乌海市地下水资源状况及可持续利用对策

乌海市地处西北干旱地区 ,它的地下水资源已被严重超采和污染。为了实现区域经济和生态的可持续发展 ,我们必须采取一系列有效措施来保护有限的地下水资源     

Concentrations of polychlorinated dibenzo‐p‐dioxins and dibenzofurans in outdoor air of North‐Rhine‐Westphalia,Germany

Measurements of polychlorinated dibenzo‐p‐dioxins (PCDD) and dibenzofurans (PCDF) in outdoor air of North‐Rhine‐Westphalia were carried out. Fifty‐six samples were taken at different sites in areas of different land use and emission structures. A special filter system allowed analysis of the gas and particle phases separately. It was found that higher chlorinated PCDD/PCDF (7 or 8 chlorine atoms) are collected on glass fiber filter and lower chlorinated PCDD/PCDF (tetra‐ and penta‐CDD/CDF) are absorbed on polyurethane foam. The following isomers were determined: OCDD, OCDF and 11 isomers with chlorine substitution in 2,3,7,8‐position as well as the sum of TCDD, PeCDD, HxCDD, HpCDD, TCDF, PeCDF, HxCDF, HpCDF and the sum of PCDD (4–8) and PCDF (4–8). No 2,3,7,8‐TCDD could be detected but 2,3,7,8‐TCDF was found at 15 sites. Mean concentration in the Rhine‐Ruhr‐District for the sum of PCDD (4–8) and PCDF (4–8) was 3.2pg/m³ and 5.5pg/m³ respectively. Detection limit for TCDD and PCDD/PCDF (5–8) was 0.1–0.2 pg/m³ and 0.005–0.015 pg/m³ respectively. There is no significant indication that 2,3,7,8‐chlorinated isomers of PCDD/PCDF are predominantly decomposed by photochemical reactions in outdoor air.     

林地大气氮沉降通量观测对比研究

以中国科学院红壤生态实验站森林微气象分站阔叶林为研究对象,采用穿透雨量法和微气象学推论法对该阔叶林地大气氮沉降通量进行了对比研究.结果表明,穿透雨量法观测2006年10月～2007年9月林地NH4+-N干沉降通量为37.66kgN/(hm2.a),NO3--N干沉降通量为18.53kgN/(hm2·a),其中NH4+-N是氮化物干沉降的主要贡献者,占总干沉降的67.0％.该研究方法所得结果与微气象学方法观测结果具有较好的一致性,表明穿透雨量法估算林地氮干沉降通量具有一定的可靠性.微气象学法与穿透雨量法观测结果共同说明研究地大气氮沉降量较高,过量的氮输入对研究地生态系统的影响值得关注.     

Monte Carlo based calibration of scintillation detectors for laboratory and in situ gamma ray measurements

The calibration of scintillation detectors for gamma radiation in a well characterized setup can be transferred to other geometries using Monte Carlo simulations to account for the differences between the calibration and the other geometry. In this study a calibration facility was used that is constructed from bricks of well-known activity concentrations of ⁴⁰K and of radionuclides from the ²³⁸U- and ²³²Th-series. Transfer of the calibration was attempted to a Marinelli beaker geometry with the detector inside a lead shield and to an in situ application with the detector positioned on a sand bed. In general this resulted in good correspondence (within 5-10%) between the activity concentrations derived using the transferred calibration and activities that were derived by independent measurements. Some discrepancies were identified that were attributed to coincident summing in the natural decay series and interference of radon.     

Two error components model for measurement error: application to radon in homes

In this paper, a simple model for analysing variability in radon concentrations in homes is tested. The approach used here involves two error components, representing additive and multiplicative errors, together with variation between-houses. We use a Bayesian approach for our analysis and apply this model to two datasets of repeat radon measurements in homes; one based on 3-month long measurements for which the original measurements were close to the current UK Radon Action Level (200 Bq m⁻³), and the other based on 6-month measurement data (from regional and national surveys), for which the original measurements cover a wide range of radon concentrations, down to very low levels. The model with two error components provides a better fit to these datasets than does a model based on solely multiplicative errors.     

