%D 2004 %0 ARTICLE %T Effects of propanil , tebufenozide and mefenacet on growth of four freshwater species of phytoplankton : a microplate bioassay . %J Chemosphere %V 56 ( 4 ) %P 315-20 %A Gmez de %A Barreda Ferraz %A D Sabater %A C Carrasco %M pub15183992 %X The Albufera Natural Park situated in Valencia ( Spain ) , with a very rich flora and fauna is surrounded by rice fields in which pesticide spraying is a regular practice . With this in mind , the sensitivity of four algal species , Scenedesmus acutus , Scenedesmus subspicatus , Chlorella vulgaris and Chlorella saccharophila to pesticides propanil , tebufenozide and mefenacet was studied using single species toxicity tests . Organisms were exposed to different concentrations of these herbicides and the algal growth was measured in a microplate reader at 410 nm , at 0 , 24 , 48 and 72 h . Tebufenozide appeared to be the most inhibitory to Scenedesmus and Chlorella species growth . 72 h EC50 of propanil , tebufenozide and mefenacet ranged from 0 . 29 to 5 . 98 mg/l , 0 . 12 to 0 . 15 mg/l and from 0 . 25 to 0 . 67 mg/l , respectively for the four algal species . The two species of Chlorella were more tolerant than the two species of Scenedesmus .