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Abstract The contents of ten heavy metals (Cr, Hg, As, Pb, Ni, Cd, Ti, Cu, Zn and V) in 413 topsoil samples from Puning City, Guangdong Province, China were investigated. Obvious enrichment of Hg, As, Pb, Cd and Zn were presented, and the contents of Hg and As in 5.8% and 3.4% samples respectively were higher than the guideline values recommended by the Chinese Environmental Quality Standard for Soils. Chromium and V were presented no enrichment and no pollution. According to one-way analysis of variance, the mean contents of Hg, Pb, Cu and Zn in land for construction were significantly higher than farmland and natural vegetation, but the land use had no obvious effect on other heavy metals. Furthermore, the potential sources of ten heavy metals were identified and apportioned in combination with geostatistics, correlation analysis and positive matrix factorization model. The results were following as: a) Pb, Zn and Cu mainly origin from vehicle emission and atmosphere deposition, and the hotspots approximately distributed in the areas of intensive traffic and near main roads; b) Hg and Cd were derived to industrial activities related to pharmaceutical industries, the textile and dyeing industries and e-waste recycling industries, and high-value areas were mainly concentrated in the northeast of the urban area where the industrial parks have been distributed; c) Soil parent material (Jurassic shale) was the main source of Cr, Ni, V and Ti; d) As mainly came from agricultural inputs such as pesticides or herbicides, livestock and fertilizers. Meanwhile, the contributions of four sources were 33.08%, 24.04%, 27.11% and 15.77% of the total contribution, respectively. Graphical abstract Unlabelled Image Highlights • Obvious enrichment of Hg, Cd, Pb and Zn were found in Puning soils. • Four sources of soil heavy metals were apportioned by geostatistics and PMF. • Vehicle emission and industrial activities were the main anthropogenic source. [ABSTRACT FROM AUTHOR]

Abstract Nanosized TiO 2 photocatalysis technology is one of the most promising technologies for the treatment of wastewater containing azo dyes. In this work, TiO 2 was deposited on a mesoporous SBA-15 molecular sieve by chemical deposition, and rare earth (RE) metal neodymium (Nd) was further deposited on the surface of the catalyst to obtain an Nd–TiO 2 –SBA-15 photocatalyst. The prepared photocatalyst was analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and N 2 adsorption–desorption. The activity of the Nd–TiO 2 –SBA-15 photocatalyst was evaluated by using methyl orange to represent the azo dye. The effects of different Nd deposition amounts and different solution pH values on the photocatalyst performance were principally studied. The results show that the synthesized photocatalyst formed an anatase crystal with a mesoporous structure. The specific surface area and pore size of the photocatalyst are 548.2 m2/g and 6.5 nm, respectively. As the amount of Nd deposition gradually increases, the activity of photocatalyst undergoes a process of first rising and then decreasing. In addition, the photocatalyst maintains high photocatalytic activity in the pH range of 2–10, exhibiting good acid–base adaptability. This work demonstrates that the Nd–TiO 2 –SBA–15 nanophotocatalyst has broad practical application prospects on a large scale. Graphical abstract Unlabelled Image Highlights • A rare earth metal Nd-deposited TiO 2 nanophotocatalyst with a mesoporous structure was successfully prepared. • The nanophotocatalyst has good acid-base adaptability and has high photocatalytic activity in the range of pH 2-10. • The proper amount of Nd deposition can increase the activity of the nanophotocatalyst. • Excessive Nd deposition may reduce the activity of the nanophotocatalyst. [ABSTRACT FROM AUTHOR]

Abstract: Considering the limitation of the traditional method to assess the ecological carrying capacity and the complexity of the water ecological system, we used system dynamics, ANN, and CA–Markov to model a water ecological system. The social component was modeled according to Granger causality test by system dynamics. The natural component consists of the water resource and water environmental capacity, which were forecasted through the prediction of precipitation and change in land use cover. The interaction of the social component and the natural component mainly reflected environmental policies, such as the imposition of an environmental fee and environmental tax based on their values. Simulation results showed the different assessments on water ecological carrying capacity under the two policies. The population grew (2.9million), and less pollution (86,632.37t COD and 2854.5t NH4N) was observed with the imposition of environmental tax compared with the imposition of an environmental fee (2.85million population, 10,8381t COD and 3543t NH4N) at the same GDP level of 585billionCNY in 2030. According to the causality loop, we discussed the different states under the policies and the reasons that caused the differences in water ecological carrying capacity state. According to game theory, we explained the limitation of the environmental fee policy on the basis of marginal benefit and cost. The externality was cleared up by the environmental tax policy. [Copyright &y& Elsevier]

