Prevalence, distribution, accumulation, and risk of environmental corticosteroids and estrogens in biofilms from the Pearl River Delta.

Biofilms play a significant role in the biogeochemical processing of organic matter and the environmental fate of emerging pollutants. In this study, we investigated the occurrence and distribution of 32 endocrine-disrupting chemicals (EDCs), including 24 environmental corticosteroids (ECs) and 8 environmental estrogens (EEs), in natural biofilms from the Pearl River system. Their association between biofilms and water and environmental risk were assessed. The ECs and EEs ubiquitously occurred in the biofilms, ranging from <0.61-6.57 ng/g and <0.8-2535 ng/g, respectively. Temporally, there was no obvious variance in either ECs or EEs in the biofilms during the winter and summer, and their concentrations exhibited a spatial trend of upward to midstream, descending downstream, and then seaward attenuation at the estuary. For ECs and EEs, the similar levels of field-derived bioconcentration factors (BCFs) (logarithm values: 2.42-2.86 and 2.72-2.98, respectively) and biofilm organic carbon-normalized partitioning coefficients (Kboc) (3.39-3.69 and 3.35-3.95) suggest the comparable potential of accumulation and sorption by biofilms between these two classes of EDCs. In addition, higher values of BCF and Kboc for the EEs were found in winter and were correspondingly comparable to their distribution coefficients (Kd) and Koc derived from suspended particles and sediment, revealing that biofilms are a competitive environmental compartment for capturing EDCs, particularly during the mature period. A positive logKboc-logKow relationship suggests hydrophobic partitioning as a primary interaction mechanism between the biofilm and EEs. Moreover, high risks from biofilm-associated ECs and EEs might have posed to the fluvial ecosystem. This study provides original insights into the occurrence, fate, and risk of ECs in natural biofilms for the first time and demonstrates that biofilms may not only serve as reservoirs but also serve as sentinels for fluvial EDC contamination. These results contribute to the further understanding of the behavior and fate of EDCs in aquatic environments.

Rapid on-site detection of underground petroleum pipeline leaks and risk assessment using portable gas chromatography-mass spectrometry and solid phase microextraction.

Locating underground pipeline leaks can be challenging due to their hidden nature and variable terrain conditions. To sample soil gas, solid-phase microextraction (SPME) was employed, and a portable gas chromatography/mass spectrometry (GC/MS) was used to detect the presence and concentrations of petroleum hydrocarbon volatile organic compounds (pH-VOCs), including benzene, toluene, ethylbenzene, and xylene (BTEX). We optimized the extraction method through benchtop studies using SPME. The appropriate fibre materials and exposure time were selected for each BTEX compound. Before applying SPME, we preconditioned the soil vapour samples by keeping the temperature at around 4 °C and using ethanol as a desorbing agent and moisture filters to minimize the impact of moisture. To conduct this optimisation, airbags were applied to condition the soil vapour samples and SPME sampling. By conditioning the samples using this method, we were able to improve analytical efficiency and accuracy while minimizing environmental impacts, resulting in more reliable research data in the field. The study employed portable GC/MS data to assess the concentration distribution of BTEX in soil vapour samples obtained from 1.5 m below the ground surface at 10 subsurface vapour monitoring locations at the leak site. After optimization, the detection limits of BTEX were almost 100 µg/m3, and the measurement repeatabilities were approximately 5% and 15% for BTEX standards in the laboratory and soil vapour samples in the field, respectively. The soil vapour samples showed a hotspot region with high BTEX concentrations, reaching 30 mg/m3, indicating a diesel return pipeline leak caused by a gasket failure in a flange. The prompt detection of the leak source was critical in minimizing environmental impact and worker safety hazards.

Suspended particulate matter-associated environmental corticosteroids in the Pearl River, China: Occurrence, distribution, and partitioning.

