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Explore the use of sterol molecular markers to evaluate faecal contamination levels in the environment, specifically focusing on Attenborough Ponds. Identify sewage markers and their pathways to assess environmental and human health impacts over time.
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Organic Sewage Tracers • Sterols are components of cells & are synthesized by most organisms • In humans cholesterol is biohydrogenated by intestinal microflora to 5b-cholestrol • Other animals also produce 5b-cholestrol but at much lower concentrations • Herbiverous animals produce 24-ethyl coprostanol in greater concentrations Sterol structure
Assessment of Faecal Contamination Using Sterol Molecular Markers Attenborough Ponds Nature: Long Term Effects of River Diversion
Conneries dating 1986 ? 1963 ?
Resolving co-elution Sediment Sample TIC coprostanol m/z = 333 Cholesterol-d6 m/z = 231 Coprostan-3-one m/z = 329 Cholesterol m/z 333 m/z 231 m/z 329 Identification of Sewage Markers Target mix 5b-epicoprostanol coprostanol fucosterol + b-sitosterol 17b-estradiol 5a-cholestane 5a-cholestanol stigmasterol estrone campesterol 5b-stigmastanol Environment & Human Health Theme
Ten of eleven sewage marker • compounds were identified • in the Attenborough cores • 5-cholestane not detected
Sterol & Stanol Marker Pathways Environmental (5) Intestinal (5)
2 1 3 • Sitosterol: Clifton and Church = Input from plants & or avian FM • Stigmastanol: Conneries = Input from ruminants / manure, slurry ? • Coprostanol: Concs. >0.5ug/g = received appreciable amounts of sewage
Coprostanol/Cholesterol: human sewage >0.2 criteria= Only Conneries • Coprostanol/(Coprostanol+Cholestanol) human sewage >0.7= Conneries • Epicoprostanol/coprostanol:treatment or age in environ. =Church & • Clifton little sewage or high degree of treatment
1.5 1.0 0.5 0.0 0.0 0.5 1.0 1.5 2.0 2.5 Bi-plot of sewage marker compounds Low sewage, old or treated High sewage, untreated
Ratio 5Cholestanol/Cholesterol:anaerobic process marker • Conneries possible more reducing environ at 20 to 50 cm ?