Investigation of Different Degradation Treatments on Pesticide Contaminated Water with Toxicity Bioassay on Daphnia magna

Overview

Pesticides help to ensure crop productivity, but they contaminate the surrounding environment with toxic substances that can directly affect a local ecosystem’s organisms. Microbial degradation of pesticides occurs naturally, but with today’s higher levels of pesticide usage, toxic pesticides persist longer in the environment and can run-off or leach into human water systems. In this experiment, I measured the effectiveness of several degradation techniques at degrading a wide variety of pesticides. Fifteen types of organophosphate pesticides were degraded using UV light (254 nm) photolysis, potassium permanganate, hydrogen peroxide and combined treatments. I applied the UV light photolysis treatment method for six days with measurements being taken on each day using a GC/MS/MS. Concentration levels for nine out of the 15 pesticides dropped to non-detectable amounts, and the other six dropped by over 83%. The other treatments using hydrogen peroxide and potassium permanganate yielded drops of 54-83% and 59-100% for all pesticides, respectively. After combining pesticide degradation treatments, I found that the chromatogram peaks of all pesticides dropped over 93% for the hydrogen peroxide/UV combination and over 94% for the permanganate/UV combination. In addition, a water safety test using Daphnia magna has been conducted for 6-hour durations. The UV treatment and the combined permanganate/UV treatment resulted in a higher surviving Daphnia magna count and thus better water quality. However, the combined hydrogen peroxide/UV treatment resulted in higher toxicity levels for Daphnia magna. These results indicate that pesticide degradation can be achieved through a variety of treatments and combining these treatments greatly improve pesticide degradation.

Competition history

• ISEF 2014 Materials Science · Entry EV038

Resources

• ISEF abstract page ↗

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