环评监测现场采样中应注意的问题

根据环境影响评价监测的要求,提出了环评监测中方案的细化、点位布设方面存在的问题,阐述了如何合理设置监测点位、准确把握采样方法、科学选择分析方法等问题。     

黑岱沟露天矿排土场不同植被配置土壤水分研究——土壤水分垂直动态研究

文章通过黑岱沟露天煤矿排土场不同植被配置土壤水分垂直动态研究,阐述了不同植被配置类型对土壤水分的影响。结果显示：9种植被配置类型的土壤台水量随土层深度的增加而减小,但变化幅度有差异;原生植被处的土壤水分利用层厚度大于人工植被。     

周口店地质遗迹保护现状分析及对策建议

周口店地区地质遗迹丰富,在考古界和地质界都拥有极高的地位.通过实地考察,发现目前的保护中存在很多问题,如开山采石破坏了有价值的地质遗迹、众多水泥厂排放的烟尘污染了空气等,笔者针对存在的问题,提出了加强立法、严格执法、保护第一、积极开发、充分发挥其旅游文化价值等一系列方案措施;对比较典型突出的问题,提出了具体解决方案,希望以此唤起社会的进一步重视,以更好保护这一人类共有的财富.     

Effect of soil moisture dynamics on dense nonaqueous phase liquid (DNAPL) spill zone architecture in heterogeneous porous media

The amount, location, and form of NAPL in contaminated vadose zones are controlled by the spatial distribution of water saturation and soil permeability, the NAPL spill scenario, water infiltration events, and vapor transport. To evaluate the effects of these processes, we used the three-phase flow simulator STOMP, which includes a new permeability-liquid saturation-capillary pressure (k-S-P) constitutive model. This new constitutive model considers three NAPL forms: free, residual, and trapped. A 2-D vertical cross-section with five stratigraphic layers was assumed, and simulations were performed for seven cases. The conceptual model of the soil heterogeneity was based upon the stratigraphy at the Hanford carbon tetrachloride (CT) spill site. Some cases considered co-disposal of NAPL with large volumes of wastewater, as also occurred at the Hanford CT site. In these cases, the form and location of NAPL were most strongly influenced by high water discharge rates and NAPL evaporation to the atmosphere. In order to investigate the impact of heterogeneity, the hydraulic conductivity within the lower permeability layer was modeled as a realization of a random field having three different classes. For six extreme cases of 100 realizations, the CT mass that reached the water table varied by a factor of two, and was primarily controlled by the degree of lateral connectivity of the low conductivity class within the lowest permeability layer. The grid size at the top boundary had a dramatic impact on NAPL diffusive flux just after the spill event when the NAPL was present near the ground surface. NAPL evaporation with a fine grid spacing at the top boundary decreased CT mass that reached the water table by 74%, compared to the case with a coarse grid spacing, while barometric pumping had a marginal effect for the case of a continuous NAPL spill scenario considered in this work. For low water infiltration rate scenarios, the distribution of water content prior to a NAPL spill event decreased CT mass that reached the water table by 98% and had a significant impact on the formation of trapped NAPL. For all cases simulated, use of the new constitutive model that allows the formation of residual NAPL increased the amount of NAPL retained in the vadose zone. Density-driven advective gas flow from the ground surface controlled vapor migration in strongly anisotropic layers, causing NAPL mass flux to the lower layer to be reduced. These simulations indicate that consideration of the formation of residual and trapped NAPLs and dynamic boundary conditions (e.g., areas, rates, and periods of different NAPL and water discharge and fluctuations of atmospheric pressure) in the context of full three-phase flow are needed, especially for NAPL spill events at the ground surface. In addition, NAPL evaporation, density-driven gas advection, and NAPL vertical movement enhanced by water flow must be considered in order to predict NAPL distribution and migration in the vadose zone.     

土压平衡矩形顶管施工引起的地表沉降规律研究

为了分析与掌握矩形顶管施工引起的地表沉降变形规律,提出基于MIDAS-GTS有限元软件的分析方法,首先,通过工程实例验证MIDAS-GTS有限元软件在分析顶管施工引起地表沉降变形的有效性;其次,通过影响因素的敏感性分析确定不同影响因素作用下的地表沉降变形特性,这些影响因素主要包括开挖面支护压力、侧摩阻力、地层结构特性等;最后,通过地表沉降变形特性分析得出矩形顶管的适用范围。研究结果表明:基于MIDAS-GTS有限元软件的地表沉降规律分析方法和结果,可为矩形顶管施工过程提供相关参考和借鉴。     

Characterization of peroxyacetyl nitrate (PAN) under different PM2.5 concentration in wintertime at a North China rural site

As a secondary pollutant of photochemical pollution, peroxyacetyl nitrate(PAN) has attracted a close attention. A four-month campaign was conducted at a rural site in North China Plain(NCP) including the measurement of PAN, O₃, NO_x, PM_2.5, oxygenated volatile organic compounds(OVOCs), photolysis rate constants of NO₂ and O₃ and meteorological parameters to investigate the wintertime characterization of photochemistry from November 2018 to Fe...     

