On the contribution of uncertainty factors to the risk assessment of the adverse impact of water chemical pollution

Introduction. Assessing the human health risks associated with exposure to chemicals is the foundation of modern preventive medicine and environmental policy. However, any risk assessment model relies on a number of assumptions, simplifications, and limited data. This is where the problem of “uncertainty factors” arises, many of which are often left outside the scope of standard calculations. Unaccounted for, their contribution can lead to a significant underestimation or, less commonly, overestimation of the actual risk, jeopardizing the effectiveness of management decisions and the protection of public health.

Materials and methods. Chemico-analytical studies were aimed at identifying a wide range of pollutants in various types of water. The comparison of chemical substances and the analysis of the obtained results were performed using the Kramer method, including the Threshold of Toxicological Concern (TTC) approach.

Results. The conducted studies confirmed the primary challenge for the centralized water supply systems in the region to be producing drinking water that meets regulatory standards when treating low-mineralized water with a high content of natural organic compounds. The findings demonstrate the drinking water in the distribution network of the city of N. in the Murmansk Region to be unsafe. This is due to both the chloroform content, which exceeds the Maximum Allowable Concentration (MAC) by 1.5 times, and the level of 3-chlorobutan-2-ol, which surpasses the Threshold of Toxicological Concern (TTC) by 3.5 times.

Limitations. The use of the TTC method is currently only possible for scientific purposes.

Conclusion. The TTC principle offers a rational approach to managing the risks of chemical substances for which complete toxicological information is lacking. It establishes a level of human exposure considered safe, below which the risk of adverse effects is deemed negligible, even in the absence of full data on the specific compound. Thus, the TTC principle provides a tool for the comparative assessment of different water sources or treatment technologies based on an integral indicator of chemical safety. This approach reduces toxicological uncertainty and provides specific quantitative benchmarks for further regulatory action.

Compliance with ethical standards. The study does not require the conclusion of the Biomedical Ethics Committee.

Contribution:
Alekseeva A.V. – concept and design of the study, writing the text, collecting material and processing data, editing, approval of the final version of the article, responsibility for the integrity of all parts of the article;
Rakhmanin Yu.A. – concept and design of the study, editing;
Malysheva A.G. – writing the text, collecting material and processing data.
All authors are responsible for the integrity of all parts of the manuscript and approval of the manuscript final version.

Conflict of interest. The authors declare no conflict of interest.

Funding. The study had no sponsorship.

Received: October 14, 2025 / Accepted: November 3, 2025 / Published: December 19, 2025

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