Clothianidin alters leukocyte profiles and elevates measures of oxidative stress in tadpoles of the amphibian, Rana pipiens.

Neonicotinoid pesticide use is widespread and highly debated, as evidenced by recent attention received from the public, academics and pesticide regulatory agencies. However, relatively little is known about the physiological effects of neonicotinoid insecticides on aquatic vertebrates. Amphibians (larval stages in particular) are excellent vertebrate bioindicators in aquatic systems due to their risk of exposure and sensitivity to environmental stressors.

Effects of two pesticides on northern leopard frog (Lithobates pipiens) stress metrics: Blood cell profiles and corticosterone concentrations.

Amphibians are declining globally. Exposure to pesticides has been implicated in decreasing amphibian immune function, thus increasing their susceptibility to parasites and disease and thereby negatively affecting individuals and populations. Amphibians are likely exposed to neonicotinoids because these widely used insecticides are highly soluble in water and because amphibian freshwater habitats are often embedded in agroecosystems.

Effects of 2 Neonicotinoid Insecticides on Blood Cell Profiles and Corticosterone Concentrations of Wood Frogs (Lithobates sylvaticus).

Neonicotinoids are widely used insecticides that are detectable in agricultural waterways. These insecticides are of concern due to their potential impacts on nontarget organisms. Pesticides can affect development of amphibians and suppress the immune system, which could impact disease susceptibility and tolerance.

Sublethal effects on wood frogs chronically exposed to environmentally relevant concentrations of two neonicotinoid insecticides.

Neonicotinoids are prophylactically used globally on a variety of crops, and there is concern for the potential impacts of neonicotinoids on aquatic ecosystems. The intensive use of pesticides on crops has been identified as a contributor to population declines of amphibians, but currently little is known regarding the sublethal effects of chronic neonicotinoid exposure on amphibians. The objective of the present study was to characterize the sublethal effect(s) of exposure to 3 environmentally relevant concentrations (1 μg/L, 10 μg/L, and 100 μg/L) of 2 neonicotinoids on larval wood frogs (Lithobates sylvaticus) using outdoor mesocosms.

Determining in situ periphyton community responses to nutrient and atrazine gradients via pigment analysis.

Agrochemicals, including fertilizers and herbicides, are significant contributors of non-point source pollution to surface waters and have the potential to negatively affect periphyton. We characterized periphyton communities using pigment markers to assess the effects of nutrient enrichment and the herbicide atrazine with in situ experimental manipulations and by examining changes in community structure along existing agrochemical gradients. In 2008, the addition of nutrients (20 mg/L nitrate and 1.

Atrazine contamination at the watershed scale and environmental factors affecting sampling rates of the polar organic chemical integrative sampler (POCIS).

Polar organic chemical integrative samplers (POCIS) were used to estimate atrazine contamination at 24 stream/river sites located across a watershed with land use ranging from 6.7 to 97.4% annual crops and surface water nitrate concentrations ranging from 3 to 5404 μg/L.

Comparing the sensitivity of geographically distinct Lemna minor populations to atrazine.

The objectives of this study were to compare the sensitivities of field populations and a laboratory culture of a duckweed species (Lemna minor) to the herbicide atrazine using three different endpoints and to determine whether sensitivity to atrazine was affected by past exposure to the herbicide. L. minor cultures were purchased commercially or collected from field sites within an agricultural watershed and exposed to atrazine for 7 days under greenhouse conditions.

Comparison of the effects of glyphosate and atrazine herbicides on nontarget plants grown singly and in microcosms.

Intensification of agriculture and the corresponding increase in herbicide use has led to concern regarding the effects these chemicals may have on nontarget plants of agroecosystems. Current pesticide registration guidelines are focused on testing crop species grown singly in pots under greenhouse conditions and may not provide adequate measures of protection to noncrop species. The objective of the present study was to compare the response of terrestrial and wetland plants to the herbicides glyphosate and atrazine when grown singly in pots versus under different microcosm conditions.

Germination requirements for 29 terrestrial and wetland wild plant species appropriate for phytotoxicity testing.

Background: Species selected for phytotoxicity testing have been limited to a few standard crop species owing to restrictive recommendations at the regulatory level. However, guidelines by the Organisation for Economic Development and Cooperation (OECD) were recently amended in 2006 to include a list of herbaceous non-crop plant species suitable for testing. The objective of this study was to outline the optimum germination requirements for a selection of wild species for which seeds were readily available from commercial suppliers.