PROBIEN   20416
INSTITUTO DE INVESTIGACION Y DESARROLLO EN INGENIERIA DE PROCESOS, BIOTECNOLOGIA Y ENERGIAS ALTERNATIVAS
Unidad Ejecutora - UE
artículos
Título:
Risk assessment of Magnacide® H herbicide at Río Colorado irrigation channels (Argentina). Tier 3: studies on native species
Autor/es:
VENTURINO A; MONTAGNA M; PECHEN DE D'ANGELO A.M
Revista:
ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY
Referencias:
Año: 2007 vol. 26 p. 177 - 182
ISSN:
0730-7268
Resumen:
We evaluated the potential environmental risk of the herbicide MAGNACIDE® using native species from Argentina, representing the ecosystem at the Irrigation Corporation (CORFO) channels at the Colorado River mouth. Six species including fish, toads, snails, crustaceans and insects were selected to perform studies on acute toxicity and repeated exposure effects. MAGNACIDE® H susceptibility ranking was: Bufo arenarum (LC50= 0.023 mg/L), rainbow trout (LC50= 0.038 mg/L), Heleobia parchappii (LC50= 0.21 mg/L), Hyalella curvispina (LC50= 0.24 mg/L), Simulium spp. (LC50= 0.60 mg/L), Chironomus spp. (LC50= 2.83 mg/L). The risk limit of 10th percentile (0.013 mg/L) determined by Probit analysis on sensitivity distribution was similar to the one calculated from literature data. Risk assessment based on field application data suggested lethal exposures for more than 70-90% of the species up to 20 km downstream from the application point. Repeated exposures to MAGNACIDE® H of amphibian larvae at the lowest-observed-effect concentration caused some effects during the first exposure, but without cumulative effects. Amphipods were insensitive to repeated exposures showing no cumulative effects. Whether short term exposures may result in long term sublethal effects on the organism´s life history was not addressed by these laboratory tests. In conclusion, tier 3 studies indicate that MAGNACIDE® H application schedule is extremely toxic for most native species at CORFO-Río Colorado channels, representing a high potential risk in the environment. The real environmental impact must be addressed by field studies at tier 4 giving more information on population effects and communities.