Contamination, groundwater

All these substrates can be degraded nnder aerobic conditions and, althongh there appear to be important differences among the xylene isomers and mutant strains have been isolated that can degrade all three isomers (Di Lecce et al. 1997). Reviews have covered varions aspects of this problem  

Biodegradation in gas-condensate-contaminated gronndwater with emphasis of the role of inorganic nntrients and oxygen (Morgan et al. 1993) 

Determinative factors for treating aquifer plumes after accidental spillage of automobile fuel with discussions on the design of systems, and the role of the indigenous microflora (Salanitro 1993) 

General procednres inclnding the provision of oxygen and comments on anaerobic treatment (Bowlen and Kosson 1995) 

The pathways for the aerobic biodegradation of alkylated benzenes have been elncidated in extensive investigations and have been discussed in Chapter 8, Part 1, so that only salient featnres are briefly snmmarized here. The genes for the degradation of toluene may be either chromosomal or 

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Biocides should not be present in water used for aquaculture. Sources of herbicides and pesticides are mnoff from agricultural land, contamination of the water table, and spray drift from crop-dusting activity. Excessive levels of phosphoms and nitrogen may occur where mnoff from fertilized land enters an aquaculture faciUty either from surface mnoff or groundwater contamination. Trace metal levels should be low as indicated in Tables 4 and 5. 

An extensive pesticide properties database was compiled, which includes six physical properties, ie, solubiUty, half-life, soil sorption, vapor pressure, acid pR and base pR for about 240 compounds (4). Because not all of the properties have been measured for all pesticides, some values had to be estimated. By early 1995, the Agricultural Research Service (ARS) had developed a computerized pesticide property database containing 17 physical properties for 330 pesticide compounds. The primary user of these data has been the USDA s Natural Resources Conservation Service (formerly the Soil Conservation Service) for leaching models to advise farmers on any combination of soil and pesticide properties that could potentially lead to substantial groundwater contamination. 

Although many environmental and safety problems can be avoided using UCG, there is some concern about groundwater contamination as a result of the process (see Groundwatermonitoring). 

Groundwater contaminated with chlorinated hydrocarbons is being remediated by a conventional air stripper or a rotary stripper, producing an air stream containing the halogenated hydrocarbon vapors and saturated with water vapor (45), which is then passed through a catalyst bed. 

During the site visit, auditors should identify any potential groundwater contamination sources or unusual odors observed at the facility. If any, explain. 

Electromagnetic (EM) Conductivity Measures the electrical conductivity of materials in microohms over a range of depths determined by the spacing and orientation of the transmitter and receiver coils, and the nature of the earth materials. Delineates areas of soil and groundwater contamination and the depth to bedrock or buried objects. Surveys to depths of SO to 100 ft are possible. Power lines, underground cables, transformers and other electrical sources severely distort the measurements. Low resistivities of surficial materials makes interpretation difficult. The top layers act as a shunt to the introduction of energy info lower layers. Capabilities for defining the variation of resistivity with depth are limited. In cases where the desired result is to map a contaminated plume in a sand layer beneath a surficial clayey soil in an area of cultural interference, or where chemicals have been spilled on the surface, or where clay soils are present it is probably not worth the effort to conduct the survey. 

When groundwater contaminant plumes are suspected of having significant depth as well as lateral distribution, a three-dimensional array of monitoring points is needed to identify and characterize such plumes. Thus, groundwater data must be obtained from a number of different locations and from a number of different depths at each location. As a result, either a large number of drillholes are required, each with separate instrumentation installed, or instruments must be combined and installed at multiple levels in each of a smaller number of drillholes. 

Lappala, E. and G. Thompson. Detection of Groundwater Contamination by Shallow Soil Gas Sampling in the Vadose Zone and Applications. In Management of Uncontrolled Hazardous Waste Sites Proceedings, Hazardous Materials Control Research Institute,Washington, D.C., 1984. 

