Evaluation of anthropic influences in an estuarine system of Southeastern Brazilian Coast by applying enrichment factors

This study presents an evaluation of metals and As deposition in the Bertioga Channel (Santos Region, Southeastern Brazilian coast) along the last 150 years, which corresponds to the main anthropogenic activity in the area. The studied area is located in the so-called Baixada Santista, where the main Brazilian harbor and one of the most important industrial centers of the country are located. This work consisted of sampling five sediment cores along this channel. The cores were sliced every 2 cm, and the samples were analyzed by ICP-OES to determine the levels of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) and As. The enrichment factors (EF) were calculated to identify the relative heavy-metal toxicity of the sediments and the anthropogenic contribution of the investigated elements. EFs indicated the absence of contamination for the heavy metals but a higher input of As in two cores (B2 and B5). According to the age models of the cores, this enrichment corresponds to the end of the 19th century, when Santos harbor was inaugurated, and to the 1970s, when Santos harbor activities expanded.