Monitoring ecosystem health of the Terminos Lagoon region using heavy metals as environmental indicators

Abstract

The Terminos Lagoon region is one of the most important biodiversity hotspots of Mexico and Mesoamerica. However, this high biodiversity is threatened by the activities of the Mexican oil industry, urban development, and land use change in the watersheds of the rivers that drain into it. This study presents the results of a monitoring program undertaken from 2006 to the present using heavy metals (Cd, Pb, Hg, Cu, Zn, As, Al, V and Cr) as environmental indicators. Heavy metals were measured in water, sediments and oysters as sentinel organisms, three times a year for 15 different sites. Eventually, metals concentration has been measured on selected marine-estuarine organisms (shrimp, fishes, sea turtles, dolphins, and manatees) to see the effect of bioaccumulation. Although heavy metals levels remained in low concentrations in water, some samples of oysters and mammals presented contamination levels above Mexican Legislation, suggesting effects of bioaccumulation. © 2012 WIT Press.