title: The ability of indigenous micro-organisms to degrade isoproturon, atrazine and mecoprop within aerobic UK aquifer systems.
abstract: The potential for the herbicides isoproturon, atrazine and mecoprop to degrade in the major UK aquifers of chalk, sandstone and limestone was studied using laboratory microcosms spiked at 100 microg litre(-1). Significant mecoprop degradation was only observed in sandstone groundwater samples. Atrazine transformation, based on the formation of metabolites, did occur in most groundwater samples, but only at a rate of 1-3% per year. A potential to degrade isoproturon was observed in groundwater samples from each of the aquifer types, with the most rapid and consistent degradation occurring at the sandstone field site. Biodegradation was confirmed by the formation of monodesmethyl- and didesmethyl-isoproturon. Isoproturon degradation potential rates obtained from the groundwater microcosms could not be correlated with either dissolved organic carbon or numbers of bacteria in the groundwater. It was noted that the ability of the groundwater at a field site to degrade a pesticide was not related to performance of the soil above.
authors.affiliation: Centre for Ecology and Hydrology, Wallingford, Oxon, OX10 8BB, UK. ajo@ceh.ac.uk
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Johnson
authors.forename: Craig
authors.initials: C
authors.lastname: White
authors.forename: C Lal
authors.initials: CL
authors.lastname: Bhardwaj
authors.forename: Andy
authors.initials: A
authors.lastname: Dixon
mesh_terms: D008456:2-Methyl-4-chlorophenoxyacetic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001280:Atrazine / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development*; D002119:Calcium Carbonate / Q000032:analysis; D003625:Data Collection; D006540:Herbicides / Q000378:metabolism*; D008782:Methylurea Compounds / Q000378:metabolism; D008954:Models, Biological; D010671:Phenylurea Compounds; D012822:Silicon Dioxide / Q000032:analysis; D012987:Soil / Q000032:analysis; D006113:United Kingdom; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism; D014877:Water Pollution, Chemical / Q000517:prevention & control; D014881:Water Supply / Q000032:analysis*
chemical_list: D006540:Herbicides; D008782:Methylurea Compounds; D010671:Phenylurea Compounds; D012987:Soil; D014874:Water Pollutants, Chemical; C028904:isoproturon; C008340:mecoprop; D012822:Silicon Dioxide; D008456:2-Methyl-4-chlorophenoxyacetic Acid; D002119:Calcium Carbonate; D001280:Atrazine