Application and test of a simple tool for operational footprint evaluations

We present a user-friendly tool for footprint calculations of flux measurements in the surface layer. The calculations are based on the analytical footprint model by Kormann, R. and Meixner, F.X. [2001. An analytical footprint model for Non-neutral Stratification. Boundary-Layer Meteorology 99, 207-224]. The footprint density function of a flux sensor is determined using readily available data from standard eddy covariance measurements. This footprint density function is integrated over defined surface areas given as quadrangular polygons representing e.g. agricultural fields. We illustrate the use and performance of the tool by applying it to CO2 flux measurements with three eddy covariance system at the Swiss CarboEurope grassland site. Two flux towers were positioned in the centre of two neighbouring fields, respectively, that showed a very different CO2 flux during the study period. The third tower was located near the border of the two fields and was frequently influenced by both fields to a similar degree. The calculated footprint fractions were used to simulate the latter flux from the other two systems. The measured and simulated fluxes showed a good agreement and thus support the reliability of the footprint calculation. The presented simple footprint tool can be used as a routine quality check for flux monitoring stations influenced by surface areas with varying vegetation covers and/or land-use.     

巢湖水质状况及污染防治措施

简述了娟湖湖区水质状况,指出工业废水和生活污水以及农田过量地使用化肥和农药等是导致巢湖水质经的主要原因,并担子同相应的防治措施。     

白银市土壤重金属污染源分析及防治措施

通过对白银市土壤调查结果进行评价分析,发现东大沟土壤重金属污染较为严重。同时对土壤重金属污染来源进行讨论,认为大面积土壤重金属来源主要是农民节流灌溉所引起的,小范围的土壤污染可能由于固体废弃物(如铬渣等)的堆存造成。其他污染源对土壤造成的污染较轻,但长期的污染物积累也会造成很大的污染。在此基础上提出防治重金属污染的措施。     

Inter-laboratory comparison study on measuring semi-volatile organic chemicals in standards and air samples

Measurements of semi-volatile organic chemicals (SVOCs) were compared among 21 laboratories from 7 countries through the analysis of standards, a blind sample, an air extract, and an atmospheric dust sample. Measurement accuracy strongly depended on analytes, laboratories, and types of standards and samples. Intra-laboratory precision was generally good with relative standard deviations (RSDs) of triplicate injections <10% and with median differences of duplicate samples between 2.1 and 22%. Inter-laboratory variability, measured by RSDs of all measurements, was in the range of 2.8-58% in analyzing standards, and 6.9-190% in analyzing blind sample and air extract. Inter-laboratory precision was poorer when samples were subject to cleanup processes, or when SVOCs were quantified at low concentrations. In general, inter-laboratory differences up to a factor of 2 can be expected to analyze atmospheric SVOCs. When comparing air measurements from different laboratories, caution should be exercised if the data variability is less than the inter-laboratory differences.     

Heat map visualization of complex environmental and biomarker measurements

Over the past decade, the assessment of human systems interactions with the environment has permeated all phases of environmental and public health research. We are invoking lessons learned from the broad discipline of Systems Biology research that focuses primarily on molecular and cellular networks and adapting these concepts to Systems Exposure Science which focuses on interpreting the linkage from environmental measurements and biomonitoring to the expression of biological parameters. A primary tool of systems biology is the visualization of complex genomic and proteomic data using “heat maps” which are rectangular color coded arrays indicating the intensity (or amount) of the dependent variable. Heat maps are flexible in that both the x-axis and y-axis can be arranged to explore a particular hypothesis and allow a fast overview of data with a third quantitative dimension captured as different colors. We are now adapting these tools for interpreting cumulative and aggregate environmental exposure measurements as well as the results from human biomonitoring of biological media including blood, breath and urine. This article uses existing EPA measurements of environmental and biomarker concentrations of polycyclic aromatic hydrocarbons (PAHs) to demonstrate the value of the heat map approach for hypothesis development and to link back to stochastic and mixed effects models that were originally used to assess study results.