Suspended particulate matter (SPM) plays an important role in the geochemical behavior and fate of organic micropollutants in aquatic environments. However, the presence of trace emerging endocrine disruptors such as environmental corticosteroids (ECs) in SPM is less well understood. This study focused on the occurrence, distribution, and partitioning of SPM-associated ECs in the Pearl River system, China. Ubiquitous particulate ECs were found in the surface water of the rivers at average concentrations (dry weight) between 0.46 ng/g (flumethasone) and 8.83 ng/g (clobetasone butyrate). The total EC (∑ECs) concentrations of the 24 selected target compounds varied from <1.03 ng/g to 62.3 ng/g, with an average and median of 17.6 ng/g and 13.7 ng/g, respectively. Higher SPM-bound EC levels were commonly observed in winter (dry season), and spatially, their relatively high contamination in urban tributary networks decreased while flowing to mainstreams and then gradually attenuated from upstream to the estuary. Despite the approximately 90 % mass distribution of ∑ECs in the aqueous phase, approximately 50 % of their effect burden was derived from the suspended particulate fractions. For the first time, in situ SPM-water partitioning coefficients (Kp) and their organic carbon-normalized ones (Koc) of ECs were determined in surface waters, and a field-derived preliminary linear equation was proposed to estimate Koc for ECs using basic physicochemical parameters n-octanol/water partitioning coefficient (Kow), which is of importance with regard to the assessment of transport, fate, and risk of these emerging hazardous chemicals. Furthermore, the significant logKoc-logKow relationship for ECs reveals that nonspecific hydrophobic partitioning is a major association mechanism between SPM and ECs. Moreover, hydrogen bonding is suggested to be a prevailing specific binding mechanism and provides more contribution to nonhydrophobic interactions between ECs and particulate organic matter than environmental estrogens.

[Simultaneous determination of 24 corticosteroids in sediments based on ultrasonic extraction, solid-phase extraction, liquid chromatography, and tandem mass spectrometry].

Corticosteroids (CSs) are widely used to treat various inflammatory and immune diseases in humans and animals, such as arthritis and lupus. Thus far, CSs have been frequently detected in diverse pollution sources, such as in the influent and effluent of traditional wastewater treatment plants, livestock farms, and aquaculture. Owing to incomplete removal or limited treatment, CSs can enter the water environment and eventually be adsorbed in the sediment. Due to hydrodynamic effects, CSs can re-enter the surface water through the resuspension of sediments, and pose a hazard to the ecosystem and human health via the enrichment of aquatic organisms and transmission through the food chain. Therefore, trace analysis of CSs in sediments is significant for exploring their prevalence and behavior in multiple environments. However, existing research mainly focuses on the determination of glucocorticoids in water samples, and studies on the systematic quantitative analysis of CSs in environmental solid samples with more complex matrices are scarce. Moreover, majority of previous investigations focused on a limited number of glucocorticoids, making it important to widen the range of target compounds to be studied, including mineralocorticoids. In this study, the main factors which could influence the accuracy and sensitivity in the determination of 24 target CSs were systematically optimized in the sample pretreatment and instrument analysis. A novel method based on ultrasonic extraction coupled with solid phase extraction (SPE) for sample pretreatment was developed for the simultaneous determination of the 24 CSs in sediments using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sediment sample was ground to homogenize the particle sizes after freeze-drying. The analytes from 2.0 g of the sample were ultrasonicated and extracted with methanol-acetone (1∶1, v/v). After concentrating and diluting each extract, SPE was performed. The water sample was extracted and purified using hydrophile-lipophile balance (HLB) cartridges, following which the extract was further purified with LC-NH2 cartridges. The extracts were concentrated using a rotary evaporator, dried under a gentle stream of nitrogen, and re-dissolved in methanol for instrumental analysis. Chromatographic separation was conducted on an Agilent ZORBAX Eclipse Plus C8 column (100 mm×2.1 mm, 1.8 µm), with a column flow rate of 0.3 mL/min and a gradient of mobile phases A (water with 0.1% acetic acid) and B (acetonitrile). The column temperature was set to 30 ℃ and the injection volume was fixed at 5 µL. Electrospray ionization MS in the dynamic multiple reaction monitoring (DMRM) and selected ion monitoring (SIM) modes were performed in the positive mode for the qualitative and quantitative analysis of the target compounds. Quantitation of the target compounds was carried out using the internal standard method. The effects of different extraction solvents, purification conditions, and MS conditions on the recoveries of the target compounds were investigated. The limits of detection (LODs) (S/N≥3) and limits of quantification (LOQs) (S/N≥10) of all 24 compounds were in the ranges of 0.14-1.25 µg/kg and 0.26-2.26 µg/kg, respectively. The correlation coefficients of linear calibration curves were higher than 0.995 in the range of 1.0-100 µg/L. The recoveries of the 24 CSs at 5, 20, and 50 µg/kg spiked levels ranged from 64.9% to 125.1% with relative standard deviations of 0.4%-12.6% (n=5). The developed method was applied to analyze the CSs in three sediment samples from the rivers of the Pearl River Delta. In all, 11 target compounds were detected in these samples, with contents in the range of 1.25-29.38 µg/kg. The characteristic of this method is efficient, sensitive, reliable, and suitable for the trace determination of varieties of natural and synthesized CSs in environmental sediments.

