The Importance of Long and Short-Term Air-Soil Exchanges of Organic Contaminants
- 1 April 1995
- journal article
- research article
- Published by Taylor & Francis in International Journal of Environmental Analytical Chemistry
- Vol. 59 (2-4), 167-178
- https://doi.org/10.1080/03067319508041325
Abstract
Retrospective analysis of archived soil samples collected and stored from long-term agricultural experiments in the UK has shown how soil organic chemical composition has changed over time. High molecular weight polycyclic aromatic hydrocarbons (e.g. benzo[a]pyrene) and polychlorinated dibenzo-p-dioxins and -furans have increased in concentration through this century as a result of cumulative atmospheric depositional inputs. Concentrations of polychlorinated biphenyls and low molecular weight hydrocarbons (e.g. phenanthrene) peaked in the late 1960s/early 1970s, but have declined subsequently. This reflects declining atmospheric inputs of these compounds and losses from surface soils by volatilisation back to the atmosphere and biodegradation. PCBs and low molecular weight PAHs exist predominantly in the vapour phase in air, whilst heavy PAHs and PCDD/Fs are predominantly particulate-bound. Outgassing from soils is probably the most important contemporary source of PCBs to the atmosphere in the UK. Future UK PCB air concentrations will presumably therefore be influenced (controlled) by the rate of desorption and outgassing, as soil and air concentrations move towards a condition of equilibrium partitioning. Archived soils collected and stored before the commercial manufacture of PCBs contain no PCBs indicating that there is no ‘natural production’ of these compounds. However, within a few hours of exposure to contemporary air these samples contain detectable quantities of PCBs. Short-term air-soil exchange, such as during soil drying in the laboratory, can lead to contamination of samples which contain low concentrations of PCBs and loss from samples which contain high concentrations.Keywords
This publication has 30 references indexed in Scilit:
- PCBs and PAHs in U.K. urban airChemosphere, 1993
- Sources and sinks of dioxins: GermanyChemosphere, 1992
- Evidence for an increase in the cadmium content of herbage since the 1860sEnvironmental Science & Technology, 1992
- Significance of atmospheric inputs of lead to grassland at one site in the United Kingdom since 1860Environmental Science & Technology, 1991
- Organic contaminants in an agricultural soil with a known history of sewage sludge amendments: polynuclear aromatic hydrocarbonsEnvironmental Science & Technology, 1990
- Human exposure to environmental polychlorinated dibenzo-p-dioxins and dibenzofurans: An exposure commitment assessment for 2,3,7,8-TCDDScience of The Total Environment, 1989
- Cadmium in cereal grain and herbage from long-term experimental plots at Rothamsted, UKEnvironmental Pollution, 1989
- Retrospective analysis of an archived soil collection II. CadmiumScience of The Total Environment, 1987
- Retrospective analysis of an archived soil collection I. MetalsScience of The Total Environment, 1987
- Cadmium accumulation in soils from long‐continued applications of superphosphateEuropean Journal of Soil Science, 1986