title: Mechanistic insights into the role of river sediment in the attenuation of the herbicide isoproturon.
abstract: Mechanistic insights into the relative contribution of sorption and biodegradation on the removal of the herbicide isoproturon (IPU) are reported. (14)C-radiorespirometry indicated very low levels of catabolic activity in IPU-undosed and IPU-dosed (0.1, 1, 100 μg L(-1)) river water (RW) and groundwater (GW) (mineralisation: <2%). In contrast, levels of catabolic activity in IPU-undosed and IPU-dosed river sediment (RS) were significantly higher (mineralisation: 14.5-36.9%). Levels of IPU catabolic competence showed a positive log-linear relationship (r(2) = 0.768) with IPU concentration present. A threshold IPU concentration of between 0.1 μg L(-1) and 1 μg L(-1) was required to significantly (p < 0.05) increase levels of catabolic activity. Given the EU Drinking Water Directive limit for a single pesticide in drinking water of <0.1 μg L(-1) this result suggests that riverbed sediment infiltration is potentially an appropriate 'natural' means of improving water quality in terms of pesticide levels at concentrations that are in keeping with regulatory limits.
authors: School of Environmental Sciences, University of East Anglia, Norwich, UK.
authors: Son B
authors: SB
authors: Trinh
authors: Kevin M
authors: KM
authors: Hiscock
authors: Brian J
authors: BJ
authors: Reid
mesh_terms: D000327:Adsorption; D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000737:chemistry*; D006540:Herbicides / Q000032:analysis*; D008956:Models, Chemical; D010671:Phenylurea Compounds / Q000032:analysis*; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006540:Herbicides; D010671:Phenylurea Compounds; D014874:Water Pollutants, Chemical; C028904:isoproturon