Ground Water Contamination from Creosote Sites

Field data from 44 waste sites contaminated with creosote have been compiled in a database. The data from each site included geological and hydrogeological parameters and the concentrations of creosote compounds in the ground water at various distances from the pollution sources. The creosote compounds that were measured included mononuclear aromatic hydrocarbons and polynuclear aromatic hydrocarbons (PAH) and phenols. Already 50 m down-gradient of the creosote waste sites, 90 percent of the concentrations were from three to 50 times lower than at the source, and most of the median concentrations were below detection limit (0.1 to 0.5 μg/L). The maximum concentrations of benzene, toluene, and xylenes (BTX) and phenols were much lower under aerobic than under anaerobic conditions. Among the phenols, the xylenols (dimethylphenols) appear in higher concentrations under aerobic conditions than phenol and the cresols do. The highest concentrations found were of the same order of magnitude as the calculated solubilities found in the literature, except the chrysene and benz(a)pyrene concentrations, which were one to two orders of magnitude higher than the solubilities.     

Ground Water Contamination at Wood Treatment Facilities

Ground water contamination profiles from five wood treatment facilities across the country have been compared. The distributions of organic priority pollutants at the five sites are similar, with the most common contaminants being polynuclear aromatic hydrocarbons and phenolic compounds. These contaminants are the predominant constituents of creosote, which is a common wood preservative. Inorganic contaminants have also been detected at these sites, but their distributions are not uniform across all sites. The distributions of the organic priority pollutants at the five sites appear to differ from those at other hazardous waste sites. Suggested recommendations for choosing monitoring parameters for wood treatment facilities are presented.     

Organic Halogen Group Parameters as Indicators of Ground Water Contamination

A regional survey of Danish ground water demonstrated the presence of adsorbable organic halogens (AOX) in almost all of 142 wells (99 percent). Generally, the presence of AOX was not related to point or non-point source contamination with halogenated organics. However, the AOX concentrations varied with the geology of the aquifers. Extractable organic halogens (EOX) and volatile organic halogens (VOX) were far less prevalent (detected in 4 percent of sampled wells) and the detection could, in most cases, be explained by contamination or chlorination of the wells. The VOX concentrations corresponded to the concentrations of identified, volatile contaminants. The study demonstrates the presence of a natural background level of AOX in the investigated aquifers. This must be considered in the interpretation of AOX results as an indicator of ground water contamination with haloorganics. Similar background levels of EOX or VOX were not delected.     

Interpretation of VLF Resistivity Data for Ground Water Contamination Surveys

Very low frequency (VLF) military communications systems provide a primary field that can be used for shallow geophysical surveys to locate ground water contamination and vertical geologic contacts. Useful properties that can be easily obtained from the interaction of the earth and the primary field are the magnitude of the vertical secondary magnetic field, the surface impedence, and the phase angle between the electrical and magnetic horizontal components. The variations in the secondary magnetic field can be related to vertical geologic contacts, such as the edges of landfill trenches. The surface impedence yields an apparent terrain conductivity, which can be used to locate low-resistivity anomalies often associated with contaminated ground water. The phase angle gives information on vertical variations in resistivity, phase angles less than 45° indicating increasing resistivity with depth. The depth of penetration of the VLF field is about one skin depth. For a frequency of 20 kHz, the skin depth in meters is approximately equal to 3.67 where p is terrain resistivity in ohmmeters.     

Geophysical Monitoring of Ground Water Contamination Around Waste Disposal Sites

The potential and the problems for geophysical monitoring programs at waste disposal sites are discussed. No data are presented, but the expectations, design criteria and implementation of a geophysical monitor are examined for a hypothetical landfill. We conclude that any geophysical monitor must be designed to allow for future changes in the physical setting, geophysical technology and the personnel who will record, process and interpret the data. This suggests that permanent installations be kept to a minimum, and that a high priority be given to simplicity and reliability. It is also important that the detection limits of the monitor be clearly established, that the noise levels in readings unrelated to changes in contamination levels are well defined and that the monitor is integrated into an overall hydrogeological monitoring program.     

Investigation of Ground Water Contamination by Fenamiphos and Atrazine in a Residential Area: Source and Distribution of Contamination

Ground water in a residential area of Perth. Western Australia, was contaminated with fenamiphos and atrazine. probably as a result of the storage and handling of these chemicals at a residential properly. Sampling of existing wells indicated that atrazine and fenamiphos concentrations in ground water beneath a neighboring property were 2000 μg/L and 1000 μg/L, respectively. Fenamiphos concentrations were sufficiently high to be toxic on prolonged skin contact, and contamination posed a public health threat to nearby residents with private wells. Management of the contamination problem included restricting ground water use in the area and using a recovery well to pump contaminated ground water.     

Control of Ground Water Contamination at an Active Uranium Mill

Seepage from tailings ponds associated with an active uranium mill in Utah has resulted in contamination of ground water contained in the Dakota-Burro Canyon Formation. This aquifer is used in the area as a supply for domestic and industrial wells.
Results of very low-frequency electromagnetic surveys and ground water quality investigations at the site indicated that the flow of ground water and contaminants is primarily fracture-controlled. Pumping tests were conducted to determine the hydraulic characteristics of the fractured system. The extent of contaminant migration was then determined using an analytical model of transport in fractured aquifers.
Based on these investigations, a plan was designed to control future and remediate past ground water contamination. This plan consists of pumping from a single well intersecting the main fracture that transports contaminants off the site. The effectiveness of the plan was analytically modeled, taking account of the anisotropy of the ground water system. Subsequent monitoring of water levels in the area indicates that the plan has been effective since its inception in November 1983.     

Investigation of Possible Contamination of Shallow Ground Water by Deeply Injected Liquid Industrial Wastes

The objective of this study was to assess the possible impact of deep well disposal operations, conducted between 1958 and 1974, on the ground water quality in a shallow fresh water aquifer beneath Sarnia, Ontario, Canada. Because of the breakout of formation fluids in Sarnia and Port Huron, Michigan, in the early 1970s, it had been hypothesized that liquid waste from the disposal zone in bedrock had leaked through numerous abandoned oil, gas, and salt wells in the area up to the shallow fresh water aquifer and from there to the surface.
A monitoring well network of 29 5cm (2 inch) diameter piezometers was established in the thin sand and shale aquifer system, which exists between 30 and 70m (100 and 230 feet) below ground surface. In addition, a 300m (1000 foot) deep borehole was drilled and instrumented with a Westbay multilevel casing, which permitted sampling of the disposal zone.
Ground water samples from the shallow monitoring wells and the Westbay multilevel casing were analyzed for volatiles by GC/MS. Those volatile aromatics that were conspicuously present in the deep disposal zone, e.g., ethyl toluenes and trimethyl benzene, were not detected in the shallow monitoring wells. Thus, if contaminants from the disposal zone did indeed migrate to the shallow aquifer, contamination was not widespread and probably consisted mostly of displaced chloride-rich formation waters.     

Modeling Management Practice Effects on Pesticide Movement to Ground Water

The assessment of agricultural impacts on water quality are now being redirected to include both ground water and surface water. Mathematical models have enhanced the ability of scientists'to evaluate these impacts. A variety of public domain models are available that can aid in evaluating the effects of managerial activities on pesticide movement to ground water. However, the ideal non-point source (NPS) pollution management model does not exist. Current models fail to adequately describe the transport of chemicals to ground water and, simultaneously, the effect of managerial practices on transport mechanisms. Much more work is necessary to develop a model that can describe water quality impacts of agricultural practices in a holistic framework that includes ground water and surface water concerns.