Stereoselective Degradation of Estradiol and Trenbolone Isomers in Alluvial Sediment

Degradation kinetics of veterinary antibiotics and estrogenic hormones in a claypan soil

Veterinary antibiotics and estrogens are excreted in livestock waste before being applied to agricultural lands as fertilizer, resulting in contamination of soil and adjacent waterways. The objectives of this study were to 1) investigate the degradation kinetics of the VAs sulfamethazine and lincomycin and the estrogens estrone and 17β-estradiol in soil mesocosms, and 2) assess the effect of the phytochemical DIBOA-Glu, secreted in eastern gamagrass (Tripsacum dactyloides) roots, on antibiotic degradation due to the ability of DIBOA-Glu to facilitate hydrolysis of atrazine in solution assays. Mesocosm soil was a silt loam representing a typical claypan soil in portions of Missouri and the Central United States. Mesocosms (n = 133) were treated with a single target compound (antibiotic concentrations at 125 ng g-1 dw, estrogen concentrations at 1250 ng g-1 dw); a subset of mesocosms treated with antibiotics were also treated with DIBOA-Glu (12,500 ng g-1 dw); all mesocosms were kept at 60% water-filled pore space and incubated at 25 °C in darkness. Randomly chosen mesocosms were destructively sampled in triplicate for up to 96 days. All targeted compounds followed pseudo first-order degradation kinetics in soil. The soil half-life (t0.5) of sulfamethazine ranged between 17.8 and 30.1 d and ranged between 9.37 and 9.90 d for lincomycin. The antibiotics results showed no significant differences in degradation kinetics between treatments with or without DIBOA-Glu. For estrogens, degradation rates of estrone (t0.5 = 4.71-6.08 d) and 17β-estradiol (t0.5 = 5.59-6.03 d) were very similar; however, results showed that estrone was present as a metabolite in the 17β-estradiol treated mesocosms and vice-versa within 24 h. The antibiotics results suggest that sulfamethazine has a greater potential to persist in soil than lincomycin. The interconversion of 17β-estradiol and estrone in soil increased their overall persistence and sustained soil estrogenicity. This study demonstrates the persistence of these compounds in a typical claypan soil representing portions of the Central United States.

Multiomics Sequencing and AlphaFold2 Analysis of the Stereoselective Behavior of Mefentrifluconazole for Bioactivity Improvement and Risk Reduction

As the first isopropanol chiral triazole fungicide, mefentrifluconazole has broad prospects for application. In this study, the stereoselective stability, bioactivity, fate, and biotoxicity were systematically investigated. Our results indicated that the stability of mefentrifluconazole enantiomers differed between environmental media, and they were stable in water and sediment in the dark. The bactericidal activity of R-mefentrifluconazole against the four target pathogens was 4.6-43 times higher than that of S-mefentrifluconazole. In the water-sediment system, S-mefentrifluconazole dissipated faster than R-mefentrifluconazole in water; however, its accumulation capacity was higher than that of R-mefentrifluconazole in sediment and zebrafish. S-Mefentrifluconazole induced more differentially expressed genes (DEGs) and differentially expressed proteins (DEPs) in zebrafish than did R-mefentrifluconazole. Multiomics sequencing results showed that S-mefentrifluconazole enhanced the antioxidant, detoxification, immune, and metabolic functions of zebrafish by interacting with related proteins. Based on AlphaFold2 modeling and molecular docking, mefentrifluconazole enantiomers had different binding modes with key target proteins in pathogens and zebrafish, which may be the main reason for the stereoselective differences in bioactivity and biotoxicity. Based on its excellent bioactivity and low biotoxicity, the R-enantiomer can be developed to improve the bioactivity and reduce the risk of mefentrifluconazole.

