涪陵页岩气开发主要环境风险分析及对策研究

涪陵国家级页岩气示范区取得重大突破对中国页岩气行业产生了重大影响,但开发过程中的环境风险也不容忽视,主要包括:钻井液漏失、废水污染物、固体废物等.对此,涪陵示范区创新环境管理模式,通过构建完善的环境管理体系、优化井场选址、强化井场标准化建设、细化污染防治措施、开展环境监理工作、强化日常环境监测、加强新技术研究与应用等手段,有效的控制了页岩气开发过程中的环境风险,较好的保护了当地的环境,具有很好的示范和推广作用.     

臭氧对颗粒物中有机组分形成的关键作用

基于2019年10月广东省鹤山大气超级监测站的观测数据分析了臭氧浓度特征与单颗粒气溶胶中的有机物组分.结果表明,PM_2.5中OC的含量显著大于EC,OC/EC比值为0.7～10.4,其中,OC/EC>2的比例占91%,表明有机碳主要来自二次生成.高臭氧浓度下二次组分(Sec)单颗粒和老化有机无机碳(ECOC-aged)单颗粒的数浓度显著增加,Sec和ECOC-aged单颗粒中含乙酸根(⁵⁹CH₃CO₂^-)和乙醛酸(⁷³C₂HO₃^-)的单颗粒数浓度呈单峰分布,两种有机单颗粒的增加都发生在下午臭氧浓度升高光化学反应较强的时段,表明大气氧化性增强有利于含氧有机物的生成.此外,Sec单颗粒中两种有机单颗粒的峰值出现在16:00,而ECOC-aged单颗粒中两种有机单颗粒的峰值出现在18:00之后,这种差异产生的原因可能与含氧有机物氧化形成的过程有关,ECOC-aged粒子中的含氧有机物主要来自...     

垃圾渗滤液污染羽中的最终电子受体作用研究

通过土柱模拟实验研究了最终电子受体和TOC在垃圾渗滤液污染羽各氧化还原带中的变化规律,并建立了相应的模型.结果表明,各种还原产物出现峰值的时间和相应的最终电子受体利用最终电子的能力有一定的关系,利用电子能力强的最终电子受体其还原产物出现急剧升高的时间较早,如NO-2出现峰值的时间比Fe2 早;TOC的浓度在产甲烷带、硫酸盐还原带、铁还原带、硝酸盐还原带和氧还原带中不断增加,增加速率分别为8.27、8.56、8.85、9.06和9.11 mg/(L·h).不同种类的微生物降解污染物的速度受最终电子受体的多少和有效性的限制,其反应速度和最终电子受体利用最终电子的能力大小相一致,也就是说,利用最终电子能力越强的最终电子受体越容易被微生物利用、消耗,对污染的反应也就越灵敏.     

北京市饮用水源水重金属污染物健康风险的初步评价

对北京市城区8个区和郊区10个区、县120个样点的饮用水中Cu, Hg, Cd和As的浓度进行了调查研究,并应用目前美国环保局推荐的健康风险评价模型对北京市各区县饮用水中重金属所引起的健康风险作了初步评价.结果表明,城区8个区和郊区10个区、县重金属的平均浓度范围分别为Cu:0.81～6.96 μg·L^-1,Cd: 0.34～0.82 μg·L^-1,Hg: 0.10～0.74 μg·L^-1,As: 0.19～3.02 μg·L^-1.通过饮水途径所致健康风险中,As在通州区所引起的致癌风险最大(2.0×10^-5·a^-1),Cd在昌平区的致癌风险最大(2.3×10^-6·a^-1), 但均低于国际辐射防护委员会(ICRP)推荐的通过饮水途径最大可接受风险水平(5×10^-5·a^-1);在北京市通过饮水途径引起的非致癌健康风险中,Hg的风险最大,Cu次之,但是两者风险水平均在10-8～10^-9·a^-1,远低于ICRP推荐的最大可接受风险水平.     

基于水足迹的山东省水资源可持续利用时空分析

以人均水资源占有量低、水资源利用结构不平衡省份山东省为研究区,首先计算2005—2014年山东省水足迹及2014年17地市水足迹,实现水足迹时空分析;从DPSIR视角出发,基于水足迹计算结果,融合构建水资源可持续利用评价指标体系,通过因子综合得分来反映全省10 a间水资源可持续利用强度,以2014年为水平年,对17地市因子综合得分进行空间聚类,实现水资源可持续利用时空分析。结果表明：研究区2005—2014年水资源可持续利用综合评价得分呈现增长态势,表明水资源可持续利用程度趋于加强,但分值总体较低,仍需提高利用效率;2014年17地市水资源可持续利用水平整体呈现东优西劣、南优北劣的空间格局。     

Developing chemical signatures of particulate air pollution in the Pearl River Delta region, China

