Diaryl ethers such as dibenzo-p-dioxin (DD) and dibenzofuran (DF), particularly the chlorinated derivatives, are extremely persistent in the environment due to their high toxicity and limited biodegradation. These compounds may have significant deleterious effects upon green algae which are essential components of aquatic and soil ecosystems. Therefore we evaluated the toxicity of such pollutants on algal populations. This study tested the toxicity of several diaryl ethers to Chlorella vulgaris (CCAP 211/11B), a Scenedesmus species and an Ankistrodesmus species, the latter two algae being axenic environmental isolates. Calculation of EC_(50) values showed that these diaryl ethers inhibited the growth of these algal species at very low concentrations, mainly below 0.1 mM, C. vulgaris being the least sensitive species. The presence of a chloro-substituent further increased the toxicity severely, except in the case of C. vulgaris. These EC50 values are much lower than those obtained using the monoaromatic pollutant phenol but only a little lower than those obtained for the diaryl naphthalene.
展开▼
