房地产开发项目的环境污染和防治措施

随着我国房地产事业的蓬勃发展 ,建设开发过程中的环境问题日益突出 ,如果防治措施不当 ,会对环境造成一定危害。根据房地产开发项目的污染特点 ,分别采取不同的防治措施后 ,可以实现项目开发和环境保护的双赢。     

Towards eliminating systematic errors caused by the experimental conditions in Biochemical Methane Potential (BMP) tests

The Biochemical Methane Potential (BMP) test is increasingly recognised as a tool for selecting and pricing biomass material for production of biogas. However, the results for the same substrate often differ between laboratories and much work to standardise such tests is still needed. In the current study, the effects from four environmental factors (i.e. ambient temperature and pressure, water vapour content and initial gas composition of the reactor headspace) on the degradation kinetics and the determined methane potential were evaluated with a 2⁴ full factorial design. Four substrates, with different biodegradation profiles, were investigated and the ambient temperature was found to be the most significant contributor to errors in the methane potential. Concerning the kinetics of the process, the environmental factors’ impact on the calculated rate constants was negligible. The impact of the environmental factors on the kinetic parameters and methane potential from performing a BMP test at different geographical locations around the world was simulated by adjusting the data according to the ambient temperature and pressure of some chosen model sites. The largest effect on the methane potential was registered from tests performed at high altitudes due to a low ambient pressure. The results from this study illustrate the importance of considering the environmental factors’ influence on volumetric gas measurement in BMP tests. This is essential to achieve trustworthy and standardised results that can be used by researchers and end users from all over the world.     

Radon mapping by retrospective measurements - an approach based on CDs/DVDs

This article points out the ability to map retrospective ²²²Rn concentrations by home stored CDs/DVDs. The method employs the high radon absorption ability of the polycarbonate material of CDs and DVDs and their track-etch properties. The principle steps for the application of the method are addressed. The possibility for individual a posteriori calibration is studied, demonstrating that better than 10% accuracy in retrospective measurements is potentially achievable. Results from retrospective measurements in three different regions are shown, demonstrating the potential of the method for large-scale radon mapping. Comparison with independently evaluated retrospective ²²²Rn concentrations in places with known radon history was made and very good correspondence was observed. The experience indicates that the method can be used for large scale retrospective radon mapping and its applications can be expanded towards mapping of radon concentrations in water and soil gas.     

Evaluation of Monte Carlo-based calibrations of HPGe detectors for in situ gamma-ray spectrometry

The aim of this work was to evaluate the use of Monte Carlo-based calibrations for in situ gamma-ray spectrometry. We have performed in situ measurements at five different sites in Sweden using HPGe detectors to determine ground deposition activity levels of ¹³⁷Cs from the 1986 Chernobyl accident. Monte Carlo-calculated efficiency calibration factors were compared with corresponding values calculated using a more traditional semi-empirical method. In addition, results for the activity ground deposition were also compared with activity densities found in soil samples. In order to facilitate meaningful comparisons between the different types of results, the combined standard uncertainty of in situ measurements was assessed for both calibration methods. Good agreement, both between the two calibration methods, and between in situ measurements and soil samples, was found at all five sites. Uncertainties in in situ measurements for the given measurement conditions, about 20 years after the fallout occurred, were found to be in the range 15–20% (with a coverage factor k = 1, i.e. with a confidence interval of about 68%).     

Characterization of phosphogypsum wastes associated with phosphoric acid and fertilizers production

