Cholesterol, -Sitosterol, Ergosterol, and Coprostanol in Agricultural Soils

represent a minor source of cholesterol (Ibanez et al., 2000). In this work we analyzed the sterol content of agricultural soils. Ergosterol is the main endogenous sterol of fungi and Three eukaryotic sterols, cholesterol, -sitosterol, and ergosterol were of some microalgae. Ergosterol content in fungal cells chosen as representative of the animal, plant, and fungal kingdoms, varies in different species and under different environwhile coprostanol was validated as a marker of human fecal matter mental conditions. Its concentration is an important incontamination. Three soils subjected to different treatments (sewage sludge application, irrigation by saline waters, and contamination by dicator of fungal growth in organic substrates such as industrial and municipal wastes) were sampled and their sterol content foods (Battilani et al., 1996) and it has been proposed was measured and compared with adjacent untreated soils. The effects as an indicator of living fungal biomass in soils, because of time, location, and treatment were evaluated by means of a number it is easily mineralized at the cell’s death (West and of statistical techniques. -Sitosterol concentration varied from 0.9 Grant, 1987). In addition, a clear correlation between to 30 mg kg 1. Lesser values were measured in Cremona (2.1 mg kg 1) ergosterol and fungal iphae length was shown (Stahl than in Bari (4.0 mg kg 1) and Naples (10.9 mg kg 1) soils. No signifiand Parkin, 1996). Some soil fungi are able to degrade cant effects were detected for cholesterol and ergosterol. Coprostanol a number of organic pollutants (Barr and Aust, 1994), was present after sewage sludge disposal and contamination by indusand ergosterol has therefore been proposed as a marker trial and municipal wastes, while it was absent in the soil treated with of soil bioremediation potential (Barajas-Aceves et al., saline water and in the adjacent untreated soil. Coprostanol concentra2002). tion did not vary much within site and time of sampling, with a mean The 5 -stanols are transformation compounds provalue of 0.2 mg kg 1. We confirmed coprostanol as a useful persistent duced by microbial hydrogenation of cholesterol, campmarker of human fecal matter contamination. Multivariate analysis highesterol, -sitosterol, and stigmasterol in the intestinal lighted a clear distinction between the eukaryotic sterols and coprostanol. In addition, a different behavior between ergosterol and cholestract of most higher animals. Coprostanol (5 -cholesterol on one side and -sitosterol on the other was detected. This tan-3 -ol) is the main sterol (about 60% of total) in preliminary work suggests that sterols deserve a deeper study of their human feces (Bull et al., 2002). Several studies focused use as indicators in agricultural soils. on coprostanol as an important biomarker of fecal contamination in water, sediments, and soils (see GonzálezOreja and Saiz-Salinas, 1998). Also, cats and pigs proS are components of eukaryotic cells. Their duce coprostanol as the main sterol, but in quantities that are 10 times less than in humans. Concentration of detection in soil is an important tool for characterizcoprostanol is therefore a reliable measure of human ing biomass (e.g., plant and animal biomass) and other fecal pollution. Further information may be given by the organic pools, as different classes of organisms have relative quantities of other fecal sterols. For example, different sterols pattern. ruminants produce a higher relative proportion of Plant sterol composition varies within different spe5 -campestanol and 5 -stigmastanol, produced respeccies and physiological stage of development. Typical tively by biohydrogenation of campesterol and -sitoplant sterols include -sitosterol, campesterol, stigmasterol (Nichols et al., 1996). In locations where both sterol, and -sitosterol, which has been reported to be herbivorous and human sources of fecal pollution are the main plant sterol by several researchers (e.g., Ebrasuspected, the ratio of coprostanol and 5 -stigmastanol himzadeh et al., 2001). These sterols are also contained has been proposed as a discriminatory tool (Leeming in seeds, with -sitosterol being the main one, in concenet al., 1996). trations that in several species of Astragalus exceed 70% There is a growing interest in the determination of (Knights and Berrie, 1971). -Sitosterol increases during chemical and biochemical properties, which can be used development, and in turnip rape [Brassica rapa L. subsp. to assess the status of agricultural soils (Gianfreda et al., campestris (L.) A.R. Clapham], reaches its peak in the unpublished data, 2002; Trasar-Cepeda et al., 1998). In early phases of floral development (Hobbs et al., 1996). this work we studied the soil content of the main eukaryIts fate in agricultural soils has been studied in longotic sterols cholesterol, -sitosterol, and ergosterol, repterm experiments, and appears to be a labile compound resenting the three eukaryotic kingdoms, and of coprowhose concentration diminishes greatly, presumably stanol, a known marker of fecal pollution. Samplings due to assimilation by soil arthropods (Bull et al., 2000). were repeated three times in soils that are different in Cholesterol is the main animal sterol, and its detection cultivation and alteration events, to obtain a preliminary in soil samples is directly related to microand mesodescription of the effects of time, location, and treatfauna biomass. Plant matter and organic fertilizer may ment on sterol content of agricultural soil. MATERIALS AND METHODS Istituto di Chimica Agraria ed Ambientale, Università Cattolica del Sacro Cuore, 29100 Piacenza, Italy. Received 24 June 2002. *CorreStudy Sites sponding author ([email protected]). Three sites in different parts of Italy, with different pedological and climatic conditions and subjected to various alteration Published in J. Environ. Qual. 32:466–471 (2003).