A comprehensive study of water quality in the Western Black Sea: Implementation of prospective human health risk assessment in Kastamonu, Turkey

Abstract

Water scarcity is becoming an increasing problem due to population growth and rapid urbanization. This study evaluates the water quality of Kirazlı Stream, located in the Kastamonu Province, in Turkey's Western Black Sea Region. To determine its suitability for regional use, samples were collected from 12 stations over 12 months between December 2021 and November 2022. A total of 24 physicochemical parameters were analyzed. Water quality classifications were assigned based on threshold values ​​from the European Union (EU), World Health Organization (WHO), and Turkey's Surface Water Quality Regulation (TSWQR). The results revealed that Kirazlı Stream, categorized as Class I water quality, is suitable for use. The order of the mean values ​​of cations were as follows: Na + > Ca 2+ > Mg 2+ > K + (39.14, 14.09, 12.45, and 5.95; mg/L), and order of anions: SO₄ 2− > Cl − > NO₃ − > PO₄ 3− (34.66, 7.48, 1.72, and 0.02; mg/L). Indices such as WQI (weighted arithmetic water quality index), HEI, HPI, and ERI indicated excellent to good water quality, whereas SAR and Na% indices supported its usability for irrigation purposes. However, the MH index suggested unsuitability for irrigation. Moreover, 25% of the sampling points met irrigation standards in terms of KR, while 75% did not. Potential health risks for both adults and children were below the threshold (HI < 1). Statistical approaches, including Spearman correlation, PCA and HCA, were employed to assess the physicochemical datasets representing water quality. This study is the first study conducted in the region to evaluate the water quality of the Kirazlı Stream and is an important reference for optimizing resource use and promoting sustainable water management.