The present work is directed to characterize the phosphogypsum (PG) wastes associated with phosphoric acid produced by the wet process in industrial facility for the production of fertilizers and chemicals in Egypt. The PG waste samples were characterized in terms of spectroscopic analysis (X-ray diffraction, X-ray fluorescence, IR spectra) and radiometric analysis (γ- and α-measurements). The γ-ray measurements showed that the average activity concentrations are 140 ± 12.6, 459 ± 36.7, 323 ± 28.4, 8.3 ± 0.76 and 64.3 ± 4.1 Bq/kg for U-238, Ra-226, Pb-210, Th-232 and K-40, respectively. The α-particle measurements of uranium isotopes showed that the average activity concentrations of U-238, U-235 and U-234 were 153 ± 9.8, 7 ± 0.38, 152 ± 10.4 Bq/kg, respectively. The average radiochemical recovery (%) of the destructive α-particle measurements is ∼70% with a resolution (FWHM) of ∼30 keV. Activity ratios of U-238/Ra-226 and U-238/Pb-210 were less than unity (i.e., <1) and equal to 0.31 ± 0.02 and 0.47 ± 0.16, respectively. The isotopic ratios of U-238/U-235 and U-238/U-234 (in PG and PR samples) were close to the normal values of ∼21.7 and ∼1, respectively and are not affected by the wet processing of phosphate rock (PR). The obtained results of PG waste samples were compared with phosphate rock (PR) samples. The radiation hazard indices are namely, radium activity index (Ra-Eq > 370 Bq/kg), total absorbed gamma dose rate (D_γr > 5 nGy/h) and radon emanation fraction (Rn-EF > 20%). Uncertainty of the sample counting was 95% confidence level of σ. The results indicated the necessity to find suitable routes to decrease and/or redistribute the radionuclide of environmental interest (i.e., Ra-226) in PG wastes, consequently to reduce its radiation impacts in the surrounding environment.     

An approach to the subslab depressurization remedial action in a high Rn concentration dwelling

Galicia (NW Spain) is a radon-prone area in the Iberian Peninsula. Measurements were carried out at a rural dwelling, with an annual average of radon concentration over 4000 Bq m⁻³ and a maximum of 9000 Bq m⁻³, found during a radon screening campaign held in the Autonomous Community of Galicia. We performed a detailed study to identify the main contamination source and the behaviour of the radon concentration, in which a linear dependence with temperature was verified, once corrected for relative humidity. We used different passive methods (charcoal canisters and two types of etched track detectors) as well as a radon concentration monitor that provided continuous measurement. Subsequent to this characterization, and in order to reduce the high radon concentration, a remedial action was developed using different passive and forced ventilation methods. A modified subslab depressurization technique was found to be the most effective remedy, providing a radon concentration reduction of around 96%. This method also has the advantages of being inexpensive and reliable over time.     

普光气田开发对地下水环境的影响分析

为最大程度缓解工程实施对当地地下水环境的破坏,文章在综合分析普光气田地质和水文地质特征的基础上,开展现场水质监测工作,选用内梅罗指数法评价区域地下水质量现状。结果表明:普光气田开发建设工程对区域地下水环境质量影响较小,地下水水质良好。在此基础上,探讨项目建设过程中的地下水环境影响因素,据此提出针对性的环境保护措施,以期为研究区地下水环境保护提供科学参考依据。     

工作场所手传振动测量

在职业卫生领域中,振动加速度有效值是最常用的测量值,振动加速度级的运用方便了运算和表述。给出频率计权和时间加权的计算公式和方法、加速度与加速度级间的换算。测量中强调了传感器定位和紧固方法会影响测量结果。     

基于车载的天津市不同交通流特征下机动车排放率精细分析

利用OBS2200车载测试系统,对天津市的道路行驶车辆进行测试,在3种不同交通流特征（交通高峰期、低峰期和平峰期）下获得了道路车载排放污染物（HC、CO、NOx和CO2）的逐秒数据,结果显示,高峰期HC和CO平均排放率（0.027±0.018 g/s和0.330±0.196 g/s）明显高于低峰期和平峰期,大约分别是低峰期的5.4倍和4.3倍,平峰期的3.9倍和9.2倍。低峰期NOx和CO2平均排放率（0.006±0.006 g/s和1.904±0.960 g/s）稍高于高峰期和平峰期。加速工况下4种排放物的平均排放率：0.022±0.019 g/s、0.243±0.234 g/s、0.007±0.007 g/s和1.766±0.946 g/s,大约分别是减速工况下4种排放物平均排放率的1.1倍、1.4倍、2.3倍和1.9倍。随着加速度增大4种排放物的排放率逐渐增大。