DISINFECTION BY-PRODUCTS FORMATION DURING HYPOCHLORINATION OF ISOPROTURON CONTAMINATED GROUNDWATER

An investigation has been carried out to identify the by-products form ed during the disinfection by hypochlorite of water contaminated with isoproturon, one of the herbicides most used in Europe. The reaction o f isoproturon with sodium hypochlorite (NaClO) has been investigated i n synthetic aqueous solutions, over 48h, in presence and in absence of interfering bromide ions, at room temperature, within the pH range 6- 9, using two different (NaClO)/(isoproturon) mass ratios:(40ppm)/(10pp m) and (3ppm)/(10ppb). When the effect of bromide ions was studied, (N aClO):(Isoproturon):(Bromide) mass ratios were (40ppm):(10ppm):(20ppm) and (3ppm):(10ppb):(100ppb). By-products were detected by liquid chro matography and identified by HPLC-MS and GC-MS. The results indicated that: the higher the reagent concentrations the faster the reaction, t he presence of bromides speeds up the reaction, pH does not influence the reaction, four and three identified isoproturon substitution by-pr oducts are formed in the absence and in the presence of bromides respe ctively. Copyright (C) 1996 IAWQ.