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Chlorpyrifos (O, O-diethyl O-3,5,6-trichloropyridin-2-yl phosphorothioate) and carbaryl (1-naphthyl methylcarbamate) are often applied concurrently as insecticides in food production. The aim of this study was to research their migration behavior in a real environment. We researched the leaching of both pesticides by setting up field lysimeters on a farm with the typical soil used in fruit production today. In order to analyze the variables involved in this process, we performed complementary adsorption studies, we performed complementary adsorption studies using batches and undisturbed soil laboratory columns for both compounds. The results for pesticide transport through the lysimeters showed that less than 1% of chlorpyrifos was recovered in the leachates, while almost 17% was recovered for carbaryl. Having completed the experiment in undisturbed laboratory columns, soil analysis showed that chlorpyrifos mainly remained in the first 5 cm, while carbaryl moved down to the lower sections. These results can be explained in view of the sorption coefficient values (KD) obtained in horizons A and B for chlorpyrifos (393 and 184 L kg-1) and carbaryl (3.1 and 4.2 L kg-1), respectively. By integrating the results obtained in the different approaches, we were able to characterize the percolation modes of these pesticides in the soil matrix, thus contributing to the sustainable use of resources.

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Spatial distribution and probable sources of aliphatic and polyaromatic hydrocarbons (AHs, PAHs) were investigated in surface sediments collected along the bank of the Neuquen River, Argentina. Total concentrations of aliphatic hydrocarbons ranged between 0.41 and 125 µg/g dw. Six stations presented low values of resolved aliphatic hydrocarbons and the n-alkane distribution indexes applied suggested a clear biogenic source. These values can be considered the baseline levels of aliphatic hydrocarbons for the river sediments. This constitutes important information for the assessment of future impacts since a strong impulse in the exploitation of shale gas and shale oil in these zones is nowadays undergoing. For the other 11 stations, a mixture of aliphatic hydrocarbons of petrogenic and biogenic origin was observed. The spatial distribution reflects local inputs of these pollutants with a significant increase in concentrations in the lower course, where two major cities are located. The highest values of total aliphatic hydrocarbons were found in this sector which, in turn, was the only one where individual PAHs were detected.

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An assessment of the off-site migration of pesticides from agricultural activity into the environment in the Neuquen River Valley was performed. The aim of this study was to evaluate the distribution of pesticides in several compartments of a small agricultural sub-catchment. Soil, surface water, shallow groundwater and drift deposition were analyzed for pesticide residues. Results showed the presence of some pesticide residues in soil, surface water and shallow groundwater compartments. The highest detection frequencies in water (surface and subsurface) were found for azinphos-methyl and chlorpyrifos (>70%). In terms of concentration, the highest levels were observed in shallow groundwater for azinphos methyl (22.5 µg/L) and carbaryl (45.7 µg/L). In the soil, even before the application period had started, accumulation of residues was present. These residues increased during the period studied. Spray drift during pesticide application was found to be a significant pathway for the migration of pesticide residues in surface water, while leaching and preferential flows were the main transport routes contributing to subsurface contamination.

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Aunque el manejo integrado de plagas se aplica en forma creciente en la Región Norpatagónica, todavía una amplia gama de plaguicidas es utilizada con el fin de controlar apropiadamente las principales plagas agrícolas. Otros agroquímicos también son aplicados en las actividades industriales asociadas. El objetivo del presente trabajo es evaluar el impacto potencial causado por estos plaguicidas sobre los organismos acuáticos y para ello se utilizan datos bibliográficos de toxicidad aguda y resultados analíticos locales. Se utilizó un procedimiento escalonado, permitiendo la selección de aquellos xenobióticos ambientales que justificarían un estudio de ecotoxicidad posterior. Los residuos máximos de metil azinfos (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl)O,O-dimethyl phosphordithioate), indican la probabilidad de efectos agudos en el 37% de las especies estudiadas en el río, principalmente peces y zooplancton. Este valor se incrementa en los drenajes hasta un 42%. En el caso del carbaril (1-napthylmethylcarbamate) los residuos encontrados en drenajes afectarían al 14% de las especies estudiadas, mientras que en el río el impacto es despreciable.(AU)

Although the Integrated Pest Management (IPM) is increasingly being applied in the Northern Patagonia Region, different pesticides are still used in order to properly control agricultural pests. Other agrochemicals are also applied in the agriculture associated activities like conservation and packaging industries. The potential impact caused by these pesticides on aquatic organisms is assessed in the present study by means of acute toxicity data available in the literature and local analytical results. A tiered procedure was used allowing the selection of those environmental xenobiotics that need further ecotoxicity studies. The observed maximum residues of azinphos-methyl, (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl) O,O-dimethyl phosphordithioate), indicate the probability of acute effects in 37 % of the studied species in the river, mainly fish and zooplankton.This value increased in drainage channels samples up to 42 %. Additionally, carbaryl (1-napthylmethylcarbamate) residues foundin drainage channels affect 14 % of the studied species, while in the river samples the impact was negligible.(AU)

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RESUMEN

Aunque el manejo integrado de plagas se aplica en forma creciente en la Región Norpatagónica, todavía una amplia gama de plaguicidas es utilizada con el fin de controlar apropiadamente las principales plagas agrícolas. Otros agroquímicos también son aplicados en las actividades industriales asociadas. El objetivo del presente trabajo es evaluar el impacto potencial causado por estos plaguicidas sobre los organismos acuáticos y para ello se utilizan datos bibliográficos de toxicidad aguda y resultados analíticos locales. Se utilizó un procedimiento escalonado, permitiendo la selección de aquellos xenobióticos ambientales que justificarían un estudio de ecotoxicidad posterior. Los residuos máximos de metil azinfos (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl)O,O-dimethyl phosphordithioate), indican la probabilidad de efectos agudos en el 37% de las especies estudiadas en el río, principalmente peces y zooplancton. Este valor se incrementa en los drenajes hasta un 42%. En el caso del carbaril (1-napthylmethylcarbamate) los residuos encontrados en drenajes afectarían al 14% de las especies estudiadas, mientras que en el río el impacto es despreciable.

Although the Integrated Pest Management (IPM) is increasingly being applied in the Northern Patagonia Region, different pesticides are still used in order to properly control agricultural pests. Other agrochemicals are also applied in the agriculture associated activities like conservation and packaging industries. The potential impact caused by these pesticides on aquatic organisms is assessed in the present study by means of acute toxicity data available in the literature and local analytical results. A tiered procedure was used allowing the selection of those environmental xenobiotics that need further ecotoxicity studies. The observed maximum residues of azinphos-methyl, (S-(3,4-dihydro-4-oxobenzo[d]-[1,2,3]-triazin-3-ylmethyl) O,O-dimethyl phosphordithioate), indicate the probability of acute effects in 37 % of the studied species in the river, mainly fish and zooplankton.This value increased in drainage channels samples up to 42 %. Additionally, carbaryl (1-napthylmethylcarbamate) residues foundin drainage channels affect 14 % of the studied species, while in the river samples the impact was negligible.

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