Photochemical degradation study of irgarol 1051 in natural waters: influence of humic and fulvic substances on the reaction

The photochemical degradation of irgarol 1051 has been studied in different natural waters (sea, river, lake) as well as in distilled water under natural and simulated solar irradiation. The effect of dissolved organic matter (DOM) such as humic and fulvic substances on the photodegradation rate was also studied under simulated sunlight. The addition of DOM in distilled water was shown to greatly increase the rate of degradation, however, a decrease was observed in natural waters. The photodegradation proceeds via pseudo-first-order reaction in all cases with half-lives ranged from 2 to 1432 h. In natural and humic water irgarol 1051 photodegradation gave rise to the dealkylated derivative demonstrating that the transformation of irgarol 1051 depend on the constitution of the irradiated media and especially from DOM concentration and type. The byproducts identified by GC–MS techniques were: 2-methylsulfonyl-4-terbutylamino-6-cyclopropylamino-s-triazine, 2-hydroxy-4-terbutylamino-6-cyclopropylamino-s-triazine, 2-methylthio-4-terbutylamino-6-ethylamino-s-triazine, 2-methylsulfonyl-4-terbutylamino-6-amino-s-triazine and diaminohydroxy-s-triazine. [Copyright &y& Elsevier]