The effects of photosynthetic pigments on Hydrilla verticillata and Vallisneria spiralis induced by toluene, ethylbenzene and xylene

Effects of toluene, ethylbenzene and xylene on the contents of chlorophylls (a and b) were investigated in Hydrilla verticillata and Vallisneria spiralis. Hydrilla verticillata exhibited increases at lowest concentrations, while the loss in chlorophyll contents at higher chemicals concentrations occurred. Linear regression analyses were performed. IC10 values were 7.30mg/L, 1.15mg/L and 2.36mg/L for toluene, ethylbenzene and xylene. Chlorophylls contents of Vallisneria spiralis showed the erratic reduces at all concentrations of pollutants except three sampling points, showing photosynthesis of Vallisneria spiralis was negatively affected because of the toxicity of pollutants. The results indicated that the mechanism of the toxicity induced by toluene, ethylbenzene and xylene may have some differences, and Hydrilla verticillata was more suitable to be used in toxicity tests.