Relationship between types of urban forest and PM2.5 capture at three growth stages of leaves

Particulate matter diameter ≤ 2.5 μm (PM_2.5) causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM_2.5 from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM_2.5 concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air, but can reduce dust pollution caused by dust from the ground blown by the wind back into the air.     

“一带一路”沿线国家PM2.5污染与人口暴露风险的时空分布特征

使用1999—2016年0.01°×0.01°高空间分辨率的卫星反演PM_2.5浓度数据集，结合精度为1 km×1 km的人口栅格数据，分析了"一带一路"沿线65个国家PM_2.5污染与暴露风险的时空变化特征.结果表明：①PM_2.5浓度存在着明显的区域分布差异，PM_2.5浓度高值区（>35 μg·m^-3）主要分布在地形平坦、人口密集的恒河平原、华北平原和中南半岛等区域，中值区（10~35 μg·m^-3）主要集中在俄罗斯西部、中东欧、沙特东部和缅甸等区域，而低值区（<10 μg·m^-3）主要分布在高海拔、高纬度与荒漠化地区，如青藏高原、西伯利亚、西亚卢特沙漠等区域；②65国年均PM_2.5浓度从1999年的12.0 μg·m^-3上升到2016年的14.1 μg·m^-3，年均增长超过0.1 μg·m^-3，累计有22.5%的区域有显著的增加趋势，仅有5.2%的区域呈显著下降趋势；③2000—2016年，PM_2.5浓度在35 μg·m^-3以上的区域面积比重从2.2%上升到7.2%，暴露人口占比从18.9%增加至41.9%；④人口暴露风险平均值从2000年的665.2增加至2016年的1140.4，Hurst总体均值为0.59，其中大于0.5的持续性区域占82.3%，持续性特征以弱持续性为主.     

Multicomponent photocatalysts for synergic removal of antibiotics in aqueous media: a review

Environmental Chemistry Letters - Pollution of waste and natural waters by antibiotics is a major health issue that induces the development of resistant pathogens. Pollutant may be removed by...     

Three-phase partitioning for the separation of proteins,enzymes, biopolymers,oils and pigments: a review

Environmental Chemistry Letters - Modern biomass and organic waste are becoming major, carbon-neutral sources of fine chemicals, biomolecules and fuels to replace fossil fuel products. As a...     

Current scenario and challenges of plastic pollution in Bangladesh: a focus on farmlands and terrestrial ecosystems

● A global snapshot of plastic waste generation and disposal is analysed. ● Effect of plastic pollution on environment and terrestrial ecosystem is reviewed. ● Ecotoxicity and food security from plastic pollution is discussed. Plastic is considered one of the most indispensable commodities in our daily life. At the end of life, the huge ever-growing pile of plastic waste (PW) causes serious concerns for our environment, including agricultural farmlands, groundwater quality, marine and land ecosystems, food toxicity and human health hazards. Lack of proper infrastructure, financial backup, and technological advancement turn this hazardous waste plastic management into a serious threat to developing countries, especially for Bangladesh. A comprehensive review of PW generation and its consequences on environment in both global and Bangladesh contexts is presented. The dispersion routes of PW from different sources in different forms (microplastic, macroplastic, nanoplastic) and its adverse effect on agriculture, marine life and terrestrial ecosystems are illustrated in this work. The key challenges to mitigate PW pollution and tackle down the climate change issue is discussed in this work. Moreover, way forward toward the design and implementation of proper PW management strategies are highlighted in this study.     

Controlling various contaminants in wastewater effluent through membranes and engineered wetland

For effective wastewater reclamation and water recovery, the treatment of natural and effluent organic matters (NOM and EfOM), toxic anions, and micropollutants was considered in this work. Two different NOM (humic acid of the Suwannee River, and NOM of US and Youngsan River, Korea), and one EfOM from the Damyang wastewater treatment plant, Korea, were selected for investigating the removal efficiencies of tight nanofiltration (NF) and ultrafiltration (UF) membranes with different properties. Nitrate, bromate, and perchlorate were selected as target toxic anions due to their well known high toxicities. Tri-(2-chloroethyl)-phosphate (TCEP), oxybenzone, and caffeine, due to their different K _ow and pK _a values, were selected as target micropollutants. As expected, the NF membranes provided high removal efficiencies in terms of all the tested contaminants, and the UF membrane provided fairly high removal efficiencies for anions (except for nitrate) and the relatively hydrophobic micropollutant, oxybenzon. Through the wetlands, nitrate was successfully removed. Therefore, a fair process of combining membranes with an engineered wetland could be proposed for sustainable wastewater reclamation and optimum control of contaminats.     

