Tracking the historical urban and rural sources of fecal pollution in a South American tropical semi-arid region using sterols and endocrine-disrupting chemicals.

Sterols and endocrine-disrupting chemicals were analyzed in two dated sediment cores collected in the Jaguaribe river to determine the recent decades' influence of urbanization and agropastoral activities on the inputs of fecal pollution in a semi-arid region of Brazil. Stigmasterol and sitosterol were the most abundant of the 6 sterols examined in both cores, indicating an important contribution of organic matter from mangrove forests to the study region. Coprostanol presented a continuous increase in concentrations from the 1930s to the 2000s in one core, however, showing higher concentrations (>100 ng g ^-1 ) in the upper layers of both cores. The sterols diagnostic ratios indicated fecal pollution through both cores, especially from the 1940s to 1970s. The coprostanol levels followed the variations in population growth in the state of Ceará. Estriol and estrone were the most abundant estrogenic hormones found in both cores. These compounds are probably related to the intense livestock activities in the Ceará state, especially after the 1970s. The baseline levels of fecal sterols and estrogen hormones found in this study possibly represent a previous unimpacted scenario and may be used for future evaluations of fecal pollution from urbanization and livestock activities.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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