Influence of commercial formulation on leaching of four pesticides through soil

Khan, Majid Ali; Brown, Colin D.

doi:10.1016/j.scitotenv.2016.09.076

Cited by 22 publications

(11 citation statements)

References 22 publications

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“…It is established that the half-life of pesticide active ingredients in soil is extended by the presence of adjuvants as has been demonstrated for chloridazon ( 50 ). A study investigating the leaching of four pesticide formulations (azoxystrobin, propyzamide, triadimenol, and cyproconazole) through a sandy loam soil found that leaching was greater than was the case with their respective active ingredients alone ( 51 ).…”

Section: Regulatory Guidance Values For Pesticides Can Be Miscalculatmentioning

confidence: 99%

Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides

Mesnage

Antoniou

2018

Front. Public Health

221

126

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Commercial formulations of pesticides are invariably not single ingredients. Instead they are cocktails of chemicals, composed of a designated pesticidal “active principle” and “other ingredients,” with the latter collectively also known as “adjuvants.” These include surfactants, antifoaming agents, dyes, etc. Some adjuvants are added to influence the absorption and stability of the active principle and thus promote its pesticidal action. Currently, the health risk assessment of pesticides in the European Union and in the United States focuses almost exclusively on the stated active principle. Nonetheless, adjuvants can also be toxic in their own right with numerous negative health effects having been reported in humans and on the environment. Despite the known toxicity of adjuvants, they are regulated differently from active principles, with their toxic effects being generally ignored. Adjuvants are not subject to an acceptable daily intake, and they are not included in the health risk assessment of dietary exposures to pesticide residues. Here, we illustrate this gap in risk assessment by reference to glyphosate, the most used pesticide active ingredient. We also investigate the case of neonicotinoid insecticides, which are strongly suspected to be involved in bee and bumblebee colony collapse disorder. Authors of studies sometimes use the name of the active principle (for example glyphosate) when they are testing a commercial formulation containing multiple (active principle plus adjuvant) ingredients. This results in confusion in the scientific literature and within regulatory circles and leads to a misrepresentation of the safety profile of commercial pesticides. Urgent action is needed to lift the veil on the presence of adjuvants in food and human bodily fluids, as well as in the environment (such as in air, water, and soil) and to characterize their toxicological properties. This must be accompanied by regulatory precautionary measures to protect the environment and general human population from some toxic adjuvants that are currently missing from risk assessments.

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Section: Regulatory Guidance Values For Pesticides Can Be Miscalculatmentioning

confidence: 99%

Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides

Mesnage

Antoniou

2018

Front. Public Health

221

126

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“…Effectively control weeds with few or no adverse environmental must be observed in a well-planned management system. However, the high amount of herbicides used in agronomic practices leads to the existence of contaminated groundwater sources, mainly through the leaching process [2][3][4]. The most important parameters that determine herbicide capacity to leach, and so capable to reach groundwater, are the herbicide properties, being persistence in soil and sorption the most relevant ones.…”

Section: Introductionmentioning

confidence: 99%

Lignin and ethylcellulose in controlled release formulations to reduce leaching of chloridazon and metribuzin in light-textured soils

Flores‐Céspedes

Daza-Fernández

Villafranca‐Sánchez

et al. 2018

Journal of Hazardous Materials

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In this research, controlled release formulations (CRFs) of the herbicides chloridazon and metribuzin, identified as potential leachers, have been evaluated in soils with different texture. To prepare the CRFs, ethylcellulose (EC) and dibutylsebacate (DBS) have been used as coating agents in lignin-polyethylene glycol based formulations. Mobility experiments have been carried out in two light textured soils (sandy and sandy-loam). Breakthrough curves have shown that the use of CRFs reduces the presence of chloridazon and metribuzin in the leachate compared to technical and commercial products, being the lignin CRF coated with EC and DBS the most efficient to diminish the herbicide leaching. Mass balance study has shown a higher amount of chloridazon and metribuzin recovered in soils when these herbicides were tested as CRFs compared to technical and commercial products. The gradual release of herbicides from the CRFs resulting in a rather available levels of chloridazon and metribuzin in soil for a longer time. A good correlation between percentages of herbicide recovered in leachates and T values (time corresponding to 50% release of herbicide in water) was obtained, which allows to select the most appropriate CRF in each agro-environmental practice to reduce the potential pollution of groundwater by chloridazon and metribuzin.

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“…Finally, it will also be important to investigate the extent to which the effect of commercial formulation demonstrated here for propyzamide can be generalised to other compounds. We have undertaken leaching experiments with a further three pesticides to start addressing this requirement (Khan and Brown, 2016).…”

Section: Discussionmentioning

confidence: 99%

Influence of commercial formulation on the sorption and leaching behaviour of propyzamide in soil

Khan

Brown

2017

Science of The Total Environment

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Experiments compared sorption and leaching behaviour for the herbicide propyzamide when applied to two soils either as technical material or in the commercial formulation Kerb® Flo. Sorption was investigated in batch systems as well as using a centrifugation technique to investigate changes in pesticide concentration in soil pore water over incubation periods of up to 28days. Studies with small soil columns compared leaching of technical and formulated pesticide for irrigation events (6 pore volumes) 1, 7, 14, 21 and 28days after treatment. There were no differences in sorption of technical and formulated propyzamide when measured by batch systems. Sorption of technical material was significantly greater than that of formulated pesticide in sandy loam (p<0.05), but not in sandy silt loam when measured by centrifugation of soil incubated at field capacity. Partition coefficients measured by batch and centrifugation methods were similar after 1day and those measured by centrifugation increased by factors of 5.3 to 7.5 over the next 4weeks. The mass of propyzamide leached from soil columns ranged between 1.1±0.33% and 14.4±3.2% of the applied amount. For all time intervals and in both soils, the mass of propyzamide leached was significantly greater (two-sided t-tests, p<0.001) for the formulated product than for the technical material. Leached losses decreased consistently with time in the sandy loam soil (losses after 28days were 14-17% of those after 1day), but with less consistency in the sandy silt loam. There was a highly significant effect of formulation on the leaching of propyzamide through soil (two-way ANOVA, p<0.001) as well as highly significant effects of time and soil type (p<0.001). Results are consistent with modelling studies where leaching from commercial products in the field could only be simulated by reducing sorption coefficients relative to those measured with technical material in the laboratory.

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Influence of commercial formulation on leaching of four pesticides through soil

Abstract: 12Studies with small soil columns (2 cm i.

Cited by 22 publications

References 22 publications

Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides

Ignoring Adjuvant Toxicity Falsifies the Safety Profile of Commercial Pesticides

Lignin and ethylcellulose in controlled release formulations to reduce leaching of chloridazon and metribuzin in light-textured soils

Influence of commercial formulation on the sorption and leaching behaviour of propyzamide in soil

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