title: Gamma-ray induced degradation of diazinon and atrazine in natural groundwaters.
abstract: Degradation of diazinon and atrazine pesticides present in natural groundwaters was investigated on a laboratory scale upon gamma-irradiation from a (60)Co source. The effects of pesticide type, initial concentration, characteristics of natural groundwater, potential radical scavengers and absorbed dose on efficiency of pesticide degradation were investigated using GC-MS. gamma-Irradiation experiments were carried out for three concentrations (i.e. 0.329, 1.643 and 3.286 microM/diazinon and 0.464, 2.318 and 4.636 microM/atrazine) with irradiation doses over the range 0.5-5.6 kGy for diazinon and 0.2-21 kGy for atrazine. gamma-Radiolysis showed that diazinon was much easier to degrade by ionizing radiation compared to atrazine in all natural groundwater samples. This was observed at the three initial concentrations over the range irradiation doses. The irradiation doses required for degradation of 50 and 90% diazinon (distilled water) and atrazine (humic aqueous solution) at the three concentrations were not sufficient to degrade the same concentrations in different natural groundwater samples. Moreover, the presence of naturally occurring inorganic scavengers in solutions of diazinon and atrazine decreased significantly the efficiency of radiolytic degradation of pesticides, especially at higher concentrations.
authors.affiliation: Radiation Technology Center, Atomic Energy Research Institute, King Abdulaziz City for Science and Technology, P.O. Box 6086, Riyadh 11442, Saudi Arabia.
authors.forename: K A
authors.initials: KA
authors.lastname: Mohamed
authors.forename: A A
authors.initials: AA
authors.lastname: Basfar
authors.forename: A A
authors.initials: AA
authors.lastname: Al-Shahrani
mesh_terms: D001280:Atrazine / Q000528:radiation effects*; D003976:Diazinon / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D052918:Environmental Restoration and Remediation; D005720:Gamma Rays; D010575:Pesticides / Q000528:radiation effects*; D010865:Pilot Projects; D014874:Water Pollutants, Chemical / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods*
chemical_list: D010575:Pesticides; D014874:Water Pollutants, Chemical; D001280:Atrazine; D003976:Diazinon