Are fecal stanols suitable to record and identify a pulse of human fecal contamination in short-term exposed shellfish? A microcosm study

Abstract

In this study, the capacity of oysters to bioaccumulate fecal stanols and to record a source-specific fingerprint was investigated by the short-term contamination of seawater microcosms containing oysters with a human effluent. Contaminated oysters bioaccumulated the typical fecal stanols coprostanol and 24-ethylcoprostanol and their bioaccumulation kinetics were similar to that of the Fecal Indicator Bacteria Escherichia coli used in European legislation. Although stanol fingerprints of contaminated water allowed the identification of the human specific fingerprint, this was not the case for oysters. This discrepancy is attributed to (i) high concentrations of endogenous cholestanol and sitostanol, responsible for "unbalanced" stanol fingerprints, (ii) different accumulation/depuration kinetics of fecal coprostanol and 24-ethylcoprostanol and (iii) the limits of the analytical pathway used. These results show that fecal stanols bioaccumulated by oysters are useful to record fecal contamination but the usefulness of stanol fingerprints to identify specific sources of contamination in shellfish currently seems limited.

Faecal biomarkers can distinguish specific mammalian species in modern and past environments

“…Among omnivores, the distinction between species, or at least between humans and others (pigs and dogs), has already been studied using stanol ratios [7, 10, 20, 21, 33, 58] or with multivariate analyses [4, 19, 23, 24, 27, 28, 31].…”

“…Mainly because of their respective diets, cholesterol-derived 5β-stanols are found in high proportions in the faeces of omnivores and carnivores (coprostanol and epicoprostanol), while 5β-stanols derived from β-sitosterol, a phytosterol (plant sterol), are found in high proportions in herbivore faeces (24-ethylcoprostanol and 24-ethylepicoprostanol) [1]. In order to improve the distinction between the faecal signature of different mammal species in modern [16, 17, 20, 21, 24, 28, 29] and ancient [2, 3, 5, 7, 9, 11–15, 18, 32–34] environments, efforts have been made to develop the technique of faecal steroid biomarker analysis, mainly focused on the ratios of the four above-mentioned important 5β-stanols, sometimes in combination with the analysis of another group of faecal steroids, bile acids. However, the use of ratios calculated from four compounds has significant limitations.…”

Veterinary pharmaceutical residues in water resources and tap water in an intensive husbandry area in France

“…Several tools have been developed and efficiently applied to distinguish human and animal fecal contamination in environmental matrices, such as microbiological markers (Ahmed et al, 2016;Derrien et al, 2012;Gourmelon et al, 2010;Heaney et al, 2015;Ohad et al, 2015;Raith et al, 2013;Seurinck et al, 2005;Solecki et al, 2011), viral markers (Cole et al, 2003;Gourmelon et al, 2010;Jofre et al, 2014;Lee et al, 2009;Muniesa et al, 2009;Tyagi et al, 2009) or chemical markers such as fecal stanols (Biache and Philp, 2013;Derrien et al, 2012;Gourmelon et al, 2010;Harrault et al, 2014;Jardé et al, 2018;Jeanneau et al, 2011;Leeming et al, 1996;Shah et al, 2007;Tran et al, 2015;Tyagi et al, 2009), pharmaceuticals or other compounds related to human consumption (caffeine, nicotine, artificial sweeteners) (Madoux-Humery et al, 2013;Tran et al, 2015;Wade et al, 2015). Markers of fecal contamination are often used in association in what is called a "Fecal Source Tracking (FST)…”

“…Their distribution in feces will vary according to the specie's diet, the ability of animals to biosynthesize endogenous sterols and the composition of the intestinal flora which will converts sterols into stanols by biohydrogenation (Leeming et al, 1996). This species distribution, called "stanol fingerprint", has been successfully used, via stanol ratio analysis or by multivariate analysis, to distinguish human and animal contamination in water (Biache and Philp, 2013;Derrien et al, 2012;Gourmelon et al, 2010;Harrault et al, 2014;Jardé et al, 2018;Jeanneau et al, 2011;Leeming et al, 1996;Shah et al, 2007;Tran et al, 2015;Tyagi et al, 2009). Besides, stanols demonstrate a significant persistence in the environment (Harrault et al, 2014) and sufficient concentrations to be detected.…”

“…This species distribution, called "stanol fingerprint", has been successfully used, via stanol ratio analysis or by multivariate analysis, to distinguish human and animal contamination in water (Biache and Philp, 2013;Derrien et al, 2012;Gourmelon et al, 2010;Harrault et al, 2014;Jardé et al, 2018;Jeanneau et al, 2011;Leeming et al, 1996;Shah et al, 2007;Tran et al, 2015;Tyagi et al, 2009). Besides, stanols demonstrate a significant persistence in the environment (Harrault et al, 2014) and sufficient concentrations to be detected. Regarding the limitations of the use of stanols, some studies report a difficulty in identifying the source of fecal contamination via the "stanol fingerprint" in the case of watersheds affected by several sources of pollution (Shah et al 2007).…”