title: Environmental occurrence and degradation of the herbicide n-chloridazon.
abstract: A sampling campaign was carried out for n-chloridazon (n-CLZ) and its degradation product desphenyl-chloridazon (DPC) in the Hesse region (Germany) during the year 2007: a total of 548 environmental samples including groundwater, surface water and wastewater treatment plant (WWTP) effluent were analysed. Furthermore, aerobic degradation of n-CLZ has been studied utilising a fixed bed bioreactor (FBBR). In surface water, n-CLZ was detected at low concentrations (average 0.01+/-0.06mugL(-1); maximum 0.89mugL(-1)) with a seasonal peak, whereas DPC was present throughout the year at much higher concentrations (average 0.72+/-0.81mugL(-1); maximum 7.4mugL(-1)). Higher n-CLZ concentrations were observed in the North compared with South Hesse, which is ascribed to a higher density of agricultural areas. Furthermore, methylated DPC (Me-DPC), another degradation product, was detected in surface water. In the degradation test, n-CLZ was completely converted to DPC at all concentrations tested (Me-DPC was not formed under the test conditions). DPC was resistant to further degradation during the whole experimental period of 98 days. The results obtained suggest persistence and high dispersion of DPC in the aquatic environment.
authors.affiliation: Politecnico di Milano, DIIAR-Environmental Section. P.za Leonardo da Vinci 32, 20133 Milano, Italy.
authors.forename: Gianluigi
authors.initials: G
authors.lastname: Buttiglieri
authors.forename: Manuela
authors.initials: M
authors.lastname: Peschka
authors.forename: Tobias
authors.initials: T
authors.lastname: Frömel
authors.forename: Jutta
authors.initials: J
authors.lastname: Müller
authors.forename: Francesca
authors.initials: F
authors.lastname: Malpei
authors.forename: Peter
authors.initials: P
authors.lastname: Seel
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Knepper
mesh_terms: D001673:Biodegradation, Environmental; D005060:Europe; D006540:Herbicides / Q000737:chemistry* / Q000378:metabolism*; D015394:Molecular Structure; D011724:Pyridazines / Q000737:chemistry* / Q000378:metabolism*; D045483:Rivers / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000378:metabolism
chemical_list: D006540:Herbicides; D011724:Pyridazines; D014874:Water Pollutants, Chemical; C005586:pyrazon