Abstract: A novel, simple, cost-effective, and sensitive method was developed for the determination of atrazine and its principal metabolites namely deisopropyl-atrazine (DIA) and deethyl-atrazine (DEA) in water and soil samples using multi-walled carbon nanotubes as solid-phase extraction (SPE) adsorbents coupled with gas chromatography-mass spectrometry (GC-MS). Several condition parameters, such as sample loading flow-rate, eluent and elution volume, extractant and ratio of extraction solvent to sample, were optimized to achieve good sensitivity and precision for the extraction and elution of analytes. A methanol/water solution (50%, v/v) was used to extract atrazine, DIA and DEA from soil. After the extracts went through SPE cartridges (packed with multi-walled carbon nanotubes) at a flow-rate of 4 mL min−1, the analytes were eluted by 4 mL ethyl acetate at the rate of 1 mL min−1 under a vacuum pump. The limit of detection (S/N=3) of the proposed method was 0.02 μg kg−1 for atrazine in water and 0.3 μg kg−1 in soil; 0.04 μg kg−1 for DIA in water and 1.0 μg kg−1 in soil; 0.05 μg kg−1 for DEA in water and 0.8 μg kg−1 in soil. Mean recoveries were in the range of 72.27–109.68%, and the reproducibility was accepted (RSD <13%) under the optimum conditions. This developed method was applied to determine the analytes in real environmental samples, and the concentrations of atrazine were 0.77–10.83 μg kg−1, while DEA and DIA were not detected. [Copyright &y& Elsevier]

Based on the collection and analysis of essential data from wastewater treatment plants (WWTPs) in recent ten years, the work provides the wastewater characteristics and energy consumption performance in full-scale membrane bioreactor (MBR) process in East Taihu basin, China. High-quality effluent was achieved although the influent carbon source was not beneficial to total nitrogen and total phosphorus removal. The average specific energy consumption (SEC) was 0.52 kWh/m3, which was remarkably lower than that of full-scale MBR process in developed countries, however, the average SEC value was higher than that of conventional activated sludge (CAS) process in China. In addition, the SEC value was largely reduced in 2018, and the regulation of suction pump and aeration mode were considered as the main control methods. Energy consumption will increase along with the influent volume, while the elevation of COD and NH 4 +-N reduction will bring about relatively low energy consumption. Furthermore, sustainability index was established to comprehensively evaluate the performance of full-scale MBR process, meaning that with relatively low permeate ratio of effluent, full-scale MBR process presented to be inferior to CAS process in sustainability and not feasible to be applied in the upgradation and construction of WWTPs. Unlabelled Image • Carbon source was generally insufficient whereas good TN and TP removal were obtained. • The SEC of full-scale MBR process was remarkably higher than that of CAS process. • Energy consumption accounted for 48.09% of the operation cost. • Increase of COD and NH 4 +-N reduction will lead to relatively low energy consumption. • S I value of MBR process presented to be inferior to CAS process in sustainability. [ABSTRACT FROM AUTHOR]

