Detection Of Groundwater Contamination Research Articles

Efficacy and Challenges of Using Springs for Early Detection of Contaminant Release from Waste Disposal Facilities Constructed in Karst Terranes

Early detection of groundwater contamination from waste disposal facilities is challenging in karst terranes. First, one needs to demonstrate that the groundwater system at the study site is monitorable. Both springs and wells are potential monitoring locations if they are effectively connected to the groundwater system, and they are not impacted by any other disposal facilities. Second, due to dynamic responses to recharge events, particularly discharge and chemical constituents at karst springs, multiple-parameter, long-term, and high-frequency monitoring may be required to collect background data. Sampling and analysis plans should be designed to reflect the unique characteristics of the monitoring locations. Characterization of the natural variations in water quality may require sampling efforts under different flow conditions. Third, evaluation of the potential impact of waste disposal units on the groundwater system requires an effective statistical evaluation program. Due to heterogeneity of karst aquifers, intra-locational comparison is generally preferred to inter-locational comparison. Sufficient groundwater monitoring data prior to construction of waste disposal units are required to develop the intra-locational statistical evaluation. In the case study presented in this paper, procedures to address these above-mentioned challenges were presented for two springs using seven dye tracing tests, two spring instrumentations, nine background sampling, flow-weighted concentrations, and an innovative statistical evaluation method were presented. These procedures were developed to evaluate potential contaminant release from a solid waste disposal facility constructed in a relatively isolated karst terrane. Although the specific procedures may not be duplicated, the overall technical approaches discussed in the paper may shed light on groundwater monitoring programs in other karst areas.

NovCare 2013 (Novel methods for subsurface characterization and monitoring: from theory to practice)

As safe and effective use of the subsurface environment is a major challenge facing our society, there is a great need to improve our understanding of the subsurface and to observe and investigate natural and anthropogenically influenced systems. Characterization of the subsurface includes the investigation of both groundwater and subsurface soils and their interaction processes. The range of monitoring tools used can be extended to include remote sensing tools [e.g., Fourier transform infrared spectroscopy (FTIR)], applicable at the near-surface to estimate gas–soil gas exchange processes. One example that highlights the importance of subsurface characterization and monitoring is the detection of groundwater contamination, to provide data for developing plans to prevent any further contamination and remediate existing contamination. With an increasing demand for investigation methods that have both high accuracy and resolution across a variety of spatial scales, there are several challenges for monitoring and exploration technologies in environmental research. These challenges include, among others, the identification and parameterization of system relevant physical, chemical, biological processes, as well as the determination of interactions between different scales. These challenges require high-resolution methods or novel data processing and common interpretation of data measured by different methods. In particular, cost-effective methods that are minimally destructive and can be rapidly applied are taken into consideration. Methods for subsurface characterization include e.g., geophysical, hydrogeological and direct push (DP) technologies, borehole-based, and tomographic methods. The NovCare conference (Novel methods for subsurface characterization and monitoring: from theory to practice— established in 2009) provides a platform to present and discuss state of the art developments and concepts. Existing methods are often refined and new methods are continually being developed. Therefore, this symposium presents recent developments, examples of field applications and introduces method concepts such as direct push, geophysical methods, adaptive (sensor) networks, and novel monitoring sensors. It also highlights the application of these methods in different thematic areas. The NovCare 2013 International Conference (Novel methods for subsurface characterization and monitoring: from theory to practice) took place from May 13–16th 2013 at the Helmholtz Centre for Environmental Research in Leipzig. This conference, which was organized by the Helmholtz Centre for Environmental Research, the University of Tuebingen, the Kansas Geological Survey and the Michigan State University, was the third successive annual conference. This conference series, which began in Leipzig in 2009 and then moved to Cape Cod in the US in 2011, has proven to be an excellent forum for exchanging ideas and experiences related to the challenges of subsurface characterization and monitoring. NovCare 2013 again provided a rare opportunity and an outstanding platform for researchers and practitioners from all over the world to exchange their ideas and experiences in dealing with the challenges of subsurface characterization and monitoring using a variety of methods. The conference had a strong interdisciplinary and international flavor, with around 100 participants from 13 countries taking part. Twelve companies and institutes presented their expertise and novel equipment and U. Sauer (&) P. Dietrich Department of Monitoring and Exploration Technologies, UFZ-Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany e-mail: uta.sauer@ufz.de

