Combined toxic effects of typical mutagens-dimethylphenol, tribromethane and dinitroaniline, on unicellular green algae Dunaliella salina

摘要

By the use of the Organization for Economic Co-operation and Development (OECD) standard method for algal growth inhibition test, the combined toxicities test (48 h, EC) for Dunaliella salina was conducted with the four kinds of mixtures to study the application of toxicological test with algae in water quality monitoring. Using dimethylphenol, tribromethane and dinitroaniline as the typical mutagenic toxicants, their concentrations were set according to the national drinking water health standard (GB5749-85). Four groups of the tests were set by combining any two of the three compounds, while another group was the control group. D. salina was cultivated in these groups and the EC of each group was obtained. Results showed that when dimethylphenol and tribromethane were combined, the inhibit action to the growth of D. salina showed a weak synergism; when the dimethylphenol and dinitroaniline were combined, the inhibit action was additive action; when tribromethane and dinitroaniline were combined, the inhibit action showed antagonism; when all the three kinds of compounds were combined, the inhibit action was also antagonism. It was concluded that the application of toxicological test with D. salina in water quality monitoring is feasible. Derived from water environmental contaminants or the processing of water treatment, dimethylphenol, tribromethane and dinitroaniline are potential residues in drinking water, which may cause toxicity, mutagenicity and teratogenicity to the human body even in trace amounts. Thus, the test and evaluation of the dose-response for these compounds is very important. In addition, the three compounds may occur in water together and the combined toxicity tests between them to investigate the combined effects become necessary. In this study, Dunaliella salina, a unicellular green algae, was used as the test organism to perform the investigation. These tests were preferred because they are simple, cost-effective and efficient, and D. salina is easily cultured. The methods established in this study are practicable and will provide further studies with useful reference information.