The Fairchild Camera and Instrument Corporation site in South San Jose, California, proved to be a complex and difficult groundwater contamination... 

For question 9, the municipal landfill has had public relations problems with the community. There has been concern over both odor issues and possible groundwater contamination. Taking these concerns into consideration, can you develop addional arguments that make the investment more finacially attractive ... 

Water pollution —Groundwater contamination — Waste disposal... 

The major energy-related sources of water pollution are from thermal pollution, surface water pollution from oil spills, polychlorinated biphenyls, and groundwater contamination. 

Batt AL, Aga DS (2005) Simultaneous analysis of multiple-classes of antibiotics by ion trap LC/MS/MS for assessing surface water and groundwater contamination. Anal Chem 77 2940-2947... 

Air, soil, and water are vital to life on this planet. We mnst protect these resonrces and nse them wisely— onr snrvival as a species depends on them. Despite recent impressive strides in improving the environment, evidence is overwhelming that more effective action mnst be taken to address snch critical issnes as acid rain, hazardons waste disposal, hazardous waste landfills, and groundwater contamination. It is also vital that we assess realistically the potential health and enviromnental impacts of emerging chemical products and technologies. The problems are clearly complex and demand a broad array of new research initiatives. 

Considerable work has been done on the behavior of pollutant species at air-water and air-soil interfaces. For example, wet and diy deposition measurements of various gaseous and particulate species have been made over a wide range of atmospheric and land-cover conditions. Still, the problem is of such complexity that species-dependent and particle-size-dependent rates of transfer from the atmosphere to water and soil surfaces are not completely understood. There is much to be learned about pollutant transfer at water-soil interfaces. Concern about groundwater contamination by mineral... 

Hirschfeld, T. Deaton, T. Milanovich, F. Klainer, S. Fitzsimmons, C. Project Summary—Feasibility of Using Fiber Optics for Monitoring Groundwater Contaminants U.S. Environmental Protection Agency, Environmental Monitoring Systems Lab. Las Vegas, NV, January 1984. 

Another groundwater contaminant that can be removed by reduction reactions is perchlorate. Ammonium perchlorate is a solid rocket fuel, and wastes from its manufacturing have contaminated some irrigation and drinking water sources, among them the lower Colorado River in the American Southwest. Elevated perchlorate levels have been linked to human health effects, and because perchlorate has been found in vegetable crops such as lettuce, there is concern that this contamination could have serious consequences. 

A possible source for much of the groundwater contamination is landfill leachate containing trichloroethylene. Trichloroethylene was the most commonly found chemical at NPL sites in New York State (Mumtaz et al. 1994). The compound was detected in leachate samples from Minnesota municipal solid waste landfills at levels ranging from 0.7 to 125 pg/L (0.7-125 ppb) and in groundwater near landfills at levels ranging from 0.2 to 144 pg/L (0.2-144 ppb) (Sabel and Clark 1984). Trichloroethylene was also detected in landfill leachate from a landfill in New Jersey at concentrations of up to 7,700 pg/L (7,700 ppb) (Kosson et al. 

Constan AA, Yang RSH, Baker DC, et al. 1995. A unique pattern of hepatocyte proliferation in F344 rats following long-term exposures to low levels of a chemical mixture of groundwater contaminants. Carcinogenesis 16 303-310. 

Apart from its application to the specific problem of groundwater contamination, this procedure offers a potentially valuable procedure for simulating bioremediation of contaminated soils. 

Considerable effort has been devoted to the anaerobic transformation of polychlorinated Cj alkanes and C2 alkenes in view of their extensive use as industrial solvents and their identification as widely distributed groundwater contaminants. Early experiments, which showed that tetrachloroethene was transformed into chloroethene (Vogel and McCarty 1985) (Figure 7.67), aroused concern though it has now been shown that complete dechlorination can be accomplished by some organisms. 

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