Spatiotemporal distribution, source apportionment, and ecological risk of corticosteroids in the urbanized river system of Guangzhou, China.

We investigated the occurrence and distribution of 24 selected corticosteroids (CSs) in the surface water of the Zhujiang River (ZR) system in Guangzhou, a highly urbanized river system receiving both treated and untreated municipal wastewater effluents. Twenty-two and sixteen CSs were detected in the tributaries and the main stream of the ZR system, and their concentrations ranged from less than the method quantification limit (fluticasone propionate) to 94 ng/L (clobetasone butyrate) and from 0.24 ng/L (cortisol) to 7.2 ng/L (clobetasone butyrate), respectively. We observed higher total CSs (∑CSs) concentrations in the tributaries (11-396 ng/L) relative to the main stream (5.5-33 ng/L) due to their proximity to densely populated residential areas. ∑CSs concentrations in the dry season were generally higher than those in the wet season due to low dilution from decreased river discharge. Principal component analysis and multiple linear regression analysis identified untreated domestic sewage to be the dominant source of CSs (t2, contribution rate: 42.7%) in the urban rivers. Additional source contributions were from naturally attenuated treated and/or raw sewage (t1, 21.5%) and effluents from wastewater treatment plants (t3, 26.7%). CSs contribution was dominated by t2 in the dry season, and the contributions from t1, t2, and t3 showed no significant difference in the wet season. Risk assessment inferred that the ZR system is at medium to high ecological risk from CSs and is therefore a potential threat to the health of aquatic ecosystems. To prevent CSs pollution, our results demonstrate the need to develop effective control strategies to minimize the discharge of untreated waste to nearby rivers and to improve the capacity of wastewater treatment plants in Guangzhou. Further, we demonstrate that the concentrations of cortisone and fludrocortisone acetate are effective chemical indicators to estimate the level of natural and synthetic CSs contamination in urban rivers.

Occurrence, distribution, and potential risks of environmental corticosteroids in surface waters from the Pearl River Delta, South China.

The occurrence, spatiotemporal distribution, and potential risks of 21 glucocorticoids (GCs) and 3 mineralocorticoids (MCs) in four rivers were studied by investigating the surface waters from the Pearl River Delta (PRD), South China. These environmental corticosteroids (ECs) were commonly present in the river surface waters with average concentrations varying from <0.17 ng/L for fluticasone propionate to 5.6 ng/L for clobetasone butyrate; and cortisone had the highest concentration, 32.9 ng/L. The total ECs ranged in concentration from undetectable to 83.3 ng/L, with a mean and median of 8.1 ng/L and 4.8 ng/L, respectively. Spatially the total EC concentration levels in the Pearl River system occurred in the following order: Zhujiang River (ZR) > Dongjiang River (DR) > Shiziyang waterway (SW) > Beijiang River (BR). These levels generally demonstrated a trend of increasing from upstream to midstream or downstream then attenuating toward the estuary. Considerable seasonal variations in the ECs differed among rivers. Higher ECs concentrations in winter were mostly found in the ZR, whereas lower levels were found in the DR. Moreover, the temporal variations of the ECs were marginal in the BR and SW. These spatiotemporal distributions of the ECs might have been simultaneously influenced by pollution sources derived from anthropogenic activities and river hydrologic conditions. Correlation analyses indicated that dissolved organic carbon (DOC) could play a key role in the occurrence and distribution of ECs in an aquatic environment. Risk assessment demonstrated that the occurrence of ECs might have posed medium to high risk to aquatic organisms in the Pearl River.