Monitoring Groundwater Contamination Using Surface Electrical Resistivity and Geochemical Methods

Surface electrical resistivity has been used as a tool in the detection of groundwater contamination. In this work, five geoelectric soundings with two at waste dumpsites have been carried out in Uyo, Southwestern Nigeria to map the gross layered structure of the refuse as well as the extent of groundwater contamination. The geology of the area (Benin Formation) mainly consists of fine-medium-coarse grained sands. The data of five Schlumberger Vertical Electrical Soundings (VES), with a maximum of AB/2=500 m, were analyzed using Hemkler computer program. In general, there exists a common feature in the resistivity variation pattern of high-low-high-low-high in the area. The result shows a wide range of resistivity variation ranging from 2.0 to 60700 ?m. Based on the survey results, the resistivity values less than 75 ?m shows contamination due to waste at Eka street and Udo street. Also, the high resistivity value at mechanic village (60700 ?m) may be related to the waste oil deposit due to the automobile repair activities. A comparison of the resistivity values and the curve types at the dumpsites (Eka street and Udo street) and other locations show that the two dumpsites have an H curve type indicating contaminated zones, while other locations have a K curve type indicating non contaminated zones. Hydrochemical analysis of groundwater samples collected in the area was also carried out for some physico-chemical parameters. The results produced higher concentration of conductivity, total dissolved solids and chloride values for water collected at close locations to dumpsites than those far away from the dumpsites: an evidence for a quantitative assessment of groundwater contamination.

Detection of groundwater contamination with hydrocarbons

The task was to detect the groundwater contamination with hydrocarbons (gasoline, kerosene, diesel fuel) without drilling special boreholes, by means of NMR geotomography. Near the town of Abakan (Khakasia, RF), experimental measurements were carried out at a gas station where gasoline leakage is possible and the contamination of groundwaters was monitored through observation wells. In the immediate vicinity of the source of pollution, signals with essentially different times of relaxation were rather distinct: Short signals came from hydrogen protons of water, and much longer signals, from hydrogen protons of gasoline.

Modeling the Effect of Chemical Fertilizers on Ground Water Quality in the Nile Valley Aquifer, Egypt

AbstractChemical fertilizer use in Egypt has increased significantly since the construction of the Aswan High Dam in 1968. Increased applications of chemical fertilizers in irrigated lands are likely to create nonpoint contamination sources of chemical fertilizer species. This study was conducted to investigate the contamination of ground water by nitrogen and phosphorus chemical fertilizers, as well as the availability of ground water for irrigation and public water supply for the next century. Future concentrations of NO3, and PO3‐ in shallow and deep ground water in the Nile Valley were assessed under realizable rates of fertilizer application. A ground water modeling system (GMS) was used to simulate the three‐dimensional ground water flow and contaminant transport in the Tahta region of the Nile Valley Aquifer, and to predict the future concentrations of chemical fertilizer species. Results of the transport simulation predict the occurrence of ground water contamination at shallow depths (30 m) due to the high rate and method of chemical fertilizer applications. Best management practices should be employed to control and reduce the nitrate leaching and future impact of phosphorus and potassium fertilizer applications. At the same time, new deeper wells should be constructed. In addition, the use of hand pumps, in zones close to croplands (15 m depth) must be avoided due to susceptibility to fertilizer contamination. Ground water from existing deep wells can be used as an alternative water supply. Furthermore, a ground water quality monitoring system should be established for early detection of ground water contamination and to determine progress of the fertilizer contaminant plume. A properly designed system should monitor nitrate and phosphate composition in observation and water supply wells.

Time series electrical potential field measurements for early detection of groundwater contamination

Abstract The adequacy of groundwater monitoring systems that consist of up‐gradient and downgradient monitoring wells is often questioned by regulatory agencies. Groundwater contaminants frequently migrate along preferred pathways formed by lateral and vertical heterogeneities within definable stratigraphic units. Many monitoring wells must be completed correctly within individual heterogeneities to provide for early detection of contaminant migration along these preferred flowpaths. The adequacy of a specific groundwater monitoring system is usually directly dependent upon the number of monitoring wells. Time series electrical potential field measurements in combination with groundwater monitoring wells can greatly improve the capability of groundwater monitoring systems to detect the presence of contaminants. An electrical geophysical method known as the mise‐a‐la‐masse method involves the measurement of electrical current flow through earth materials under investigation. Changes in the electrical poten...