Title: The Influence of Sorption on the Degradation of Pesticides and other Chemicals in Soil 
Resource Type: document --> technical publication --> report 
Country: Denmark 
Year: 2004 
Availability: Environmental project, Miljørapport nr.902 
Author 1/Producer: Formsgaard, I. S. 
Author / Producer Type: Agency, regulator or other governmental or inter-governmental body 
Publisher: The Danish Environmental Protection Agency, Miljøstyrelsen 
Publisher City: Strandgade 29, DK-1405 Copenhagen K, Denmark 
ISBN: 87-7614-185-3 
Report / download web link (=direct link): http://www2.mst.dk/Udgiv/publications/2004/87-7614-185-3/pdf ...  
Format (e.g. PDF): PDF 
Size: (e.g. 20mb) 1861 
EUGRIS Keyword(s): Contaminated land-->Soil and groundwater processes-->Microbiology
Soil-->Processes
 
Short description: This literature study provides a description of the very complex connection between the sorption of xenobiotic chemicals to the soil organic matter and the microbial degradation of the substances in the soil environment. Investigation of microbial degradation of chemicals in soil under conditions as close to the real environment as possible has demonstrated that sorption has a limiting effect on the degradation rate of pesticides, since only the pesticide present in the aqueous phase of the soil is available for microbiological degradation. 
Long description: The sorption of chemicals to soil may vary from being completely reversible to being completely irreversible, and since only pesticides present in the aqueous phase are available for degradation; a very complex relationship exists between the sorption of xenobiotic chemicals to the soil organic matter and microbial degradation. Degradation of sorbed chemicals may however still occur to a certain extent. If desorption occurs with time and at a similar rate or lower than the degradation rate, the dependence of the degradation on the sorption leads to complex kinetics even though the degradation kinetics itself is simple first-order kinetics. Recent studies indicate that two compartment first-order kinetics provides a better description of the degradation of chemicals in soil when systems are used that simulate the natural degradation under field conditions. The two-compartment kinetics expresses a distribution of the added chemical between the aqueous phase and the soil phase and indicates a first-order rate constant for the degradation in the fluid phase and the soil phase, respectively. The two-compartment kinetics is often preferred, both for chemicals that are mainly bound to the soil organic matter and for chemicals that are mainly bound to the clay minerals. 
Submitted By: Dr Jacqueline Falkenberg WhoDoesWhat?      Last update: 02/04/2007