Insecticides and heavy metals are frequently distributed in the environment, but few studies have assessed the joint toxicity of the mixture of such substances. This project focused on two toxicants that occur to-gether in the aquatic environment as a result of human activities. The chemicals chosen were copper, an abundant toxicant in sewage sludge, and cypermethrin the active compound of many insecticides. This report investigate the combined effect of cypermethrin and copper on Daphnia magna. The acute toxicity was investigated on D. magna in a 48 hour immobilisation test. The experiments were conducted to test the effects of the two toxicants separately and in a mixture. We found individual EC50 values of 125±22 μg/L and 0.87±0.12 μg/L for copper and cypermethrin, respectively, each corresponding to 1 TU (Toxic unit). A mixture of copper and cypermethrin (30:70) gave an EC50 value of 0.685±0.137 TU. These results indicate a more-than-additive mixture toxicity for copper and cypermethrin according to the concentration addition model, but owing to high uncertainties in the experiment this cannot be conclusively interpreted as synergism.
|Uddannelser||Miljøbiologi, (Bachelor/kandidatuddannelse) Bachelor el. kandidat|
|Udgivelsesdato||24 jan. 2013|
|Vejledere||Amalie Thit Jensen & Katrine Banke Nørregård|
- Mixed toxicity
- Concentration addition
- Isobole method