Spatial distribution of polychlorinated biphenyls (PCBs) in surface sediments of streams from the southeastern region of Buenos Aires province, Argentina

MIGLIORANZA, KARINA SILVIA BEATRIZ; GONZALEZ, MARIANA; GERPE, MARCELA SILVIA; MENONE, MIRTA LUJAN; AIZPÚN, JULIA ELENA; MORENO, VICTOR JORGE

Buenos Aires

Congreso; 6ta Reunión Anual SETAC Latina; 2003

SETAC Latina

This research project was initiated to refine the knowledge available on the land-based source of marine pollution in the southeastern region of Buenos Aires Province. PCBs residues were analyzed by GC-ECD in samples of surface sediments from two creeks, which flow into the coast of Mar del Plata city. Five stations in each creek were selected and four samples were taken in each station. Las Brusquitas creek located in the south side of the city, pass through vast agricultural areas dedicated to extensive practices. Moreover, its head is in the vicinity of Otamendi city. On the other hand, La Tapera creek pass through horticultural areas and urban zone along the north side of Mar del Plata.  The results showed that La Tapera creek had a higher PCB pollution than Las Brusquitas creek with mean concentrations of 999 and 203 ng/g total organic carbon), respectively. The stations located in urban areas of both creeks showed the highest total PCB concentration (ng/g TOC) suggesting a punctual pollution source in these zones. Likewise, the head of La Tapera creek had also higher total PCB levels. It is located in a natural wetland, Los Padres lake, which is impacted by anthropogenic activities. In both creeks, a 33% decline in total PCB levels with distance away from the urban areas suggest a high attenuation of these compounds by the stream environment. However, La Tapera outfall presented 3-fold higher total PCB levels than Las Brusquitas outfall. It could be related with the distance to higher polluted stations. The distribution of PCBs in sediments from both creeks was relatively similar, with a predominance of higher chlorinated congeners. These results are consistent with an in situ pollution rather than long-range PCB transport. Keywords: PCBs, sediments, land-based sources.