Capillary electrophoresis applied to kinetic studies of photocatalytic oxidation of substituted anilines

Cyclodextrin modified capillary electrophoresis (CMCE) and micellar electrokinetic chromatography (MEKC) were tested for their ability to analyze mixtures containing substituted anilines. CMCE separated analytes by their partitioning preference between the two substituted cyclodextrins while MEKC exploited the analyte partitioning between the micelles and the bulk aqueous phase. MEKC was selected to analyze samples that were subjected to photocatalytic oxidation using TiO₂ and/or SnO₂ as the semiconductor catalyst. The rate constant for each compound was determined when it was degraded individually or in the presence of other derivatives in the same family, indicating a significant degree of analyte competition and synergism offered by the mixed catalyst. The results demonstrated that CE, with its minimal sample preparation and requirement, is a valuable tool, particularly suitable for studying highly toxic pollutants, without generating a high volume of waste.     

Self-build packed-bed bioreactor for rapid and effective BOD estimation

This work demonstrated a simple, low-cost, rapid, and effective biochemical oxygen demand (BOD) estimation system based on a packed-bed bioreactor that can be easily self-built on-site at a particular wastewater treatment plant for continuous monitoring of the influent and effluent. The use of natural microbial consortium that were collected from the target wastewater and immobilized on a cheap porous carrier simply by adhesion resulted in an acceptable accuracy of over 95%. The newly developed semi-continuous operating mode with peak-type signals was shown to be able to continuously estimate BOD at a high flow rate to overcome the flow dependence of the oxygen electrode, limit clogging issues, enhance the response time, and lower the limit of detection. The resulting packed-bed bioreactors could work continuously for 22 h with a coefficient of variance (CoV) of only 1.8% or for 13 h a day for several days with a maximum CoV of 1.4% and their response was observed to be stable over 80 consecutive measurements. They exhibited stable responses at a wide pH range of 6.5–8.5, which is also the recommended range for aerobic wastewater treatment, emphasizing the greater ease of use of natural microorganisms for BOD estimation.

     

Redundancy analysis for characterizing the groundwater quality in coastal industrial areas

Groundwater quality in coastal area has been an issue of interest because of excessive groundwater extraction for human use, for example, industrialization, irrigation, which can lead to saltwater intrusion. The study develops an integrated data analysis procedure based on multivariate statistics principal component analysis (PCA), hierarchical cluster analysis (HCA) and redundancy analysis (RDA), to determine the effects of key environmental conditions on the formulation of groundwater pollutants. This proposed method was demonstrated by analyzing groundwater quality monitoring data collected between 2011 and 2014 from four coastal industrial areas in Changhua county of Taiwan, namely Chuansing, Xianxi, Lukang and Fangyuan industrial parks. First, different environmental conditions in each industrial region were explored by PCA. The spatial hierarchy and spatial distribution of pollutant categories were then identified using HCA with the kriging method. Finally, the effect of environmental conditions on constitutive pollutants were identified with RDA. The three environmental patterns identified from the analytical results in Chuansing, Lukang and Xianxi were the salination factor (including conductivity and general hardness (GH)), water level and redox condition (including dissolved oxygen and oxidation–reduction potential). Fangyuan industrial park had only two patterns, namely salination (including conductivity and GH) and oxygen content (including DO and depth). The pollutant category indicated high concentrations of all pollutants in Chuansing and Fangyuan, and higher concentration of SO₄^2?, TDS, Cl^? in Xianxi, and of NH₃-N, Mn, Fe and TOC in Lukang. According to RDA results, salination caused the high concentrations of NH₃N, Cl^?, TDS in Chuansing, and of Cl^?, TDS and SO₄^2? in Xianxi and Lukang. Additionally, salination caused high concentrations of Fe in both Lukang and Fangyuan industrial parks in combination with those three pollutants. The redox condition was linked to high content of NO₃^? in Chuansing and Lukang, and of TOC in Xianxi. In Fangyuan industrial park, NO₃^? was also linked to high oxygen concentration. In summary, the combination of PCA, HCA and RDA enables the analysis of monitoring data to support policy decision-making.     

Analysis of COVID-19 waste management in Vietnam and recommendations to adapt to the ‘new normal’ period

Journal of Material Cycles and Waste Management - Amid the 4th wave of COVID-19, Vietnam reopened its economy, which placed extra burdens on the COVID-19 waste management system. This study...