New evidences of Roundup® (glyphosate formulation) impact on the periphyton community and the water quality of freshwater ecosystems

• Published in: Ecotoxicology (London) Vol. 19; no. 4; pp. 710 - 721
• Main Authors: Vera, María S, Lagomarsino, Leonardo, Sylvester, Matías, Pérez, Gonzalo L, Rodríguez, Patricia, Mugni, Hernán, Sinistro, Rodrigo, Ferraro, Marcela, Bonetto, Carlos, Zagarese, Horacio, Pizarro, Haydée
• Format: Journal Article
• Language: English
• Published: Boston Boston : Springer US 01-04-2010; Springer US; Springer Nature B.V
• Subjects: active ingredients; Agricultural practices; Algae; Aquatic ecosystems; Aquatic plants; Argentina; Bacillariophyta; Biomass; chlorophyll; Chlorophyll - metabolism; Chlorophyll A; Colonization; Cyanobacteria; Cyanobacteria - drug effects; Cyanobacteria - growth & development; Earth and Environmental Science; Ecology; Ecosystem; ecosystems; Ecotoxicology; Environment; Environmental Management; Environmental Monitoring - methods; Eukaryota - drug effects; Eukaryota - growth & development; Eukaryota - metabolism; Eutrophication; Fresh Water - chemistry; freshwater; Freshwater ecosystems; Glycine - analogs & derivatives; Glycine - metabolism; Glycine - toxicity; Glyphosate; Herbicides; Herbicides - metabolism; Herbicides - toxicity; lakes; macrophytes; mortality; nontarget organisms; periphyton; phosphorus; Phosphorus - metabolism; Phytoplankton; Risk Assessment; Soybeans; Suspended inorganic matter; Time Factors; Water Pollutants, Chemical - metabolism; Water Pollutants, Chemical - toxicity; Water quality; United States; Argentina; Mesocosms; Clear and turbid shallow lakes; Roundup; Glyphosate; Periphyton; Water quality
• ISSN: 0963-9292; 1573-3017
• DOI: 10.1007/s10646-009-0446-7

Argentina is the second largest world producer of soybeans (after the USA) and along with the increase in planted surface and production in the country, glyphosate consumption has grown in the same way. We investigated the effects of Roundup® (glyphosate formulation) on the periphyton colonization. The experiment was carried out over 42 days in ten outdoor mesocosms of different typology: “clear” waters with aquatic macrophytes and/or metaphyton and “turbid” waters with great occurrence of phytoplankton or suspended inorganic matter. The herbicide was added at 8 mg L⁻¹ of the active ingredient (glyphosate) in five mesocosms while five were left as controls (without Roundup® addition). The estimate of the dissipation rate (k) of glyphosate showed a half-life value of 4.2 days. Total phosphorus significantly increased in treated mesocosms due to Roundup® degradation what favored eutrophication process. Roundup® produced a clear delay in periphytic colonization in treated mesocosms and values of the periphytic mass variables (dry weight, ash-free dry weight and chlorophyll a) were always higher in control mesocosms. Despite the mortality of algae, mainly diatoms, cyanobacteria was favored in treated mesocosms. It was observed that glyphosate produced a long term shift in the typology of mesocosms, “clear” turning to “turbid”, which is consistent with the regional trend in shallow lakes in the Pampa plain of Argentina. Based on our findings it is clear that agricultural practices that involve the use of herbicides such as Roundup® affect non-target organisms and the water quality, modifying the structure and functionality of freshwater ecosystems.