###### Abstract  
Groundwater quality and human health assessment in the vicinity of landfills can be performed with the use of numerous index methods. The aim of this paper is to present the results of the Environmental Risk Assessment (ERA) and Health Risk Assessment (HRA) in the vicinity of a municipal landfill complex for monitoring data from 1995, 2003, 2010, and 2021 and in the context of average statistical data about Poles. The calculations take into account an extended range of parameters, including sulphates, chlorides, and ammonium ions. The calculation results for the Horizontal ratio indicate that it should not be used for all parameters. This was mainly reflected in the low sulfate content of the water monitored by a piezometer directly below the old landfill. Other indicators, reaching as high as around 2000 (the Nemerov Pollution Index) or approx. 18,000 (the enrichment factor), confirm the negative impact of the landfill. The Hazard Index values reached almost 700, which would indicate a high risk to human health when consuming water with similar parameters. Overall, the results illustrate that using the selected indices to assess groundwater risk can be a valuable method for supporting long-term observations of groundwater quality, which can be used to make predictions using artificial intelligence methods. landfill; hydrogeology; risk; pollution indices; public health; Tychy; Poland +
Footnote †: journal: Applied Sciences  
assessed in many papers [17; 18; 19] due to the fact that even small concentrations of metals have negative and long-lasting effects. Negative effects on human health due to the type of metal and the amount of pollution can manifest as neurological problems, kidney disease, and an increased risk of cancer [20; 21; 22]. In the case of municipal landfills, it is necessary to pay attention to the monitoring of the main ions in groundwater [23; 24]. Chloride content in groundwater which does not exceed 250 mg/L is not regarded as an impurity [25]. However, groundwater and soil may contain increased chloride and sulphate concentrations as a result of the migration of pollutants from landfill leachate [26; 27]. In the case of water in the vicinity of landfills, the values of chlorides can reach 2000 mg/L [28]. There are a number of methods which can be used to assess the risk of groundwater pollution, such as estimation methods, parameter methods, ranking methods, hydrogeochemical modeling, and artificial neural networks. In the case of areas where the constant monitoring of changes in physicochemical parameters in groundwater is carried out, artificial intelligence methods can be used to assess the water quality and risk along with providing a forecast of changes [29; 30]. However, in areas where monitoring is carried out in accordance with the legal requirements or with an extended range of parameters, methods using indicators can be applied. There are a number of indicators that may be helpful in assessing the quality of groundwater in the vicinity of pollution sources [31; 32; 33; 34; 35; 36]. Many of the proposed indicators have been specifically designed to assess the metal content of water. Examples of these include the heavy metal pollution index and the metal pollution index [37; 38; 39]. In studies devoted to the impact of landfill leachate, it is extremely important to pay attention to the selection of the parameters for the assessment of water quality [40; 41]. However, the formulae used to calculate the indicators are constructed in such a way that in almost every case it is possible to change the range of the parameters and calculate the indicator based on another set [42]. The aim of this paper is to present the results of the Environmental Risk Assessment (ERA) and Health Risk Assessment (HRA) in the vicinity of a municipal landfill complex in Tychy (Southern Poland) using groundwater monitoring data from 1995-2021.