Environmental assessment of steroid endocrine disruptors in stranded cetaceans: A methodological approach to detection and analysis

Abstract

Exploring the presence of endocrine disrupting compounds in marine organisms, particularly cetaceans, is crucial to evaluate contamination within the ocean's food web and the detection of synthetic hormones in cetaceans is a strong indication of anthropogenic pollution in marine ecosystems. Due to their characteristics, blubber samples are a key component in assessing the analysis of cetaceans, but this type of sample require precise and sensitive analytical methods. Despite some methodologies have been developed for the analysis of natural steroid hormones in cetacean blubber, a significant gap persists in the comprehensive analysis of synthetic steroids within these samples. In this work, a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction combined with UHPLC-MS/MS (ultra-high-performance liquid chromatography with tandem mass spectrometry) analysis was performed to determine six synthetic steroid hormones (nandrolone, prednisolone, prednisone, megestrol acetate, norethisterone, and norgestrel) in 11 stranded cetacean blubber samples. Despite the complex nature of blubber samples, the developed methodology showed promising results, with recoveries ranging from 70 % to 120 % for most target compounds at low concentration levels (150 ng·g⁻¹). The method demonstrated high precision with relative standard deviations under 20 % in both intra- and inter-day experiments. Regarding the matrix effect, ion suppressions of about 50 % were also calculated for those samples spiked at concentration levels of 150 ng·g⁻¹, nevertheless, all compounds were still able to be detected, in most cases below quantification limits. Notably, one sample presented a quantified concentration of megestrol acetate, a steroid hormone used in contraceptives and cancer treatments, at 26.98 ± 2.62 ng·g⁻¹. The results affirm the methodology's effectiveness for analyzing synthetic steroid hormone levels in cetacean blubber, providing a valuable tool for assessing environmental concentrations of these anthropogenic endocrine disruptors and their impact on cetacean welfare and conservation.