The paper analyses to the adsorption purification of river waters from oxadiazon by chitin, active coal, bentonite and its Fe(III) cation form adsorbents. It became obvious that effectiveness of purification of river waters from oxadiazon herbicidine depends both on sorbents and pH. The influence of pH on adsorption of oxadiazon in sorbents was analyzed. It was determined that at pH=6 value chitin, pH=2 value active coal, natural and Fe(III) cation form bentonite has maximum adsorption capacity from river waters and liquid solutions. With respect to oxadiazon according to Lengmur equation, distribution coefficient of oxadiazon in natural Fe(III) cation form bentonite was calculated. The obtained results show that by using chitin and Fe(III) bentonite it is possible to purify treat river water which has weak and strong acidity, from oxadiazon herbicidine.