Temporal / spatial fluctuations of Cu in water and sediments from an estuary under environmental changes (Argentina).

BOTTÉ, S.E.; ARLENGHI, J.; CHIARELLO, M.N.; ASTEASUAIN, R.; MARCOVECCHIO, J.E.

Kiel

Conferencia; AQUASHIFT: FINAL WORKSHOP & OPEN SCIENCE CONFERENCE; 2010

AQUASHIFT

Heavy metals occur in the environment both as a result of natural processes and as pollutants from human activities. Contamination of the marine environments such as estuaries by metals has risen in recent years to the population increase and industrial and harbor development. The estuarine systems have particular hidrogeochemistry characteristics. They are highly productive and sensitive areas and are seriously affected by different sources of pollution. The estuary burden of heavy metals is actually a serious environmental concern and public interest regarding this topic has been increasing. The effluent discharges may be the main sources that cause effects of impact by heavy metals in the sediment. The studies about presence of Cu in the sediment and water from Bahía Blanca estuary have beginning at earlier of 1970 and a monitoring program comes from since 2002. The objective of this work was to evaluate the temporal and spatial cupper distribution in the bottom sediments and dissolved fraction of water from the inner part of the estuary. It were evaluated eight samples sites between 2002 and 2007 over the Principal Channel of Navigation and one situated at the end of sewage effluent. All samples were taken aboard of “Buen Día Señor” vessel with a sledge. The analytical methodology was based in a web mineralization (percloric plus nitric acids) or extraction with organic solvent (MIBK), and lecture of absorbance in an atomic absorption spectrometry. The results show that in general for each sample site the Cu concentrations no differ between years within both sediment and dissolved fraction analyzed. Considering all joint years is detected statistical significant difference between sites (p<0.01). When the Tukey test was applied was demonstrated that the main source of Cu to the system is sewage effluent (higher concentrations in the sediment), and the outer evaluated points differ from the rest of sites showing lower concentrations. However, the same point shows the lower concentration in the dissolved fraction which possibly depends of the particulate suspended matter that setting and forms the bottom sediment. In addition of sewage, other point of Cu intake was the middle industrial area. The analysis in the water shows the main punctual intake of Cu to the system is industrial-petrochemical area. Particular environmental conditions within the systems (temperature, pH, dissolved oxygen) were considered to understand these results and thus evaluated the ecology consequences that could be reflected through changes within biodiversity.