CYPERMETHRIN NON-TARGET IMPACT ON SOIL MICROBIAL COMMUNITIES: LABORATORY ARTIFICIAL INCUBATION EXPERIMENT

Abstract

Intensive and excessive use of pesticides is a real pollution issue in agricultural lands. There is little knowledge on how these could change soil microbiota health status which are strongly involved in important soil functions. The objective of the present study was to assess under laboratory conditions if use of a common pyrethroid pesticide, cypermethrin, will change soil microbiota structure and abundance. Cypermethrin exposure dose and removal in time were accounted also. Its amount was quantified on GC-ECD while information about microbiota, expressed as PLFA, were acquired on GC-FID. Incubation period after artificial contaminations between 7 – 288 gkg-1 was set at 45 days, time during samples were picked up from incubation containers for chemical analysis. Experiment revealed that during the first ten days of exposure experiment, cypermethrin amount in soil decreased almost with half. It was removed with 68.8 – 43.3 %, depending positively by the exposure dose, thus it increased once that exposure dose decreased. The calculated half-life values under our experimental conditions vary between 4.59 - 10.54 days, depending by exposure dose. Compared with control soil gram-negative bacteria community was enhanced under cypermethrin exposure up to day 45 around 5.4 – 20.3 %, although the control has shown a slightly decreases from day 10 and 45 day. Fungal population decreased also between exposure time, as well exposure dose. After 10 days of incubation they weren’t be present in samples. Similar was obtained after measurement of anaerobe bacteria. Considering our obtained experimental data, we could consider that cypermethrin have the potential to change the soil equilibrium once that it changes both the structure as well the abundance of soil microbiota.

Keywords

• microbiota community structure, abundance, cypermethrin, exposure dose, incubation