Acute toxicity of herbicide formulations and chronic toxicity of technical‐grade trifluralin to larval green frogs (<i>Lithobates clamitans</i>)

Weir, Scott M.; Yu, Shuangying; Salice, Christopher J.

doi:10.1002/etc.1910

Cited by 16 publications

(11 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Animal studies on toxic effects of insecticides are more common than of herbicides (Weir et al, 2012). In the Americas and Europe, corn cultivation has already increased in the last few decadesespecially for fodder crop production -but currently, corn cultivation is remarkably expanding for biofuel production (Landis et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Effects of an environmentally relevant temporal application scheme of low herbicide concentrations on larvae of two anuran species

et al. 2015

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Effects of an environmentally relevant temporal application scheme of low herbicide concentrations on larvae of two anuran species

et al. 2015

View full text Add to dashboard Cite

“…Fewer amphibian toxicological studies have been performed with herbicides, although they are applied in higher amounts than, for instance, insecticides (Weir et al 2012). Therefore, we chose an herbicide formulation as test substance that is commonly used in corn production.…”

mentioning

confidence: 98%

Acute Toxic Effects of the Herbicide Formulation Focus® Ultra on Embryos and Larvae of the Moroccan Painted Frog, Discoglossus scovazzi

Wagner

Lötters

Veith

et al. 2015

Arch Environ Contam Toxicol

View full text Add to dashboard Cite

For regulatory and scientific purposes, there is a need to understand the sensitivity of a wider variety of wild species of amphibians and the sensitivities within their life stages to chemicals of widespread use such as herbicides. We investigated the acute toxic effects of the herbicide formulation Focus Ultra [with the active ingredient (a.i.) cycloxydim plus solvent naphtha and sodium dioctylsulphosuccinate as added substances] on embryos and early stage larvae of the Moroccan painted frog (Discoglossus scovazzi). Different clinical signs (twitching, convulsion, and narcosis) occurred at 40 and 80 mg/L in embryos (4 and 8 mg a.i./L) and narcotic effects (total immobilization or irregular escape responses) at 10, 15, and 20 mg/L in larvae (1, 1.5, and 2 mg a.i./L). Growth inhibition (total length), starting at 20 mg/L in embryos and 2.5 mg/L in larvae (2 and 0.25 mg a.i./L, respectively) was understood as sign of toxicity (retardation) and not as sign of teratogenicity. However, the connection to teratogenesis remained unclear though total length reduction occurred at concentrations <20 % of the 96-h LC50 value and at a minimum concentration that inhibits growth of only 17 % of the 96-h LC50 value. Starting at 20 mg/L, mortality in embryos significantly increased and at 15 mg/L in early larvae (2 and 1.5 mg a.i./L, respectively). Mortality of larvae was enhanced during the first 24 h of exposure to 15 and 20 mg/L (1.5 and 2 mg a.i./L). Morphology of the embryos remained unobtrusive. In contrary, axial malformations significantly increased in the early larvae starting at 10 mg/L (1 mg a.i./L), a concentration free of lethal effects. In all considered end points, larvae were significantly more sensitive than embryos, probably because of developmental and physiological properties or different exposure and bioavailability of the compound. Focus Ultra induced comparable lethal and immobilization effects in D. scovazzi as it does to standard test organisms in pesticide approval. However, to validate the apparent safety in the field, which is based on calculated surface water concentrations of the a.i., more data on real contamination levels is necessary (e.g., peak concentrations, concentrations of added substances). Furthermore, sufficient buffer strips between the farmland and amphibian ponds must be considered, and the effects of the substance on terrestrial life stages have not been assessed yet.

show abstract

“…Furthermore, there are a lack of data for terrestrial amphibian exposures needed to relate our pesticide body burdens to reported LC50 or LD50 values. Estimates of lethal concentrations or doses for larval amphibians have been published for several of the pesticide active ingredients we tested (e.g., Overmyer et al 2007;Weir et al 2012), but they are much lower than the body burdens we measured in our treefrogs, which indicates significant differences in pesticide tolerance between life stages. An extensive data set on dermal pesticide LD50 values among birds has been published (Mineau et al 2001), but amphibian skin is much less keratinized and has adaptations to enhance water uptake, thus preventing a meaningful comparison.…”

Section: Exposure Versus Effectsmentioning

confidence: 94%

Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures

Meter

Glinski

Henderson

et al. 2015

Arch Environ Contam Toxicol

View full text Add to dashboard Cite

For terrestrial amphibians, accumulation of pesticides through dermal contact is a primary route of exposure in agricultural landscapes and may be contributing to widespread amphibian declines. To show pesticide transfer across the amphibian dermis at permitted label application rates, our study was designed to measure pesticide body burdens after two simulated exposure scenarios. We compared direct exposures, where amphibians were present when spraying occurred, to indirect exposures, where amphibians were exposed to soils after pesticide application. During summer 2012, we reared barking (Hyla gratiosa) and green treefrogs (H. cinerea) through 60-90 days post-metamorphosis at a United States Environmental Protection Agency research laboratory. We tested exposure for 8 h to five pesticide active ingredients (imidacloprid, atrazine, triadimefon, fipronil, or pendimethalin) in glass aquaria lined with soil in the laboratory. We quantified total pesticide body burden and soil concentrations using liquid chromatography-mass spectrometry. All individuals in both treatments had measurable body burdens at the end of the study. A randomized block design analysis of variance (n = 18) showed that body burdens (p = 0.03) and bioconcentration factors (BCFs) (p = 0.01) were significantly greater in the direct overspray treatment relative to the indirect soil spray treatment for both species and tested pesticides. BCFs ranged from 0.1 to 1.16 and from 0.013 to 0.78 in the direct and indirect treatments, respectively. Our study shows dermal uptake for multiple pesticides from both direct spray and indirect soil exposures and provides empirical support for the degree to which terrestrial phase amphibians have higher body burdens after overspray pesticide exposure.

show abstract

Acute toxicity of herbicide formulations and chronic toxicity of technical‐grade trifluralin to larval green frogs (Lithobates clamitans)

Cited by 16 publications

References 22 publications

Effects of an environmentally relevant temporal application scheme of low herbicide concentrations on larvae of two anuran species

Effects of an environmentally relevant temporal application scheme of low herbicide concentrations on larvae of two anuran species

Acute Toxic Effects of the Herbicide Formulation Focus® Ultra on Embryos and Larvae of the Moroccan Painted Frog, Discoglossus scovazzi

Pesticide Uptake Across the Amphibian Dermis Through Soil and Overspray Exposures

Contact Info

Product

Resources

About