Free and conjugated forms of metabolites are indispensable components of steroids: The first evidence from an estuarine food web. (15th May 2023)

• Record Type: Journal Article
• Authors: Liu, Shan; Xu, Ru; Pan, Yun-Feng; Huang, Qian-Yi; Wu, Nian-Nian; Li, Heng-Xiang; Lin, Lang; Hou, Rui; Xu, Xiang-Rong
• Is Part Of: Water research. Volume 235(2023)
• Publication Date: 2023-05-15
• Subjects: Steroid -- Metabolite -- Conjugate -- Bioaccumulation -- Trophic transfer; AED 4-androstene-3, 17-dione -- 17β-BOL 17β-boldenone -- BAF Bioaccumulation Factor -- CCA Canonical Correlation Analysis -- CRL cortisol -- CRN cortisone -- CPTA cyproterone acetate -- DCA Detrended Correspondence Analysis -- DGT dydrogesterone -- 1-DHP 1-dehydroprogesterone -- 16-DHP 16-dehydroprogesterone -- 20α-DHP 20α-dihydroprogesterone -- 20β-DHP 20β-dihydroprogesterone -- DIE dienogest -- DOC 11-deoxycorticosterone -- 17α 20α-DOHP, 17α 20α-dihydroxyprogesterone -- EDI Estimated Daily Intake -- HQ Hazard Quotient -- 11-KP 11-ketoprogesterone -- LOD Limit of Detection -- LOQ Limit of Quantitation -- MGTA megestrol acetate -- MPA medroxyprogesterone acetate -- MRL Maximum Residue Limit -- 17α-MT 17α-methyltestosterone -- NGT norgestrel -- 19-NT 19-nortestoserone -- 19-NTD 19-norethindrone -- NVT norvinisterone -- 17α-OHP 17α-hydroxyprogesterone -- 17α-OHPA 17α-hydroxyprogesterone acetate -- P progesterone -- PREL prednisolone -- RQ Risk Quotient -- T testosterone -- 17α-TBL 17α-trenbolone -- 17β-TBL 17β-trenbolone -- 3α 5β-THCRL tetrahydrocortisol -- TL Trophic Level -- TMF Trophic Magnification Factor -- ww wet weight -- lw lipid weight; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2023.119913
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Trophic transfer of free and conjugated steroids was observed for the first time. Water contained more metabolites, while sediment contained more natural steroids. Free and conjugated metabolites were indispensable components of steroids in biota samples. Most synthetic steroids are bioaccumulative or very bioaccumulative. For invertebrates, 17α-MT was biomagnified, while 17β-BOL was bio-diluted. Abstract: Steroids have attracted particular attention as environmental contaminants because of their severe endocrine-disrupting effects. Previous studies have predominantly focused on parent steroids; however, the levels and proportions of the free and conjugated forms of their metabolites remain largely unclear, especially in food webs. Here, we first characterized the free and conjugated forms of parent steroids and their metabolites in 26 species in an estuarine food web. The steroids were dominated by their metabolites in water samples, whereas parent compounds were predominant in sediment samples. The total mean steroid concentrations in the biota samples that underwent non-enzymatic hydrolysis decreased in the following order: crabs (27 ng/g) > fish (5.9 ng/g) > snails (3.4 ng/g) > shrimps and sea cucumbers (1.2 ng/g); and those in the biota samples that underwent enzymatic hydrolysis decreased in the following order: crabs (57 ng/g) > snails (9.2 ng/g) > fish (7.9 ng/g) > shrimps and sea cucumbers (3.5 ng/g). The proportion of metabolites in the enzymatic hydrolysis biota samples was higher (38−79%) than that (2.9−65%) in non-enzymatic ones, indicating that the free and conjugated forms of metabolites in aquatic organisms were not negligible. Most synthetic steroids were either bioaccumulative or highly bioaccumulative. Importantly, in the invertebrate food web, 17α-methyltestosterone was biomagnified, while 17β-boldenone underwent trophic dilution. Although the estuarine water had a median ecological risk level, the health risks via aquatic product consumption were very low. This study provides novel insights into the composition and trophic transfer of steroids in an estuarine food web for the first time and highlights that free and conjugated metabolites should receive more attention, particularly in biota samples. Graphical abstract: Image, graphical abstract