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We have investigated the possibility of sampling ammonium ion using the diffusive-gradients-in-thin-films technique (DGT) by introducing a novel binding agent that is based on micro-sized zeolite. The performance of zeolite-DGT was characterized by measurement of the following parameters: (1) the diffusion coefficient of ammonium ion in hydrogel; (2) the adsorption rate of ammonium ion by the zeolite binding gel; (3) the elution efficiency, and (4) the effects of pH, ionic strength and interfering ions on DGT. The method was validated by studying the uptake of ammonium ion from in freshwaters by zeolite gels which was found to be fast enough to meet the requirements of DGT. The concentrations determined via DGT agreed well with the concentrations determined in bulk solutions. Sampling of ammonium ion using zeolite-DGT was consistent over the pH 3 to 8 range and the 0.001 to 10 mM ionic strength range. The method also performs predictably in natural waters containing various metal ions. The technique is considered to be a viable passive tool for sampling ammonium from aqueous solutions.

For the first time, new diffusive gradients in thin film (DGT) device using molecularly imprinted polymers as the binding agents and the nylon membrane as the diffusive layer have been developed for the sampling of phenol in water. The diffusion coefficient of phenol through the nylon membrane was 0.79 × 10−6 cm2 s−1, which was measured by the diffusion cell method. The binding agent of the DGT device was prepared by precipitation polymerization by molecularly imprinted technique using methacrylic acid as the functional monomer and ethyleneglycodimethacrylate as the crosslinker. The accumulated mass of phenol by the DGT device increased linearly with time (R2 = 0.9940). The ratio of the concentrations sampled by the DGT device to the concentration of the bulk solution was 0.97 ± 0.06. The results confirmed that the developed DGT device was suitable for the quantitative sampling of phenol in aqueous solution. The performance of the DGT device was independent of pH in the range 3–7 and ionic strength 0.0001–0.1 mol L−1. As a conclusion, the DGT device can be used for accurately sampling phenol in water.

The concentration, spatial distribution, homologue profiles, sources, toxicity and risk of PCBs in urban stream sediments from a national eco-industrial park named Suzhou Industrial Park (SIP) in China were investigated in this work. Concentrations of ∑PCBs varied from 0.13 to 4.7 ng g -1 , with an average value of 1.7±1.2 ng g -1 . Spatial variations indicated that PCB concentrations had no correlation with land uses in the SIP. Tetra-PCBs and hexa-PCBs were the most abundant PCB homologues, which were different from those found in Chinese commercial PCBs and might be mainly derived from other sources. The potential toxicity and risk of PCBs here might be negligible based on the total equivalent concentration (TEQ) analysis and sediment quality guidelines (SQG).

Air quality is highly related to the health of a human being. Urban morphology has a significant influence on air quality; however, the specific relationship between urban morphology characteristics and air quality at the neighborhood scale has yet to be investigated, especially the vegetation effect on PM2.5 concentration and diffusion. The relevant morphological parameters based on the affected pathways of urban morphology on air quality were selected, and the sensitivity degree and laws of the selected morphological parameters to PM2.5 were quantified by numerical simulation, bivariate correlation analysis, and regression analysis. The results showed that Building Density (BD), Block Envelope Degree (BED), Average Building Volume (ABV), Average Building Floors (ABF), Standard Deviation of Building Height (SDH) and Greenbelt Coverage Rate (GCR) were Sensitive Morphological Parameters (SMPs). A positive and cosine curve trend of BD and BED with PM2.5 was observed. GCR was significant to dust retention along with vertical canopy height. When ABV = 40,000 m3 and ABF = 20F, the lowest PM2.5 concentration was examined, while increased SDH could promote airflow and enhance the capacity of PM2.5 diffusion. Finally, morphology-optimization strategies were proposed at the neighborhood scale: (1) Decreasing the BED along the street; (2) considering the species of vegetation with the appropriate height and increasing the GCR; (3) increasing the ABF of neighborhoods appropriately while controlling the ABV and distinguishing the internal SDH of neighborhoods. The study could apply the scientific basis for the planning and design of healthy and livable cities.