Analytical methods and environmental processes of nanoplastics

The degradation of plastic debris may result in the generation of nanoplastics (NPs). Their high specific surface area for the sorption of organic pollutions and toxic heavy metals and possible transfer between organisms at different nutrient levels make the study of NPs an urgent priority. However, there is very limited understanding on the occurrence, distribution, abundant, and fate of NPs in the environment, partially due to the lack of suitable techniques for the separation and identification of NPs from complex environmental matrices. In this review, we first overviewed the state-of-the-art methods for the extraction, separation, identification and quantification of NPs in the environment. Some of them have been successfully applied for the field determination of NPs, while some are borrowed from the detection of microplastics or engineered nanomaterials. Then the possible fate and transport of NPs in the environment are thoroughly described. Although great efforts have been made during the recent years, large knowledge gaps still exist, such as the relatively high detection limit of existing method failing to detect ultralow masses of NPs in the environment, and spherical polystyrene NP models failing to represent the various compositions of NPs with different irregular shapes, which needs further investigation.     

Reviews of emission of biogenic volatile organic compounds (BVOCs) in Asia

Biogenic volatile organic compounds (BVOCs) in the atmosphere play important roles in the formation of ground-level ozone and secondary organic aerosol (SOA) in global scale and also in regional scale under some condition due to their large amount and relatively higher reactivity. In places with high plant cover in the tropics and in China where air pollution is serious, the effect of BVOCs on ozone and secondary organic aerosols is strong. The present research aims to provide a comprehensive review about the emission rate, emission inventory, research methods, the influencing factors of BVOCs emissions, as well as their impacts on atmospheric environment quality and human health in recent years in Asia based on the summary and analysis of literatures. It is suggested to use field direct measurement method to obtain the emission rate and model method to calculate the emission amount. Several recommendations are given for future investigation and policy development on BVOCs emission.     

生物炭复合青霉菌修复砷污染土壤对其微生物群落功能多样性的影响

真菌修复砷污染土壤是一种能够有效吸附固化环境中砷的重要措施.生物炭作为目前修复重金属的热点,其多空疏松的结构、较高的离子交换量、丰富的有机碳含量等都说明了其在土壤修复中的地位.为了探究生物炭与青霉菌在修复砷污染土壤的同时对土壤中微生物活性及其多样性的影响,在室内孵育条件下,运用Biolog法研究了3×3随机区组试验（3个生物炭梯度分别为0%、2%、4%,3个青霉菌梯度分别为0%、10%、20%）下土壤微生物对不同类型碳源的利用能力以及多种功能性指数的影响.结果表明:①添加青霉菌与生物炭后,土壤中有效砷含量较对照组显著下降,从而影响其微生物群落功能多样性.②砷污染土壤中微生物群落功能多样性、碳源利用丰富度随生物炭浓度梯度的升高呈先升后降的趋势.③高接菌量（20%）与低接菌量（10%）对砷污染土壤中微生物群落功能多样性的影响没有显著性差异.④2%生物炭与10%青霉菌处理土壤中微生物群落功能多样性、碳源利用丰度最高.⑤青霉菌对胺类及少部分酸类碳源的利用能力较弱（AWCD < 0.5,AWCD为Biolog微平板孔中溶液吸光值平均颜色变化率）,对氨基酸类中大部分碳源以及脂类碳源的代谢能力较强（AWCD>1.0）,对糖类、酚酸类的代谢能力稍弱（AWCD为0.3~1.0）,青霉菌对D-半乳糖醛酸、L-天冬酰胺酸、L-丝氨酸、L-精氨酸、r-羟基丁酸这5种碳源的利用率最高（AWCD>1.2）.研究显示,低浓度生物炭可增加砷污染土壤中微生物群落多样性,生物炭含量的继续增加会对微生物产生抑制作用;青霉菌添加到砷污染土壤后,会显著提升砷污染土壤中微生物的群落功能多样性,改善砷污染土壤中微生的物群落结构;青霉菌的优势碳源大多为植物根系分泌物,可为后续青霉菌与超积累植物复合修复砷污染土壤提供参考.      

UASB启动运行特征及互营丙酸氧化菌定量分析

为揭示升流式厌氧污泥床（UASB）反应器启动运行效能与互营丙酸降解菌群数量之间的关系,以稀释的玉米淀粉生产废水为底物,考察了UASB启动期的运行特征,并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群（丙酸氧化菌和产甲烷菌）的演替规律.结果表明,在进水COD 2000mg/L和水力停留时间（HRT）24h条件下,经过38d的连续运行,COD去除率达到了91.9%.当HRT分阶段缩短至8h时,比产甲烷速率达到了315LCH₄/（kg COD·d）,且形成了沉降性能良好的颗粒污泥.qPCR检测结果表明,至少有5种已鉴定的丙酸氧化菌存在于UASB反应器中.Pelotomaculum propionicum为接种污泥中的主要丙酸氧化菌,约占检测到丙酸氧化菌总数的45.7%.它的数量随着HRT缩短不断减少.而Syntrophobacter sulfatireducens和S.wolinii的数量随着HRT缩短不断增加,并在启动完成时达到最大值,分别为1.3×10³,5.5×10³个16S rRNA基因拷贝数/ng DNA,演替成为成熟颗粒污泥中的优势丙酸氧化菌群.Methanobacterium和Methanosarcina为接种污泥中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌,其数量随着HRT的缩短而逐渐减少,而Methanospirillum和Methanosaeta的数量随HRT的缩短逐渐增加,成为成熟颗粒污泥中的优势产甲烷菌群.     

