INVESTIGADORES
GUIÑAZU ALANIZ natalia Lorena
congresos y reuniones científicas
Título:
RISK ASSESSMENT OF PESTICIDES IN DRAINAGE CHANNELS FROM THE RÍO NEGRO AND NEUQUEN VALLEY (ARGENTINA)
Autor/es:
MACCHI PABLO; MONZA LILIANA; GUIÑAZÚ NATALIA; MONTAGNA MONICA; LATINI LORENA; LOEWY MIRIAM
Reunión:
Congreso; XIII Congreso Brasilero de Ecotoxicologia; 2014
Institución organizadora:
Sociedad Brasilera de Ecotoxicología
Resumen:
Agriculture
represents the second most important economic activity in the North Patagonia. Despite
the implementation on 2006 of an integrated pest management, non-selective
insecticides are still being used with significant implications to the environment
quality. Previous studies have demonstrated the presence of pesticides in both groundwater
and drainage channels2. The aim of this study was to evaluate the
risk to aquatic organisms from pesticide-contaminated waters. The study area involves
an irrigated 100 ha section of fruit production. Pesticides concentrations were
determined during the application period (October to March)
from 2008 to 2011 at five sites along drains, and one site from an upstream
irrigation channel. In the last two seasons, a macroinvertebrate biomonitoring
was also accomplished. The pesticides risk to aquatic organisms was assessed by
a tier approach3. A preliminary deterministic assessment of the
potential risk was determined by the acute and chronic hazard quotient (HQ). Additionally,
the frequency distribution of exposure concentrations was integrated with the
concentration-response relationship to generate a Joint Probability Curves
(JPC). Finally, in situ analyses of
benthic macroinvertebrates were incorporated to compare species density and richness
between control site and drains. The concentration ranges (µg/L)
determined for azinphosmethyl, chlorpyrifos and carbaryl in drains, during the
monitoring period, were from non-detected to 1.02, 1.45, and 11.21;
respectively. The pesticide most frequently detected was chlorpyrifos (61%)
followed by azinphosmethyl (44%) and carbaryl (21%), in accordance with
previously reported data1. For all three pesticides, the acute
and chronic HQ exceeded the risk criteria (0.5 and 1; respectively) for invertebrates.The
effects of the three pesticides on aquatic organisms, characterized by JPC,
showed that azinphosmethyl, chlorpyrifos and carbaryl concentrations over
the LC50 of 5% of the species were exceeded 7, 5 and 2 times during the analyzed
period; respectively. The benthic community at drains was comprised by 43 invertebrate
taxa and 8589 individuals. Relative abundance of macroinvertebrates at the control
site was mostly represented by Diptera (Chironomidaespp.and Simulium spp.), Amphipoda (Hyalella
curvispina) and Ephemeroptera (Americabaetis
alphus, Baetodes sp.). In contrast, the most abundant taxa in drains were
Amphipoda (H. curvispina), Mollusca (Heleobia parchapii, Chillina dombeyana)
and some Diptera. Taxa richnessat the control
site was always significantly higher than at drain channels. Moreover, both
taxa richness and abundance were significantly decreased in drains during
November, where peak concentrationsof chlorpyrifos and azinphosmethylwere detected
in water. The correlation between the pesticide concentration and taxonomic
richness and density of the benthic community indicated that only chlorpyrifos
concentrations were negatively correlated (Spearman r2 -0.61,
p=0.0051 and Spearman r2 -0.59, p=0.0068 for taxonomic richness and
density correlation; respectively). Other field studies had also found that Ephemeroptera spp3,4 were among the most
pesticide sensitive species. In conclusion, both drain macroinvertebrates taxa richness
and abundance were affected by pesticide concentrations, mainly by chlorpyrifos.