O uso de esteróis e hormônios para estudo de contaminação por esgoto na plataforma interna adjacente ao Rio Acaraú (Ceará, Brasil)

Abstract

Sewage pollution can be one of the biggest problems for this aquatic environment, mostly, because of its illegal discharges. In this system, these compounds can associate with sediments because of its physical chemistry properties and once contamined they can be exported for continental shelves by rivers or direct input. Continental shelves are transition zones located in the continent-ocean interface, being directly affected by those environments. Contamination state of the sediments in the inner shelf adjacent to the Acarau river was made using sterols and hormones as sewage tracers in six samples. Other parameters as grain size, calcium carbonate and organic matter was used to check the influence of them in the compounds distribution. The analytes was quantified by gas chromatography coupled to a mass spectrometer (CG/MS), after being purified. The sterols sum was 4139.75 ng/g varying from 3.89 ng/g (S99) to 2246 ng/g (S67). The most abundant sterol was stigmasterol (sum 3266.33 ng/g), maybe denoting continental input. Coprostanol, fecal sterol, varied from absent (S99) to 252.38 (S67). Using diagnostic ratios, only S79 was classified as uncontaminated. Hormones varied from 88.05 ng/g (S101) to 420.96 ng/g (S98). Naturals hormones 17α-E2 and 17β-E2 were the most abundant, followed by DIE. The findings of the present study revealed that the sediments in the zone can be contamined by some sewage input.