Hongmei Hu

As a class of low-cost and broad-spectrum antibiotics in wide aquaculture use, residues of tetracyclines (TCs) are imperiling aquatic organisms and public health worldwide, leading to a high demand for TC removal from the aquaculture environment. In addition, considerable consumption of thick-shell mussels generates massive mussel shell waste, and their treatment has been an economic and environmental issue. Herein, a low-cost and high-efficiency mussel shells-based material was successfully prepared for TC removal by thermal modification of shell waste of Mytilus coruscus. Morphological and structural characterizations revealed the phase transformation of calcium carbonate to calcium oxide. The shell-based material calcined at 1050 °C (MC1050) yielded a Langmuir-fitted maximum removal capacity (q_m) of 68.0 mg/g towards oxytetracycline (OTC). Thermodynamic calculations indicate that OTC removal by MC1050 is a spontaneous and endothermic process. OTC removal by MC1050 is likely achieved via multiple co-existing pathways, where Ca-OTC co-precipitation driven by CaO-phase hydration and resultant high-pH conditions dominates, accompanied by auxiliary surface-interaction contributions. Furthermore, MC1050 achieves removal efficiencies exceeding 96% for the ten target TCs spiked at 20 μg/L in real-world freshwater and marine aquaculture effluent matrices. Overall, the developed shell-based material shows promising performance for wastewater treatment and facilitates the resource utilization of waste mussel shells.

Organophosphate esters (OPEs) are ubiquitous in the global water environment and may pose potential risks to aquatic ecosystems and human health. Herein, we present a simple and efficient method for accurate quantification of nineteen OPEs in water based on automated liquid–liquid extraction (LLE) with dichloromethane and hexane, followed by gas chromatography–tandem mass spectrometry (GC-MS/MS) with isotope dilution calibration. This method demonstrated a negligible matrix effect, satisfactory recoveries (70–120%), and low limits of detection (0.46–2.32 ng/L). A total of 3, 9, 10, and 11 OPEs were detected in Wahaha pure water, tap water, river water, and seawater, respectively, with total OPE (∑OPE) concentration ranges of 8.23–18.5 ng/L, 159–218 ng/L, 202–623 ng/L, and 111–175 ng/L, respectively. Among the detected OPEs, tris(2-chloroethyl) phosphate (TCEP) and tris(1-chloro-2-propyl) phosphate (TCIPP) were the predominant compounds in four test water matrices. The risk quotient (RQ) results revealed that OPEs exhibited a low risk to algae, crustaceans and fish in the river water of Zhoushan and seawater of Sanmen Bay. Overall, the proposed method is sensitive and reliable for routine OPE analysis in drinking and environmental waters.

Quinolone antibiotics (QNs) contamination in the aquatic environment is a global public health issue considering their resistance and mobility. In this study, a simple, efficient, and sensitive method was developed for the accurate quantification of fifteen QNs in water using automated disk-based solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS). By utilizing a 3M SDB-XC disk to enrich QNs from a 1000 mL water sample, the detection limits were improved to 0.008–0.055 ng/L due to the satisfactory enrichment factors of 897−1136, but only requiring about 60 min per six samples. The linearity of the method ranged from 0.05 to 100 μg/L for the 15 QNs, with correlation coefficients of 0.9992–0.9999, and the recoveries were in the range of 81–114%, with relative standard deviations of 0.2–13.3% (n = 6). The developed method was applicable for the quantification of trace QNs at low ng/L levels in drinking and environmental waters. The results showed that no QNs were detected in tap water, while three and four QNs were detected in the river water of Zhoushan and the seawater of Daiquyang and Yueqing Bay, East China, respectively, with a total concentration of 1.600–8.511 ng/L and 1.651–16.421 ng/L, respectively. Among the detected QNs, ofloxacin (OFL) was the predominant compound in river water, while enrofloxacin (ENR) was predominant in seawater. The risk quotient (RQ) results revealed that QNs posed a low risk to crustaceans and fish, but a low-to-medium risk to algae, and OFL presented the main ecological risk factor in river water, while ENR and CIP in seawater. Overall, the proposed automated disk-based SPE–UPLC–MS/MS method is highly efficient and sensitive, making it suitable for routine analysis of QNs in drinking and environmental waters.

Volatile halogenated hydrocarbons (VHHs) are annually produced and released into the environment, posing a threat to public health. In this study, a simple, rapid, sensitive and automated method based on headspace and gas chromatography (GC) with electron-capture detection was described for the determination of VHHs in different concentration levels in water samples. The proposed headspace GC method was initially optimized, and the optimum experimental conditions found were 10-mL water sample containing 20% w/v sodium chloride placed in a 20-mL vial and stirred at 60°C for 35 min, and then 14 VHHs were well separated on DB-35 MS capillary column with a split ratio of 12.5: 1. The limits of detection were in the low μg/L level, ranging between 0.01 and 0.6 μg/L. Finally optimized method was applied for determination 14 VHHs in drinking and environmental waters. The total mean concentrations of VHHs were 34.962, 26.183, 3.228 and 647.344 μg/L in tap water, purified water with 1-year-old filter element, seawater and effluents, respectively. However, no VHHs was detected in purified water with a new filter element. The main composition is different among different water matrix, which may be attributed to their different sources.

The abuse and irrational use of tetracyclines (TCs) in human medicine and animal husbandry has become a serious concern, affecting the ecological environment and human health. The aim of this study was to develop a sensitive and selective method using fully automatic solid-phase extraction coupled with ultra-performance liquid chromatography–tandem mass spectrometry for the determination of twelve TCs in water. Four isotope-labeled internal standards for TCs were used to correct matrix effects. Several parameters affecting extraction efficiency were systematically optimized, and the optimum experimental conditions found were 1.0 L water sample with 0.5 g/L Na₂EDTA (pH 3.0) extracted and enriched by CNW HLB cartridge and eluted by 4 mL of acetone:methanol (v/v, 1:1). The enrichment factors were up to 798−1059 but only requiring about 60 min per six samples. Under the optimized conditions, the linearity of the method ranged from 0.2 to 100 μg/L for 12 TCs, the detection limits were as low as 0.01−0.15 ng/L, and the recoveries were in the range of 70%–118%, with relative standard deviations less than 15%. The developed method can be successfully utilized for the determination of 12 TCs in pure water, tap water, river water, and mariculture seawater. In summary, three and six TCs were detected in river water and mariculture seawater, respectively, with total concentrations of 0.074–0.520 ng/L (mean 0.248 ng/L) and 0.792–58.369 ng/L (12.629 ng/L), respectively. Tetracycline (TC) and oxytetracycline (OTC) were the dominant TCs in river water, while doxytetracycline (DXC) and OTC were dominant in mariculture seawater.