基于生态安全格局与生态脆弱性评价的生态修复关键区域识别与诊断——以汶上县为例

以山东省济宁市汶上县为研究区,基于最小阻力模型构建生态安全格局,结合脆弱性评价识别生态修复关键区域,对关键区域分类提出针对性修复保护措施.结果表明在汶上县共识别出11处生态源地,总面积38.72km²,35条生态廊道,总长度259.56km;生态脆弱性分级以中度脆弱与低度脆弱为主,两类型区域总面积594.32km²,占比67.40%.中部城区脆弱性较高,西南洼地脆弱性较低;识别出生态修复关键区域5处,总面积107.14km²,分布于中部城区及周边;根据区位特征将关键区域分为三类,并分类别提出其生态修复策略,以期为国土空间生态修复提供参考.     

Effect of photo-biodegradation and biodegradation on the biogeochemical cycling of dissolved organic matter across diverse surface water bodies

The objective of this research was to quantify the temporal variation of dissolved organic matter(DOM) in five distinct waterbodies in watersheds with diverse types of land use and land cover in the presence and absence of sunlight. The water bodies were an agricultural pond, a lake in a forested watershed, a man-made reservoir, an estuary, and a bay. Two sets of samples were prepared by dispensing unfiltered samples into filtered samples in 1:10 ratio(V/V). The first set was exposed to sunlight(10 hr per day for 30 days) for examining the combined effect of photo-biodegradation, while the second set was stored in dark for examining biodegradation alone. Spectroscopic measurements in tandem with multivariate statistics were used to interpret DOM lability and composition. The results suggest that the agricultural pond behaved differently compared to other study locations during degradation experiments due to the presence of higher amount of microbial humic-like and protein-like components derived from microbial/anthropogenic sources. For all samples, a larger decrease in dissolved organic carbon(DOC) concentration(10.12% ±9.81% for photo-biodegradation and 6.65% ± 2.83% for biodegradation) and rapid transformation of DOM components(i.e., terrestrial humic-like components into microbial humic and protein-like components) were observed during photo-biodegradation experiments.Results suggest that sunlight facilitated DOM biodegradation, resulting in simpler recalcitrant molecules regardless of original composition. Overall, it was found that combined effects of light and bacteria are more efficient than bacterial effects alone in remineralizing and altering DOM, which highlights the crucial importance of sunlight in transforming aquatic DOM.     

PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) in Beijing: Seasonal variations, sources, and risk assessment

Polycyclic aromatic hydrocarbons(PAHs) have been of health concern due to its carcinogenesis and mutagenesis. In this study, we aimed to assess the variations, sources, and lifetime excessive cancer risk(ECR) attributable to PAHs bound to ambient particulate matters with aerodynamic diameter less than 2.5 μm(PM_(2.5)) in metropolitan Beijing, China. We collected24-hour integrated PM_(2.5) samples on daily basis between November 2014 and June 2015 across both central heating(cold months) and non-heating(warm months) seasons, and further analyzed the PAH components in these daily PM_(2.5) samples. Our results showed that total concentrations of PM_(2.5)-bound PAHs varied between(88.6 ± 75.4) ng/m~3 in the cold months and(11.0 ± 5.9) ng/m~3 in the warm months. Benzo[a]pyrene(Ba P), the carcinogenic marker of PAHs,averaged at 5.7 and 0.4 ng/m~3 in the cold and warm months, respectively. Source apportionment analyses illustrated that gasoline, biomass burning, diesel, coal combustion and cooking were the major contributors, accounting for 12.9%, 17.8%, 24.7%, 24.3% and 6.4% of PM_(2.5)-bound PAHs, respectively. The BaP equivalent lifetime ECR from inhalation of PM_(2.5)-bound PAHs was 16.2 cases per million habitants. Our results suggested that ambient particulate reduction from energy reconstruction and adaption of clean fuels would result in reductions PM_(2.5)-bound PAHs and its associated cancer risks. However, as only particulate phased PAHs was analyzed in the present study, the concentration of ambient PAHs could be underestimated.     

Physicochemical analysis of individual atmospheric fine particles based on effective surface-enhanced Raman spectroscopy

Fine particles associated with haze pollution threaten the health of more than 400 million people in China. It is therefore of great importance to thoroughly investigate and understand their composition. To determine the physicochemical properties in atmospheric fine particles at the micrometer level, we described a sensitive and feasible surface-enhanced Raman scattering(SERS) method using Ag foil as a substrate. This novel method enhanced the Raman signal intensities up to 10,000 a.u. for ν(NO_3~-) in fine particles.The SERS effect of Ag foil was further studied experimentally and theoretically and found to have an enhancement factor of the order of ～10~4. Size-fractionated real particle samples with aerodynamic diameters of 0.4–2.5 μm were successfully collected on a heavy haze day,allowing ready observation of morphology and identification of chemical components, such as soot, nitrates, and sulfates. These results suggest that the Ag-foil-based SERS technique can be effectively used to determine the microscopic characteristics of individual fine particles, which will help to understand haze formation mechanisms and formulate governance policies.     

