isognomon alatus</i> BY STAGES AND CLIMATIC SEASONS IN SAN ANDRÉS ISLAND, COLOMBIAN CARIBBEAN

Abstract

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 Andrés 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 µg/g dry weight) of Zn in seston, compared to Cd (Max: 0.078 µg/g dry weight) and Cu (Max: 0.069 µg/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&lt;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.

Changes in mercury content in oysters in relation to sediment and seston content in the Colombian Caribbean lagoons

“…TORT-1 (lobster hepatopancreas) from the National Research Council of Canada (NRCC) was used as reference material. Recovery percentages were 100 ± 1.4% in sediments (limit of detection, LOD, = 0.00073 µg/g Hg), 100 ± 5.4% in seston (LOD = 0.000015 µg/g Hg) and 100 ± 1.4% in oysters (LOD = 0.00073 µg/g Hg) [12].…”

“…The bioconcentration factor (BCF) was calculated as the ratio of Hg concentration in oyster tissue to its presence in sediment (sd) and seston (st), expressed in parts per million (ppm, µg/g) in dry weight (d.w.). This calculation was based on Mountouris et al [1] and Romero-Murillo et al [12].…”

“…The response of bivalves to environmental variables during their life cycle [12] complicates the understanding of Hg accumulation. In turn, the differences in Hg concentrations between sites highlight [9,10] the need to further understand the factors that in uence Hg concentrations in marine and coastal organisms such as the oyster C. rhizophorae, determine the speci c sources of contamination, and assess the impacts on local ecosystems in Colombia.…”