title: Distribution of aged 14C-PCB and 14C-PAH residues in particle-size and humic fractions of an agricultural soil.
abstract: Organic matter is considered to be the single most importantfactor limiting availability and mobility of persistent organic pollutants (POPs) in soil. This study aimed to characterize the distribution of 14C-PCB (congeners 28 and 52) and 14C-PAH (fluoranthene and benzo[a]pyrene) residues in an Orthic Luvisol soil obtained from two lysimeter studies initiated in 1990 at the Agrosphere Institute (Forschungszentrum Jülich GmbH, Germany). The lysimeter soils contained a low-density OM fraction, isolated during soil washing, which contained a significant fraction (3-12%) of the total 14C-activity. Soils were also fractionated according to three particle sizes: >20, 20-2, and <2 microm. Relative affinity values of 14C-activity for the different particle sizes varied in the order 20-2 microm > (<2 microm) approximately (>20 microm) for the PCBs. Relative affinity values of 14C-activity for the different particle sizes varied in the order 20-2 microm > (<2 microm) > (>20 microm) for the PAHs. The distribution of 14C-PCB or 14C-PAH residues in the organic and inorganic matrixes of the particle-size fractions was determined using methyl isobutyl ketone (MIBK). 14C-PCB and 14C-PAH-associated activities were primarily located in the humin fraction of the 20-2 and <2 microm particle-size fractions of the soil. A small fraction was associated with the fulvic and humic acid fractions; these were quantitatively more important for the PAHs than the PCBs. There appeared to be a high degree of association of 14C-activity with the mineral fraction following MIBK separation of the humic fractions, ranging between 8 and 52% for 14C-PCBs and 57-80% for 14C-PAHs. The mineral (inorganic) component of the soils apparently played a significant (previously unreported) role in the sequestration of both PCBs 28 and 52 and the PAHs fluoranthene and benzo[a]pyrene.
authors.affiliation: Department of Environmental Science, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, LA1 4YQ, United Kingdom.
authors.forename: Kieron J
authors.initials: KJ
authors.lastname: Doick
authors.forename: Peter
authors.initials: P
authors.lastname: Burauel
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Jones
authors.forename: Kirk T
authors.initials: KT
authors.lastname: Semple
mesh_terms: D000383:Agriculture; D001564:Benzo(a)pyrene / Q000032:analysis / Q000378:metabolism; D001673:Biodegradation, Environmental; D002247:Carbon Isotopes; D004785:Environmental Pollutants / Q000032:analysis / Q000378:metabolism; D005449:Fluorenes / Q000032:analysis / Q000378:metabolism; D006812:Humic Substances / Q000032:analysis*; D008742:Methyl n-Butyl Ketone / Q000032:analysis / Q000378:metabolism; D010316:Particle Size; D011078:Polychlorinated Biphenyls / Q000032:analysis* / Q000378:metabolism; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis* / Q000378:metabolism; D012987:Soil / Q000032:analysis*; D012988:Soil Microbiology
chemical_list: D002247:Carbon Isotopes; D004785:Environmental Pollutants; D005449:Fluorenes; D006812:Humic Substances; D011084:Polycyclic Aromatic Hydrocarbons; D012987:Soil; C001861:humin; D001564:Benzo(a)pyrene; C007738:fluoranthene; D008742:Methyl n-Butyl Ketone; D011078:Polychlorinated Biphenyls; C005458:methyl isobutyl ketone