Sea Cucumber as Bioindicator of Trace Metal Pollution in Coastal Sediments

Sea cucumbers are fished worldwide for export to Asia, but few studies have evaluated metal pollution and risk assessment. This study assessed concentration of trace metals and the potential ecological risk in sea cucumber (Holothuria floridana) and sediments at the Cispatá Bay, in the Caribbean Coast of Colombia. The trace metal concentrations in biota and sediments showed a similar decreasing trend as follows: Cu > Zn > Hg > Pb > Cd. The highest bioconcentration factor was found for Hg, and according to the sediment quality guidelines, Cu levels indicate adverse biological effects in the ecosystem. In this regard, Cu levels were higher than effects range low and the threshold effect levels (TEL) and lowest effect level in all the stations, whereas Hg levels were higher than TEL in most of them. Results for health risk assessment based on the maximum allowable daily consumption rate (CRlim) suggest that there is no risk to adults; however, children should limit or avoid its consumption. Results from multivariate statistical analysis suggest that agricultural activities (i.e., application of fertilizers and agrochemicals) were identified as the main anthropogenic sources of metal pollution. This research suggest that sea cucumber could be used as a bioindicator species in studies of monitoring metal contamination, with special attention to the highly significant correlation between Zn in tissue and sediments. This study also reveals that anthropic activities may have negative effects in the quality of the sediments of the bay and contributing to the knowledge of metal accumulation in sea cucumber.