Dark transformation from 17β-estradiol to estrone initiated by hydroxyl radical in dissolved organic matter

The occurrence and fate of 17β-estradiol (E₂) in natural water have gained extensive attention owing to its high ecotoxic risk to wildlife. Dissolved organic matter (DOM) is a ubiquitous water constituent and contributes significantly to E₂ removal, although the reaction mechanism is rarely clarified. The present study aims to investigate E₂ transformation in water containing fresh or aged DOM surrogates at environmentally relevant concentrations in the dark. Experiments along with radical probes of benzene and furfuryl alcohol reveal that reactive radicals, particularly hydroxyl radical (·OH), formed non-photochemically at higher concentrations in aged DOM than in fresh DOM. The contribution of ·OH in E₂ removal is indicated by the decreases in the removal of radical probes in the presence of E₂; moreover, E₂ removal is inhibited in the presence of radical scavengers. The dose-dependent inhibitive effect of substrate concentrations, including E₂ and coexistent propylparaben, shows that the radical concentration is a limiting factor for E₂ removal, which could be enhanced by increasing DOM concentration, dissolved oxygen, and light supply. As the main byproduct, estrone (E₁) is persistent in the current DOM water in the dark, but it can be easily photodegraded when exposed to light. Theoretical analysis reveals that the initial step is ·OH-initiated H- abstraction on the hydroxyl group in the cyclopentane ring of E₂. The formed singlet excited state of E₂ undergoes further intramolecular rearrangement and oxidative dehydrogenation to generate E₁ and the hydroperoxy radical (·HO₂). Considering the universal occurrence of E₂ in DOM-rich aquatic matrices, the present findings have special implications for the biogeochemical cycle and risk assessment of this pollutant in natural aquatic environments, particularly those beyond the photic zone.

Environmental fate and toxicity of androgens: A critical review

Androgens are released by humans and livestock into the environment and which cause potent endocrine disruptions even at nanogram per liter levels. In this article, we reviewed updated research results on the structure, source, distribution characteristics and the fate of androgens in ecological systems; and emphasized the potential risk of androgens in aquatic organism. Androgens have moderately solubility in water (23.6-58.4 mg/L) and moderately hydrophobic (log Kow 2.75-4.40). The concentration of androgens in surface waters were mostly in ng/L ranges. The removal efficiencies of main wastewater treatment processes were about 70-100%, except oxidation ditch and stabilization ponds. Sludge adsorption and microbial degradation play important role in the androgens remove. The conjugated androgens were transformed into free androgens in environmental matrices. Global efforts to provide more toxicity data and establish standard monitoring methods need a revisit. Of the day available, there is an urgent need for comprehensive consideration of the impact of androgens on the environment and ecology.

Zinc-Based Metal-Organic Framework with MLCT Properties as an Efficient Electrochemiluminescence Probe for Trace Detection of Trenbolone

In this work, we utilized polycyclic aromatic hydrocarbon (PAH) derivatives as ligands to develop a zinc-based metal-organic framework (Zn-MOF) as an effective detection probe to construct an electrochemiluminescence (ECL) sensor for trenbolone detection. As traditional ECL emitters, PAHs and their derivatives have limited luminescence efficiency because of the aggregation-induced quenching (ACQ) effect. Therefore, Zn-PTC was designed by the coordination of 3,4,9,10-perylenetetracarboxylic (PTC) in the MOF to eliminate the ACQ effect. Meanwhile, Zn-PTC formed based on an aromatic ligand possessed the metal-to-ligand charge-transfer (MLCT) effect, which could transfer the energy of Zn²⁺ to the aromatic ligand for strong luminescence. The ECL efficiency of Zn-PTC was calculated to be approximately 2.2 times that of the ligand (K₄PTC). Second, the Ag@Fe core-shell bimetallic nanocrystal was prepared for efficient activation of persulfate (S₂O₈^2-), thereby generating more sulfate radicals (SO₄^•-) to further promote ECL emission. According to ECL characterizations, UV-vis and fluorescence spectra, and density functional theory calculations, the luminescence and signal amplification mechanisms were investigated. In addition, NKFRGKYKC (NKF) was introduced as an affinity ligand to directionally immobilize the target antibodies, thus releasing specific sites in their Fab fragment to enhance binding activity. Based on the above strategies, the constructed biosensor exhibited high sensitivity, realizing trace detection of TBE with a wide detection range (10 fg/mL-100 ng/mL) and a low detection limit (3.28 fg/mL). This study provided an important reference for sensitive monitoring of steroid pollutants in the environment.

