Quantification of Groundwater Quality A Polish Case

The above-discussed different methods of characterisation of hydrogeochemical field can be adopted to assessment of groundwater quality in the framework of national (European) legislation. In order to achieve appropriate protection of

Fig. 27.6 Cumulative frequency diagrams of SO4 (a) and regionalization of SO4 distribution (b) in the K^dzierzyn aquifer (the NE region of MGWB 332) in southern Poland [7]. A - 4 to 10 mg/L, B - 5 to 50 mg/L, C - 30 to 200 mg/L

observed concentrations (classified)

concentration

Fig. 27.7 Separation of natural and anthropogenic contribution to the observed complex-shape distribution of the given element in groundwater [6, 8]

observed concentrations (classified)

sum of calculated natural and influenced components natural component influenced componenl concentration

Fig. 27.7 Separation of natural and anthropogenic contribution to the observed complex-shape distribution of the given element in groundwater [6, 8]

groundwater, the EU Member States have to establish threshold values for pollutants, groups of pollutants and indicators of pollution, which will be used in the assessment of chemical status of groundwater bodies [9]. Below, the Polish approach to this problem is presented.

Considerable experience exists in Poland with respect to setting up threshold values for pollutants present in groundwater. Groundwater quality criteria leading to several quality classes are in use in Poland since the 1980s. Numerous studies have been accomplished since that time, focusing on the evaluation of natural background levels of chemical constituents in groundwater (e.g. [10, 11]). In the framework of this approach, the process of derivation of thresholds for specific constituents in groundwater includes the assessment of the following aspects of groundwater quality: (i) typical natural background, (ii) the origin of constituents (natural and/or anthropogenic), (iii) the reasons of introducing specific constituents and thresholds into the adopted classification as well as the receptors on which they are acting. The Polish approach towards the assessment of groundwater quality is focused on human health as a main risk receptor, and contains also other elements of aquatic and terrestrial ecosystems dependant on groundwater. The approach proposes classification of groundwater quality into five classes (Table 27.1). The first three classes represent a good chemical status of a groundwater body. They help to protect the pristine water quality and allow to draw attention to the anthropogenic changes in the early stages of groundwater contamination. The last two classes include waters having poor chemical status.

The list of parameters and constituents used for determining the chemical status of groundwater within the Polish approach includes obligatory part, necessary for

Table 27.1 Groundwater quality classes according to Polish classification [12]

Quality classes

Description

Class I: Groundwater of very good quality

Class II: Groundwater of good quality

Class III: Groundwater of acceptable quality

Class IV: Groundwater of poor quality

Class V: Groundwater of poor quality

Chemical composition derived exclusively from natural sources. None of the components exceeds maximum permissible level of a parameter in drinking water (MPL). No treatment is required. Lack of indications of anthropogenic influences.

Chemical composition derived exclusively from natural sources. One or more dissolved constituents exceed MPL due to natural processes. Some treatment may be required in case of the use of such waters for drinking purposes. No indications of significant anthropogenic influences.

Chemical composition derived mainly from natural sources, with elevated concentrations of some natural and/or anthropogenic components, without discernible trends. The use of such waters for drinking purposes requires treatment.

Chemical composition derived from natural and anthropogenic sources, with elevated and variable concentrations of some components. The use of such water for drinking purposes requires advanced treatment. These waters usually occur in unconfined aquifers in areas of intensive human activity.

Chemical composition derived from natural and/or anthropogenic sources, with high concentrations of some components which makes treatment of such water uneconomical at present stage of technology.

typical groundwater quality assessment as well as specific parameters which may be found in contaminated areas of groundwater body at risk.

In the framework of Polish classification, the pollutants and pollution indicators (55 in total) are subdivided into four groups:

• general indicators (pH, TOC/DOC, conductivity, temperature, DOX);

• major inorganic species (necessary for ionic balance calculations: Ca, Mg, Na, K and Cl, SO4, alkalinity);

• secondary and trace inorganic species (Ag, Al, As, B, Ba, Be, Cd, CN, Co, Cr, Cu, F, Fe, Hg, Mn, Mo, Ni, NH4, NO2, NO3, Pb, PO4, Sb, Se, Sn, Ti, Tl, U, V, Zn);

• organic substances (AOX, BTX, petroleum hydrocarbons, PAH, individual Pesticides, total Pesticides, anionic surfactants, anionic and non-ionic surfactants, phenols, benzene, BaP, trichloroethylene, tetrachloroethylene).

The Polish classification differs from the approach proposed by EU, which is based on the concept of single threshold value. By introducing five classes of water quality it allows a deeper insight into the quality status of groundwater bodies. If only single threshold value is used, groundwater body which is subject of quality assessment can be characterized only by two values of chemical status: good or poor.

Figure 27.8 shows the application of both approaches (recommended by EU and the Polish one) to a small river catchment in southern Poland. The quality

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Fig. 27.8 Chemical status of groundwater in Raba river basin, Poland ([13], modified)

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Fig. 27.8 Chemical status of groundwater in Raba river basin, Poland ([13], modified)

classes can be presented on maps, either for individual points or in a generalized way for the entire aquifer. It is apparent from Fig. 27.8 that although the whole river basin is characterized by a good status, the quality of water varies with the region, including areas with poor quality status. This allows a more flexible management of groundwater body and early reaction to any undesirable trends in groundwater quality.

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