Toxicity Effect Of Omethoate To Danio Rerio

In this paper, Danio rerio were test organisms, and omethoate was used to poisoning substances. To study the toxic effects of omethoate on danio rerio and the BCF7 d that the danio rerio to omethoate with variable static method. First of all by acute toxicity test to measure omethoate 96h-LC₅₀ of danio rerio. Next four concentrations（2.5 5.0 7.5 10.0 mg/L） were setted up with a control group（0 mg/L） to carry out the toxicity experiments. The activities of superoxide dismutase（SOD）, peroxidase（POD）, catalase（CAT） and acetylcholinesterase（Ach E） of concentration groups were measured after infected 1, 3, 5days.Finally the setting concentrations were 0 2.0 4.0 6.0 8.0 10.0 mg/L, and danio rerio exposed to 7 days, then measured the biological enrichment factor of 7 days(BCF_7d) in danio rerio that omethoate. The mean results of experiments are summarized as follows:1. For danio rerio the LC₅₀ value of omethoate was 31.62 mg/L for 96 h, and security concentration was 3.16 mg/L.2. Exposed to different concentrations of omethoate for 1,3 and 5d respectively, the activities of SOD and Ach E in danio rerio had the same variation tendency, showed downtrend wholly, only the activity of SOD in 10.0mg/L group was higher than that in 7.5mg/L group when exposed for 5 days. And by the omethoate stress, the activities of SOD and Ach E were inhibited, while the lowest activity, compared with the control group, SOD and Ach E activity decreased by 77.2%, 71.11%. The activity of POD increased at first and then decreased, and the activity of POD in low concentration group（2.5, 5.0mg/L） was promoted, while the POD activity of high concentration group（7.5, 10.0mg/L） was inhibited. The activity of CAT, in low concentration group（2.5mg/L） with exposure time, showed a downward trend, while the high concentration group（5.0, 7.5, 10.0mg/L） CAT activity showed a trend of first increased and then decreased. The inhibition order of omethoate on the enzyme activity was SOD > Ach E > POD > CAT roughly.3. With the increasing of the exposure concentration, the omethoate concentration in water and in danio rerio gradually increased; the BCF7 d of danio rerio to omethoate gradually decreased and the speed changed from fast to slow, in the end it came to the balance. The BCF indicated that danio rerio had certain enrichment capability to omethoate in water, enrichment coefficient was 1.54 5.8, so omethoate belonged to low-enriched pesticides.