Research progress of disinfection and disinfection by-products in China

Disinfection is an indispensable water treatment process for killing harmful pathogens and protecting human health. However, the disinfection has caused significant public concern due to the formation of toxic disinfection by-products(DBPs). Lots of studies on disinfection and DBPs have been performed in the world since 1974. Although related studies in China started in1980 s, a great progress has been achieved during the last three decades. Therefore, this review summarized the main achievements on disinfection and DPBs studies in China, which included:(1) the occurrence of DBPs in water of China,(2) the identification and detection methods of DBPs,(3) the formation mechanisms of DBPs during disinfection process,(4) the toxicological effects and epidemiological surveys of DBPs,(5) the control and management countermeasures of DBPs in water disinfection, and(6) the challenges and chances of DBPs studies in future. It is expected that this review would provide useful information and reference for optimizing disinfection process, reducing DBPs formation and protecting human health.     

Insights into measurements of water-soluble ions in PM2.5 and their gaseous precursors in Beijing

To better understand the characteristics and transformation mechanisms of secondary inorganic aerosols, hourly mass concentrations of water-soluble inorganic ions (WSIIs) in PM_2.5 and their gaseous precursors were measured online from 2016 to 2018 at an urban site in Beijing. Seasonal and diurnal variations in water-soluble ions and gaseous precursors were discussed and their gas-particle conversion and partitioning were also examined, some related parameters were characterized. The (TNH₃) _Rich was also defined to describe the variations of the excess NH₃ in different seasons. In addition, a sensitivity test was carried out by using ISORROPIA II to outline the driving factors of gas-particle partitioning. In Beijing, the relative contribution of nitrate to PM_2.5 has increased markedly in recent years, especially under polluted conditions. In the four seasons, only a small portion of NO₂ in the atmosphere was converted into total nitrate (TNO₃)_, and more than 80% of TNO₃ occurred in the form of nitrate due to the abundant ammonia. The concentration of total ammonia (TNH₃) was much higher than that required to neutralize acid gases, and most of the TNH₃ occurred as gaseous NH₃. The nitrous acid (HONO) concentration was highly correlated with NH₃ concentration and had increased significantly in Beijing compared with previous studies. The total chloride (TCl) was the highest in winter, and ε(Cl^?) was more sensitive to variations in the ambient temperature (T) and relative humidity (RH) than ε(NO₃^?).     

Inconsistent seasonal variation of antibiotics between surface water and groundwater in the Jianghan Plain: Risks and linkage to land uses

Antibiotics are widely used in humans and animals, but their transformation from surface water to groundwater and the impact of land uses on them remain unclear. In this study, 14 antibiotics were systematically surveyed in a complex agricultural area in Central China. Results indicated that the selected antibiotic concentrations in surface waters were higher in winter (average: 32.7 ng/L) than in summer (average: 17.9 ng/L), while the seasonal variation in groundwaters showed an opposite trend (2.2 ng/L in dry winter vs. 8.0 ng/L in summer). Macrolides were the predominant antibiotics in this area, with a detected frequency of over 90%. A significant correlation between surface water and groundwater antibiotics was only observed in winter (R² = 0.58). This study further confirmed the impact of land uses on these contaminants, with optimal buffer radii of 2500 m in winter and 500 m in summer. Risk assessment indicated that clarithromycin posed high risks in this area. Overall, this study identified the spatiotemporal variability of antibiotics in a typical agricultural area in Central China and revealed the impact of land uses on antibiotic pollution in aquatic environments.     

一种土工合成材料加筋土界面拉拔行为分析∗

为研究试验过程中不同位置的筋土界面拉拔行为,以补充试验测量的不足,提出了一个能够预测筋材任意位置拉力和位移的界面拉拔公式,并给出了其具体的应用和分析步骤。首先预测给定筋材长度的最大峰值拉力,然后在最大峰值拉力范围内预测给定峰值拉力的筋材有效长度,其次确定界面摩擦系数大小,最后预测沿筋材任意位置的位移变化关系。同时,对界面拉拔公式进行了参数影响分析,并将界面拉拔公式预测结果与试验结果进行对比。研究结果表明:界面摩擦系数可以间接验证界面拉拔公式的准确性,对拉拔试验结果提供一致性解释。界面拉拔公式的预测结果与拉拔试验结果吻合良好,表明了分析模型的合理性。研究成果对分析和完善筋土界面特性具有重要意义。     

