Effect of eight polynuclear hydrocarbons on growth of Anabaena flos-aquae

The effects of acenaphthene, benzanthracene, chrysene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene on the growth of Anabaena flos-aquae were studied. A 48 per cent (2427 ug per litre) exposure to acenaphthene produced a maximum standing crop which was 26 per cent greater than that of control, while other exposures did not affect growth. A 48 per cent (14,851 ug per litre) exposure to naphthalene caused a 56 per cent growth stimulation. All but pyrene had an effect on growth over 14 days. Benzanthracene, chrysene, fluoranthene, fluorene and phenanthrene all inhibited growth. With the exception of pyrene, four-ringed (hydrophobic) aromatics were most inhibitory. Phenanthrene and fluorene did not affect growth when at less than 96 per cent of saturation. Hydrophobic polynuclear aromatic hydrocarbons markedly inhibit the growth of Anabaena flos-aquae and could be more toxic to algae than hydrophilic aromatics.