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Pesticides
Published in José L. Tadeo, Analysis of Pesticides in Food and Environmental Samples, 2019
José L. Tadeo, Beatriz Albero, Rosa Ana Pérez
Glyphosate and glufosinate are broad spectrum, nonselective, post-emergence contact herbicides, active only for foliar application. They are extensively used in various applications for weed control in aquatic systems and vegetation control in non-crop areas. Aminomethylphosphonic acid (AMPA) is the major degradation product of glyphosate found in plants, water, and soil. The main properties of these compounds are shown in Table 1.7.
Removal of glyphosate and aminomethylphosphonic acid from synthetic water by nanofiltration
Published in Environmental Technology, 2018
Jiang Yuan, Jinming Duan, Christopher P. Saint, Dennis Mulcahy
Glyphosate (C3H8NO5P) is an active ingredient of the most widely used herbicide and it is supposed to be specific on plant metabolism and less toxic than other pesticides. However, glyphosate was found to be toxic to human embryonic and placental cells and can disrupt the animal cell cycle in urchin eggs [1]. Aminomethylphosphonic acid (AMPA) is an important metabolite produced during microbial degradation of glyphosate. The applications of glyphosate can result in detectable glyphosate and AMPA residues in groundwater in the vicinity with glyphosate application [2,3].
Assessment of the bioaccessibility of glyphosate in soil using a physiologically based extraction test
Published in Human and Ecological Risk Assessment: An International Journal, 2022
Nnanyelugo G. Odezulu, Y.W. Lowney, Mohammad-Zaman Nouri, Stephen M. Roberts, Leah D. Stuchal
Extraction of glyphosate in soil was conducted under simulated gastrointestinal conditions using the PBET method as used previously for dioxin (Roberts et al. 2019). This method includes a simulated gastric environment, followed by a simulated intestinal phase extraction. Briefly, extraction fluid was prepared by adding 30 g glycine to 1.5 L of MilliQ water and warming the solution to 37 ± 2 °C before adjusting the pH to 1.50 ± 0.05 with concentrated hydrochloric acid. To simulate stomach fluid, 17.6 g of sodium chloride, 2.0 g of pepsin (800–2500 units of activity/mg), 10 g of bovine serum albumin (Fraction V), and 5 g of mucin (Type III porcine stomach) were then added to the solution and thoroughly mixed. This simulated stomach fluid (95 ml) was placed in a 125 ml Nalgene bottle with 0.6 ml oleic acid (90%) and maintained at 37 ± 2 °C. One gram of a test soil sample was added to the bottles, tightly capped, and immersed in a “Toxicity Characteristic Leaching Procedure (TCLP) extractor” water bath maintained at 37 ± 2 °C and rotated at 30 rpm for one hour to simulate the gastric phase. After one hour, the bottles were removed from the extractor and allowed to settle for 10 minutes after which a 10 ml aliquot was taken and stored in 15 ml centrifuge tubes for quantification of glyphosate and AMPA in the “stomach phase” fluid. The pH of the remaining extraction fluid (85 ml) in each bottle was adjusted to 7.2 ± 0.2 with sodium hydroxide (50% w/w). To simulate intestinal contents, 53.7 mg of porcine pancreatin and 0.36 g of porcine bile extract were added after which the bottles were tightly capped, returned to the rotator and rotated for 4 h to simulate the intestinal phase. After the 4 h of extraction, the bottles were removed from the rotator, the temperature and pH of the extraction solution were measured, and the extraction solution was allowed to settle for 10 minutes. A 10 ml aliquot was taken from each of the bottles for measurement of glyphosate and aminomethylphosphonic acid (AMPA) concentration in the “intestinal phase” extract. AMPA is the principal breakdown product of glyphosate in the environment. At the time of PBET extraction, a representative split of each of the test soils was collected for measurement of concentration of glyphosate and AMPA in the weathered soils.