The influence of beach geology and morphodynamics on chemical pollution assessments following a mining accident

Abstract

In the present study the distribution of chemical elements in beaches adjacent to the Doce River mouth hit by the tailings mud from a mining accident were assessed. Sedimentological and morphological coastal aspects were also considered. The results indicate that wave-exposed delta plain beaches exhibit high resiliency, despite their proximity to potential pollution sources. On the other hand, shore platform beaches tend to accumulate chemical elements, mainly due to limited cross-shore sediment exchanges. Arsenic concentrations in the evaluated shore platform beaches were significantly higher than the delta plain beach. Shore platform beaches are more susceptible to frequent flooding and to higher elemental concentrations at the berm and beach face. Thus, the morphological characteristics of the assessed shore platform beaches, and input from the mud plume must be considered in a joint assessment strategy in order to obtain a broad understanding of the actual scenario regarding beach contamination.

Keywords: Metals; Morphodynamics; Pollution assessment; Sandy beaches.