Accounting for geophysical information in geostatistical characterization of unexploded ordnance (UXO) sites

Efficient and reliable unexploded ordnance (UXO) site characterization is needed for decisions regarding future land use. There are several types of data available at UXO sites and geophysical signal maps are one of the most valuable sources of information. Incorporation of such information into site characterization requires a flexible and reliable methodology. Geostatistics allows one to account for exhaustive secondary information (i.e.,, known at every location within the field) in many different ways. Kriging and logistic regression were combined to map the probability of occurrence of at least one geophysical anomaly of interest, such as UXO, from a limited number of indicator data. Logistic regression is used to derive the trend from a geophysical signal map, and kriged residuals are added to the trend to estimate the probabilities of the presence of UXO at unsampled locations (simple kriging with varying local means or SKlm). Each location is identified for further remedial action if the estimated probability is greater than a given threshold. The technique is illustrated using a hypothetical UXO site generated by a UXO simulator, and a corresponding geophysical signal map. Indicator data are collected along two transects located within the site. Classification performances are then assessed by computing proportions of correct classification, false positive, false negative, and Kappa statistics. Two common approaches, one of which does not take any secondary information into account (ordinary indicator kriging) and a variant of common cokriging (collocated cokriging), were used for comparison purposes. Results indicate that accounting for exhaustive secondary information improves the overall characterization of UXO sites if an appropriate methodology, SKlm in this case, is used.     

Multivariate Statistics of the Pyrolysis Products of High Molecular Components in Pulping Wastewaters to Explain Their Toxicity (6 pp)

Background, Aim and Scope At present, large-scale paper manufacture involves delignification and bleaching by elemental chlorine free (ECF) or totally chlorine free (TCF) processes. The wastewater is purified by secondary treatment (mechanical, chemical and biological) which removes most of the toxic substances from the discharge. However, we found residual toxicity in the high molecular (> 1000 D) matter (HMWM) of the discharge by test of the RET (reverse electronic transfer) inhibition. This fraction consists mainly of polydisperse lignin (LIG) and carbohydrate (CH) macromolecules. Structural units in these molecules are studied by pyrolysis gas chromatography / mass spectrometry (Pyr-GC/MS). In the present work, our aim was to find out those structural units which could explain the RET toxicity of LIG or CH molecules. We compared statistically RET toxicity values of the HMWM samples from treated wastewaters of pilot pulping experiments and intensity variation of the pyrolysis product gas chromatograms of these samples. This application is a novel study procedure. Methods Pyrolysis products (Py-GC/MS results) and inhibition of RET (reverse electronic transport toxicity) as TU50 and TU20 of HMWM (High Molecular Weight Material; Mw > 1000 D) were compared by multivariate statistics. The samples were from laboratory pilot stages of TCF (Totally Chlorine Free) and ECF (Elemental Chlorine Free) manufacture of softwood pulp. Py-GC/MS was done without and with addition of TMAH (Tetra Methyl Ammonium Hydroxide). The name and structure of each abundant fragment compound was identified from its retention time and mass spectrum compared to authentic reference compounds or literature. Four sets of Toxicity Units (TUs) and GC peak areas of the pyrolysis fragments were obtained. The data were normalized by division with LIG (lignin content of each sample). TU values were dependent and the fragment values independent (explanatory) variables in statistical treatments by SPSS system. Separate analyses of correlations, principal components (PCA) and stepwise multiple linear regression (SMLR) were performed from the four sample sets TCF and ECF with and without TMAH. Results and Discussion From the CH fragments, 2-furfural in TCF, and from the LIG fragments, styrene in ECF showed the highest probabilities to originate from source structures of toxicity. Other possible compounds in concern were indicated to be CH fragment 2-methyl-2-cyclopenten-1-one in ECF and LIG fragments 2-methoxy-4-methylphenol, 4,5-dimethoxy-2-methylphenol and 2-methylphenol in TCF.     

