Evaluation on toxicity of Cymoxanil to environmental organism

1. Test purpose:
Determine the toxicity of cymoxanil tech to environmental organism as per “documents requirements of pesticide registration” and “Experimental Guideline for Environmental Safety Evaluation of Chemical Pesticides”. The aim is to grasp the environment safety of the product to provide scientific gist for rational application and registration.

2. Materials:
Test pesticide: Cymoxanil 98% tech, white solid, was provided by Saturn.
Test animals:
--fish: carp (Cyprinus carpio L innaeus) with average body length 42cm, body weight 23g, fed for 7d indoor in advance for test with natural death ratio 1% below. All test fish was healthy and equirotal. Stop feed 24h prior to test and don’t feed during test, either.
-daphnia: Daphnia magna, was 8～24h –instar and fed for 7d indoor in advance without death found.

3. Toxicology test method:
For Carp: use half-static method. Pre-test to get toxicity effect concentration scale. Water temperature kept at 25±2℃ during test period. Place 10 fish and 10L of tap water in a aquarium (50X20X30cm) and connect inflation fitting. Add into Cymoxanil tech to get designed concentration. In formal test, design five disposals and one contrast. Each disposal included three repeatition. Investigate the number of death in 96h, respectively to get LC50 and 95%of fiducial limit.
For daphnia: use static method. Before formal test, determine the lowest death concentration and highest adiaphorous concentration by pre-test. Design seven disposals and one contrast in formal test. Place 100L of tap water into 150mL-beaker and feed ten daphnia every beaker. Add quantitative Cymoxanil into the beaker to get different designed concentration. Repeat three times every disposal. Place the beaker into incubator at 22℃. Adjust the ratio of light-darkness to 16:8. Stop supplying baits for daphnia during the test period. Observe and record death number in 24h. Calculate LC50 and 95%of fiducial limit by Horn method.

4. Results
Toxicology to fish: after treatment, poisoning symptoms appeared at once including action slowness, side swim, abdomen upside, even death in high dosage group. According to the test, LC50 (96h) of Cymoxanil to carp was 89.25mg/L. Cymoxanil was classified as low toxic pesticide to fish. The results showed as follows.