Mycoestrogens-contg. deionized, tap and surface waters (concn. 5 mu g/L) was purified by membrane nano filtration (active area 2.6 m(2), cut-off 200-400 Da), at 20 degrees C, transmembrane pressure 2.0 MPa and the linear velocity of the feed 3.4 m/s. The effect of water recovery degree 10-80% by vol. of the initial feed volume (20 L) on the retention of mycoestrogens was studied. The retention of zearalenone was 57-75%, while a-zearalenole 70-100%. The microcontaminant retention decreased with increasing the degree of permeate recovery.