Bayesian entropy for spatial sampling design of environmental data

We develop a spatial statistical methodology to design national air pollution monitoring networks with good predictive capabilities while minimizing the cost of monitoring. The underlying complexity of atmospheric processes and the urgent need to give credible assessments of environmental risk create problems requiring new statistical methodologies to meet these challenges. In this work, we present a new method of ranking various subnetworks taking both the environmental cost and the statistical information into account. A Bayesian algorithm is introduced to obtain an optimal subnetwork using an entropy framework. The final network and accuracy of the spatial predictions is heavily dependent on the underlying model of spatial correlation. Usually the simplifying assumption of stationarity, in the sense that the spatial dependency structure does not change location, is made for spatial prediction. However, it is not uncommon to find spatial data that show strong signs of nonstationary behavior. We build upon an existing approach that creates a nonstationary covariance by a mixture of a family of stationary processes, and we propose a Bayesian method of estimating the associated parameters using the technique of Reversible Jump Markov Chain Monte Carlo. We apply these methods for spatial prediction and network design to ambient ozone data from a monitoring network in the eastern US.     

Including spatial contiguity information in the analysis of multispecific patterns

In this paper we analyse an ordination method in which spatial contiguity information is included. The original method, proposed by Ver Hoef and Glenn-Lewin (1989), is extended, using graphs to describe spatial contiguity for several sampling schemes where locations are given. Extensions for two dimensional grids and for the case of discrete measures of abundance are analysed. Applications to simulated transect frequency data and real data collected on a regular grid are reported.     

贵溪冷水坑银矿田银元素富集规律研究

贵溪冷水坑银矿田具超大型规模,矿化型式多样,主要有产于花岗斑岩体内及接触带附近的斑岩型矿化和产于上侏罗统打鼓顶组火山岩中层控叠改型矿化二大类。它们各自拥有不同的空间展布、矿物组成、结构构造、围岩蚀变和伴生元素特征。深入探讨银元素的空间分布特征,可以开拓矿田深部及外围找矿的思路。     

数理统计分析法在确定仪器最佳分析条件中的应用

为了能用最少的实验次数，找到最佳的实验条件，将数理统计中的均匀设计与正交设计方法联用，对气相色谱法分析CO实验条件进行重新筛选，找到了一条新途径。该方法既节省人力、物力，又能避免一些被忽视或遗漏的条件。     

Identification of key issues for further investigation in improving the reliability of life-cycle assessments

The interative nature of life-cycle assessment (LCA) means that more details are looked for until a certain level of reliability has been achieved. This paper is concerned with the identification of key issues for further investigation in such an iterative procedure. Key issues in this context are defined as those aspects of an LCA which need more detailed research to arrive at a solid conclusion. The main concept in the context of finding key issues is the study of the propagation of uncertainties in underlying data. The structured procedure of LCA can be described in mathematical terms, so that standard mathematical techniques for the study of the propagation of uncertainties can be employed. The influence of uncertainties in input data on uncertainties in output data can be calculated, and the main source of the resulting uncertainties can be identified. The result of the analysis is a list of prioritized key issues for more detailed research and more accurate data.     

酸雨对汉白玉的危害研究

采用模拟的方法研究了酸雨对天然汉白玉危害，研究结果表明，酸雨对汉白玉石材的危害主要是溶解腐蚀。根据数量统计获得了影氧化钙损失的因素和腐蚀速率“ｂ”以及腐蚀的规律。     

企业环境统计问题及对策

企业环境统计是一项基础性工作，对企业环境统计工作中存在的问题及对策进行了研究，提出了应从企业内部和外部两方面加强企业环境统计工作。     

2003年1-4月国内环境事件数据

简要统计了2003年1—4月国内发生的各种环境事件48件，包括沙尘天气(11件)、污染事件(17件)、山体滑坡和泥石流(4件)、地震(5件)以及其他自然灾害(11件)。最后对沙尘天气和污染问题进行了讨论。