PM2:5 samples were collected in a regional sampling network with three sites in Hong Kong and four sites in the adjacent inland Pearl River Delta (PRD) or Guangdong Province during four months/seasons from 2002–2003. Trans-boundary transport between Hong Kong and the inland PRD is inevitable under the influence of Asian monsoon. In summer, Hong Kong serves as the upwind site of the inland PRD while during other seasons it is under the influence of continental emissions. Previous studies have recognized the importance of using chemical signatures to differentiate local vs. regional contributions to air pollutants in Hong Kong such as the CO/NOx ratio, ratios of different VOC species. In this study, detailed chemical speciation by gas chromatography-mass spectrometry was performed with PM2:5 samples to identify new chemical signatures to distinguish aerosols in Hong Kong from those from the inland PRD. Since Hong Kong is not influenced by the continental emissions from the inland PRD during summer, comparison focused on chemical data obtained from this season for chemical signatures. The new ratios developed from the current study include LCPI/HCPI ratio of alkanes (0.39 0.02 in Hong Kong vs. 0.78 0.08 in the inland PRD), pyrene to benzo[ghi]perylene ratio (0.97 0.21 in Hong Kong compared to 0.20 0.06 in the inland PRD), and the ratio of 1,2-benzenedioic acid to 1,4-benzenedioic acid (1.8 0.1 in Hong Kong vs. 0.6 0.05 in the inland PRD). Results from this study also revealed that Hong Kong was impacted by ship emissions as reflected by substantially high V/Ni ratio (9 2) while this ratio was about 1–2 at all sites in the inland PRD, which is very close to typical ratios from residual oil combustion.     

Effects of surfactants on the combined toxicity of TiO2 nanoparticles and cadmium to Escherichia coli

The combined ecological toxicity of TiO₂ nanoparticles (nano-TiO₂) and heavy metals has been paid more attention. As the common pollutants in water environment, surfactants could affect the properties of nanoparticles and heavy metals, and thus further influence the combined toxicity of nano-TiO₂ and heavy metals. In this study, the effects of sodium dodecyl benzene sulfonate (SDBS) and Tween 80 on the single and combined toxicities of Cd^2 + and nano-TiO₂ to Escherichia coli (E. coli) were examined, and the underlying influence mechanism was further discussed. The results showed both SDBS and Tween 80 enhanced the toxicity of Cd^2 + to E. coli in varying degrees. The reaction of SDBS and Cd^2 + could increase the outer membrane permeability and the bioavailability of Cd, while Tween 80 itself could enhance the outer membrane permeability. The combined toxicity of nano-TiO₂ and Cd^2 + to E. coli in absence of surfactant was antagonistic because of the adsorption of Cd^2 + to nano-TiO₂ particles. However, in the presence of SDBS, both SDBS and nano-TiO₂ influenced the toxicity of Cd^2 +, and also SDBS could adsorb to nano-TiO₂ by binding to Cd^2 +. The combined toxicity was reduced at Cd^2 + lower than 4 mg/L and enhanced at Cd^2 + higher than 4 mg/L under multiple interactions. Tween 80 enhanced the combined toxicity of nano-TiO₂ and Cd^2 + by increasing the outer membrane permeability. Our study firstly elucidated the effects of surfactants on the combined toxicity of nano-TiO₂ and Cd^2 + to bacteria, and the underlying influencing mechanism was proposed.     

基于连续监测的城市内河返黑返臭机制初探:以南宁市二坑溪为例

黑臭水体严重危害城市生态功能,"水十条"的颁布为实现城市黑臭水体的污染整治目标制定了时间表.城市黑臭水体治理过程中,大量治理后的水体出现返黑返臭现象.为研究这一现象的原因,采用多参数水质检测仪和化学分析方法,对治理后返黑返臭的南宁市二坑溪水体进行了24 h连续监测和月度动态监测.结果表明,降雨过程与水体氨氮浓度相关性显著(P0.01),气温与水体氨氮浓度变化趋势正相关(r=0.23,P0.05),与水体透明度变化趋势负相关(r=-0.33,P0.01),显示治理后水体返黑返臭与内源污染物的微生物降解和外源污染物的输入有关.综上,为了防止治理后的城市黑臭水体返黑返臭,应当关注河道底泥等内源污染物及其控制技术,综合采取生态治理手段减少外源污染物输入,才能最终实现城市黑臭水体长效治理.     

纱帽山不同海拔大气氮湿沉降通量差异及递变规律的数学模拟

通过对毕节市七星关区城郊纱帽山不同海拔大气沉降进行采样,检测了湿沉降中的水溶性总氮、铵态氮、亚硝态氮和硝态氮等指标.结果表明：①采样点位总氮湿沉降通量随海拔升高呈明显下降趋势,海拔每升高1 km年均垂直递减梯度为5.43 kg·hm^-2·a^-1.冬季山顶通量占最低海拔样点通量均值的29.23%,而夏季为87.80%.这是由季节性降水差异所导致的,夏季雨水冲并作用使得大气气溶胶浓度为全年最低（冬季最高）,因此,在有限海拔高度内垂直梯度在夏季最小而冬季最大.②各路径不同程度地出现了沉降峰值带（步梯路除外）,这与下垫面污染气体的垂直扩散有关.以车辆尾气为污染源,借助高斯模式推导其最大浓度出现的高度为56.11 m,而实测峰值带为理论计算高度的2~3倍,这与污染物扩散条件复杂及经验公式的非普适性有关.③铵态氮和硝态氮为无机氮的主要形式,亚硝态氮仅占9.04%,且冬季沉降量最大,这与氨氧化细菌在应对低温等不利环境方面有更强的适应性有关.④借助指数模型模拟了氮的湿沉降通量随海拔高度的递变规律,拟合公式为M=15.2534k·exp（-0.00079602x）,随机检验拟合程度较高,具有实际应用价值和推广前景.     

树脂吸附-耐盐菌生化组合工艺处理含酚、高含盐农药废水

结合工程实例,介绍了大孔树脂吸附预处理及耐盐菌水解酸化-接触氧化工艺在处理含酚、高含盐农药废水处理工程中的实际应用。运行结果表明,该工艺可回收废水中大部分酚类,能够耐受较高的含盐量,运行稳定,处理效果好,各项出水指标均能达GB 8978—1996《污水综合排放标准》三级排放标准。