Occurrence and levels of glyphosate and AMPA in shallow lakes from the Pampean and Patagonian regions of Argentina.
Castro Berman, M., Marino, D. J. G., Quiroga, M. V. and Zagarese, H.
Instituto de Investigaciones Biotectonogicas de Chascomus (IIB-INTECH), Av. Intendente Marino Km 8,200 CC 164, 7130, Chascomus, Prov. de Buenos Aires, Argentina. Electronic address: manu-10-89@intech.gov.ar.
Centro de Investigaciones del Medio Ambiente (CIMA - CONICET), Facultad de Ciencias Exactas, Universidad Nacional de La Plata, Calle 47 y 115 s/n, 1900, La Plata, Buenos Aires, Argentina.
Instituto de Investigaciones Biotectonogicas de Chascomus (IIB-INTECH), Av. Intendente Marino Km 8,200 CC 164, 7130, Chascomus, Prov. de Buenos Aires, Argentina.
Glyphosate (N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide used to kill weeds that compete with commercial crops. In Argentina, the use of glyphosate-based herbicides increased dramatically (up to approximately 200,000 tons on 2012) since the introduction of glyphosate-resistant crops, such as transgenic soy and resistant corn, and the adoption of non-till practices in the 1990's. Sallow lakes within the Pampa region may be potentially impacted by continuous herbicide usage. We surveyed 52 shallow lakes from the Pampa region (Buenos Aires Province, Argentina) to assess the occurrence and concentrations of glyphosate and its main degradation product (AMPA). For comparison, we also sampled 24 shallow lakes from an area with no agricultural use of glyphosate (Northern Patagonia). Glyphosate and AMPA were analyzed by UPLC-MS/MS ESI (+/-) in lake water, suspended particulate matter (SPM), and sediment samples. Within the Pampa region, glyphosate residues were detected in >40% of samples. Glyphosate residues were detected more frequently in sediment and surface water than in SPM samples. The mean (maximum) concentrations of glyphosate were 2.11 (4.52) mug l(-1) for surface water; 0.10 (0.13) mug l(-1) for SPM and 10.47 (20.34) mug kg(-1) for sediment samples, respectively. Whereas, mean (maximum) concentrations of AMPA were 0.84 and (0.90) mug l(-1) for surface water; 0.07 (0.07) mug l(-1) for SPM; and 22.53 (32.89) mug kg(-1) for sediment samples. The herbicide was not detected in samples from the Patagonian region. To our knowledge, this is the first study reporting the occurrence and concentrations of the herbicide in freshwater lakes of Argentina.
Chemosphere 200: 513-522 (2018)