Experimental approaches to studying the photostability of selected pesticides in water and soil

The pesticides carbofuran, diazinon, isoproturon, metamitron, terbuthylazine and pendimethalin were irradiated with UV light of different wavelengths in water or water/soil suspensions under various conditions. As compared to pure distilled water, photodegradation was increased in the presence of titanium dioxide, hydrogen peroxide or ozone, or by using natural river or lake water. In a water/soil suspension, diazinon was converted, besides to other products, to the isomeric isodiazinon. When subjected to various direct or indirect photolysis conditions, pendimethalin was transformed to various products resulting from dealkylation and reduction.