title: Degradation of 4-nonylphenol, 4-t-octylphenol, bisphenol A and triclosan following biosolids addition to soil under laboratory conditions.
abstract: Land application of biosolids is common practice in many countries, however, there are some potential risks associated with the presence of contaminants within the biosolids. This laboratory study examined the degradation of four commonly found organic compounds, 4-nonylphenol, 4-t-octylphenol, bisphenol A, and triclosan, in soil following the addition of two biosolids over 32 weeks. The pattern of degradation was assessed to determine if it followed a standard first-order decay model or if a biphasic model with a degrading and a recalcitrant fraction better described the data. The time taken for the initial concentrations to decrease by 50% (DT50), based on a first-order model, was 12-25 d for 4-nonylphenol, 10-14 d for 4-t-octylphenol, 18-102 d for bisphenol A, and 73-301 d for triclosan. For 4-nonylphenol, bisphenol A and triclosan, the biphasic model fitted the degradation data better than the first-order model, indicating the presence of a degrading fraction and a non-degrading recalcitrant fraction. The recalcitrant fraction for these three compounds at the completion of the 32 week experiment was 17-21%, 24-42%, and 30-51% of the initial concentrations, respectively. For 4-t-octylphenol, the first-order model was sufficient in explaining the degradation data, indicating that no recalcitrant fraction was present. This study showed that biphasic degradation occurred for some organic compounds in biosolids amended soil and that the use of standard first-order degradation models may underestimate the persistence of some organic compounds following land application of biosolids.
authors.affiliation: School of Agriculture, Food and Wine, University of Adelaide, South Australia, 5005 Adelaide, Australia.
authors.forename: K A
authors.initials: KA
authors.lastname: Langdon
authors.forename: M St J
authors.initials: MS
authors.lastname: Warne
authors.forename: R J
authors.initials: RJ
authors.lastname: Smernik
authors.forename: A
authors.initials: A
authors.lastname: Shareef
authors.forename: R S
authors.initials: RS
authors.lastname: Kookana
mesh_terms: D001559:Benzhydryl Compounds; D001673:Biodegradation, Environmental; D004784:Environmental Monitoring; D008401:Gas Chromatography-Mass Spectrometry; D010636:Phenols / Q000737:chemistry / Q000378:metabolism*; D012987:Soil; D012988:Soil Microbiology; D014260:Triclosan / Q000737:chemistry / Q000378:metabolism*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D010636:Phenols; D012987:Soil; D014260:Triclosan; C080417:4-octylphenol; C041594:4-nonylphenol; C006780:bisphenol A; D000098826:Bisphenol A Compounds