Monitoring gas- and particulate-phase short-chain polychlorinated paraffins in the urban air of Dalian by a self-developed passive sampler

The concentration of short-chain polychlorinated paraffins(SCCPs) in the urban air of Dalian,China was monitored from September 2016 to August 2017 with a self-developed passive sampler(PAS1) and an active high-volume sampler, simultaneously. PAS1 successfully collected the entire target SCCPs in the ambient air. Air SCCPs sampled by PAS1 were found be in the linear uptake stage during 181 days of sampling. Passive and active samples showed comparable congener profiles, and the dominant contributors of SCCPs in the two kinds of samples were similar. A significant linear correlation was observed between the total concentration of SCCPs sampled by PAS1 and active sampler in the four seasons. The passive sampling rates of the PAS1 for the gas and particulate phases of SCCPs were measured. The quantitative structure–property relationship of the sampling rate of PAS1(Rair) for gas-phase SCCPs was studied. From the molecular point of view, Rairwas mainly affected by the molecular weight and sub-cooled liquid vapor pressure of SCCPs. In general, SCCPs in the urban air of Dalian mainly existed in gas phase,lower molecular weight SCCPs primarily occurred in the gas phase, whereas higher molecular weight SCCPs were predominately adsorbed or absorbed on airborne particles. The air concentration of SCCPs in the four seasons were different, the correlation of the concentration of SCCPs in the air with the meteorology parameters was conducted. The exposure risk by intake air SCCPs of the residents around the sampling sites was evaluated according to the European risk assessment standards.     

污水特质(水征)评价及其在污水再生处理工艺研究中的应用

近年来,在污水高标准处理研究和工程实践中,发现和遇到越来越多的现有常规水质指标、工艺理论和技术知识等难以解释的新现象和难以解决的新问题.以逐步建立水质复杂体系研究理论和方法体系,构筑科学、有效的污水处理风险管理和安全保障管理系统为目标,介绍了污水的复杂体系特征,阐述了污水高标准处理中工艺设计、运行和诊断面临系统理论方法缺失的问题及其根源,提出了可有效支撑污水工艺研究的污水特质,即"水征（water feature）"的概念.通过分析污水中污染物的浓度水平、组分特征、安全性和稳定性及其时空变化,定义了水征"四维度"内涵,即污染物污染程度、组分特征、毒害效应和转化潜势等4个维度.研究和实践案例表明,水征能有效支撑水质安全评价、处理特性预测、处理工艺设计和工艺诊断优化等.在以水环境质量改善和环境风险控制为目标的污水高标准处理新阶段,基于水征研究,发展高效处理工艺、构筑科学有效的风险管理和安全保障体系尤为重要.今后需深入、持续开展污水处理中水征指标评价方法与理论体系、水征与污染物处理关键技术开发与工艺优化、水征与风险评价管理等方面的研究.      

Screening hydroxyapatite for cadmium and lead immobilization in aqueous solution and contaminated soil: The role of surface area

Hydroxyapatite (HAP) has been widely used to immobilize many cationic metals in water and soils. The specific reason why an increase in the surface area of HAP enhances cadmium (Cd) uptake, but has no effect on lead (Pb) uptake, is not clear. The aim of this study was to determine the factors causing the differences in sorption behavior between Cd and Pb by evaluating HAPs with different surface areas. We synthesized HAPs with two different surface areas, which were characterized by X-ray diffraction, N₂ adsorption, and scanning electron microscopy, and then evaluated them as sorbents for Cd and Pb removal by testing in single and binary systems. The sorption capacity of large surface area HAP (1.85 mmol/g) for Cd in the single-metal system was higher than that of small surface area HAP (0.64 mmol/g), but there were no differences between single- and binary-metal solutions containing Pb. After the Cd experiments, the HAP retained a stable structure and intact morphology, which promotes the accessibility of reactive sites for Cd. However, a newly formed precipitate covered the surface and blocked the channels in the presence of Pb, which reduced the number of potential adsorption sites on HAP for Cd and Pb. Remediation experiments using Cd- and Pb-contaminated soil produced similar results to the solution tests. These results indicate that alterations of the structure and morphology during the reaction is an important factor influencing metal sorption to HAP.     

GIS-based analysis of population exposure to PM2.5 air pollution—A case study of Beijing

PM_(2.5), formally defined as particulate matter with diameter less than 2.5 μm, is one of most harmful air pollutants threatening human health. Numerous epidemiological studies have shown that both short-term and long-term exposures to PM_(2.5) are strongly linked with respiratory diseases. In this study, various types of spatio-temporal data were collected and used to estimate the spatio-temporal variation of PM_(2.5) exposure in Beijing in 2014. The seasonal and daily variation of the population-weighted exposure level(PWEL) in 2014 was estimated and compared. The results show that the population exposure to ambient air pollution differs significantly in the four seasons, and the exposure levels in winter and spring are notably higher than the other seasons; the exposure level changes greatly from North to South, and each sub-district maintains similarity to neighboring sub-districts.     

