Degradation of Cypermethrin by indigenous bacteria in local industrial, beech- and spruce-forest soil

University essay from Högskolan i Halmstad/Sektionen för ekonomi och teknik (SET)


Soil from local beech-forest, spruce-forest and an industrial area was taken. Control- and test-microcosms containing 150 ml soil were spiked with cypermethrin 0,4 mg/ml soil. Cypermethrin residues were extracted on day seven and 14.

Cyclohexane and deionized water was utilized in multiple step extraction processes. Samples were analyzed in a Gas Chromatograph (GC) with electron capture detector (ECD).

Concentration values for the samples were highest for beech-forest soil and lower for the other two soil-types. Statistical differences in concentrations between control- and test-microcosms for each soil-type on day seven and day 14 were evaluated with Mann Whitney U tests. Significant result was only found in the industrial 14-day group. The small amounts of cypermethrin in the extracts could not only be ascribed to a bacterial degradation process. Used insecticide has a high bonding affinity for particles and is sequestered in soil.

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