[Simultaneous determination of 28 corticosteroids in surface water by ultra-high performance liquid chromatography-electrospray tandem mass spectrometry].

A comprehensive analytical method was developed for simultaneous determination of 28 corticosteroids in surface water based on ultra-high performance liquid chromatography- electrospray tandem mass spectrometry (UHPLC-ESI-MS/MS). The solid-phase extraction was performed using hydrophilic-lipophilic balance (HLB) cartridges, and the chromatographic separation was achieved on a reversed-phase C8 column. Qualitative and quantitative analyses were performed in the dynamic multiple reaction monitoring (DMRM) mode using positive and negative electrospray ionization (ESI±). The 28 target compounds were quantified by the internal standard method. Good linear relationships were obtained (R2>0.99) for the 28 analytes in the concentration range of 1.0-100 µg/L. The method limits of detection and quantification were in the range of 0.21-0.48 ng/L and 0.32-0.72 ng/L, respectively. When the matrix spiking levels were at 5.0, 10, and 50 ng/L, the average recoveries for the target compounds ranged from 68.6% to 108.7%, and the relative standard deviations (RSDs) were between 0.1% and 8.1%. Because of its high sensitivity, good precision, and reliability, this method can be widely applied to trace monitoring of glucocorticoids and mineral ocorticoids for investigating their behaviors and risks of corticosteroids in the environment.

[Determination of phthalates in water by dispersive liquid-liquid microextraction based on solidification of floating organic drop followed by high performance liquid chromatography].

A rapid method for the determination of six phthalates (PAEs) in water samples was established by dispersive liquid-liquid microextraction (DLLME) based on solidification of floating organic drop (SFO) coupled with high performance liquid chromatography (HPLC). The influences of the SFO-DLLME parameters on extraction efficiencies were studied. Dodecanol (extraction solvent, 20 µL) was added to the water samples (containing 20 g/L NaCl) at 60℃, and the solution was shaken for 1 min. The results showed that the six PAEs were linear in the range of 2-2000 µg/L with correlation coefficients (r) between 0.9995 and 0.9999. The limits of detection (S/N=3) of the six PAEs ranged from 0.3 to 0.6 µg/L. The proposed method was applied to the analysis of the seven water samples obtained from different sources (tap water, lake water, river water, waste water, sea water, plastic bottled pure water and mineral water), and some PAEs were detected. The recoveries of the six PAEs in the spiked water samples were 84.9%-94.5%, and relative standard deviations were 4.1%-6.8% at three levels of 10, 100 and 1000 µg/L. The method is an environmentally friendly and convenient method for the routine analysis of the PAEs in water samples.

Multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid with high-performance liquid chromatography for the determination of steroid sex hormones in water and urine.

The development of a simple and sensitive analytical approach that combines multiple monolithic fiber solid-phase microextraction with liquid desorption followed by high-performance liquid chromatography with diode array detection is proposed for the determination of trace levels of seven steroid sex hormones (estriol, 17ß-estradiol, testosterone, ethinylestradiol, estrone, progesterone and mestranol) in water and urine matrices. To extract the target analytes effectively, multiple monolithic fiber solid-phase microextraction based on a polymeric ionic liquid was used to concentrate hormones. Several key extraction parameters including desorption solvent, extraction and desorption time, pH value and ionic strength in sample matrix were investigated in detail. Under the optimal experimental conditions, the limits of detection were found to be in the range of 0.027-0.12 µg/L. The linear range was 0.10-200 µg/L for 17ß-estradiol, 0.25-200 µg/L estriol, ethinylestradiol and estrone, and 0.50-200 µg/L for the other hormones. Satisfactory linearities were achieved for analytes with the correlation coefficients above 0.99. Acceptable method reproducibility was achieved by evaluating the repeatability and intermediate precision with relative standard deviations of both less than 8%. The enrichment factors ranged from 54- to 74-fold. Finally, the proposed method was successfully applied to the analysis of steroid sex hormones in environmental water samples and human urines with spiking recoveries ranged from 75.6 to 116%.

