Yuqiu Wang

Simultaneous extraction and determination of fluoroquinolones, tetracyclines and sulfonamides antibiotics in soils using optimised solid phase extraction chromatography-tandem mass spectrometry

An analytical method was developed for the simultaneous extraction and determination of 18 fluoroquinolones (FQs), tetracyclines (TCs) and sulfonamides (SAs) antibiotics from soils using solid phase extraction and liquid chromatography-tandem mass spectrometry. The soils were extracted by different solvents with the help of mechanical shaking and ultrasonic treatment at 59 kHz, followed by a strong anion exchange (SAX) cartridge to clean up soil samples and a hydrophilic lipophilic balance (HLB) cartridge as enrichment. The method was evaluated by testing the following variables: extraction solvents, the type of SPE cartridges, solvent volumes, initial spiking levels and soil types (silty clay loam and clay loam soils). The soil extraction method was validated using these two types of soils, representing two typical agricultural soils in northern China. For 2 g soil, the extraction steps with the mixture of potassium phosphate buffer and acetonitrile (ACN) (1/1, v/v, pH 3.2) provided satisfactory recoveries. In the clay loam soil, the recoveries of all the compounds were from 56% to 89% at the spiking level of 50 µg kg−1 soil, and from 69% to 97% at the spiking level of 200 µg kg−1 soil, respectively. Recoveries in silty clay loam soil were similar to that in clay loam. The method was successfully employed using soil samples collected from a farmland and afforestion area irrigated with sewage in northern China. The result indicates that trace antibiotics in sewage may accumulate in soil irrigated by river water containing sewage.

A Bayesian modeling approach for phosphorus load apportionment in a reservoir with high water transfer disturbance

AbstractPhosphorus loading from external and internal sources poses a potential risk to eutrophication of lakes or reservoirs. However, the relative contribution of external and internal sources to eutrophication is still unclear especially for reservoirs with water transfer disturbance. The objective of this paper is to estimate the phosphorus loading from external (water transfer and diffusing emission) and internal sources (sediment release) in Yuqiao Reservoir (YQR) and compare their relative contribution of external and internal sources. In this study, we estimated the phosphorus loading considering both external (water transfer and diffusing source emission) and internal (release from sediment) sources of YQR. The phosphorus loading from water transfer was estimated by total phosphorus (TP) concentration × monthly flow of inflow. The phosphorus loading from nonpoint source emission was estimated using a generalized watershed loading function (GWLF). The phosphorus loading from internal sources was estimated with a Bayesian phosphorus budget model. Our result showed that water transfer TP load is the biggest (45.2%) source of TP load in YQR and internal TP load (20.5%) accounts for a comparable proportion of TP load as nonpoint source (34.3%) in YQR and dominates the total loading in some months. Analysis of seasonal total phosphorus load apportionment indicated that water transfer TP load takes the largest proportion in winter (60.8%), spring (60.2%), and autumn (47.8%). Nonpoint source TP load takes the largest proportion in summer (60.1%), and internal TP load is the second source of YQR in summer (22.4%). Our study indicates that water transfer may be the major driver of eutrophication for some reservoir systems, and sediment release may prevent recovery of many eutrophic lakes and reservoirs. Our analysis suggests that TP pollution control strategies in YQR should be preferentially focused on the improvement of water quality in the upstream reservoir, and nonpoint source TP load reductions should be focused on summer. Compared with conventional nutrient apportionment model applications, this paper provides a new approach to estimate external and internal TP loads simultaneously. Graphical abstractᅟ

Simultaneous Analysis of Multiple Classes of Antibiotics in Water and Soil Samples via Solid Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

The analytical protocols were developed and tested for simultaneous determining three groups of antibiotics including four fluoroquinolones (FQs), three tetracyclines (TCs) and eleven sulfonamides (SAs), in water and soil samples. Solid phase extraction (SPE) was used to enrich and to clean up the aqueous samples. The potassium phosphate buffer and acetonitrile mixture solutions were used to extract the compounds from the soil samples. The target compounds were determined by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The recoveries for the investigated antibiotics in water samples ranged from 60% to 105% with 2-14% of relative standard deviation (RSD). In soil samples, the recoveries were between 56% and 97% with 1-20% of RSD. The limits of quantification (LOQs) in water and soil samples were in the range of 1.2-10.6 ng/L and 0.2-29.6 µg/kg, respectively. Finally, the protocols were applied to environmental samples colleted from the Yuqiao Reservoir region. The FQs and SAs were detected in the water samples but none of target compounds were found in soil samples.

Study on the Combined Toxicity of Diesel Exhaust Particles and Allergic Pollen

Diesel exhaust particles (DEPs) may increase symptom severity in allergic diseases. To examine possible interaction between DEPs effects and allergic responses, a pollen-sensitized and challenged mouse model of allergic airways disease was utilized. BAL mice were sensitized with 0.15 ml pollen extract or saline injected intraperitoneally on day 0 and day 7. One week after sensitization, mice were exposed to air or different doses of DEPs for 7days. Challenge with pollen was performed at day 21. Blood and lung samples were taken at day 22 after the first sensitization. IgE, IL-4 and oxidative damage indices were measured. IgE and IL-4 was higher in mice immunized with pollen extracts and DEPs than in mice immunized with pollen only. DEPs decreased intracellular superoxide dismutase and glutathione peroxidase, and increased Malondialdehyde in pollen sensitized mice when compared with mice exposed to DEPs alone. In conclusion, this study shows that allergen challenge and exposure to DEPs can interact to enhance allergic responses in sensitized mice, and the oxidative stress may be one of the main mechanisms.

Study on GWLF-BATHTUB Model Linkage to Watershed Management

Degradation of water quality is the major health concern for lakes and reservoirs in the regions of north china as a result of highly diverse non-point source emissions caused by human activities. For describing the dynamic response between emission loads and receiving water conditions factually, model systems have became the typically decision support tools during the reservoir management strategy development, which is the vital key to estimate source loading inputs, evaluate receiving water quality, and determine source loading allocations for meeting water quality standards[*]. This study integrated GWLF (Generalized Watershed Loading Functions) watershed and BATHTUB water-quality model to simulate actual reservoir water quality conditions of Yuqiao Reservoir, Tianjin, China and illustrated the use of this coupled model for simulating water quality response to changes in different watershed land use and management scenarios. The Generalized Watershed Loading Functions (GWLF) indicated that livestock breeding and agricultural planting were the two leading contributions of non-point pollution sources to TN and TP loads. In addition, water diversion from upstream and enclosed aquaculture in reservoir are the main point pollution sources discharged. The Bathtub, designed to facilitate application of empirical eutrophication models to reservoirs, suggested that there were great relationships between land use type and water quality conditions. As it was phosphorus limitation that determined the possibility for eutrophication happening, different management scenarios concerning phosphorus control had be evaluated for raw water protecting.