Natural and anthropogenic heavy metals in estuarine cohesive sediments: geochemistry and bioavailability

Abstract

The geochemistry, mineralogy, and grain size distribution of several estuarine cohesive sediment samples from potentially human-influenced areas without such an influence were analyzed to determine the natural heavy metal content and evaluate its impact on the Bahía Blanca estuarine environment. The data were compared with different ranges of concentrations for heavy metals in marine sediments established by the NOAA Screening Quick Reference Tables in which values range from background levels to those considered toxic to the marine environment. Our total heavy metal contents were below the established hazardous levels in all the analyzed samples, even though the potentially human-influenced areas (harbors, industry, urban spread) showed the highest total concentration values as well as greater percentages of bioavailable compounds. This would imply a low and not extensive anthropogenic input into the environment. The relatively high proportions in which Cd, Pb, and Cr appear as bioavailable compounds at some sites not influenced by human activity suggest the presence of a natural source for these elements. This could be attributed to the weathering of naturally occurring volcanic minerals, indicating that special care must be taken when monitoring of sediment for anthropogenic activity is carried out within this environment. According to the results obtained, and in order to minimize the environmental impact caused by periodic water injection dredging, relocation of sewage outfalls from vessel mooring areas into open waters is strongly recommended.

Systematic Review of Fish Ecology and Anthropogenic Impacts in South American Estuaries: Setting Priorities for Ecosystem Conservation

“…Metal contamination in sediments and water were assessed in Río de La Plata Estuary (Tatone et al, 2013(Tatone et al, , 2015, Mar Chiquita Lagoon (Marcovecchio et al, 2001;Beltrame et al, 2009), and Bahía Blanca Estuary (Botté et al, 2007;Grecco et al, 2011). Sources and highs levels of metals are related to polluted discharges from agricultural, urban and industrial sources (Camilión et al, 2003;Marcovecchio et al, 2016;Santucci et al, 2017).…”

Tracing Cr, Pb, Fe and Mn occurrence in the Bahía Blanca estuary through commercial fish species

“…The port system contributes to the rapid resuspension of great volumes of cohesive sediment by means of the maintenance and deepening dredging activities. These activities promote the abrupt transfer of immobilized substances into bioavailable compounds that then are disseminated throughout the estuarine environment (Grecco et al, 2011). Several other industries taking part of a petrochemical center are also located in this harbor area (Limbozzi and Leit ao, 2008).…”

The impact of sewage effluents on the fecundity and survival of Eurytemora americana in a eutrophic estuary of Argentina

“…The high turbidity found in I water indicates resuspension of bottom sediments and this, in turn, implies an increase in bioavailability of contaminants associated with the BBE sediments like Cu, Cr, Pb, and Zn (Table 1), generating a higher risk for organisms in water column (Grecco et al, 2011). In fact, the negative Table 1 Water characterization from the sewage effluent from Bahía Blanca (SW-BBE) and Monte Hermoso (MH).…”