Purification, characterization and application of dual coagulants containing chitosan and different Al species in coagulation and ultrafiltration process

The objective of this study was to investigate the effect of different Al species and chitosan (CS) dosages on coagulation performance, floc characteristics (floc sizes, strength and regrowth ability and fractal dimension) and membrane resistance in a coagulation–ultrafiltration hybrid process. Results showed that different Al species combined with humic acid in diverse ways. Al_a had better removal efficiency, as determined by UV₂₅₄ and dissolved organic carbon, which could be further improved by the addition of CS. In addition, the optimal dosage of different Al species was determined to be 4.0 mg/L with the CS concentration of 1.0 mg/L, by orthogonal coagulation experiments. Combining Al_a/Al_b/Al_c with CS resulted in larger flocs, higher recovery, and higher fractal dimension values corresponding to denser flocs; in particular, the floc size at the steady state stage was four times larger than that obtained with Al species coagulants alone. The results of ultrafiltration experiments indicated that the external fouling percentage was significantly higher than that of internal fouling, at around 85% and 15%, respectively. In addition, the total membrane resistance was significantly decreased due to CS addition.     

人工替代栖息地对长江口湿地的补充作用研究

利用恢复生态学和景观生态学原理构建人工替代栖息地是恢复和重建生物栖息地环境的重要手段之一,是用于滨海河口区修复或重建滩涂湿地等栖息地的一种替代方法。人工替代栖息地构建出了接近自然原貌的人工系统,创造一种湿地植被和湿地动物可以协调共存的生境,不仅可以为鸟类资源和渔业资源提供良好的栖息环境,其中多样化组合的植被群落在滨水景观、水质净化等方面也起到了重要的作用,对长江口自然湿地的恢复和自然保护区的动态管理具有不可忽视的补充作用。在迁徙鸟类重要中转驿站,珍稀或者经济鱼类的洄游通道,特殊价值的重要湿地景观格局以及水资源战略储备区域中布局人工替代栖息地,可以发挥其对长江口湿地的补充作用,使高度开放而又极为敏感的长江河口地区循着生态健康道路发展。     

白塔堡河不同粒级有机物的三维荧光特征解析

利用三维荧光扫描(3DEEM)和体积积分法(FRI),分析了辽河流域白塔堡河在春汛期水中溶解性有机物(DOM)、小粒径有机物(0.22~0.7μm)和大粒径有机物(>0.7μm)的分布。结果显示:白塔堡河中有机物以芳香类蛋白质和溶解性微生物代谢产物为主,腐植酸类物质含量极少;5类组分在不同粒径有机物中分布相似,在0.22μm以下的DOM中分布最多;溯源分析显示,DOM来源较单一,表现出较强的内源生物降解特性,而颗粒状有机物则表现出内源和陆源的双重特性;多元统计分析显示,白塔堡河点位有机物分布基本上呈现区域性分布特征。     

国外化学品环境管理中关于商业保密信息的实践及其对中国的借鉴

化学品环境管理实践中,化学品危害特性和暴露评估相关数据涉及的化学品所有者的商业保密信息(CBI)是管理部门和企业重点关注的焦点之一.通过信息的公布,可以让公众了解化学品的有毒有害特性,提前防范其环境和健康风险,实现管理目标,但同时也可能影响化学品企业的商业利益、竞争地位和技术优势,损害企业的利益.美国和欧盟的化学品管理法规均对CBI提出了规定和要求,其管理实践对完善中国化学品环境管理中保密信息的管理具有积极的借鉴意义.     

江门市燃生物质成型颗粒锅炉的排污现状与对策研究

生物质成型颗粒是《江门市能源发展"十三五"规划》中着力发展的能源之一.根据江门市燃生物质成型颗粒锅炉当前的使用状况和排污情况,分析总结了造成颗粒物和氮氧化物超标的原因主要为锅炉内部结构、燃烧操作以及燃生物质成型颗粒质量等.在此基础上,探讨改善江门市燃生物质成型颗粒锅炉污染的对策,提出了科学定位生物质成型颗粒,促进行业健康发展,加快各相关企业升级改造,藉此也为其他地区的燃生物质成型颗粒锅炉提供参考.     

单次降水对高寒草地温室气体通量昼夜变化的影响研究

在全球变化背景下,青藏高原降水格局发生改变,并影响高寒草地温室气体排放.为了更好地认识降水变化与高寒草地温室气体排放的关系,在2015年7月24日,通过人工降水6.7 mm,研究了单次降水对高寒草地温室气体昼夜变化的影响.表明:(1)单次降水没有改变土壤温度,但显著增加了土壤湿度;(2)单次降水后24小时内,高寒草地CH4吸收量降低了2.46倍,CO2和N2 O排放量分别提高15.3%和98.9%;(3)单次降水弱化了高寒草地CH4和N2 O排放量与土壤温度的关系.