OXIDATION OF SIMAZINE - BIOLOGICAL OXIDATION OF SIMAZINE AND ITS CHEMICAL OXIDATION BY-PRODUCTS

Batch biodegradation studies were conducted to assess the biodegradabi lity of single s-triazines. s-Triazines tested included simazine, a wi dely used herbicide, and its products resulting from oxidation with oz one, ultraviolet (UV) light, and combined ozone and UV light oxidation . Degradation rates for each s-triazine were calculated as mu M N/hr. Rates ranged from 0 to 10.3 mu M N/hr. s-Triazine degradation rates we re a function of the ring substituents and followed the order of hydro xy much greater than amino much greater than chlorine greater than or equal to ethylamino. Chemical oxidation methods capable of oxidizing t he more persistent simazine substituent groups (chlorine and ethylamin e) to more easily biodegraded substituents (amine and hydroxy) proved attractive in enhancing the s-triazine mineralization of simazine. Whe n simazine was pretreated with combined ozone and UV, the s-triazine b iodegradation rate was increased by an order of magnitude. s-Triazine biodegradation rates also were enhanced with ozone and UV pretreatment but not to the same extent.