An assessment of contamination and ecological risk of metals in sediments of the Guaracara, Caparo and Couva rivers in Trinidad, West Indies

Abstract

ABSTRACTThe presence of metals in an aquatic environment can serve as a biomarker for pollution and can be used to evaluate its contamination status. Rapid industrialisation in recent decades has propelled Trinidad and Tobago to be one of the most developed nations within the Caribbean region and has stimulated the awareness of potential ecological risks from various industrial activities affecting the rivers of Trinidad. Sediment samples from three rivers along the West coast of Trinidad were analysed for Cd, Cr, Cu, Mn, Ni, Pb and Zn. For all three rivers, the metal concentrations in sediments were in the range of 0.40–2.31 μg/g, 12.77–33.04 μg/g, 14.51–72.89 μg/g, 224.90–4472.83 μg/g, 8.20–43.08 μg/g, 22.63–38.34 μg/g and 92.0–5462.60 μg/g for Cd, Cr, Cu, Mn, Ni, Pb and Zn, respectively. Assessment of the pollution status indicated that all three rivers were considered polluted, with significant contributions from Cr, Cu, Mn, Ni and Zn. The potential ecological risk for all three rivers, however, was low and multivariate statistics revealed that mainly anthropogenic sources contributed to the metal concentrations in sediments of all three rivers.