TY - JOUR
T1 - The formation and fate of chlorinated organic substances in temperate and boreal forest soils
AU - Clarke, Nicholas
AU - Fuksová, Květoslava
AU - Gryndler, Milan
AU - Lachmanová, Zora
AU - Liste, Hans Holger
AU - Rohlenová, Jana
AU - Schroll, Reiner
AU - Schröder, Peter
AU - Matucha, Miroslav
N1 - Funding Information:
Acknowledgements We thank the Czech–German Future Fund, Helmholtz Zentrum München, the Ministry of Agriculture of the Czech Republic (project 0002070201) and the Research Council of Norway for funding the international workshop ‘Biogeochemical cycles: chlorine in forest ecosystems’ (Garmisch-Partenkirchen, 2–4 November 2006) and the Programme Coordinating Centre, National Focal Centres and participating institutions of ICP Forests for providing data on chloride in deposition. We further appreciate the research concepts AVOZ 50380511 (Institute of Experimental Botany, ASCR, v.v.i., Prague) and AV0Z50200510 (Institute of Microbiology, ASCR, v.v.i., Prague) and the Grant Agency of the Czech Republic for supporting research connected with the topic of this article. We also thank three anonymous referees for the constructive comments on the manuscript.
PY - 2009/3
Y1 - 2009/3
N2 - Background, aim and scope: Chlorine is an abundant element, commonly occurring in nature either as chloride ions or as chlorinated organic compounds (OCls). Chlorinated organic substances were long considered purely anthropogenic products; however, they are, in addition, a commonly occurring and important part of natural ecosystems. Formation of OCls may affect the degradation of soil organic matter (SOM) and thus the carbon cycle with implications for the ability of forest soils to sequester carbon, whilst the occurrence of potentially toxic OCls in groundwater aquifers is of concern with regard to water quality. It is thus important to understand the biogeochemical cycle of chlorine, both inorganic and organic, to get information about the relevant processes in the forest ecosystem and the effects on these from human activities, including forestry practices. A survey is given of processes in the soil of temperate and boreal forests, predominantly in Europe, including the participation of chlorine, and gaps in knowledge and the need for further work are discussed. Results: Chlorine is present as chloride ion and/or OCls in all compartments of temperate and boreal forest ecosystems. It contributes to the degradation of SOM, thus also affecting carbon sequestration in the forest soil. The most important source of chloride to coastal forest ecosystems is sea salt deposition, and volcanoes and coal burning can also be important sources. Locally, de-icing salt can be an important chloride input near major roads. In addition, anthropogenic sources of OCls are manifold. However, results also indicate the formation of chlorinated organics by microorganisms as an important source, together with natural abiotic formation. In fact, the soil pool of OCls seems to be a result of the balance between chlorination and degradation processes. Ecologically, organochlorines may function as antibiotics, signal substances and energy equivalents, in descending order of significance. Forest management practices can affect the chlorine cycle, although little is at present known about how. Discussion: The present data on the apparently considerable size of the pool of OCls indicate its importance for the functioning of the forest soil system and its stability, but factors controlling their formation, degradation and transport are not clearly understood. It would be useful to estimate the significance and rates of key processes to be able to judge the importance of OCls in SOM and litter degradation. Effects of forest management processes affecting SOM and chloride deposition are likely to affect OCls as well. Further standardisation and harmonisation of sampling and analytical procedures is necessary. Conclusions and perspectives: More work is necessary in order to understand and, if necessary, develop strategies for mitigating the environmental impact of OCls in temperate and boreal forest soils. This includes both intensified research, especially to understand the key processes of formation and degradation of chlorinated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on OCls, as management can be used to produce desired effects.
AB - Background, aim and scope: Chlorine is an abundant element, commonly occurring in nature either as chloride ions or as chlorinated organic compounds (OCls). Chlorinated organic substances were long considered purely anthropogenic products; however, they are, in addition, a commonly occurring and important part of natural ecosystems. Formation of OCls may affect the degradation of soil organic matter (SOM) and thus the carbon cycle with implications for the ability of forest soils to sequester carbon, whilst the occurrence of potentially toxic OCls in groundwater aquifers is of concern with regard to water quality. It is thus important to understand the biogeochemical cycle of chlorine, both inorganic and organic, to get information about the relevant processes in the forest ecosystem and the effects on these from human activities, including forestry practices. A survey is given of processes in the soil of temperate and boreal forests, predominantly in Europe, including the participation of chlorine, and gaps in knowledge and the need for further work are discussed. Results: Chlorine is present as chloride ion and/or OCls in all compartments of temperate and boreal forest ecosystems. It contributes to the degradation of SOM, thus also affecting carbon sequestration in the forest soil. The most important source of chloride to coastal forest ecosystems is sea salt deposition, and volcanoes and coal burning can also be important sources. Locally, de-icing salt can be an important chloride input near major roads. In addition, anthropogenic sources of OCls are manifold. However, results also indicate the formation of chlorinated organics by microorganisms as an important source, together with natural abiotic formation. In fact, the soil pool of OCls seems to be a result of the balance between chlorination and degradation processes. Ecologically, organochlorines may function as antibiotics, signal substances and energy equivalents, in descending order of significance. Forest management practices can affect the chlorine cycle, although little is at present known about how. Discussion: The present data on the apparently considerable size of the pool of OCls indicate its importance for the functioning of the forest soil system and its stability, but factors controlling their formation, degradation and transport are not clearly understood. It would be useful to estimate the significance and rates of key processes to be able to judge the importance of OCls in SOM and litter degradation. Effects of forest management processes affecting SOM and chloride deposition are likely to affect OCls as well. Further standardisation and harmonisation of sampling and analytical procedures is necessary. Conclusions and perspectives: More work is necessary in order to understand and, if necessary, develop strategies for mitigating the environmental impact of OCls in temperate and boreal forest soils. This includes both intensified research, especially to understand the key processes of formation and degradation of chlorinated compounds, and monitoring of the substances in question in forest ecosystems. It is also important to understand the effect of various forest management techniques on OCls, as management can be used to produce desired effects.
KW - Carbon cycle
KW - Chlorination
KW - Chlorine biogeochemistry
KW - Forest management
KW - Forest soil
KW - Microbial soil processes
KW - Organochlorines
KW - Soil organic matter (SOM)
KW - Temperate and boreal forests
UR - http://www.scopus.com/inward/record.url?scp=61349086651&partnerID=8YFLogxK
U2 - 10.1007/s11356-008-0090-4
DO - 10.1007/s11356-008-0090-4
M3 - Review article
C2 - 19104865
AN - SCOPUS:61349086651
SN - 0944-1344
VL - 16
SP - 127
EP - 143
JO - Environmental Science and Pollution Research
JF - Environmental Science and Pollution Research
IS - 2
ER -