Assessing Toxicity of Organic Aquatic Micropollutants Based on the Total Chlorophyll Content of Lemna minor as a Sensitive Endpoint

The present study examined the chlorophyll content in a 7-day contact time experiment series. Lemna minor was exposed to caffeine, benzophenone, bisphenol A, 3,4-dichlorophenol, metamizole-Na, Na-diclofenac, acetochlor, atrazine, diuron, metazachlor and metolachlor to find a convenient sensitive response to the tested chemicals including some emerging micropollutants. The results demonstrated the differences in sensitivity to the tested micropollutants. As anticipated the industrial chemicals and the pesticides were the most toxic. The lowest observed effect concentration (LOEC) values determined for 3,4-dichlorophenol, acetochlor, diuron, metazachlor and metolachlor were 2.5 mu g/L, 0.05 mu g/L, 0.5 mu g/L, 5 mu g/L and 0.5 mu g/L, respectively. These values were comparable with the environmental concentrations reported in literature. Our study provides valuable information on the feasibility of Lemna minor total chlorophyll method as a sensitive and reliable bioassay for testing toxicity at mu g/L range and it may support risk assessment of organic micropollutants in freshwater ecosystems.