Our research aimed to evaluate groundwater pollution risk in the study area in southeastern Poland, that is, in an area where the hydrogeological conditions and land use forms are similar to those of European plains. The authors’ own qualitative classifications of the potential impact of major forms of land use on groundwater quality and groundwater pollution risk are proposed. The degree of this risk was assessed as the sum of ratings of intrinsic vulnerability of groundwater to pollution assessed with the original DRASTIC method and ratings of the potential impact of land use. The obtained map of groundwater pollution risk showed that 0.3% of the study area was characterized as being at very high risk, 50% as high, 45% as moderate, and 4.7% as low. In a graphical manner, spatial relationships between selected factors affecting the groundwater pollution risk and the assessed degree of risk are presented. The assessment of groundwater pollution risk employing intrinsic vulnerability of groundwater to pollution and potential impact of land use forms, together with the proposed classification of groundwater pollution risk, made it possible to determine areas of high risk of groundwater pollution in the study area in an effective manner.

The predicting groundwater nitrate pollution risk, especially in terms of changes in fertilizing, has not been fully investigated so far. In particular, there is no comprehensive method to assess this risk in areas of different land use type, and not only in agricultural areas. The aim of this study was to develop a novel multicriteria methodology for groundwater nitrate pollution risk assessment, which meets these issues. A further aim was to determine how much this risk would change if the amount of organic and synthetic fertilization was reduced. An assumption was that groundwater pollution risk is a combination of the potential adverse impacts of land use, fertilization, and intrinsic groundwater vulnerability to pollution. The impact of fertilization was holistically evaluated by balancing nitrogen from spatially differentiated the size of the breeding, species of livestock, manure and synthetic fertilizers input, and spatially differentiated topsoil, with nitrogen uptake by different crops. The nitrate concentration in the leachate was used as a measure of the impact of fertilization. This concentration was compared to the natural baseline nitrate concentration in groundwater. Three fertilization scenarios for groundwater pollution risk assessment in two study areas were discussed. Under typical agricultural, climatic, soil, and geological conditions in Europe for the current total fertilization level of 95-120 kg N ha⁻¹ groundwater nitrate pollution risk is low and moderate, but for fertilization of 150-180 kg N ha⁻¹, a reduction in the total fertilization (synthetic and manure) by 40 to 50% may be required to achieve low risk of degradation of natural groundwater quality. Predictive simulations of groundwater nitrate pollution risk confirmed that reducing synthetic and organic fertilization has an effect, especially in areas with intensive fertilization. This method may allow for a holistic and scenario-based assessment of groundwater pollution risk and may help decision-makers introduce solutions to manage this risk under conditions of climate change, preservation of groundwater quality, and food security.

The layout of the dewatering system in open-cast mining must be adapted to mining assumptions and to the size of expected inflows, which, in turn, depend on natural conditions and the operation of other mines and groundwater intakes, affecting the arrangement of the hydrodynamic field. This case study analyses possible dewatering solutions related to a change in the mining drainage system: decommissioning by flooding of a depleted deposit and dewatering of a new one located in the vicinity. As part of numerical modelling, a solution was sought to minimise the environmental impact of drainage. Forecast calculations for two drainage alternatives were made. One of the solutions follows the classic approach: independent dewatering of the new excavation. The second solution assumes the recirculation of waters from dewatering of the new mine through their discharge into a closed and flooded pit located in the vicinity. The results of the forecasts for both variants point to the modification of the hydrodynamic field resulting from expected volumes of inflows and different environmental effects. The use of numerical simulations assisted the selection of the optimal dewatering solution.

This research was conducted in the lacustrine environment of Lake Wigry, one of the largest and deepest lakes in Poland. The main objective was to determine the relationship between the chemical composition of interstitial water, overlying water and bottom sediment in the different sedimentation conditions. Therefore, seven research positions were selected, taking into account different zones of lake and lithological type of deposits. Overlying water samples taken from zones with carbonate type of sediment (lacustrine chalk or calcareous gyttja) were characterized by slightly alkaline pH, similar hydrogeochemical type (HCO₃–Ca–Mg, HCO₃–SO₄–Ca–Mg), low values of mineralization and low metal concentrations. The situation is different with the water taken from the zone of organic: detritus gyttja or dy deposits. Overlying water collected from the Hańczańska Bay (estuary of Czarna Hańcza River) had the highest mineralization 552 mg/L, HCO₃–Ca type and low metal concentrations, while water collected from the dystrophic lake was SO₄–Ca–Mg type, low mineralized and acidic type. Studies of interstitial solutions collected from different lithological type of sediments showed noticeable chemical composition differences, both between the carbonate and organic sediments in the same reservoir, as well as in the same kind of sediment but exposed to different external conditions. The highest mineralization (2032 mg/L) was generally found in the interstitial water obtained from the detritus gyttja localized in the shallow positions, which are more exposed to pollution. The highest trace metals and nutrients content in the sediment and interstitial water found in the Czarna Hańcza River estuary were a result of the input from increasing industrial wastewater, domestic sewage discharge and runoff from agricultural soil. A greater resistance to adsorption of contaminants characterizes sediments composed of the lacustrine chalk; mineralization of their pore solutions was significantly lower. This fact is probably also affected by very low mineralization and chemical composition of overlying water and sediment.

Potable groundwater resources are at risk as a result of industrial development and an increase in fertilizer use. Protection of the groundwater supply may require the establishment of groundwater source protection zones (GSPZs) to allow the implementation of protective measures. The aim of this study was to develop a new approach to groundwater source risk assessment (GSRA). The risk was defined as the highest of the risks identified for individual potential sources of contamination (PSCs). The risk resulting from a given PSC is the combination of its adverse impact on groundwater, unwanted event probability, and adverse effect and annoyance to the population. A multicriteria assessment method was designed to estimate indices of the potential groundwater impact of industrial facilities and noninert waste landfills with the range and weight method. Application of the proposed approach was tested considering an idealized model and three scenarios involving various industrial PSCs and fertilization practices. The overall nitrogen load was compared to the maximum effective nitrogen load for the crops in question. Sensitivity analysis of this methodology revealed that the main factors influencing the risk to the water supply include the nonreactive contaminant mass load in PSC leachate and the ratio of the groundwater volume abstracted from wells to the amount of water flowing from PSCs into wells, which determines the dilution degree of the contaminant mass. This proposed interdisciplinary approach to GSRA provides a robust basis to reach decisions on GSPZ establishment and the development of a groundwater risk analysis methodology.