title: Chemodynamics of methyl parathion and ethyl parathion: adsorption models for sustainable agriculture.
abstract: The toxicity of organophosphate insecticides for nontarget organism has been the subject of extensive research for sustainable agriculture. Pakistan has banned the use of methyl/ethyl parathions, but they are still illegally used. The present study is an attempt to estimate the residual concentration and to suggest remedial solution of adsorption by different types of soils collected and characterized for physicochemical parameters. Sorption of pesticides in soil or other porous media is an important process regulating pesticide transport and degradation. The percentage removal of methyl parathion and ethyl parathion was determined through UV-Visible spectrophotometer at 276 nm and 277 nm, respectively. The results indicate that agricultural soil as compared to barren soil is more efficient adsorbent for both insecticides, at optimum batch condition of pH 7. The equilibrium between adsorbate and adsorbent was attained in 12 hours. Methyl parathion is removed more efficiently (by seven orders of magnitude) than ethyl parathion. It may be attributed to more available binding sites and less steric hindrance of methyl parathion. Adsorption kinetics indicates that a good correlation exists between distribution coefficient (Kd) and soil organic carbon. A general increase in Kd is noted with increase in induced concentration due to the formation of bound or aged residue.
authors.affiliation: Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi 46000, Pakistan.
authors.forename: Noshabah
authors.identifier: 0000-0002-6264-646X
authors.initials: N
authors.lastname: Tabassum
authors.affiliation: Department of Environmental Sciences, Fatima Jinnah Women University, The Mall, Rawalpindi 46000, Pakistan.
authors.forename: Uzaira
authors.initials: U
authors.lastname: Rafique
authors.affiliation: Department of Hydrology and Water Resources Management, King Abdulaziz University, Jeddah 22254, Saudi Arabia.
authors.forename: Khaled S
authors.initials: KS
authors.lastname: Balkhair
authors.affiliation: Department of Geology, Centre for Research in Biotechnology for Agriculture, University of Malaya, 50603 Kuala Lumpur, Malaysia.
authors.forename: Muhammad Aqeel
authors.initials: MA
authors.lastname: Ashraf
mesh_terms: D000327:Adsorption; D000383:Agriculture; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008743:Methyl Parathion / Q000737:chemistry*; D008956:Models, Chemical; D010278:Parathion / Q000737:chemistry*; D012987:Soil; D013696:Temperature; D013997:Time Factors
chemical_list: D012987:Soil; D008743:Methyl Parathion; D010278:Parathion