Acetic acid and sodium acetate are generally supplied to wastewater treatment plants (WWTPs) in China to improve total nitrogen (TN) and total phosphorus (TP) removal, and the addition of carbon source also facilitates to increase sludge growth rate and further provides material basis for the extraction of proteins and amino acids from activated sludge. To recycle ammonia nitrogen resources, a system that combined adsorption and anaerobic–anoxic–oxic (A/AAO) process for treating low strength wastewater was established. Experimental results showed that by the addition of carbon substrate from a mixture of anaerobically fermented adsorption sludge, the average removal efficiency of chemical oxygen demand (COD), ammonia nitrogen, TN, and TP were 88%, 96.9%, 93.9%, and 92.1%, respectively, and the ratio of nitrogen assimilation to nitrogen dissimilation significantly increased by a factor of 2.5. Through energy analysis (based on adenosine triphosphate, ATP), sludge flocculation capacity and settling property, it was found that the AAO process sludge presented the logarithmic growth characteristics. The respective sludge protein and amino acids contents increased by over 11.4% and 40.3%, and the synthetic products of glutamic acid, alanine and aspartate increased through the assimilation of ammonia nitrogen, thereby indicating that replenishing the carbon substrate could markedly enhance protein and amino acids contents in AAO process sludge. Moreover, the diversity of the microbial community in adsorption process was relatively rich, the diversity in the adsorption process sludge was the highest, while the diversity of the AAO process sludge evidently decreased. The microbial community in each process was similarly based on 16S rDNA gene sequence analysis, microflora was prominent in the AAO process, with Dechloromonas , Flavobacterium , Zoogloea , Unclassified_Rhodocyclaceae and Thauera as the dominant species. Promising carbon utilization facilitates contaminants removal in low strength wastewater treatment and is conducive to protein production through ammonia nitrogen assimilation. Unlabelled Image • 61.3% of COD and 91.0% of particle COD were entrapped in adsorption process. • The Yobs reached 0.49 g VSS/g COD in AAO process sludge. • The ratio of NH 4 +-N assimilation to nitrogen removal was up to 60% in AAO process. • The sludge protein and amino acid contents increased more than 11.4% and 40.3%. • Dechloromonas , Flavobacterium and Zoogloea became greater prevalence in AAO process. [ABSTRACT FROM AUTHOR]

Abstract Background Few studies have explored PM 10 's connection with specific respiratory and cardiovascular emergency department admissions (EDAs). This study aimed to examine the overall effects of PM 10 on EDAs for cardiovascular and respiratory diseases, including specifically, cerebrovascular events (CVE), ischemic heart disease (IHD), arrhythmia, heart failure (HF), upper respiratory tract infection (URTI), lower respiratory tract infection (LRTI), chronic obstructive pulmonary disease (COPD) and asthma. Methods We collected daily data for EDAs from the 10 largest hospitals in Beijing, between January 2013 and December 2013 as well as daily measurements of PM 10 from 17 stations in Beijing. The generalized-additive model was utilized to evaluate the associations between daily PM 10 and cardio-pulmonary disease admissions. Differences in gender, age, and season groups were also examined by models. Relative risks (RR) with 95% confidence interval (CI) were calculated based on subtype, age, gender and seasonal groups. In all, there were approximately 56,212 cardiovascular and 92,464 respiratory emergency admissions presented in this study. Results The largest estimate effects in EDAs of total cardiovascular disease, CVE, IHD, total respiratory diseases, URTI, LRTI and COPD were found for PM 10 at day 4 (accumulative) moving average, were 0.29% (95% CI:0.12%, 0.46%), 0.36% (95% CI:0.11%, 0.61%), 0.68% (95% CI:0.25%, 1.10%), 0.34% (95% CI:0.22%, 0.47%), 0.35% (95% CI:0.18%, 0.51%), 0.34% (95% CI:0.14%, 0.55%), 2.75% (95% CI:1.38%, 4.12%) respectively. In two-pollutant models and full-pollutant model modified confounding factors, the positive correlation remained unchanged. The elderly (age ≥ 65 years) and male subjects were more susceptible to specific respiratory diseases. PM 10 's impact on EDAs for HF was found higher during the hot season however, EDAs for COPD peaked during the cold season. Conclusion The study markedly informed that PM 10 pollution was strongly associated with EDAs for cardio-pulmonary diseases. The effects of PM 10 pollution on COPD and heart failure EDAs were clearly determined by seasonal-temperatures. Graphical abstract Unlabelled Image Highlights • Patients with cardiopulmonary diseases are vulnerable to PM10. • Subjects ≥65 years old and male gender tend to be more vulnerable to respiratory illnesses owing to PM10. • PM10 is a significant health hazard greatly impacting cardio-pulmonary emergency admissions. • Polluted areas can greatly curb the health care burden associated with costs of needlessly increased emergency admissions. [ABSTRACT FROM AUTHOR]

