Project description and importance
- Importance in the context of existing groundwater problems dealing with leaching of estrogens and pathogens
While the contamination risk posed by nutrients leaching from manure-treated fields is well recognized, then leaching of steroid estrogens and pathogens received much less attention. Nevertheless, leaching though soil is identified as contamination pathways leading these contaminants to the aquatic environment. High numbers of the large Crytosporidium sp. as well as Salmonella sp. and virus are leached through clayey soil columns, and field experiments suggest that estrogens originating from manure contaminate our freshwater bodies in concentrations exceeding the effect concentration towards water-organisms (Kjær et al. 2007, Environmental Science & Technology. vol. 42: pp. 3911-3917). Given the massive production of animal waste in Denmark and worldwide (Steinfeld et al. 2006, FAO-LEAD, Rome. Online) these findings are of broad environmental concern indicating an urgent need for further research into technology/management practices minimizing the contamination risk posed by these contaminants.
While we know that anaerobic digestion (for methane production) reduces or even eliminates the problems encountered with pathogens and natural estrogens, at present there is no knowledge on how slurry separation technologies affect the risk of pathogens and natural estrogens leaching to the aquatic environment. There is an imminent need to investigate how these changes in animal manure management affect the spreading of the aforementioned contaminants to the aquatic environment.
A prerequisite for conducting this type of research is fast, highly sensitive and selective analytical chemical methods and microbiological assays that analyze mixtures of compounds in matrices as manure, soil, surface water. Pathogens are quantified using molecular technologies based on DNA for enumerating numbers of specific microorganisms and mRNA for quantification of active microorganisms (Jacobsen & Holben. 2007, Journal of Microbiological Methods). The development of highly selective MS based technologies for drugs and natural hormones is another area where new possibilities in analytical chemistry improve our knowledge on the quality of environmental waters (Jacobsen et al. 2006, Analytical and Bioanalytical Chemistry. vol. 384: pp. 1164-1174).
Separation of liquid manure (slurry) doesn’t remove contaminants or pathogens, but it produce a liquid fraction that infiltrate better in the soil, and a solid fraction that is readilycomposted (Sommer et al. 2004, Biosystematic Bioengineering. vol. 88: pp. 359-367; Petersen et al.2003a, Journal of Environmental Quality. vol. 32: pp. 2399-2409).
Preferential flow (e.g. macropore flow) enhances the transport of strongly sorbing and easilydegrading contaminants, as the contact between the contaminants and the soil matrix isreduced (Kjær et al. 2007, Environmental Science & Technology. vol. 42: pp. 3911-3917; MacCay et al. 1993, Water Resources Research. vol. 29: pp. 3879-3890).