A Portable Microfluidic-Based Electrochemiluminescence Sensor for Trace Detection of Trenbolone in Natural Water

In this study, a portable electrochemiluminescence sensor chip was designed for trenbolone (TBE) trace detection in environmental water. First, a stable ECL signal was obtained with low-toxicity 3,4,9,10-perylenetetracarboxylic acid (PTCA) as a luminophore and persulfate (S₂O₈^2-) as a coreactant. Second, hollow-structured Cu₂MoS₄ was introduced as a coreaction accelerator to catalyze S₂O₈^2- reduction. The reversible conversion of the mixed-valence transition metal ions in Cu₂MoS₄ (Cu⁺/Cu²⁺ and Mo⁴⁺/Mo⁶⁺) greatly promoted the generation of the sulfate radical (SO₄^•-). Meanwhile, the special porous structure of Cu₂MoS₄ possessed a large specific surface area, thus enhancing its catalytic performance. Based on these enhancement mechanisms, a strong ECL signal was acquired, which improved the detection sensitivity of the constructed sensor. Importantly, a microfluidic chip was introduced for sensing detection, thereby improving the practicality of the sensor. The developed sensor chip was miniature and portable, exhibiting high sensitivity for TBE detection with a wide linear range (10 fg/mL-100 ng/mL) and lower detection limit (3.32 fg/mL). This was of great significance for timely and rapid analysis of steroid pollutants in natural water.

Bacteria are better predictive biomarkers of environmental estrogen transmission than fungi

The heavy reliance on estrogens in the food industry worldwide greatly contributes to the environmental release of these compounds, begetting serious public concern of their fate. Various microorganisms capable of estrogen degradation, and their catabolic pathways, have been isolated, suggesting that they can eliminate estrogens in both engineered and natural environments. Nonetheless, it remains little understood as to how potential estrogen-degrading microorganisms are distributed within those habitats. An estrogen transmission chain from swine manure to compost, compost-amended soil, and neighboring agricultural soil was investigated in five suburban areas of Beijing, China. The concentrations of major estrogen classes decreased by > 90% from manure to soils, which did not co-vary with environmental antibiotics and heavy metal concentrations. Many bacterial taxa, such as Lactobacillus and Bacteroides, could serve as potential biomarkers of estrogen concentrations, while fungi were only occasionally accurate. To explain this phenomenon, stochasticity was found to be dominant in shaping the fungal communities across all samples, while deterministic selection, arising from biotic interactions, was important for bacterial communities. Metabolic genes involved in oxidizing phenol and catalyzing oxidative ring cleavage of catechol were detected, co-varying with estrogen concentrations. These findings are important as identifying microbial biomarkers of estrogen dynamics, spanning the levels of both taxonomy and functional genes, provides valuable information for assessing estrogen bioavailability and biomarking of estrogen fate in the environment.

Occurrence and Fate of Steroid Estrogens in a Chinese Typical Concentrated Dairy Farm and Slurry Irrigated Soil