[Combination of dispersive liquid-liquid microextraction based on ionic liquid and pre-column fluorescence derivatization-high performance liquid chromatography for determination of eight sulfonamides in water samples].

Dispersive liquid-liquid microextraction based on ionic liquid coupled with high performance liquid chromatography (HPLC) and pre-column fluorescent derivatization method (IL-DLLME-HPLC-FL) was developed for the determination of eight sulfonamides (SAs). The influence of IL-DLLME parameters on extraction efficiency and the stability of derivatives of the eight SAs were investigated. The optimized experimental conditions were as follows: 40 µL [C6MIM][PF6] as extraction solvent, 0.1 mL acetone as dispersion solvents; water sample with 0% NaCl (pH 4) was extracted by dispersive liquid-liquid microextraction without ultrasonic-assistance and then derivatized for 6 h. Under the optimized experimental conditions, the results indicated that the eight sulfanilamides showed good linearities when their mass concentrations were in 0. 2-10 µg/L and 10-500 µg/L, and the linear correlation coefficients were no less than 0. 9989. The detection limits ranged from 0. 08 µg/L to 0. 5 µg/L (S/N=3). The proposed method was applied to the analysis of four water samples from different sources (tap water, lake water, Pearl River water and pond water). The relative recoveries of the SAs spiked in water samples were 87. 2% - 101. 4% with the relative standard deviations of 3. 7% - 6. 2% at three different concentration levels of 5, 50 and 200 µg/L. It is a convenient, environmental friendly method for the routine analysis of SAs in water samples.

Electromechanical impedance response of a cracked Timoshenko beam.

Typically, the Electromechanical Impedance (EMI) technique does not use an analytical model for basic damage identification. However, an accurate model is necessary for getting more information about any damage. In this paper, an EMI model is presented for predicting the electromechanical impedance of a cracked beam structure quantitatively. A coupled system of a cracked Timoshenko beam with a pair of PZT patches bonded on the top and bottom surfaces has been considered, where the bonding layers are assumed as a Kelvin-Voigt material. The shear lag model is introduced to describe the load transfer between the PZT patches and the beam structure. The beam crack is simulated as a massless torsional spring; the dynamic equations of the coupled system are derived, which include the crack information and the inertial forces of both PZT patches and adhesive layers. According to the boundary conditions and continuity conditions, the analytical expression of the admittance of PZT patch is obtained. In the case study, the influences of crack and the inertial forces of PZT patches are analyzed. The results show that: (1) the inertial forces affects significantly in high frequency band; and (2) the use of appropriate frequency range can improve the accuracy of damage identification.

Rapid determination of vitellogenin in fish plasma by anion exchange high performance liquid chromatography using postcolumn fluorescence derivatization with o-phthalaldehyde.

An analytical method involving anion exchange high performance liquid chromatographic determination of vitellogenin (Vtg) in fish plasma after postcolumn fluorescence derivatization with o-phthalaldehyde (OPA) was developed. The retention time of Vtg was about 11 min. The reagent variables for derivatization were optimized. The fluorophore was excited at 335 nm and detected at 435 nm. A calibration curve was established ranging from 0.13 to 11.28 microg. The determination limit of Vtg was found to be as low as 0.13 microg. The spiked recovery was 93.6% and interassay variability was less than 4%. The method developed was used to determine Vtg in fish plasma obtained from red sea bream (Pagrosomus major), black porgy (Sparus macrocephalus) and skew band grunt (Hapalogenys nitens), without complicated sample pretreatment. The results confirmed that the method showed advantages of being simple, rapid, reproducible and sensitive.