Accumulation of indicators polychlorinated biphenyls (iPCBs) in sediments of the navigation channel, harbours and industrial area of the Bahia Blanca Estuary, Argentina

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

Santa Fe, Argentina

Congreso; III Congreso Argentino de la Sociedad de Toxicología y Química Ambiental (SETAC); 2010

SOCIEDAD DE TOXICOLOGIA Y QUÍMICA AMBIENTAL (SETAC)

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:EN-GB;} @page Section1 {size:595.3pt 841.9pt; margin:2.0cm 2.0cm 2.0cm 2.0cm; mso-header-margin:35.45pt; mso-footer-margin:35.45pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Anthropogenic activities such as industry, sewage, coastal sprawl, intensive agriculture and oil spills have a strong impact on coastal zones and estuaries around the world. In Argentine, a developing country, although the growing awareness of persistent organic pollutant’s release to marine ecosystems has prompted diverse conservation measures, at present there is a lack of studies and legal under-regulation on this topic. Counted among POPs, Polychlorinated biphenyls (PCBs) are a family of 209 hydrophobic chlorinated compounds characterized by high persistence, bioaccumulative and toxicity properties due to their lipophilicity and widespread distribution in the environment. The emerging problem is that the rapid development, construction, urbanisation and industrialisation may be affecting the area of study (the Bahia Blanca Estuary, 38 º 500´ S and 62º 300´ W, a heavily industrialized environment including oil, chemicals, fertilizers and plastic factories, two commercial harbours and a big industrial city with more of 350000 inhabitants). Despite this, there is only fragmented data for PCBs in selected Argentinean marine environments and no previous information about PCBs for any matrices at the area of study. This study presents the first comprehensive survey of PCBs in coastal sediments in Bahia Blanca, Argentina and intends to provide useful information on their levels of concentration, composition and potential sources. For this reason, twenty sediment samples (up to 14 m deep) were collected between November 2005 and April 2006 over nine selected areas on board of the “Buen día Señor” R.V. The sampled areas included the estuary’s main navigation channel, two harbours, an industrial zone, recreational docks and rural zones. The method was optimized for the analysis of seven “indicator” PCBs (28, 52, 101, 118, 138, 153 and 180) by a GC (HP 6890 Series) with an ECD detector (63Ni). All sediment samples contained detectable amounts of iPCBs. Total iPCBs ranged from less than 1ppb to more than 60 ppb. The mean Total iPCBs recorded in this study (19.2 ± 20.3 ppb, n=20) indicates that the study area lies between the low and moderately polluted coastal areas around the world, in the range of other industrialized coastal zones and harbours. Since the incidence of runoff can be great in urban and industrial areas it is possible that a significant contribution of PCBs (samples S4 to S6) was provided by the runoff of the 200 ha of industrially used lands. The aforementioned joint to the slower break down of highly chlorinated PCBs, may lead to a preferential transfer of heavy congeners to the sediment, in particular CB-180 which was higher at those samples. 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. Consequently, it is unlikely that water-transport pathway was the unique source and atmospheric transport (which shows preference on light congeners) could be contributing.