title: Comparative effects of technical-grade and a commercial formulation of glyphosate on the pigment content of periphytic algae.
abstract: We investigated the potentially different effects of one of the most commonly used glyphosate formulations in Argentina, Glifosato Atanor(®), and the technical-grade glyphosate on the pigment content, as biomass indicators of the algal fraction in a freshwater periphytic community. A laboratory bioassay was carried out in 250-ml beakers. Two treatments were used: technical-grade glyphosate acid and Glifosato Atanor(®) (isopropylamine salt of glyphosate 48 % w/v), which were at a concentration of 3 mg active ingredient per liter. Treatments and the control (without herbicide) were replicated in triplicate. The concentrations of chlorophyll a and b and carotenes were determined at 0, 2, 6, 10, 24, 48, 96 and 192 h after herbicide addition. A significant increase in pigment content was observed for both herbicides after a 2-day exposure. Moreover, the formulation had little or no effect compared to the active ingredient, suggesting that the additives of Glifosato Atanor(®) may not enhance glyphosate toxicity.
authors.affiliation: Departamento de Ecología, Genética y Evolución, IEGEBA UBA-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, C1428EHA, Ciudad de Buenos Aires, Argentina, msolangevera@ege.fcen.uba.ar.
authors.forename: María S
authors.initials: MS
authors.lastname: Vera
authors.forename: Ángela  B
authors.initials: Á
authors.lastname: Juárez
authors.forename: Haydée N
authors.initials: HN
authors.lastname: Pizarro
mesh_terms: D000704:Analysis of Variance; D001118:Argentina; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D005998:Glycine / Q000031:analogs & derivatives* / Q000633:toxicity; D006540:Herbicides / Q000633:toxicity*; D019684:Magnoliopsida / Q000382:microbiology*; D064307:Microbiota / Q000187:drug effects*; D010860:Pigments, Biological / Q000032:analysis*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D000097797:Glyphosate
chemical_list: D002734:Chlorophyll; D000077194:Chlorophyll A; D005998:Glycine; D006540:Herbicides; D010860:Pigments, Biological; D014874:Water Pollutants, Chemical; D000097797:Glyphosate; C037184:chlorophyll b