Passive sampling of pesticides and polychlorinated biphenyls (PCBs) along the Quequén Grande River watershed (Argentina)

SILVA-BARNI, MARÍA FLORENCIA; SMEDES, FOPPE; FILLMANN, GILBERTO; MIGLIORANZA, KARINA SILVIA BEATRIZ

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Lugar: Buenos Aires; Año: 2018

0730-7268

Water monitoring is of great importance, especially for waterbodies in agricultural or industrial areas. Grab sampling is a widely used technique for aquatic monitoring but represents only a snapshot of the contaminant levels at a specific point in time. Passive sampling, on the other hand, is an integrative technique which provides an average concentration of contaminants representative for its deployment period. Thus, the current contamination by organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and some currently used pesticides (CUPs) was assessed along the Quequén Grande River watershed using the integrative silicone rubber (SR) passive sampling technique in a year-long study. SR samplers were deployed at six sampling sites selected according to different land uses (agricultural-livestock production, agricultural and urban activities) during three periods in 2014 and 2015. OCPs were dominated by endosulfan (sum of α-, β-endosulfan, endosulfan sulfate = 0.15-23.4 ng/L). The highest endosulfan levels were registered during the pesticide application period (December-March), exceeding the international water quality guidelines for protecting freshwater biota (3 ng/L). Comparing with previous reports, no reduction in endosulfan levels were observed at the Quequén Grande River watershed. These results would suggest the illegal use of remaining stocks since water sampling was carried out after endosulfan ban in Argentina. Chlorpyrifos was the second major pesticide found in water (0.02-4.3 ng/L), associated with its widespread usage on soybean crops. A reduction in levels of legacy pesticides (heptachlors, DDTs, dieldrin and chlordanes) was evident when compared with previous reports from 2007. PCBs levels were very low indicating that probably only minor diffuse sources were still available along the Quequén Grande River watershed. This article is protected by copyright. All rights reserved.