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Aerobic degradation potential of the herbicides mecoprop, dichlorprop and bentazone in groundwater from chalk aquifers
| Content Provider | Semantic Scholar |
|---|---|
| Author | Levi, Suzi Hybel, Anne-Marie Bjerg, Poul Løgstrup Albrechtsen, Hans-Jørgen |
| Copyright Year | 2011 |
| Abstract | The aerobic degradation potential of mecoprop, dich lorprop and bentazone was studied at concentration of 1 μg/L in laboratory batch experiments with groundwate r from chalk aquifers. Within the incubation period of 129 days, C-mecoprop concentration decreased to 60-80% in the microcosms with groundwater collected from two moni t ring wells (Well 1 and 2). Dichlorprop degradation was neither observed under aerobic nor anaerobic conditions, while 17-27% of the initial concentration of C-bentazone was removed. The results indicated a de gra ation potential of mecoprop and bentazone under aerobic conditions. Introduction Organic micro pollutants such as pesticides and deg radation products are detected in an increasing number of aquifers all over the world (Barbash et a l., 2001). In some countries such as Denmark, drinking water supply is based on groundwater, trea ted with a simple aeration and filtration process before it is distributed directly to the consumers. This requires high quality groundwater that must meet the standards in EU Groundwater directive with threshold limit values for pesticides and their metabolites in groundwater at 0.1 μg/L for each pesticide or metabolite and 0.5 μg/L for the sum of pesticides and metabolites (European Parliament and Council, 2006). The frequent findings of pesticides in Danish groundwater have resulted in t he closure of many drinking water wells. In the period 1987-2007 a total of 2176 Danish abstraction wells were closed, 25% of these due to pesticide contamination (Miljøstyrelsen, 2009). Diffuse pesti cide pollution is one of the major environmental challenges since it is difficult to remediate aquif ers contaminated with trace concentrations. The natural redox conditions of aquifers are consid ere to be one of the important factors governing the degradation of pesticides in groundwater (Larse n et al, 2001). In and around drinking water abstraction fields the geological structure may be complex with dual porosity which in combination with changing abstraction patterns may lead to mixi ng of different water types, creating steep concentration gradients and drastic redox changes. Thi may stimulate microbial degradation of the contaminants by addition of relatively low oxygen c on entrations (Tuxen et al., 2006). Therefore, geological variations in combination with water abs traction may affect microbial degradation processes and redox conditions in aquifers (Ludvigs en et al., 1998; Janniche et al., 2011). The present investigation focused on three pesticid es; mecoprop, dichlorprop and bentazone which are some of the most frequently found and detected pesticides in Danish groundwater. The selected pesticides are all herbicides and are moderately so uble in water and include both non-polar compounds and dissociable compounds. The purpose of the study was to examine the aerobic degradation potential of three pesticides in slight ly pesticide contaminated groundwater from chalk aquifers. |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | http://orbit.dtu.dk/files/6350594/prod21323248710914.Extended.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
