Seasonal and spatial dynamic of current-use pesticides (CUPs) in an Argentinian watershed

PÉREZ, DÉBORA J; OKADA, ELENA; MENONE, ML.; COSTA, JOSÉ L

orlando

Congreso; 7th SETAC World Congress/SETAC North America 37th Annual Meeting.; 2016

Society of Environmental Toxicology and Chemistry (SETAC)

The Argentinian Pampa region is the major agricultural zone, in which,the agricultural lands are strongly linked to surface waters. However,Argentina has not regulation for most of the current -used pesticides(CUPs) in surface water to protect the aquatic life. The objective of thiswork was to study the seasonal and spatial variations of CUPs in surfacewaters of ?El Crespo? stream, and to determine the maximum levelsreached to evaluate the possible impact on aquatic life. ?El Crespo?stream is only influenced by farming activities, with intensive cropsystems upstream (US) and extensive livestock production downstream(DS). It is an optimal site for pesticide monitoring studies since thereare no urban or industrial inputs into the system. Water samples werecollected monthly from October 2014 to October 2015 in the US and DSsites by triplicate using 1 L polypropylene bottles and stored at -20°Cuntil analysis. The samples were analyzed using liquid chromatographycoupled to a tandem mass spectrometer (UPLC-MS/MS). The mostfrequently detected residues (>40%) were glyphosate (GLY) and itsmetabolite amino methylphosphonic acid (AMPA), atrazine, acetochlor,metolachlor, 2,4-D, metsulfuron methyl, fluorocloridone, imidacloprid,tebuconazole and epoxiconazole, which are used in the crops cultivatedin the area (i.e. soybean, potato, maize and wheat). Individual analysisshowed that the herbicide GLY and its metabolite AMPA presentedseasonal and spatial variations. The highest concentrations of GLY andAMPA were detected in US site during spring 2014 (2.09 ± 0.39 and 1.13± 0.56 μg/L, respectively) and in DS during summer 2015 (1.06 ± 1.02and 0.20 ± 0.23μg/L). Comparing totalCUPs concentration between sites,a significant increase in UP site during spring 2014 (4.03 ± 0.43 μg/L) inrelation to DS (1.54 ± 1.17 μg/L) was observed, may be due to pesticideapplications during fallow and transport via surface runoff. Data generatedin the present research could be used for evaluating the possibleimpact of pesticide mixtures on aquatic life and for regulation guidelines.