循环冷却水水垢中锌含量测定优化实验研究

对工业循环冷却水水垢中锌含量的测定方法进行了系统优化,主要考察了样品酸度、缓冲溶液添加量、试剂时效性、样品中铁离子量、掩蔽剂量和滴定剂浓度对锌含量检测效果的影响。结果表明:样品酸度控制在pH=4.9~5.1范围内,乙酸-乙酸钠缓冲溶液添加量为30 m L时,锌含量检出值最大,指示剂灵敏度最佳;试剂乙酸-乙酸钠在20 d内使用、二甲酚橙指示剂即配即用对滴定终点的判断效果较好;锌含量测定前应先检测样品中铁离子含量,若铁离子≥40%则应先沉淀过滤后方可进行测定;锌含量检出值随掩蔽剂添加量呈先升后降的趋势,并在3.2 g时滴定效果最佳;滴定剂浓度为0.010 mol/L时锌含量检出值最高;优化实验测定结果接近真实值,方法准确可靠。     

生态文明建设视角的当代中国旅游地理创新探索

推进生态文明、建设美丽中国,进而实现中华民族伟大复兴的中国梦,已成为中国共产党及其所领导的中国人民的最大追求和奋斗目标.一直为国民经济主战场服务的中国旅游地理,生态文明建设必然为其教材建设的主体内容之一.该文结合《中国旅游地理》(第四版)创新实际,仅就中国旅游地理推进生态文明建设教学内容体系构建及其构架进行了探索.参9.     

建设项目竣工环境保护验收监测报告必须阐明的内容

建设项目竣工环境保护验收监测报告是检验建设方落实环保“三同时”制度的技术手段,也是环保部门依法管理的技术支撑和依据,竣工验收监测报告除遵循行业技术规范要求外,建设内容变更、环保设施落实、污染物排放及总量、环境质量影响等成为不可或缺的重要内容,需要逐一阐述明确。     

外源水对碳酸盐侵蚀速率研究——以桂林毛村地下河为例

本文对桂林毛村地下河流域,进行了野外监测与室内分析研究,详细研究了外源水与岩溶水对碳酸盐岩侵蚀速率差异。研究结果表明,碳酸盐岩在岩溶水与外源水中的侵蚀速率存在较大差异,雨季碳酸盐岩侵蚀速率:外源水外源水补给的岩溶水岩溶水空气;旱季碳酸盐岩溶蚀速率:外源水外源水补给的岩溶水空气岩溶水;外源水中的灰岩侵蚀速率白云岩侵蚀速率;碳酸盐岩试块的侵蚀速率具有明显的季节变化,主要受控于方解石饱和指数、pH值与水动力条件。     

巴里富碳酸盐硫化物尾矿中重金属的赋存状态

本文以广西大厂锡石-硫化物矿区巴里尾矿库的富碳酸盐尾矿(堆放了20余年)作为研究对象,采用BCR三步提取法研究Zn、Cd、Pb和As的化学形态分量以及其总含量在该尾矿铅垂剖面中的分布,并结合尾矿的结构构造、次生和原生矿物成分及其变化等分析,探讨在氧化/酸化条件下富碳酸盐尾矿中重金属的释放机制。研究结果表明:(1)尾矿下层原尾矿中重金属主要以稳定或较稳定的残渣态(As、Pb、Zn、Cd)、氧化物结合态(Pb)及硫化物结合态(Zn、Cd)形式赋存。在酸水淋滤作用下,原尾矿中重金属的释放顺序为Cd≈ZnPbAs;(2)尾矿上部厚层状氧化硬层(厚度1~1.5m)中,Zn、Cd以酸可溶态大量富集,具有较强的迁移性;As、Pb主要以残渣态以及氧化物结合态赋存,其迁移性较差。因此,富含碳酸盐的硫化物尾矿经过氧化作用具有释放多种重金属的潜能。由于这类尾矿中各重金属的赋存状态存在差异性,因此对其迁移性及环境效应须具体分析。     

