Clean water is a precious resource, and policies/programmes are implemented worldwide to protect and/or improve water quality. Faecal pollution can be a key contributor to water quality decline causing eutrophication through nutrient enrichment and pathogenic contamination. The robust sourcing of faecal pollutants is important to be able to target the appropriate sector and to engage managers. Biomarker technology has the potential for source confirmation, by using, for example the biomarker suite of steroids. Steroids have been used in the differentiation of human and animal faeces; however, there is no unequivocal extraction technique. Some of the methods used include (i) Soxhlet extraction, (ii) Bligh and Dyer (BD) extraction, and (iii) accelerated solvent extraction (ASE). The less costly and time intensive technique of ASE is particularly attractive, but a current research gap concerns further comparisons regarding ASE lipid extraction from soils/slurries compared with the more traditional Soxhlet and BD extractions. Accordingly, a randomised complete block experiment was implemented to assess differences between the three extraction methods, differences between the different sample types, and the interactions between these two factors. Following GC-MS, it was found that there was no significant difference between the results of the steroid extraction methods, regardless of the type of sample used, for the quantity of each steroid extracted. It was concluded that ASE could be used confidently instead of the more established steroid extraction methods, thereby delivering time and cost savings.
Bibliographical noteFunding Information:
We acknowledge the Walsh Fellowship (Ref: 2016115) provided by Teagasc to Ulster University, the Teagasc Agricultural Catchments Programme (funded by the Irish Department of Agriculture, Food and the Marine), and Rothamsted Research for part funding this research. We thank the farmer for providing slurry, as well as Sarah Gilhespy, Karen Saunders, Rachel Matthews, and Andrew Mead at Rothamsted Research for their invaluable help. Rothamsted Research receives strategic funding from UKRI-BBSRC (UK Research and Innovation-Biotechnology and Biological Sciences Research Council) and the contribution to this work by ALC was supported by the Soil to Nutrition strategic programme under project 3 (grant award BBS/E/C/000I0330).
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- Bligh and Dyer
- Faecal pollution