Chlorination and dechlorination rates in a forest soil: A combined modelling and experimental approach
2016 (English)In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 554-555, 203-210 p.Article in journal (Refereed) PublishedText
Abstract Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Clorg). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Clorg are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Clâ transformed to Clorg per time unit) and specific dechlorination (i.e., fraction of Clorg transformed to Clâ per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 dâ 1 and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01â0.03 dâ 1 and were similar among all treatments. This study finds that soil Clorg levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Clorg compounds, while another Clorg pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils.
Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 554-555, 203-210 p.
Chlorine cycling, Chloride, Organic chlorine, Radioactive chlorine-36, Modelling
Soil Science Environmental Sciences related to Agriculture and Land-use Agricultural Sciences Ecology Forest Science
IdentifiersURN: urn:nbn:se:liu:diva-125912DOI: 10.1016/j.scitotenv.2016.02.208ISI: 000373274700022PubMedID: 26950634OAI: oai:DiVA.org:liu-125912DiVA: diva2:910021
Funding agencies: EDF, France; National Radioactive Waste Management Agency (Andra), France; Linkoping University, Sweden2016-03-082016-03-082016-05-02Bibliographically approved