Evaluation of Crude Oil Toxicity in Zayandehrud Dam and Water Treated from Isfahan Water Treatment Plant Using Daphnia Magna and Bioassay

Crude oil is a very complicated composition and contains thousands of hydrocarbons with different structures. This study measured LC50 of crude oil in water samples taken from zayandehrud dam and treated water from Isfahan water treatment plant with different chemical and physical characteristics. Different crude oil concentrations (5 to 100 mg/l) were prepared in water samples that each contains ten Daphnia. The numbers of live Daphnia were counted 4, 24 and 48 hours after adding different crude oil concentrations. The results showed that at low turbidity and TDS, crude oil was much more toxic to Daphnia.