Algicidal properties of the pesticide cosolvent Aerotex 3470: growth, ATP synthesis, and ultrastructure
The algicidal properties of Aerotex 3470, a pesticide cosolvent in several fenitrothion formulations, have been investigated under controlled laboratory conditions. Aerotex (1–100 ppm) inhibited the growth of three unicellular freshwater algae (Chlamydomonas reinhardii, Chlorella pyrenoidosa, and Scenedesmus obtusiusculus) on agar plates and in liquid culture. Prolongation of the lag phase was directly related to Aerotex concentration. Algal cultures exposed for 1 h to Aerotex (1–10 ppm) had significantly reduced ATP levels. In all cases (agar, liquid culture, and ATP bioassays), Chlamydomonas and Chlorella were more sensitive to Aerotex than Scenedesmus.Electron microscopy demonstrated gross ultrastructural changes in Chlamydomonas treated for 1 h with Aerotex (5 ppm), including swollen mitochondria, disorganization of thylakoids, and crenulation of the cell membrane. Similar membrane damage was caused by 1-methylnaphthalene (5 ppm), a constituent of Aerotex.