Persistent Organic Pollutants in soils, sediments and fish from the Negro River basin, Patagonia Argentina

MIGLIORANZA K.S.B.; ONDARZA P.M.,; GONZALEZ M.,; ISLA F.I.,; AIZPÚN J.E.; MORENO V.J.

Mission Valley Marriott, San Diego, CA, USA

Congreso; 18th Annual AEHS (Association for Environmental Health and Sciences) Meeting and West Coast Conference on Soils, Sediments and Water; 2008

Society of Environmental Toxicology and Chemistry (SETAC)

 Persistent organic pollutants (POPs), like organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs), are compounds of concern due to their distribution, global transport and toxicity. Its high hydrofobicity determines its adsorption to organic material and fine particles of soils and sediments that by runoff processes reach aquatic environments. Fish are exposed to a multitude of potentially toxic substances acting simultaneously on natural freshwater ecosystems. This is the case of pesticides that are repeatedly applied to the same agricultural areas in order to protect crop productions, like the High Valley and Medium Valley of the Negro River which constitute the main exporting fruit cultures zone of Patagonia Argentina. Thus, the fruit-tillage?derived aqueous and particle-associated OCPs and PCBs contamination, considering surface sediments and soils, respectively from the integrity of the Negro River basin was measured in a comprehensive design. Moreover muscle of rainbow trout was analyzed for OCPs and PCBs contamination. Sampling was performed in the beginning of February, in the middle of the wet season. Contaminants were analyzed by GC-ECD. The greater concentrations in soils, sediments and fish were found in the High Valley of the Negro River, diminishing towards the coast (500 km) with median values between 1.2- 45 ug/g organic carbon, 0.7-8 ug/g organic carbon and 0.21 ug/g wet weight, for soils, sediments and fish respectively. Therefore, soil plays a key role in the long term environmental cycling and fate of these chemicals. The OCPs/PCBs ratio >> 1 in all sampling stations denotes the predominance of agricultural activities in the region. Among OCPs, DDTs (sum p-p´DDE, p-p´DDD and p-p´DDT) and Endosulfans (sum of a-endosulfan, b-endosulfan and endosulfan sulphate), which technical mixture is currently used, were mainly found. High chlorinated biphenyls (5 and 6 CB), was found mainly in sediments and fish. The characterization of runoff-related pesticide input and the identification of areas of concern in the field are essential for a comprehensive assessment of risk and the planning of mitigation measures.