Application of Mathematical Models for Predicting the Trihalomethanes Content in Drinking Water in the City of Struga, North Macedonia

: Trihalomethanes (THMs) are the main disinfection byproducts created when chlorine reacts with organic matter of the drinking water. THMs in high concentrations are harmful and can be carcinogenic for the liver, pancreas, nervous system, development organs, whereas in women can cause miscarriage. Therefore, THMs recently have concerned very much the scientific community and the general public. Consequently, THMs must be constantly monitored. THMs mainly are determined by the gas chromatography method, which is a difficult procedure and very costly. To avoid this, in the past years the use of mathematical models for prediction of THMs in drinking water is practiced. By fast measuring of the values of some simple parameters of drinking water quality and replacing them in the mathematical models we can predict the THMs content. The aim of this article was the prediction of the THMs content in drinking water in the city of Struga for the spring of 2021 in four sampling points S1, S2, S3 and S4. The measured parameters and their average values with standard deviation were: water temperature (13.56± 1.17 ºC), residual chlorine (0.20  0.00 mg/L), pH (7.58  0.03), electrical conductivity (250.89  9.37 µS/cm), chemical oxygen demand (1.53  0.06 mg/L), total dissolved solids, (407.67  2.89 mg/L) and chlorides (5.26  0.32 mg/L), respectively. These values are then placed in mathematical models and with calculation is predicted the THMs content in drinking water. For prediction were used ten mathematical models and the average value of the THMs with standard deviation was 27.40 ± 10.67 µg/L). From the results we can conclude that the used models for THMs prediction have resulted successful and this content of THMs pose no risk to public health.