天津市河流生态完整性评价

对河流生态健康状况进行评价,可为河流治理和生态修复提供依据.基于2018年8—9月天津市河流现场调查获取的物理、化学和生物群落指标（浮游动物、浮游植物、底栖动物、鱼类、水生大型植物、陆生植物）数据,构建包含物理完整性、化学完整性和生物完整性在内的河流IEI（index of ecological integrity,生态完整性指数）评价体系,对天津市河流生态健康状况进行评价.根据生物栖息地评分和水质状况确定参照点位,采用标准化方法筛选候选指标,应用层次分析法计算三部分指标权重,最终得出天津市河流生态健康评价结果.结果表明:①IEI评价结果显示,天津市河流生态健康状况等级为“健康”的样点占18.8%,“较好”的样点占28.1%,“一般”的样点占40.6%,“较差”的样点占6.3%,“差”的样点占6.3%,天津市河流生态健康状况整体处于“一般”水平.②相关性分析表明,ρ（NH₄+-N）和ρ（COD_Mn）超标是造成天津市水质达不到功能区标准的主要原因,同时也是影响河流生态健康的主要因素.研究显示,IEI评价法能够较为敏感地响应研究区面临的环境压力,适用于评价研究区河流生态健康.      

小型燃煤机组烟气重金属排放特征研究

100 MW以下燃煤机组呈单台容量小、总台数大的特点,是燃煤重金属污染的主要排放源之一.选择7台12 MW燃煤机组,采用美国环境保护局Method 29法现场检测燃煤机组烟气重金属排放浓度,分析烟气中Hg、Pb、Cr、As的排放特征;采集机组产生的飞灰和底灰,分析除尘技术对重金属的富集特性.结果表明:100 MW以下燃煤机组烟气中重金属经脱硝除尘脱硫装置协同控制后,ρ（Hg）为0.20~0.44 μg/m3,烟气Hg以气态形式存在,其占比为100.0%;ρ（Pb）为0.5~2.6 μg/m3,烟气Pb主要以气态形式存在,其占比为38.7%~92.1%;ρ（As）为0.6~3.0 μg/m3,烟气As主要以气态形式存在,其占比为67.8%~100.0%;ρ（Cr）为3.6~23.9 μg/m3,烟气Cr主要以颗粒态形式存在,其占比为65.8%~99.2%.飞灰富集Hg、Pb、Cr、As的能力大于底灰.重金属主要富集于飞灰中的细颗粒物中,采取除尘技术可有效协同控制烟气中的Hg、Pb、Cr、As;飞灰中重金属元素Hg、Pb相对富集系数均与煤中硫含量呈负相关,半干法脱硫+袋式除尘技术对飞灰富集Hg有促进作用.小型燃煤机组烟气重金属Hg、Pb、Cr、As的排放因子分别为0.002 2~0.005 1、5~17、42~160、7~24 mg/t.研究显示,100 MW以下燃煤机组与100 MW及以上燃煤机组烟气重金属Hg、Pb、Cr、As排放特征不同,100 MW以下燃煤机组烟气Hg排放浓度较小,二者烟气Pb、Cr、As排放浓度相近,选用湿式电除尘技术可进一步降低烟气Hg、Pb、Cr、As的排放浓度.      

Can a low-carbon development path achieve win-win development: evidence from China’s low-carbon pilot policy

Mitigation and Adaptation Strategies for Global Change - Low-carbon pilot (LCP) policy aims to not only achieve economic development but also address climate change problems in China. With a...     

Evaluating national hydrogen refueling infrastructure requirement and economic competitiveness of fuel cell electric long-haul trucks

This study explored the national hydrogen refueling infrastructure requirement along major United States (US) interstate highway corridors to support the deployment of fuel cell electric trucks (FCETs) for the national long-haul trucking fleet. Given the long-haul trucking shipment demand in 2025 projected by the Freight Analysis Framework, locations and capacities of hydrogen stations were identified for inter-zone freight flows, and the total daily refueling demand was estimated for intra-zone flows for each FAF zone. Based on the infrastructure deployment results, we conducted an economic feasibility analysis of FCETs by evaluating the total ownership cost. We found that when the FCET penetration is relatively high (e.g., 10% penetration), FCETs become more competitive in terms of fuel cost and idling cost and could be economic viable if the incremental vehicle cost is reduced to meet the near-term FCET technology cost targets and the liquefaction cost is reduced to an optimal case. We also observed that the station cost depends on regional factors, particularly regional demand, which is used to determine station capacity. Thus, one possible strategy for station roll-out is to have early investment in target regions where station costs are expected to be relatively low such as the Pacific and West South Central regions.