Environmental risk of trace elements in mangrove ecosystems: An assessment of natural vs oil and urban inputs.

The petrochemical industry and urban activities are widely recognized worldwide as a source of pollution to mangrove environments. They can supply pollutants such as trace elements that can modify the ecosystem structure and associated services, as well as human populations. Through geochemical data, multivariate statistical analysis and pollution indices such as the enrichment factor (EF), geo-accumulation index (Igeo), adverse effect index (AEI) and the pollution load index (PLI), we evaluated the factors that control trace element distribution, punctual sources and determined the pollution level of sediments and their potential biological impact in the mangrove ecosystem of Isla del Carmen, Mexico. The factor and cluster analysis highlighted that the distribution of trace elements is influenced by the mineralogy, texture as well as urban derived sources. The pollution indices showed values in the punctual sources from the urban area of EF > 10, Igeo > 3, AEI > 3, PLI > 1 by Cu, Zn and Pb. Finally, the results revealed that mangroves from Isla del Carmen has a major influence from urban activities and natural sources rather than oil industry and also indicate a degraded environment as a result of anthropogenic activities that could have knock-on effect for human health if polluted marine organisms derived from the urban mangroves are consumed. CAPSULE ABSTRACT: Surface sediments show the influence of point sources on selected trace element concentrations correlated with human activities within the mangroves of Isla del Carmen, Mexico.