基于ALOHA软件的某化工厂选址合理性评估

为了研究化工厂选址的合理性,以山东省某化工厂为例,采用ALOHA(有害大气空中定位软件)模拟软件定量确定厂区内环氧乙烷毒气扩散事故的影响区域和敏感点毒气浓度,结合GoogleEarth地图对影响范围进行实地拟合。结果表明化工厂的环氧乙烷储罐泄漏后,毒气扩散到厂区范围之外,毒气浓度在50~500ppm之间的重伤区(ERPG-2)扩散距离可达1.7km,对周围居民的人身安全构成严重威胁;厂区应根据拟合结果重新规划工厂中环氧乙烷储罐的位置;ALOHA软件对化工厂选址评价提供了新的手段。     

某基岩区工业固体废物填埋场地递进式场地环境调查实例

针对某基岩区简易封场后的固体废物填埋场,采用多层次、递进式调查策略,配合使用地球物理探测、直压式土壤快速取样、现场快速检测等技术,分3个阶段开展填埋场及其周边环境调查。第1阶段,调查地质环境特征,开展地球物理探测;第2阶段,调查填埋物、渗滤液主要组分及对周边积水、农田土壤、民用井水的污染情况;第3阶段,划定重点污染区域,开展土壤和地下水污染调查。调查结果显示,填埋区已发生明显渗漏,对邻近区域土壤、地下水及地表积水造成了一定污染,但未对周边农用地土壤、民用井水质等产生不利影响,总体处于可控范围。提出,通过削减污染源,切断污染物迁移、暴露途径,消除已有污染影响,长期跟踪监测等多项管控治理措施进行综合整治。     

Evaluation Of Ambient Air Pollution Impact On Carrot Plants At A Sub Urban Site Using Open Top Chambers

The present experiment was done to evaluate the impact of ambient air pollution on carrot (Dacus carotavar. Pusa Kesar) plants using open top chambers (OTCs) ventilated with ambient (NFCs) or charcoal filtered air (FCs) at a suburban site of Varanasi, India. Various morphological, physiological and biochemical characteristics of the plants were studied at different growth stages. Air monitoring data clearly showed high concentrations of SO₂, NO₂and O₃in the ambient air of study site. SO₂and NO₂concentrations were higher during early growth stages of carrot, whereas O₃concentration was highest during later growth stages. Filtration of air has caused significant reductions in all the three pollutant concentrations in FCs as compared to NFCs.Plants growing in FCs showed significantly higher photosynthetic rate, stomatal conductance, water use efficiency and variable fluorescence as compared to plants growing in NFCs. Protein content also showed a similar pattern, however, lipid peroxidation, ascorbic acid content and peroxidase activity were higher in plants growing in NFCs as compared to FCs. Shoot length, number of leaves per plant, leaf area and root and shoot weight increased significantly upon filtration of ambient air. Total nitrogen decreased significantly in root, but increased significantly in shoot of plants grown in NFCs. Total P, Mg, Ca and K contents decreased significantly in plants grown in NFCs as compared to FCs. The individual pollutant concentrations were below threshold for plant injury, but the combined effect of all the three seems to act synergistically in causing greater adverse impact on dry weight and physiology of carrot plants. The study clearly indicates that air pollutants are high enough in the ambient air to cause significant unfavorable impact on carrot plants. The work further supports the usefulness of OTCs for assessing air pollution damage under field conditions in developing countries.     

鼠李糖脂洗脱氯丹和灭蚁灵污染场地土壤的工艺参数

优化了鼠李糖脂洗脱氯丹、灭蚁灵污染土壤的工艺条件,为开展有机氯农药污染场地土壤洗脱修复工程实践提供科学依据和技术参数。实验结果表明,随着洗脱剂———鼠李糖脂浓度的增加,氯丹和灭蚁灵的洗脱量呈现先增加后降低的趋势;洗脱时间和液固比对洗脱效果的影响趋势与浓度相同;在0~120 r/min范围内,氯丹和灭蚁灵洗脱量随着搅拌速度的增加而增大,80、120和200 r/min的洗脱量间差异不显著;单次洗脱量随洗脱次数的增加而降低,累计洗脱量则逐渐增大。综上所述,氯丹、灭蚁灵污染场地土壤鼠李糖脂洗脱的适宜工艺参数为鼠李糖浓度10 mmol/L,搅拌速度80 r/min,固液比1∶10,洗脱时间20 min,洗脱3次。