Dissipation of the insecticide profenofos in tropical agricultural soils (Berambadi catchment, South India): Insight from compound-specific isotope analysis (CSIA)

• Published in: Journal of hazardous materials Vol. 488; p. 137428
• Main Authors: Masbou, J., Grail, C., Payraudeau, S., Ruiz, L., Sekhar, M., Riotte, J., Imfeld, G.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 05.05.2025; Elsevier
• Subjects: Agriculture; agroecosystems; Biodegradation; Biodegradation, Environmental; carbon; Carbon Isotopes - analysis; Environmental Monitoring; Environmental Sciences; groundwater; hydrolysis; India; Insecticides - analysis; Insecticides - chemistry; Insecticides - metabolism; intensive farming; isotope fractionation; isotopes; Kinetics; Modelling; Organophosphates; Organothiophosphates - analysis; Organothiophosphates - chemistry; Organothiophosphates - metabolism; Pesticide; pesticide persistence; Photolysis; profenofos; risk assessment; Soil; Soil - chemistry; Soil Pollutants - analysis; Soil Pollutants - chemistry; Stable isotopes; Tropical Climate; volatilization; water management; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - chemistry; water pollution; watersheds; India; Biodegradation; Pesticide; Photolysis; Stable isotopes; Soil; Modelling; Organophosphates; stable isotopes; photolysis; pesticide; biodegradation; soil; organophosphates; modelling
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2025.137428

Assessing the role of agricultural lands in pesticide contamination of water ecosystems is critical for water management agencies and policymakers when formulating effective mitigation strategies. Current approaches based on concentration measurements are often insufficient to evaluate the contribution of pesticide dissipation processes in complex agroecosystems. This study focuses on the dissipation of profenofos insecticide within plots subject to intensive agriculture in the Berambadi watershed (India). We examined profenofos dissipation kinetics and related carbon isotopic fractionation in laboratory volatilisation, hydrolysis, photolysis and soil biodegradation experiments, and in a field plot experiment. Process-specific isotope fractionation analyses revealed significant carbon isotope fractionation, with εC = − 2.0 ± 0.8 ‰ during UV photolysis, and εC = − 0.9 ± 0.4 ‰ during biodegradation of profenofos in the soil. Accordingly, the formation of 4-bromo-2-chlorophenol and another profenofos transformation product indicated the cleavage of OP and CBr bonds in soil experiments. By integrating dissipation kinetics, compound-specific isotope analysis (CSIA), transformation products analysis and modelling results, biodegradation was identified as the dominant dissipation process in the agricultural plot, accounting for > 90 % of profenofos dissipation. Model predictions were consistent with the observed dissipation kinetics and isotopic data, confirming the fast degradation (T1/2 = 1.1 ± 0.6 day) and low (< 0.02 %) leaching potential of profenofos, which was not detected in the local groundwater monitored by passive samplers (POCIS). Overall, these results highlight the usefulness of profenofos CSIA to identify and unravel dissipation processes in tropical agroecosystems for improving contamination risk assessment. [Display omitted] •Rapid dissipation of profenofos in soil, with half-life of 1.1 ± 0.6 days.•Development of carbon CSIA of profenofos with precision of ± 0.3 ‰ for δ13C values.•Photolysis and biodegradation in soil of profenofos caused carbon isotope fractionation.•Profenofos biodegradation in soil reached 96 %, 3 days after a field application.•Experimental data aligned with model, showing minimal (< 0.02 %) profenofos leaching.