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The current investigation reports the synthesis of N-CDs using glucosamine, ascorbic acid, and ethylenediamine precursors by a simple hydrothermal technique. The formation of N-CDs was proved by various characterisation techniques such as X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Fourier-Transform Infrared Spectrophotometer (FT-IR). The optical properties were investigated by fluorescence and UV-vis spectrophotometer. Also, N-CDs showed high selectivity in detecting the MTZ compared to several other analytes. However, the metronidazole serves as an antibiotic against several microbial diseases but also a genotoxic, carcinogenic to the human when used in excessive dosage. The synthesised N-CDs showed high selectivity in detecting the MTZ compared to several other analytes. Besides, the cytotoxicity of the N-CDs was studied to evaluate its toxicity against the HeLa cancer cells. It showed 65.6% cell viability and 34.3% toxicity against the cancerous cells, and similarly 71% of cells viability against H9C2 cells. Thus, the current investigation explores the promising selective sensing of N-CDs against MTZ, along with that, it proved its cytotoxicity against HeLa cancerous cells and non-toxicity against H9C2 cells. The synthesised CDs can be better MTZ sensors and anti-cancer agents on further development at the industrial scale. [ABSTRACT FROM AUTHOR]

The combined biological processes of branched water-adjustment, chemical precipitation, hydrolysis acidification, secondary sedimentation, Anoxic/Oxic and activated carbon treatment were used for chemical industrial wastewater treatment in the Taihu Lake Basin. Full-scale treatment resulted in effluent chemical oxygen demand, total nitrogen, NH3–N and total phosphorus of 35.1, 5.20, 3.10 and 0.15 mg/L, respectively, with a total removal efficiency of 91.1%, 67.1%, 70.5% and 89.3%, respectively. In this process, short-circuited organic carbon from brewery wastewater was beneficial for denitrification and second-sulfate reduction. The concentration of effluent fluoride was 6.22 mg/L, which also met the primary standard. Gas Chromatography-Mass Spectrometry analysis revealed that many types of refractory compounds were present in the inflow. Microbial community analysis performed in the summer by PCR-denaturing gradient gel electrophoresis and MiSeq demonstrated that certain special functional bacteria, such as denitrificans, phosphorus-accumulating bacteria, sulfate- and perhafnate-reducing bacteria, aromatic compound-degrading bacteria and organic fluoride-degrading bacteria, present in the bio-tanks were responsible for the acceptable specific biological pollutant reduction achieved. [ABSTRACT FROM AUTHOR]

The performance of powdered zeolite (PZ) adsorption/ultrafiltration (UF) with real secondary effluents is investigated. With the assistance of PZs, the membrane fouling rate was reduced and the permeate flux recovery as well as the advanced treatment of the secondary effluents were enhanced. 3D excitation emission matrix (3D-EEM) fluorescence spectra indicate that the removal of fluorescence intensity for aromatic proteins, fulvic acid-like materials, soluble microbial by-product-like materials, and humic acid-like organics could be improved by PZs. UF membranes with PZs can increase the removal efficiency of organics, especially of those with low molecular weight. The characteristics of the cake layer on the surface of an UF membrane were determined by scanning electron microscopy and electron energy-dispersive X-ray spectroscopy for the combined adsorption/UF membrane. [ABSTRACT FROM AUTHOR]

An overall and comparative ecological risk assessment of heavy metals (including Cd, Cr, Cu, Pb, Zn, Hg and As) in surface sediments from China's eight major aquatic bodies was conducted to better understand their potential risks on a national scale. By applying the joint approach of Hakanson risk index ( RI) and Monte Carlo simulation, ecological risk in this work is expressed as probability distribution of RI values instead of single point calculations to reflect the uncertainties in risk assessment process. The results show that the highest ecological risks posed by heavy metals existed in Xiangjiang River and Dianchi Lake. Although only a slim margin of high risk (651.88/600 = 1.08 and 700.61/600 = 1.17) was identified based on average RI values, the probabilities of high risk level derived from Monte Carlo simulation reached as high as 56.7 and 52.9 % in these two aquatic bodies, respectively. And the probability of low risk level was less than 1.6 %. Furthermore, the risk was mainly contributed by Hg and Cd, discharged through local intensive mining and industrial activities. The findings indicate that rigid control and effective management measures to prevent heavy metal pollution are urgently needed in China, especially for the high-risk aquatic bodies. This study shows that the joint approach can be used to identify the high risk water bodies and the major metal pollutants. It may avoid overestimating or underestimating the ecological risk and provide more decision-making support for risk alleviation in the polluted aquatic bodies. [ABSTRACT FROM AUTHOR]

To assess aggregate exposure to polycyclic aromatic hydrocarbons (PAHs) via several environmental media and pathways, a probabilistic framework for multi-pathway health risk assessment that integrates PAHs potency equivalence factors, risk estimation modeling, and Monte Carlo simulation was applied to a case study in Nanjing, which is an important industrial city in China. Incremental lifetime risk of additional cancers posed by exposure to 16 USEPA priority PAHs in air, water, soil, and fish was assessed. Risks to three age groups, infants, children, and adults, through various exposure pathways, including oral ingestion, dermal absorption, and inhalation, were estimated. Results of the analysis of risk indicated that B[ a]P, B[ b]F, and BA were the predominant PAHs pollutants in Nanjing. Risk of additional cancer for local adults was on average 2.62 × 10. The risks were primarily due to ingestion of fish and inhalation, which contributed 99 % of the total risks. By contrast, risk to infants was essentially negligible. Results of a sensitivity analysis indicated that the input variables of concentration of PAHs in fish ( C), the body weight (BW), and the ingestion rate of fish (IR) were the major influences on estimates of risks. [ABSTRACT FROM AUTHOR]