Chemical additives leaching from microplastics and their effects on physiology of microalgae are of environmental significance. So far, these issues remain unclear. Here, the leaching behavior of fluorescent additives from polyurethane sponge microplastics in simulated (acidic, saline, and basic water) and natural waters (river, lake, wetland, and sea water) was investigated. Release amount of additives increased with increasing solution pH and leaching time. The maximum release amount was reached at the leaching time of 12–24 h and the 3,3′-diaminobenzidine-like substances were identified in the leachate. The leached concentrations of fluorescent additives in simulated and natural waters followed the order of basic water > saline water > seawater > West Lake > River > Wetland. Effects of leachate and microplastics on growth and photosynthesis of Chlorella vulgaris were further evaluated. The maximum quantum efficiency of photosystem II (F v /F m) decreased with increasing leachate concentrations. Only high content (1.6 g L−1) of microplastics exerted significant inhibitory influence on cell photosynthesis when microalgae were exposed to microplastics alone. Retention of algal cells inside the porous sponge microplastics did not change their photosynthetic efficiency. These findings indicate that leaching process of additives from microplastics depends mainly on water environments and the leached chemicals may pose ecological risks to aquatic organisms. Unlabelled Image • Release amount of additives increased with increasing solution pH and leaching time. • Different leaching patterns of additives in simulated and natural waters were observed. • The photosynthetic efficiency decreased with increasing leachate concentrations. • Retention of algal cells in microplastics did not change their photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

Abstract Nonferrous metallurgy is causing significant concerns due to its emissions of heavy metals into environment, degrading environmental quality, and consequently posing high risks to human health. In this study, the concentration levels of Cadmium (Cd), Copper (Cu), Lead (Pb), and Arsenic (As) were investigated in soil, crop, well water, and fish samples collected around the Daye Copper Smelter in Hubei province, China, and the potential health risks were assessed for local children. The results showed that soils near the smelter were heavily polluted by Cd, Cu, Pb, and As, with the mean concentrations of 4.87, 195.26, 92.65, and 35.84 mg/kg, respectively, which were significantly higher than the values of soil Cd (0.18 mg/kg), Cu (32.84 mg/kg), Pb (28.46 mg/kg), and As (13.65 mg/kg) in the reference area (p < 0.001). The concentrations of Cd and As in vegetable samples collected from smelter-affected area exceeded the maximum permissible level (MPL) for food in China by 82% and 39%, respectively. The concentrations of Cd and Pb in rice grain harvested from smelter-affected area were 9.35 and 1.35 times higher than the corresponding MPL, respectively. The concentrations of Cd, As, and Cu in fish muscle from smelter-affected area exceeded the national MPL by 72%, 41%, and 24% of analyzed samples, respectively. The concentrations of Cd (p < 0.05) and As (p < 0.01) in well water were significantly higher in the smelter-affected area than those in the reference area, respectively. The health risks to local children in the smelter-affected area were 30.25 times higher than the acceptable level of 1, and most of the risks were resulted from Cd (46%), As (27%) and Pb (20%). The intake of crops was a major source (78%) to health risks for local children. Graphical abstract Unlabelled Image Highlights • A comprehensive heavy metal pollution and health risk assessment of soil, crop, well water and fish was conducted. • Elevated concentrations of heavy metals were found in the soil, crop, well water and fish. • Health risk of heavy metal pollution was high for local children. • Consumption of crops was the major contribution to risk. • Most of the risks were due to Cd, As and Pb pollution. [ABSTRACT FROM AUTHOR]

