title: Radiolytic degradation of atrazine aqueous solution containing humic substances.
abstract: Degradation of atrazine herbicide in humic substances (HS) aqueous solutions and distilled water solutions was investigated on a laboratory scale upon gamma-irradiation from a (60)Co source. In addition, the effect of ionizing radiation on the atrazine residues removal efficiency was investigated in relation to degradation of by-products. gamma-Irradiation experiments were carried out for three targeted concentrations (i.e. 0.464, 2.318 and 4.636 microM) with doses over the range 0.1-60 kGy. The initial concentration of herbicide, scavengers and irradiation doses play a significant role in the degradation efficiency as shown by decay constants of atrazine residues. gamma-Radiolysis showed that atrazine exhibited high degradation percentages at low absorbed doses in HS aqueous solutions compared to distilled water solutions. Absorbed doses from 0.6 to 21 kGy and from 6 to 72 kGy at a dose rate of 14.52 kGyh(-1) achieved 90% degradation for atrazine with initial concentrations over the range 0.464-4.636 microM in humic and distilled water solutions, respectively. The radiolytic degradation by-products and their mass balances were qualitatively determined with good confidence using gas chromatography/quadruple mass spectrometry (GC/MS) with electron impact ionization (EI(+)) mode.
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: A A
authors.initials: AA
authors.lastname: Basfar
authors.forename: K A
authors.initials: KA
authors.lastname: Mohamed
authors.forename: A J
authors.initials: AJ
authors.lastname: Al-Abduly
authors.forename: A A
authors.initials: AA
authors.lastname: Al-Shahrani
mesh_terms: D001280:Atrazine / Q000737:chemistry / Q000528:radiation effects*; D003666:Decontamination; D004307:Dose-Response Relationship, Radiation; D004784:Environmental Monitoring; D052918:Environmental Restoration and Remediation; D005720:Gamma Rays; D008401:Gas Chromatography-Mass Spectrometry; D006540:Herbicides / Q000737:chemistry / Q000528:radiation effects*; D006812:Humic Substances / Q000528:radiation effects*; D010573:Pesticide Residues / Q000737:chemistry / Q000528:radiation effects*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000528:radiation effects*; D018508:Water Purification / Q000379:methods*
chemical_list: D006540:Herbicides; D006812:Humic Substances; D010573:Pesticide Residues; D014874:Water Pollutants, Chemical; D001280:Atrazine