Multivariate Geostatistical Analysis of Groundwater Contamination by Pesticide and Sulfate PDF Download

Author: Guru Prakash S. G. Raja
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 86

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Author: Jeffrey D. Smyth
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 48

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Book Description
A field study was conducted to determine the applicability of multivariate geostatistical methods to the problem of estimating and simulating pesticide concentrations in groundwater from measured concentrations of nitrate and pesticide, when pesticide is undersampled. Prior to this study, no published attempt had been made to apply multivariate geostatistics to groundwater contamination. The study was divided into two complementary aspects of geostatistics: estimation and simulation. The use of kriging and cokriging to estimate nitrate and the herbicide dimethyl tetrachloroterepthalate (DCPA) contaminant densities is described in Chapter I. Measured concentrations of nitrate and the DCPA were obtained for 42 wells in a shallow unconfined alluvial and basin-fill aquifer in a 16.5 km2 agricultural area in eastern Oregon. The correlation coefficient between log(nitrate) and log(DCPA) was 0.74. Isotropic, spherical models were fitted to experimental direct- and cross-semivariograms with correlation ranges and sliding neighborhoods of 4 km. The relative gain for estimates obtained by cokriging ranged from 14 to 34%. Additional sample locations were selected for nitrate and DCPA using the fictitious point method. A simple economic analysis demonstrated that additional nitrate samples would be more beneficial in reducing estimation variances than additional DCPA samples, unless the costs of nitrate and DCPA analysis were identical. These estimates are by definition, the Best Linear Unbiased Estimates (i.e., the estimates with minimized estimation variance), however the requirement of minimized variance smoothes the variability of contaminant values. The application of conditional simulations to groundwater contamination is described in Chapter 11. Conditional simulation allows the degree of fluctuation of nitrate and DCPA between sample points to be assesed. With knowledge of both the 'best' estimates and the of the variability between sample points, nitrate and DCPA groundwater contamination in the study area can be characterized Based on the semivariogram models found in Chapter I, univariate and multivariate conditional simulations of nitrate and DCPA were generated using the turning bands method and the kriging or cokriging system. Kriging was used to condition the univariate simulations, while cokriging was used to cross-correlate and condition the multivariate simulations. The mean of 25 conditional and coconditional simulations at 8 different locations in the study area were generated and compared to kriging and cokriging estimates and 95% confidence intervals. Both conditional and coconditional simulation of the DCPA and nitrate contaminant densities showed large variations when values in different simulations were compared. The fluctuation in values demonstrate the uncertainties in the contaminant distributions when sample sizes are small. As a result of this unkown component, simulated values vary widely. Coconditional simulation displayed the cross-correlation imposed by using the cokriging system to condition the simulations. After 25 simulations, the mean remained unstable indicating that more simulations would be required to enable comparisons with kriging and cokriging estimates.

Author: Yoram J. Litwin
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 234

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Author: Elizabeth G. Nielsen
Publisher:
ISBN:
Category : Agricultural chemicals
Languages : en
Pages : 48

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Author:
Publisher:
ISBN:
Category : Groundwater
Languages : en
Pages : 72

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Author: Suzanne Lesage
Publisher: CRC Press
ISBN: 9780824787202
Category : Technology & Engineering
Languages : en
Pages : 568

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Book Description
This comprehensive reference describes investigations of the fate of toxic chemicals emanating from hazardous waste sites and contaminating groundwater, discussing the hydrogeochemistry at US, Canadian, Australian, and German sites to reflect the different approaches used around the world.;Written by over 30 international experts in the field, Groundwater Contamination and Analysis at Hazardous Waste Sites: presents case histories spanning 30 years of activities by the United States Geological Survey's Organics in Water project, including studies of pesticide, munition, and wood preservative residues contaminating groundwater; outlines the U.S. Environmental Protection Agency's SW-846 methods of analysis for groundwater samples taken at hazardous waste sites; details the analytical requirements for qualitative surveys, regulatory compliance, and research programs; examines the use of statistics at site investigations and waste disposal facilities as well as data interpretation techniques such as multivariate plots; covers the application of a portable gas chromatograph in studying a vapor-phase plume of trichloroethylene, giving tips about problems that may lead to variability in the data; and explores dense nonaqueous-phase liquid dissolution using Raoult's law, biotransformation of the dissolved constituents, and their sorption to aquifer materials.;Extensively illustrated with more than 250 figures, tables, and display equations, Groundwater Contamination and Analysis at Hazardous Waste Sites is a practical tool for pollution control and environmental engineers, hydrogeologists, analytical chemists, and upper-level undergraduate and graduate students in these disciplines.

Author: Domy C. Adriano
Publisher: CRC Press
ISBN: 1000162265
Category : Technology & Engineering
Languages : en
Pages : 546

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Book Description
International experts have contributed key chapters to this major work on groundwater contamination. Section 1: Methodology and Modeling deals with both organic and inorganic contaminants, including those from agricultural operations. Section 2: Case Studies presents contamination scenarios with both inorganic and organic chemicals including agriculturally-related constituents, such as the nitrates. This important new publication is a welcome addition to the literature and will enhance recent information on methodology, modeling and real-world situations. It is of interest to scientists and planners in local and national government; environmental chemists, geochemists, geologists, and health and safety officers; river authorities; hydrologists; and the mining and land reclamation industries.

Author: Michael George Sinkevich
Publisher:
ISBN:
Category :
Languages : en
Pages : 198

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Author: National Research Council
Publisher: National Academies Press
ISBN: 0309034418
Category : Nature
Languages : en
Pages : 191

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And ConclusionsReferences; III METHODS OF WASTE DISPOSAL ; 4 Shallow Land Burial of Municipal Wastes; Introduction; Leachate Characteristics; Gas Production; Hydrogeologic Criteria; Unsaturated Flow; Site Size; Water Balance; Trench Covers; Trench Liners; Monitoring; Monitoring Methodology; Verification of Contamination; Conclusions; References; 5 Deep Burial Of Toxic Wastes; Introduction; Methods of Disposal; Advantages and Disadvantages of Deep Burial; A Hypothetical Repository; Hydrogeologic Properties of Rocks at Depth; General Data from Wells and Test Holes; Geochemical Evidence.

Author: Harriet Nash
Publisher: Springer
ISBN: 0412586207
Category : Science
Languages : en
Pages : 204

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Book Description
Groundwater quality monitoring and testing is of paramount importance both in the developed and developing world. This book presents a series of papers illustrating the varied nature of current research into groundwater quality. Urban and rural supplies are covered through a case history approach, and the importance of remedial action to prevent deterioration is emphasized.