Assessment of chemical quality of ground waters exemplified in Major Groundwater Basin 332

摘要

The chemical state of groundwater in the Major Groundwater Basin (MGWB) 332 was assessed on the grounds of hydrogeochemical monitoring conducted in 2001-2003 in the network that comprised 37 monitoring wells (points). On the basis of concentration data of organic and inorganic chemical constituents, the chemical quality of water in the monitoring wells was evaluated. Aggregated data were used for an assessment of the chemical state of the whole basin. The evaluation of the water quality in the monitoring wells was conducted in accordance with the Directive of the Minister of Environment (RMS, 2004) by the comparison of concentrations of analyzed chemical constituents with limit values in the quality classes Ⅰ-Ⅴ.In general, the water quality fulfilled the criteria of Ⅲ class, occasionally of Ⅳ and Ⅴ.class. Water chemical state in MGWB 332 was evaluated as good, following the criteria specified in the EU Water Framework Directive 2000/60/EC and the draft EU Directive on the protection of groundwater against pollution (COM 2003), based on the mean values of chemical indicators for the whole basin. The recommended method of the chemical state assessment on the basis of mean concentrations in all the monitoring points caused vanishing the zones of unsatisfactory quality (class Ⅳ) in the averaged backgrounds. In practice, this will result in desisting from any action aiming to improvement of water quality in these zones. The results of this study show the need of reporting chemical state of groundwater quality also in the specific monitoring points, and not just in the averaged hydrogeologic units or subunits.