Abiotic transformation of synthetic progestins in representative soil mineral suspensions

Altrenogest(ALT),drospirenone(DRO),and melengestrol acetate(MLA)are three highly potent synthetic progestins that can be released into agricultural soils,while their fate in soil minerals remains unclear.This study explored the transformation of these progestins in MnO_(2),SiO_(2),and ferrihydrite suspensions and identified their transformation products(TPs)via high resolution mass spectrometry and density functional theory calculations.Transformations were only observed for DRO and MLA in SiO_(2) suspension and ALT in MnO_(2) suspension(half-lives=0.86 min–9.90 day).ALT transformation was facilitated at higher MnO_(2) loadings,while DRO and MLA transformations were inhibited at higher SiO_(2) loadings.These data indicated that hydrophobic partitioning interactionwas dominant at higher SiO_(2) loadings rather than specific interaction,which limited subsequent surface-catalyzed transformation.ALT transformation rate decreased with increasing pH because MnO_(2) reduction requires proton participation.In contrast,relatively high pH facilitated MLA and DRO transformation,indicating that base-catalyzed hydrolysis occurred in SiO_(2) suspension.The clustermap demonstrated the formation of abundant TPs.Lactone ring and acetoxy group hydrolysis was the major transformation pathway for DRO and MLA,with estimated yields of 57.7%and 173.2%at 6 day,respectively.ALT experienced C12 hydroxylation and formed the major TP 326g(yield of 15.4%at 8 hr).ALT also experienced allyl group oxidation and subsequent C5 hydroxylation,forming the major TP 344a(yield of 14.1%at 8 hr).This study demonstrates that TPs ofmetastable progestins are likely the main species in soils and that TP identification is a particular priority for risk assessment.

Sorption and desorption of sex hormones in soil-and sediment-water systems:A review

Sex hormones are a group of potent endocrine disruptors that can be released into agricultural soils and sediment via wastewater discharge and manure fertilization.Sorption represents a critical determinant for the transport potential and risks of sex hormones in the environment.Therefore,this study reviewed the sorption and desorption mechanisms of sex hormones in soil-and sedimentwater systems,and summarized the effects of various factors on sorption and desorption processes.A total of 359 set of sorption data were collected from the literature.Sex hormones were mostly described by the linear model.The sorption magnitudes(logKoc)of estrogens,androgens,and progestins were in the range of 2.77–3.90,2.55–4.18,and 2.61–4.39,respectively.The average logKoc values of the sex hormones were significantly correlated with their logKow values(R^(2)=0.13,p<0.05),while the R^(2) values were much lower than those when fewer sex hormones were included for analysis.In addition,the Kd values of most sex hormones were significantly correlated with the OC%of soils and sediment(R^(2)=0.16–0.99,p<0.05),but were insignificantly correlated with the particle size distribution and surface area.These results indicated that hydrophobic partitioning interaction and other specific interactions are responsible for sex hormone uptake in soil-and sediment-water systems.The sorption of sex hormones in soil-and sediment-water systems can also be affected by other environmental variables,including pH,temperature,and ionic strength.Future studies should focus on the coupled leaching-sorption processes in manure-water-soil systems under field-scale conditions.