Preliminary evidence of aquatic and atmospheric PCB´s inputs at the Bahia Blanca estuary, Argentina

ARIAS, A.H.; DIAZ, GILBERTO; VAZQUEZ-BOTELLO, A.; MARCOVECCHIO, J.H.

Bahía Blanca

Congreso; II Reunión Argentina de Geoquímica de la Superficie; 2012

Instituto Argentino de Oceanografía (IADO)

Preliminary evidence of aquatic and atmospheric PCB´s inputs at the Bahia Blanca estuary, Argentina Counted among POPs, Polychlorinated biphenyls (PCBs) are a family of 209 hydrophobic chlorinated compounds characterized by high persistence, bioaccumulative potential and toxicity properties due to their lipophilicity and widespread distribution in the environment. PCBs stick strongly to soil and sediments and will not usually be carried deep into them with rainwater or vertical infiltration water flux. As they do not readily break down, they may stay in these matrices for months or years. To test the occurrence of these COPs at the area of study, a total of 29 samples were collected over twelve selected locations, including harbours, the estuary?s main navigation channel and several industrialized coastal locations, at three sampling legs between 2005 and 2006. All sediment samples contained detectable amounts of iPCBs. Total iPCBs ranged from less than 1ppb to more than 160 ppb. The overall mean Total iPCBs (sum of seven congeners) recorded in this study was 24.16 ± 10.02 ppb, n=29. It is not clear whether the estuary tributaries transport PCBs and deposits them in sediments or that the atmosphere transports them. Results showed simultaneous predominance of heavier congeners such as CB180 and lighter ones, such as CB52, CB101 and CB28. On the one hand, the presence of the PCB congeners 138, 153 and 180 could reflect the input of technical mixtures into the environment (in e.g.; Aroclor 1260); probably from possible non-point sources which follow water-transport pathways such as terrestrial runoff, sewage and industrial discharges. On the other hand, one of the most abundant congeners was the CB52, which is widely contributed from atmospheric transport.