An orthogonal field experiment of giant reed ( Arundo donax ) modified with organic complex fertiliser (OCF), and OCF and fly ash (O&F), at different planting densities was carried out in metal-contaminated soil. The available percentage of arsenic (As) and lead (Pb) in soil decreased from 8.45% to 2.19% and from 29.6% to 13.5% by OCF, respectively, and that of cadmium (Cd) was reduced from 25.3% to 6.49% by O&F. The total biomass of giant reed was 631 g per individual following application of O&F in contaminated soil. The accumulation of As, Cd, and Pb in giant reed was 1.57, 4.06, and 11.25 mg per individual. Urease and sucrase activity were 87.4 NH 4 -N μg/g d and 63.1 glucose mg/g d in response to the treatments modified using OCF, while the highest dehydrogenase activity was 101 TPF (triphenyltetrazolium formazan) μg/g d in the treatments modified using O&F. Dominant bacteria (frequency > 50%) were enriched with increasing planting density of giant reed. These results indicate that the phytostabilisation of metal-contaminated soil by giant reed could be improved by the application of O&F or OCF. [ABSTRACT FROM AUTHOR]

The kinetic and pathway of meta-cresol (m-cresol) degradation were studied by persulfate oxidation through UV/ozone activation (UV/O 3 –Na 2 S 2 O 8) to improve m-cresol removal to eliminate ecological risks. Experimental results showed that the degradation effect of m-cresol with an initial concentration of 50 mg/L was 99.8% in 30 min under the optimization conditions. The reaction kinetic model in the UV/O 3 –Na 2 S 2 O 8 system shows that the initial pH value, the respective ozone, and the persulfate dosage were positively correlated with the degradation rate constant value (k). The apparent degradation rate of m-cresol in the UV/O 3 –Na 2 S 2 O 8 system was 0.2216 min−1, and the synergy factor (f) was larger than 1, thereby demonstrating a synergistic effect of UV, ozone, and persulfate. The dominant free radicals in the system were sulfate radical (SO- 4·) and hydroxyl radical (·OH), and the contribution ratio of SO- 4· to m-cresol degradation was higher than ·OH. The degradation process of m-cresol by UV/O 3 − Na 2 S 2 O 8 was mainly through the electrophilic addition reaction to substitute the ortho- and para-positions of the hydroxyl group on the benzene ring, followed by the ring-opening reaction and mineralization of the aliphatic compound to achieve the complete degradation of m-cresol. Unlabelled Image • High m-cresol degradation by persulfate through UV/O 3 activation was achieved. • UV/O 3 -PS system has strong synergistic effect based on reaction enhancement factor. • The contribution ratio of SO- 4· to m-cresol degradation was higher than ·OH. • Generation of intermediate products implied m-cresol mineralization is incomplete. • Ring-opening reaction and group dehydrogenation facilitate m-cresol degradation. [ABSTRACT FROM AUTHOR]

The controlling processes of excessive ammonium in surface water and groundwater in the central Yangtze River Basin remain unclear. In this study, monitoring of water levels and temporal-spatial distributions of major N compounds were implemented at the large Jiangshan plain and at the local site scale in the central Yangtze River Basin. The results indicate that the recharge, movement and transformation of ammonium were controlled by hydrogeological conditions. Manure and sewage from anthropogenic activities were identified as the main source of nitrogen compounds. The nitrogen loading into aquifers were governed by water table and groundwater flow. After entering subsurface soils, nitrification and dissimilatory nitrate reduction to ammonium (DNRA) were proposed as the ammonium consumption and production mechanisms, respectively, by combining the concentrations of ammonium‑nitrogen and nitrate‑nitrogen with the corresponding isotopic compositions. These microbially mediated processes controlling transport and transformation of nitrogen compounds were influenced by the seasonally varying groundwater flow regime that changed the redox conditions in the aquifers. In the subsurface environments, ammonium was converted to nitrate when sufficient oxygen supply was available, and this process was reversed under anoxic conditions along the groundwater flow path. A conceptual model for the reactive transport of nitrogen compounds jointly controlled by the vertical groundwater flows and biogeochemical processes was proposed, which provides new insights into the genesis of high ammonium groundwater. Unlabelled Image • N compounds in surface water and groundwater in the central Yangtze River basin were sourced from manure and sewage. • Seasonal hydrogeological variations could contribute to the enrichment of ammonium in shallow groundwater. • High concentration of nitrate in oxic zone derived from nitrification in low groundwater level period. • Ammonium could be produced via dissimilatory nitrate reduction to ammonium under anoxic condition. [ABSTRACT FROM AUTHOR]