基于Sentinel-2A影像估算黄土高原光合/非光合植被盖度

以黄土高原为例,基于Sentinel-2A影像和地表实测地物光谱与盖度数据,分别在模拟混合场景和野外实测混合场景中,评估4种NPV植被指数(NPVI):SWIR32(短波红外比值指数)、DFI(干枯燃料指数)、STI(土壤耕作指数)和NDTI(归一化差异耕作指数)估算非光合植被盖度(f_NPV)的有效性,并利用优化法确定线性光谱混合模型的关键参数端元值,估算研究区光合植被盖度(f_PV)和f_NPV.结果表明,在模拟混合场景下,4种NPVI与模拟f_NPV线性关系的R²是0.365~0.750;在野外场景中,其相关性均有一定程度的降低,R²是0.147~0.211.研究构建NDVI-SWIR32像元三分模型,并确定了最优端元值:NDVI_PV=0.80,SWIR32_PV=0.60, NDVI_NPV=0.17,SWIR32_NPV=0.77,NDVI_BS=0.23,SWIR32_BS=0.99.模型对f_PV和f_NPV估算精度R²分别是0.817和0.463,NSE分别是0.806和0.458.利用该模型估算全区2019年4、8和12月的平均f_PV和f_NPV,分别为20.3%和59.2%,48.6%和33.1%,10.7%和59.0%.随时间推移,f_PV从东南向西北不断增加而后减小,f_NPV与之相反. NDVI-SWIR32模型可以用于Sentinel-2A影像数据来监测黄土高原地区f_PV和f_NPV的时空动态变化.     

Robust optimization approach to two-echelon agricultural cold chain logistics considering carbon emission and stochastic demand

Environment, Development and Sustainability - Cold chain logistics has become one of the main sources of carbon emissions. Meanwhile, the implementation of low-carbon economy has become an...     

Toxic effect of microcystin-LR on blood vessel development

Abstract

The effect of microcystin-LR (MC-LR) at 50–1000?nmol/L on blood vessel development of zebrafish embryos has been explored. Upon exposure 72-h-post-fertilization (hpf), the hatching rate was significantly reduced and malformation and fatality rates were increased in a dose-dependent manner. MC-LR induced cell cycle arrest in the G0/G1-phase and damaged DNA structure in a dose-dependent manner. In human umbilical vein endothelial cells (HUVECs), MC-LR led to decreased activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) and increased lipid peroxidation. These findings indicated that MC-LR could cause oxidative DNA damage, which mediated cell cycle arrest and inhibited cell proliferation afterwards, and retarded the blood vessel development.     

Effects of diethylphthalate and di-(2-ethyl)hexylphthalate on the physiology and ultrastructure of cucumber seedlings

Phthalic acid esters (PAEs) are one kind of persistent organic pollutants. This study was conducted to investigate the effects of diethylphthalate (DEP) and di(2-ethyl)hexylphthalate (DEHP) with different concentrations (0, 30, 50, 100, and 200 mg L^?1) on early seedling growth of Cucumis sativus L. Physiological, biochemical, and ultrastructure of seedling leaves were examined for 7-day exposure. The three antioxidant enzymes’ activities was stimulated at low-DEP treatments and decreased under higher levels (>200 mg L^?1) compared to the controls. Furthermore, MDA and H₂O₂ gradually enhanced with the elevation of DEP and DEHP concentration. Significant impact on the chloroplast and mitochondrion was visible, possibly as a consequence of free radical generation. DEP induced bigger and more starch grains in chloroplasts than DEHP. This study concluded that the effects of DEP and DEHP on cucumber seedlings represented the adverse impacts of DEP and DEHP on the ecosystem and agricultural production. The environmental harm caused by DEP was severer than DEHP.     

Bibliometric analysis of zerovalent iron particles research for environmental remediation from 2000 to 2019

Environmental Science and Pollution Research - Zerovalent iron (ZVI) has been a major focus of research and has attracted great attention during the last 2 decades by international researchers...     

Reduced graphene oxide modified Z-scheme AgI/Bi2MoO6 heterojunctions with boosted photocatalytic activity for water treatment originated from the efficient charge pairs partition and migration

Environmental Science and Pollution Research - In order to enhance degradation of harmful organic pollutants like Rhodamine B (RhB) dye under visible-light irradiation (λ >420 nm), a...