# Operation of Water Supply Systems in the Czech Republic--Risk Analysis
## 3 Results and Discussion
### Risk Analysis
Operator C uses a multi-source system (reservoir water and groundwater wells), three water protection zones, and also carries out inspections of activities in the protection zones. It compensates farmers who cultivate fields close to the surface water source and achieve lower production yields due to more environmentally friendly fertilization practices, i.e., it tries to prevent contamination of the source and has an elaborate system of measures in place. Possible contamination of the source with synthetic pharmaceuticals and phytopharmaceuals is another identified risk. This risk was evaluated as significant for all operators assessed. Pharmaceuticals can enter water sources through various routes and can affect not only the environment but also the health of consumers. Recently, therefore, in addition to the classical indicators, so-called micropollutants have also been investigated in drinking water analyses. Some pharmaceuticals can change form and become resistant metabolites. These risks are also mentioned in the 2020 EurEua report, which identifies micropollutants from pharmaceuticals (including veterinary drugs) as risks to water resources [1]. Although the observed concentrations in water sources are currently low for most of them, these products can have a negative impact on aquatic ecosystems. This risk is also mentioned by [PERSON] et al. in their study [18] and also by [PERSON] et al. [19]. Moreover, the detectability of these risks is difficult. In the Czech Republic, the State Environmental Fund of the Czech Republic is trying to address this by supporting innovative technologies that contribute to a demonstrable reduction in pharmaceuticals in wastewater. Operator A (a small municipality) makes only limited use of in-house water analyses, as monitoring instruments are costly. If the source is already contaminated, some commonly used measures cannot be used here, e.g., the municipality does not have interconnected water supply systems or its own backup water sources. Interconnecting water systems are certainly an effective solution, but they are too costly for small communities. Operator B monitors the presence of drugs in the water only once a year as part of a complete water analysis, which includes a total of 65 items (listed in Annex 5 to Decree No 252/2004 Coll., determining the sanitary requirements for drinking and hot water and the frequency and scope of the monitoring of drinking water). This complete analysis is costly for a medium-sized operator and is therefore carried out only at the interval specified in the decree. No other measures have been taken. Operator C carries out monitoring, but not on a continual basis. In addition, there is no recommended procedure. Operator C focuses its monitoring on pesticides rather than pharmaceuticals. Therefore, the proposed measure is to establish a recommended procedure, to adopt a list of priority substances, and to review and update it regularly. The proposed measures also include the continuous monitoring of pharmaceuticals and phytopharmaceuals in the water treatment process, the use of a combination of aerobic and anaerobic treatments, and the use of advanced oxidation processes in the water treatment. The implementation of an information campaign towards the public on the management of unused medicines and trying to minimize the overuse of medicines is another proposed measure. The other major risks identified are climate change related. Floods can pollute and devalue water sources, so the level of risk is high, as is the probability of its incidence, but the detectability of the risk is almost certain given the current high accuracy and success of hydrological flood forecasts. The most likely cause of flooding is snowmelt or torrential rainfall. The risk of prolonged drought has been, for most operators, assessed as severe with a medium probability of incidence. Existing measures to prevent these risks are the shutdown of the affected source while using an alternative or emergency supply of drinking water to the population.