Monitoring and Evolution of Highly Lead Polluted Coastal Environments: A Case Study in San Simón Bay (NW Spain)

Abstract

San Simón Bay (inner Ría de Vigo, NW Spain) is a well-known polluted area because of its high Pb concentrations caused by waste discharges from a ceramic factory. The present study is focused on the historical and diagenetic monitoring of Pb pollution in this Bay based on sediment and pore water analyses of two cores collected in October 2010 adjacent to the factory using different techniques. A chronological framework was constructed based on 137 Cs and 210 Pb dating. Lead stable isotope ratios confirmed that the ceramic factory is still the main Pb source despite its closing in 2001. The historical monitoring of Pb pollution included Itrax TM Core Scanner (Itrax) analyses on the sedimentary record and the comparison with previous geochemical studies. The location of Pb maxima values in the cores allowed the estimation of sedimentation rates which were similar to those calculated from radionuclide dating. Moreover, Itrax analyses supported the results of the other techniques, but providing results with a higher resolution, and providing information about variations in cores composition that could affect radionuclide activities. The short-time interval required for obtaining the Itrax results and the high-resolution of the data, among other applications of this scanner, confirmed its importance as a complementary tool for Environmental coastal management.