title: Response of biomarkers in amphibian larvae to in situ exposures in a fruit-producing region in North Patagonia, Argentina.
abstract: The authors evaluated biomarker responses in caged larvae of the amphibian Rhinella arenarum in water channels during fruit production season and compared them with those elicited by a transient exposure to azinphos methyl (AzM) (0.02-2 mg/L; 4 h), the main pesticide applied in the Alto Valle region, Patagonia, Argentina, taking into account the maximum environmental concentration detected in superficial water (22.5 µg/L). The traditional biomarkers of organophosphate exposure, acetylcholinesterase (AChE) and carboxylesterase, were inhibited in tadpoles after one week of exposure in channels potentially receiving pesticide drift, whereas the antioxidant glutathione (GSH) and the detoxifying activity of GSH S-transferase (GST) were induced. In a two-week monitoring study, AChE activity was induced in larvae exposed at the agricultural site, and carboxylesterase showed an inhibition followed by return to control values, suggesting an exposure-recovery episode. Antioxidant glutathione levels were first depleted and then surpassed control levels, whereas GST activity was continuously induced. These responses were mimicked in the laboratory by 2 mg/L AzM-pulse exposure, which notably exceeds the expected environmental concentrations. The results draw attention to the complexity of responses after pesticide exposure, strongly depending on exposure time-concentration and recovery periods, among other possible factors, and support the necessity of the integrated use of biomarkers to assess exposure episodes in agricultural areas.
authors: Laboratory of Biochemical, Chemical, and Environmental Research, Department of Chemistry, Faculty of Engineering and North Patagonia Multidisciplinary Institute of Research and Development, National Council of Scientific and Technical Research-National University of Comahue, Neuquén, Argentina.
authors: Enrique A
authors: EA
authors: Rosenbaum
authors: Leonardo
authors: L
authors: Duboscq
authors: Jimena
authors: J
authors: Soleño
authors: Cristina M
authors: CM
authors: Montagna
authors: Ana
authors: A
authors: Ferrari
authors: Andrés
authors: A
authors: Venturino
mesh_terms: D000110:Acetylcholinesterase / Q000032:analysis; D057914:Agricultural Irrigation; D000383:Agriculture; D000818:Animals; D001118:Argentina; D001387:Azinphosmethyl / Q000494:pharmacology*; D015415:Biomarkers / Q000032:analysis*; D002022:Bufo arenarum / Q000378:metabolism*; D043182:Carboxylesterase / Q000032:analysis; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005638:Fruit; D005978:Glutathione / Q000032:analysis; D005982:Glutathione Transferase / Q000032:analysis; D007814:Larva / Q000187:drug effects; D010575:Pesticides / Q000494:pharmacology*; D012621:Seasons; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
chemical_list: D015415:Biomarkers; D010575:Pesticides; D014874:Water Pollutants, Chemical; D001387:Azinphosmethyl; D005982:Glutathione Transferase; D043182:Carboxylesterase; D000110:Acetylcholinesterase; D005978:Glutathione