完全混合式曝气系统运行特性及微生物群落结构解析

利用某污水处理厂完全混合式曝气系统处理生活污水,探讨了系统同步硝化反硝化脱氮过程,解析了系统中污泥微生物群落结构.中试试验结果表明,系统运行稳定,且在无外加碳源的条件下,COD、氨氮和总氮平均去除率分别为93.2%、96.9%和75.2%,出水COD、氨氮和总氮均优于一级A排放标准.系统污泥具有较强的反硝化能力,其脱氮速率是污水处理厂污泥的2.86倍以上.通过对系统污泥周质硝酸盐还原酶聚合酶链式反应(polymerase chain reaction,PCR)扩增和高通量测序结果,发现系统中存在好氧反硝化菌,污泥中优势菌为动胶菌属(Zoogloea)、陶厄氏菌属(Thauera)和Dechloromonas菌属.     

天然/模拟海水中2,4,6-三溴苯酚的光化学行为研究

有机溴代苯酚类污染物在水体中普遍存在,尤其在海洋环境中,除人为污染源外,它还存在广泛的天然来源.以2,4,6-三溴苯酚为模型化合物,以氙灯(λ290 nm)作为模拟太阳光源,研究了海水中溴代苯酚的光化学过程,并系统考察了溴代苯酚初始浓度、Cl~-、Fe(Ⅲ)和pH值等环境因素的影响.实验结果表明,在海水中,2,4,6-三溴苯酚能够快速发生光化学反应,通过产物分析发现其主要产物为通过光致脱溴氯代过程产生的2,4-二溴-6-氯苯酚,并且该产物随2,4,6-三溴苯酚初始浓度、Cl~-浓度、Fe(Ⅲ)浓度的增大及溶液pH值的降低而增加.以明亮发光杆菌为受试生物的毒理学实验表明,2,4,6-三溴苯酚在海水中光化学的前期,系统的毒性效应增强,而毒性的增加可能主要由光致氯代过程导致.     

再生水中色度物质的识别及其臭氧去除特性

针对我国再生水普遍存在的色度问题,以天津市某污水厂二级出水为研究对象,采用三维荧光光谱和GC/MS技术对其进行组成分析,结果表明:再生水中主要带色物质为富里酸与腐殖酸类物质,同时还存在偶氮二甲酸二乙酯、N,N-二甲基乙醇胺、苄醚、1,4-二甲基吡啶氯化物等导致再生水色度的带色有机物。在再生水的臭氧降解实验中,臭氧可有效降解再生水中的富里酸与腐植酸类物质,去除率分别达到96.5%、97.3%。臭氧对再生水的色度与CDOM(有色溶解有机物)的降解也表现出了良好的效果,2 min内去除率可分别达到93.1%、86.2%。并且在色度物质的臭氧降解过程中,臭氧的直接反应占据主导地位,而并非与·OH的间接反应。该结果对再生水臭氧氧化工艺的设计应用有现实的指导意义。     

高寒山区典型小流域河流溶解性有机碳输出的年内变化及其成因

高寒山区河流溶解性有机碳(DOC)的输出可能有别于北极、亚北极地区,但却少有人研究。选取青藏高原黑河上游的典型高寒小流域——葫芦沟流域为研究对象,通过流域出口处河水DOC浓度的连续观测,分析了河水DOC输出的季节性变化规律,并探讨了流域水文过程对河水DOC输出的影响。结果表明:河水的DOC通量与河道径流量的变化趋势一致,从冬季至春季逐渐降低,夏季急剧增高,秋季又逐渐降低;河水DOC浓度的变化则恰好相反,冬季时最高,春季时略有下降,夏季时急剧降至最低值,秋季再次增高;河水DOC的输出主要集中在夏、秋两季,7~11月份的输出量占河水DOC年输出总量的80%。各水源和流动路径对河水贡献比例的变化是导致上述季节性差异的深层机制:在夏季,低DOC浓度的冰川融水和山区产流对径流有更高的贡献,故河水具有较低的DOC含量,但因其流量远高于其他季节,故DOC通量为全年最高;秋季至初冬,高DOC浓度的寒甸带冻土层上水对径流贡献比例逐渐增大,导致河水的DOC浓度增高;冬季时,河水全部源于秋季时储存在平原区含水层中的高DOC浓度的地下水,故河水的DOC浓度最高;春季中后期,除秋季时储存起来的地下水外,具有较高DOC浓度和极低溶解性无机碳(DIC)浓度的寒甸带融雪水对河水也有一定贡献,故河水DOC浓度变化不大,但其DIC浓度明显降低。     

高原高寒地域中重型车辆发动机预热起动辅助装置研究

目的提高中重型车辆装备在高原高寒环境下的低温起动性能。方法研制一种适应高原高寒地域低温低气压环境的冷却液加热器,加热器将燃油燃烧产生的热量传递给冷却液,通过冷却液的循环对发动机机体进行预热。结果在低温试验室内-41℃常压环境下,使用冷却液加热器预热25 min后起动发动机,一次起动成功。在高原进行环境适应性试验,预热时间在25 min内,发动机一次起动成功。结论发动机预热可有效提高-30^-41℃温度地域的发动机低温起动性能。     

基于三维成像技术的污泥菌群中抗生素抗性基因转移动态特征研究

应用活细胞三维成像技术,实时和原位观测了活性污泥菌群中抗生素抗性基因转移动态特征.微流控芯片是一种细菌生长的良好载体,活细胞成像系统低光毒性不损伤细菌活性,两者结合能有效实现基因转移的长时间原位观测,能够区分抗性基因的水平转移和垂直转移.结果表明:垂直转移是污泥菌群中抗性基因的主要转移方式,菌群纵向转移速率与其厚度有关,菌群内部转移率较高,基因转移速率为0.24～0.29 h~(-1).