Attenuation Effect of Azolla spp. on Lambda-Cyhalothrin Toxicity to Aquatic Organisms.

Wetlands play a crucial role in providing valuable ecosystem services, including the removal of various pollutants. In agricultural basins, wetlands are exposed to agrochemical loads. This study aims to assess the attenuation effect of the ubiquitous macrophyte Azolla spp.

Land-use impacts on benthic macroinvertebrate assemblages in pampean streams (Argentina).

In recent decades agriculture has intensified in the Argentine Pampa, and pesticide application has also increased. Livestock fields, although being progressively replaced by crops, are still commonly interspersed with crop fields. The objective of the present work is to assess the effects of land use on the benthic invertebrate assemblages of streams in the main Argentine agricultural region.

Fish Assemblages in Pampean Streams (Buenos Aires, Argentina): Relationship to Abiotic and Anthropic Variables.

The present study reported the effect of natural and anthropic environmental variables on the fish assemblages in the pampean streams, in the coastal strip along the Río de la Plata, Buenos Aires province, Argentina. Five streams were sampled at 12 sites surrounded by land devoted to different uses. A correspondence analysis sorted the streams into two groups: a less impacted group formed by sites surrounded by livestock- raising pastures and a more impacted one passing through urban sites and including a stream adjacent to a modest rural urbanization with a dairy in the stream's basin.

Sublethal effects on Simocephalus vetulus (Cladocera: Daphnidae) of pulse exposures of cypermethrin.

Pyrethroids are among the most widely applied insecticides worldwide and cypermethrin is the pyrethroid most used in Argentina. Pesticides used in crops can reach adjacent watercourses through runoff and may lead to non-target fauna receiving toxic pulse exposures. The aim of this study was to determine the effects of cypermethrin pulse exposures on the widely distributed crustacean Simocephalus vetulus.

Aquatic macroinvertebrate assemblages are affected by insecticide applications on the Argentine Pampas.

Agriculture intensification in Argentina has increased agrochemicals consumption in the last decades and might represent an environmental risk for adjacent water bodies. The objective of the present work was to assess the effect of land use on water quality and invertebrate assemblages in the Argentine Pampas streams. Eight streams were sampled on 4 occasions during the 2013/14 growing season.

Land use effect on invertebrate assemblages in Pampasic streams (Buenos Aires, Argentina).

Agriculture and livestock may contribute to water quality degradation in adjacent waterbodies and produce changes in the resident invertebrate composition. The objective of the present study was to assess land use effects on the stream invertebrate assemblages in rural areas of the Argentine Pampa. The four sampling events were performed at six sites in four streams of the Pampa plain; two streams were sampled inside a biosphere reserve, and another one was surrounded by extensive livestock fields.

Acute Toxicity of Endosulfan to the Non-target Organisms Hyalella curvispina and Cnesterodon decemmaculatus.

Pesticide consumption in Argentina has steadily increased over the last two decades, while one of these compounds, namely endosulfan, is commonly found in environmental samples. Also the fish Cnesterodon decemmaculatus and the amphipod Hyalella curvispina are widely distributed in agricultural areas of southern South America. The aim of the present contribution was therefore to determine the acute toxicity of endosulfan to both organisms, and compare it with species sensitivity distributions (SSD) and measured field concentrations.

Toxicity Persistence of Chlorpyrifos in Runoff from Experimental Soybean Plots to the Non-target Amphipod Hyalella curvispina: Effect of Crop Management.

Toxicity persistence to the nontarget amphipod Hyalella curvispina in runoff events following chlorpyrifos applications to soy experimental plots was compared in conventional and no-till management. Two application scenarios were compared: an early-season application with the soil almost bare and a late-season application after the foliage had attained complete soil cover. H.

Acute toxicity of chlorpyrifos to the non-target organism Cnesterodon decemmaculatus.

Chlorpyrifos is the most used insecticide in Argentina. Cnesterodon decemmaculatus is a widely distributed, endemic fish from Neotropical America. It attains high densities in the shallow water assemblages of Argentina and Brazil.

Nutrient concentrations in a Pampasic first order stream with different land uses in the surrounding plots (Buenos Aires, Argentina).

The objective of this study was to assess the effect of land use on nutrient concentrations in a Pampasic stream. Soluble reactive phosphorus (SRP) concentrations in the stream were higher at a site surrounded by fertilized double-cropped wheat/soybeans than at unfertilized soybeans plots. Nitrate and SRP concentrations in the stream were lower at sites surrounded by soybeans than livestock.

Acute toxicity of cypermethrin to the non target organism Hyalella curvispina.

The acute toxicity of cypermethrin to the amphipod Hyalella curvispina was evaluated by means of a toxicity test under laboratory conditions. Cypermethrin is one of the most widely used insecticides in Argentina. H.

Toxicity persistence in runoff and soil from experimental soybean plots following insecticide applications.

Persistence of toxicity in runoff water and soil was investigated in experimental soybean plots subjected to successive runoff events following pesticide application. Runoff events were produced by irrigation using a sprinkler system. The pesticides applied were cypermethrin and endosulfan, which are widely used in soy production in Argentina.

Toxicity persistence in runoff water and soil in experimental soybean plots following chlorpyrifos application.

Toxicity persistence in runoff water and soil was studied in experimental soybean plots in successive runoff events produced by an irrigation system. Three chlorpyrifos applications throughout the growing period were assayed. Runoff and soil toxicity to the amphipod Hyalella curvispina and the fish Cnesterodon decemmaculatus was assessed.

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

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.

Impact of cypermethrin on stream fish populations under field-use in biotech-soybean production.

The impact of biotech-soybean technology on freshwater ecosystems is being evaluated in the Rolling Pampas region, Argentina. The effect of cypermethrin, the main soybean insecticide, on low-order temperate-stream fish populations was investigated for two consecutive crop cycles under field-use conditions in biotech-soybean production. Cypermethrin was unable to induce mortality or behavioral effects on any of the fish species resident in a first-order stream across a crop field (pulsed acute exposure scenario) sprayed according to conventional practices.