STUDIES ON THE BEHAVIOR OF DIHALOGENATED HYDROXYBENZONITRILES IN WATER

The degradation behaviour of the pesticides bromofenoxim, bromoxynil, bromoxynil octanoate, ioxynil, chloroxynil and mecoprop has been studi ed in natural aerobic water. UV spectra of the herbicides dissolved in bidistilled or surface water have been recorded under different pH an d irradiation conditions as a function of time. The compounds can be d ivided into two groups; the first group - bromoxynil, ioxynil, chlorox ynil, mecoprop - is stable for several weeks, while the compounds of t he second group - bromofenoxim and bromoxynil octanoate - start to dec ompose immediately. The rate of decomposition depends mainly on the ir radiation or on the biological activity of the surface water. Therefor e, much greater stabilities can be expected during underground passage . This instability must be considered during the determination of thes e herbicides.