合肥市区典型景观水体氮磷污染特征及富营养化评价

为掌握合肥市环城河水系水环境状况,于2012年9月~2013年7月,在城区选取6个典型景观水体测定水体理化指标和叶绿素浓度,开展水体氮磷污染特征分析及富营养化评价,结果表明:①各水体氮、磷污染较为严重,TN和TP月平均浓度均远超过国际认可的发生水体富营养化临界值;②南淝河、黑池坝和雨花塘水体氮浓度表现出显著的逐月变化性,南淝河水体TP和PO3-4-P一直在较高浓度状态下波动,而银河公园水体则呈现显著的上升趋势;③雨花塘与黑池坝水体TN/TP比平均值分别为104.7和158.3,包河公园、银河公园、逍遥津公园和南淝河水体分别为16.8、18.7、6.4和16.8,表明雨花塘、黑池坝水体处于磷限制性状态,逍遥津公园为氮限制性状态;④聚类分析将6个景观水体聚为两大类,即污染严重的黑池坝和南淝河归为一类,其余4个相对封闭的水体为另一类;⑤营养状态指数评价结果表明,所有水体均处于富营养化状态,且富营养化程度排序为:银河公园>黑池坝>南淝河>逍遥津公园>雨花塘>包河公园.     

Groundwater NO3 and F Contamination Processes in Pushkar Valley, Rajasthan as Reflected from 18O Isotopic Signature and 3H Recharge Studies

Agricultural activity in the Pushkar Valley, Rajasthan is constrained due to limited availability of good quality water. In this context, occurrence of nitrate and fluoride in the groundwater was investigated and reported. Integration of stable isotope (18O) data with recharge characteristics (based on 3H-tracer studies) helps in clearly characterizing the processes controlling contamination by point and non-point sources. High nitrate and fluoride groundwaters are associated with high 18O waters. This indicates that significant quantities of evaporated (isotopically enriched) surface run-off water and rain water infiltrate along with nitrate and fluoride salts in the soil. The applicability of this approach under different hydrometeorological conditions is also confirmed.     

可燃性气体含氧量安全限值的探讨

焦炉煤气的安全含氧量目前存在一些异议。由此,提出如何确定可燃性气体含氧量安全限值的问题。笔者提出了惰性气体对含氧量安全限值的影响,探讨了采用化学计算法和作图法能对可燃性气体含氧量作简单确定,用此方法确定焦炉煤气的含氧量安全限值为４％ 。笔者认为,焦炉煤气的安全氧含量可适当放宽,以２％ 为参考值。     

GEOCHEMICAL INTERPRETATIONS OF GROUNDWATER FLOW SYSTEMS1

ABSTRACT. Interest in the geochemistry of groundwater is increasing owing to the great number of current projects involving underground liquid waste storage, artificial recharge of potable water, accidental contamination of groundwater bodies, sanitary landfills, and pollution monitoring. Geochemical techniques used to facilitate the understanding of a groundwater system range from extremely simple to those requiring sophisticated theories, equipment, and procedures. An interpretation of the simple trilinear diagram for samples collected from the Yucatan Peninsula of Mexico provided evidence that the fresh-water body was only a few tens of meters thick and was underlain everywhere by an extensive body of salt water. A geochemical technique that has been used effectively to identify the source of salt water in coastal aquifers is measurement of the carbon-14 concentrations. Carbon-14 has been used in a regional carbonate aquifer to determine the velocity of groundwater movement, rates of chemical reactions, and distribution of hydraulic conductivity. The application of principles of irreversible thermodynamics to groundwater systems provides a basis for constructing models which permit prediction, over both time and space, of changes in head distribution and chemical character of the water resulting from imposed stresses on the system. In essence, proper application of irreversible thermodynamics combines the potential theory of Hubbert with principles of reversible chemical thermodynamics, such as solution of carbonate minerals, to describe and explain controlling chemical reactions and processes of groundwater systems.     

Comparison of the Vegetation and Seed Bank on Hedge Banks of Different Ages in Brittany,France

The composition of the herbaceous cover and the seed bank of old and recent hedge banks in Brittany were studied and compared. Concentration method was used for seed bank samples. Grimes plant strategies were used to explain observed patterns. The analysis of the seed bank of these hedge banks showed that the species richness and diversity differed in relation to the date of construction of the hedge banks. The seed banks of recent hedge banks were richer and more diversified than those of old hedge banks. Differences in the floristic composition of the established plant cover between the recent and old hedge banks were determined by multivariate analyses. The species exclusively found in the seed bank and in the herb cover of recent hedge banks were mainly grassland species, whereas the species that only occurred on old hedge banks tended to be woodland species. The floristic composition of the two compartments (established vegetation and seed bank) was very different. A multivariate analysis revealed that the difference between the composition of the seed banks of recent and old hedge banks was less than that between the composition of the established vegetation and seed bank of hedge banks of the same age. Both seed bank and vegetation of recent hedge banks were dominated by ruderal species, whereas old hedge vegetation was dominated by stress-tolerant woodland species, indicating that mechanically constructed hedge banks may impose limitations on colonization by late woodland species.