Animal husbandry is the second largest source of steroid estrogen (SE) pollutants in the environment, and it is significant to investigate the occurrence and fate of SEs discharged from concentrated animal feeding operations. In this research, with a Chinese typical concentrated dairy farm as the object, the concentrations of SEs (E1, 17α-E2, 17β-E2, E3, and E1-S3) in slurry, lagoon water, and slurry-irrigated soil samples in summer, autumn, and winter were determined. The total concentrations of SEs (mainly E1, 17α-E2, and 17β-E2) in slurry were very high in the range of 263.1-2475.08 ng·L^-1. In the lagoon water, the removal efficiencies of the aerobic tank could reach up to 89.53%, with significant fluctuation in different seasons. In the slurry-irrigated soil, the maximum concentrations of SEs in the topsoil and subsoil were 21.54 ng·g^-1 to 6.82 g·g^-1, respectively. Most of the SEs tended to transport downward and accumulate in the soil accompanied with the complex mutual conversion. Correlations and hierarchical clustering analysis showed a variety of intertransformation among SEs, and the concentrations of SEs were correlated with various physicochemical indexes, such as TN and NO₃^--N of the slurry, chemical oxygen demand of the lagoon water, and the heavy metals of soil. In addition, 17β-estradiol equivalency assessment and risk quotients indicated that the slurry irrigation and discharge of the lagoon water would cause potential estrogenic risks to the environment. Consequently, reasonable slurry irrigation and lagoon water discharge are essential to efficiently control SE pollution in the environment.

Biotransformation of Ethinylestradiol by Whole Cells of Brazilian Marine-Derived Fungus Penicillium oxalicum CBMAI 1996

In this study, we report our contribution to the application of whole cells of Brazilian marine-derived fungi in the biotransformation of ethinylestradiol 1. A preliminary screening with twelve marine-derived fungi strains revealed that the fungus Penicillium oxalicum CBMAI 1996 promoted the biotransformation of ethinylestradiol 1. Then, P. oxalicum CBMAI 1996 was employed in the reactions in decaplicate in order to purify and characterize the main biotransformation products of ethinylestradiol 1. Compounds 1b and 1c were characterized by NMR, HRMS, [α]_D and mp. Compound 1b was also characterized by single crystal X-ray diffraction. In addition, kinetic monitoring of the biotransformation of ethinylestradiol 1 by P. oxalicum CBMAI 1996 was evaluated in this study in order to obtain high yields of compounds 1b and 1c with a reduction of the reaction time. In this work, we proposed a biotransformation pathway of ethinylestradiol 1, which suggests the presence of several enzymes such as phenol oxidases, monooxygenases, and ene-reductases in the fungus P. oxalicum CBMAI 1996. In summary, the rapid biodegradation of ethinylestradiol 1 and compounds 1b and 1c also has an environmental relevance, since ethinylestradiol 1 and other steroidal compounds are improperly discarded in the environment, and part of these compounds are displaced into the oceans.

The characteristics of oestrone mobility in water and soil by the addition of Ca-biochar and Fe-Mn-biochar derived from Litchi chinensis Sonn

In this study, the effect of biochar (BC) derived from Litchi chinensis Sonn. and its modification, including Ca-biochar (Ca-BC) and Fe-Mn-biochar (Fe-Mn-BC), on the transportation of oestrone (E1) in water and soil was investigated. Fe-Mn-BC showed better adsorption ability than other types of biochar (BC, Ca-BC) under different conditions (humic acid, pH, ionic strength) in an aqueous environment. The maximum mass of sorbent at 298 K increased from 1.12 mg g^-1 (BC) to 4.18 mg g^-1 (Fe-Mn-BC). Humic acid had a greater impact on aqueous E1 adsorption on these biochars than did the pH and ionic strength. Fe-Mn-BC as a soil amendment had a great control of E1 transport in soil, and no leachate of E1 was observed in the column experiment. E1 mobility showed strong retardation in amended soil with Ca-BC (R_f = 11.2) compared with raw soil (R_f = 7.1). These results suggested that Fe-Mn-BC was more effective in controlling E1 transportation, and Fe-Mn-BC could be used as an alternative and inexpensive adsorbent to reduce E1 contaminants from water and soil.

