Background concentrations and accumulation rates in sediments of pristine tropical environments

Abstract

Trace elements are pollutants that can be released into the environment and cause adverse effects to ecosystems and human health. Once released into the environment, they can be dispersed by the wind and deposited in soils and sediments of both marine and inland aquatic systems. After entering the food web, trace elements can accumulate at harmful concentrations in higher trophic levels, including humans. Background concentrations of trace elements such as As, Co, Cr, Cu, Ni, Pb, V and Zn were measured in sediment cores from pristine marine environments near Panama. Temporal records of trace element concentrations and fluxes were determined for the period 1906 to 2017, using the 210Pb dating technique. Higher accumulation rates of trace elements since the 1950s were attributed to an increase in human activities and climate shifts. The enrichment factor in cores was < 2, indicating there has been no substantial human-mediated contamination, and that trace elements were derived mainly from lithogenic sources. Nevertheless, the Threshold Effect Level and Probable Effect Level (TEL and PEL) indicated that Cr, Cu, As, and Ni can pose a risk to biota and therefore to humans, even at natural concentrations. Periodic monitoring of marine environments is recommended to minimize human health risks, reduce detrimental effects to biota, and promote monitoring of human activities that have the potential to cause trace metal contamination.