Organic pollutant levels in an agricultural watershed: the importance of analyzing multiple matrices for assessing streamwater pollution

GONZALEZ, MARIANA; MIGLIORANZA, KARINA SILVIA BEATRIZ; GRONDONA, SEBASTIÁN; SILVA BARNI, FLORENCIA; MARTINEZ, DANIEL; PEÑA, ARANZAZU

Environmental Sciences: Processes & Impacts Formerly the Journal of Environmental Monitoring

Royal Society of Chemistry

Año: 2013 p. 739 - 750

2050-7887

This study is aimed to analyze the occurrence and transport of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the Quequén Grande river basin, as representative of a catchment under diffuse pollution sources. Pollutant levels on soils, river bottom sediments (RBS), streamwater (Sw), suspended particle material (SPM), macrophytes and muscle of silverside were determined by GC-ECD. Soil Kd values for the current-used insecticides, endosulfans and cypermethrin, were established. Total levels (ng g d.w-1) in soil ranged between 0.07 - 0.9 for OCPs, 0.03 - 0.37 for PCBs and 0.01- 0.05 for PBDEs. Endosulfan insecticide (-+-+sulfate metabolite) represented up to 72.5 % of OCPs. The low soil retention for -endosulfan (Kd 77) and endosulfan sulfate (Kd 100) allow their transport to Sw, SPM and RBS. Levels of endosulfan in Sw in some cases exceeded international guidelines for aquatic biota protection (3 ng L-1). PCBs and PBDEs pollution was related to harbour, dumping sites and pile tire burning. Tri and hexa PCBs congeners predominated in allmatrices and exceeded quality guideline values of 0.04 ng L-1 in Sw. Considering levels on silverside muscle, none of the oral reference doses were exceeded, however, PCBs accounted for the 18.6 % of the total daily allowed ingest for a 70 kg individual. Although PCBs and OCPs levels on soil and RBS were low and did not go beyond quality guidelines, these compounds could still represent a risk for aquatic biota and human beings, and thus actions towards preventing this situation should be undertaken.