Pollutants possible ground water

Table II lists the highest concentrations of selected noncon-ventional and toxic organic pollutants which have been measured in drinking water wells and consequently reflect possible ground water contamination. For comparison purposes, this Table also lists the highest measured surface water concentrations. Generally, the levels of organics in surface water are much lower than in individual wells. One exception is the chlorinated compounds that are related to the chlorination of surface water. Since these values represent the highest concentrations measured, they may be related to specific site contamination instead of representing a general trend.

Due to possible infiltration of different pollutants into ground water, the contaminated stream waters in the industrial zones are a constant threat for the purity of ground waters, which serve as municipal drinking water supplies. 

Possible negative environmental effects of fertilizer use are the subject of iatensive evaluation and much discussion. The foUowiag negative effects of fertilizer usage have been variously suggested (113) a deterioration of food quaUty the destmction of natural soil fertility the promotion of gastroiatestiaal cancer the pollution of ground and surface water and contributions toward the destmction of the ozone layer ia the stratosphere. 

Another application is to combine ice production and water purification since impurities are pressed out as water freezes. It is possible to freeze sea water or polluted ground water and use the cleaned melt water for both cooling and drinking. In Greenport, New York, sea water was cleaned from 3.0% to 0.00005% by freezing (Taylor, 1985). 

It is possible to avoid short cuts and decrease outlet melt water temperature by spraying re-circulation melt water on top of the snow instead, but so far CCV has avoided this because they do not want pollutions carried in the air to the hospital. For 2006 the melt water circulation will be extended with sprayed ground water and water outlets at the pond bottom centre, to decrease the water temperature further. 

Vast areas of underground pollution are formed after the infiltration of oil and oil products to soil and soil-ground waters. Furthermore, the formation of pollutant spots isolated from the total mass is also possible (Figure 9). 

The depth of oil pollutant infiltration is not restricted by the first water layer, and often this reaches the ground water. Under continuous perennial pollution, oil products can infiltrate into the deeper ground water layers where these pollutants are conserved and can drift to discharge areas after a long period. Hypothetically this discharge from one pollution source is possible at different watersheds (Figure 11). 

Possible environmental applications of NIR probes include the measurement of trace amounts of metal pollutants in surface and ground waters and water saturated soils and sediments and the detection of lead, chromium, and other heavy metal ions for efforts in pollution control. Also OFCD could assist in the determination of caustic soda and chlorine contents in wastewaters. 

Both settle-able and suspended atmospheric particles have deleterious effects upon the environment. The scttlc-able partidcs can affect health if assimilated and also can cause adverse effects on materials, crops, and vegetation. Further, such partides settle out in streams and upon land where soluble substances, sometimes including hazardous materials, are dissolved out of the particles and thus become pollutants of soils and surface and ground waters. Suspended atmospheric particulate matter has undesirable effects on visibility and, if continuous and of sufficient concentration, possible modifying effects on the climate. Importantly, it is particles within a size range from 2 to 5 micrometers and smaller that are considered most harmful to health because particles of this size tend to penetrate the body s defense mechanisms and reach most deeply into the lungs. 

Heavy metais constitute part of these toxic substances and may be derived from particular industrial processes or from wastewater treatment processes. Therefore, the re-employment of sludges with high content of heavy metals in agriculture as fertilizers involves strong risks for human health because of their entry into the food chain and subsequent accumulation in soils or plants and also because of possible pollution of ground and/or superficial waters (4), to which pollutants contained in rainwater may also contribute (5). 

HARM II considered the toxicity and quantity of the pollutants present, two exposure routes - surface and ground water, and human and ecological receptors. To obtain a significant score, a source, a pathway and a receptor all had to exist since this ensured that exposure was a possibility. 

It is defined as a mappable unit with common hydrogeologic characteristics, and as a consequence, common vulnerability to contamination by introduced pollutants. From these factors it is possible to make generalizations about both ground-water availability and ground-water pollution potential. 

Once a DRASTIC Index has been computed, it is possible to identify areas v/hich are likely to be susceptible to ground water contamination relative to one another. The higher the DRASTIC Index, the greater the ground-water pollution potential. The DRASTIC Index provides only a relative evaluation tool and is not designed to provide absolute answers. 

Natural attenuation (NA) and enhanced natural attenuation (ENA) are possible low-cost alternatives to conventional techniques. During the NA process, pollutants are removed from ground water by different processes including volatilization, adsorption, dispersion, hydrolysis and biodegradation. 

The investigation results thus obtained can be used as a basis for assessing whether and to what extent pollution of the ground water or surface water may occur as a result of elution of the wastes. At the same time it is possible to predict whether alkaline-reacting substances may, in the course of the flow path, cause precipitation of e.g. iron, manganese, calcium, magnesium or heavy metals. 

The concentrations of individual PAH in water systems range from less than 1 ppt (pg per g) in pure ground water supplies to greater than 1 ppm (pg per g) in heavily contaminated sewage. Therefore, some preconcentration and extraction techniques are required to raise the concentrations to levels at which identification and quantitative analysis are possible. Because PAHs may only represent as little as 0.01% of the total organic fraction present in the water sample, the analytical scheme must be devised so that the PAHs can be analyzed without the interference from the other pollutants. Since the concentrations are so low, serious errors may occur from losses or contamination during sampling or the analytical... 

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