title: PCDD/Fs in Norwegian and U.K. soils: implications for sources and environmental cycling.
abstract: This paper presents data on polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in a set of well-characterized, undisturbed surface (0-5 cm) and subsurface background soils from the U.K. and Norway. The soils have been used previously to investigate the latitudinal distribution, fractionation, cold condensation, and "hopping" of other classes of persistent organic pollutants (POPs). The mono- to octa-CDD/F homologues were quantified. Woodland soils contained higher concentrations (on a dry and soil organic matter (SOM)-basis) than grassland soils, consistent with previous studies. The absolute concentrations of all the PCDDs and most of the PCDFs significantly decreased with latitude, generally supporting the idea of a "southern source region" and a "remote/ receiving northern region". There was little evidence of "fractionation" and minimal influence of PCDD/F "hopping" on PCDD/F distribution. The %SOM content had a rather minor influence on soil PCDD/F composition. These findings contrast with the trends seen in these soils for hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs). Possible reasons for these differences are discussed and may include influences of/proximity to diffusive combustion sources and/ or sources of variable homologue emissions, formation/ conversion processes for PCDD/Fs in soils, or strong soil-PCDD/F partitioning. These soils, from regionally remote/ background locations in Europe contained between 0.2 and 78 pg sigmaTEQ/g DW. Some therefore exceed recommended levels of contamination for certain land uses by some European countries. These recommendations seem unrealistic and prohibitively restrictive in light of the dataset presented here.
authors.affiliation: Environmental Science Department, Institute of Environmental and Natural Sciences, Lancaster University, Lancaster, United Kingdom.
authors.forename: Ashraf
authors.initials: A
authors.lastname: Hassanin
authors.forename: Robert G M
authors.initials: RG
authors.lastname: Lee
authors.forename: Eiliv
authors.initials: E
authors.lastname: Steinnes
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Jones
mesh_terms: D001572:Benzofurans / Q000032:analysis* / Q000737:chemistry; D000072338:Dibenzofurans, Polychlorinated; D004058:Diffusion; D009664:Norway; D000072317:Polychlorinated Dibenzodioxins / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D015203:Reproducibility of Results; D012989:Soil Pollutants / Q000032:analysis*; D006113:United Kingdom
chemical_list: D001572:Benzofurans; D000072338:Dibenzofurans, Polychlorinated; D000072317:Polychlorinated Dibenzodioxins; D012989:Soil Pollutants