An Assessment of the Suitability of Selected Analytical Procedures Based on EN ISO 10705-2:2001 and EN ISO 10705-3:2024 for the Determination of Somatic Coliphages in Water Intended for Human Consumption

The objective of this study was to evaluate selected analytical procedures based on EN ISO 10705-2:2001 and EN ISO 10705-3:2024 for the determination of somatic coliphages in 100 mL water samples, taking into account the requirements of Directive (EU) 2020/2184, and to identify a procedure that can be adapted for routine analyses, as well as points at which laboratories may encounter difficulties. The study was conducted on two types of water samples: Type 1, comprising groundwater and treated water, and Type 2, comprising surface water. Samples were collected from water treatment plants at the point of distribution network supply (treated water), deep well intakes, and surface intakes (raw water). The study demonstrated the limited reliability of the procedure when applied to routine analyses. The recovery obtained for the method incorporating the selected modifications under the tested conditions was 72% for Type 1 water samples and 73% for Type 2 water samples. The introduction of legal regulations on the quality of water intended for human consumption, along with the requirement to test a new parameter for operational purposes, can pose a significant challenge for laboratories performing water analyses.