Spatio-temporal distribution and transformation of 17α- and 17β-estradiol in sterilized soil: A column experiment

The environmental behaviors of steroid estrogens (SEs) associated with land irrigation and application are of critical concern worldwide. Understanding the spatio-temporal distribution and transformation process of these estrogenic compounds in soil is greatly significant. In this study, laboratory soil column experiments were conducted to investigate and explore the migration and abiotic transformation of 17α-estradiol (17α-E2) and 17β-estradiol (17β-E2) over spatial and time scales. Results indicated that the migration tendency of 17α-E2 and 17β-E2 was similar. Discrepancies in transport for different SEs groups might be due to the competitive sorption and isomeric transformation in the binary-solute system. 17α-E2 and 17β-E2 can also undergo the abiotic transformation during soil column transport. The soil with naturally abundant mineral substances (e.g., iron and manganese oxides) indicated that E2 isomers tended to mineral-promoted racemization, oxidation, reduction, and radical coupling reactions. Some possible transformation products (e.g., SE₂₃₉, E2₃₇₈, and SE dimer₄₇₆) were identified and proposed in soil samples. Compared to the single compound tests, the estimated 17β-estradiol equivalency (EEQ) values of E2 mixture were higher during SEs migration process.

14C-Labelling of the natural steroid estrogens 17α-estradiol, 17β-estradiol, and estrone

The worldwide environmental occurrence of natural steroid estrogens has drawn increasing concerns. However, the fate of the estrogens, especially the α-isomer of estradiol, in the environmental matrices is still obscure. Using ¹⁴C-radioactively labelled forms of these estrogens can facilitate and is sometimes a prerequisite for studying their transformation and residual distribution in the environment, but the availability of labelled compounds (owing to commercially high prices or unavailable) hampers such studies. Here we developed simple and stable methods to synthesize ¹⁴C-labelled estradiol isomers and estrone using relatively low-priced [carboxyl-¹⁴C]-labelled sodium acetate as a precursor. The radiochemical syntheses started from an enol lactone, which was prepared from nandrolone by oxidation to open the A-ring followed by recyclization. Inversion of the 17β-hydroxyl group into its 17α-form was achieved via the Walden inversion using the Mitsunobu reaction. [3-¹⁴C]-17β-estradiol, [3-¹⁴C]-17α-estradiol, and [3-¹⁴C]-estrone were synthesized in five, six, and seven steps with an overall radiochemical yield of 17.4%, 16.2%, and 13.9%, respectively. The synthesized ¹⁴C-labelled compounds provide materials for studying the fate and behavior of estrogens in complex environmental matrixes and for further synthesis of their ¹⁴C-labelled sulfate and glucuronide conjugates.

Occurrence, sorption, and transformation of free and conjugated natural steroid estrogens in the environment

Natural steroid estrogens (NSEs), including free estrogens (FEs) and conjugated estrogens (CEs), are of emerging concern globally among public and scientific community due to their recognized adverse effects on human and wildlife endocrine systems in recent years. In this review, the properties, occurrence, sorption process, and transformation pathways of NSEs are clarified in the environment. The work comprehensively summarizes the occurrence of both free and conjugated estrogens in different natural and built environments (e.g., river, WWTPs, CAFOs, soil, and sediment). The sorption process of NSEs can be impacted by organic compounds, colloids, composition of clay minerals, specific surface area (SSA), cation exchange capacity (CEC), and pH value. The degradation and transformation of free and conjugated estrogens in the environment primarily involves oxidation, reduction, deconjugation, and esterification reactions. Elaboration about the major, subordinate, and minor transformation pathways of both biotic and abiotic processes among NSEs is highlighted. The moiety types and binding sites also would affect deconjugation degree and preferential transformation pathways of CEs. Notably, some intermediate products of NSEs still remain estrogenic potency during transformation process; the elimination of total estrogenic activity needs to be addressed in further studies. The in-depth researches regarding the behavior of both free and conjugated estrogens are further required to tackle their contamination problem in the ecosystem. Graphical abstract ᅟ.