Sewage contamination of Amazon streams crossing Manaus (Brazil) by sterol biomarkers

• Published in: Environmental pollution (1987) Vol. 244; pp. 818 - 826
• Main Authors: de Melo, Moacir Guimarães, da Silva, Brina Aguiar, Costa, Gilcllys de Souza, da Silva Neto, João Cândido André, Soares, Patrícia Kaori, Val, Adalberto Luis, Chaar, Jamal da Silva, Koolen, Hector Henrique Ferreira, Bataglion, Giovana Anceski
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2019
• Subjects: Biomarkers - analysis; Brazil; Cholestadienols - analysis; Cholestanol - analysis; Cholestanols - analysis; Cholesterol - analogs & derivatives; Cholesterol - analysis; Chromatography, Liquid; Coprostanol; Drug Contamination; Environmental Monitoring - methods; Feces; Geologic Sediments - chemistry; Igarapé; Mindu Stream; Phytosterols - analysis; Quarenta Stream; Rivers - chemistry; Sewage - analysis; Sitosterols - analysis; Sterols - analysis; Tandem Mass Spectrometry; Tarumã-Açu Stream; Water Pollutants - analysis; Water Pollution - analysis; Water Quality; Brazil; Tarumã-Açu Stream; Mindu Stream; Quarenta Stream; Igarapé; Coprostanol
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2018.10.055

Sewage pollution is a principal factor of decreasing water quality, although it has not been considered a real impact in Amazonia that is still considered a pristine environment around the world. Thus, this study aimed to assess the levels of sewage contamination in sediments from three streams crossing Manaus − a Brazilian city of 2,403,796 inhabitants in the heart of the Amazon rain forest. Cholesterol, cholestanol, brassicasterol, ergosterol, stigmasterol, β-sitosterol, campesterol, stigmastanol, coprostanol, and epicoprostanol levels were determined by liquid chromatography tandem mass spectrometry (LC−MS/MS). The fecal indicator, coprostanol, was found in high concentrations (509−12 830 ng g−1) and high relative proportions (21–54%) in all samples collected in the Mindu stream that crosses many heavily populated districts of the city, and in the Quarenta stream that crosses the Industrial District of Manaus. The sediments of the Tarumã-Açu stream also presented coprostanol; however, concentrations (<LOQ−142 ng g−1) and relative proportions (0–7%) were much lower in this stream. Sterol ratios indicate a severe contamination of the urban streams (Mindu and Quarenta) and a low to moderate contamination of the partially urban stream (Tarumã-Açu). This is the first study evaluating the levels of sewage contamination of Amazon streams using sterol biomarkers and the results obtained herein indicate the need of an immediate implementation of effective sewage treatment strategies. Additionally, these findings may be considered as baseline concentrations for future monitoring programs of that globally important environment. [Display omitted] •Ten sterols were determined in sediments from three Amazonian streams.•Sterol ratios were also used to evaluate sewage contamination.•Two entirely urban streams, Mindu and Quarenta, are highly contaminated.•A partially urban stream, Tarumã-Açu, presents low to moderate contamination.•Not all Amazonia represents a pristine environment. Although Amazonia is believed to be a pristine environment around the world, accentuated pollution by domestic sewage was detected in its urban streams.