Chemometric investigation of river system contamination: Source identification and risk assessment using positive matrix factorization and Monte Carlo simulation

This study investigates the water quality of the Abdal River System in Türkiye, an important water supply for the metropolitan area, using chemometric applications, including Positive Matrix Factorization (PMF) for source apportionment and Monte Carlo Simulation (MCS) for health risk assessment. Surface water samples were analyzed for 14 potentially toxic elements (PTEs), including nutrients and other elements. Their concentrations, in ascending order, were: Cd (0.13) < Cr (1.34) < Pb (1.50) < Mn (1.89) < Hg (1.98) < Cu (2.96) < Ni (5.32) < As (7.17) < Fe (31.16) < Zn (151.48) < Al (320.86) < K (3631) < Mg (15607) < Na (18870) < Ca (72842) μg/L. The water quality was evaluated utilizing indices including Heavy Metal Pollution Index (HPI), Water Quality Index (WQI), and Contamination Degree (CD), with results indicating generally good water quality and minimal pollution levels. PMF analysis identified three primary sources of contamination: natural/geogenic processes, agricultural runoff, and urban activities including domestic runoff. Health risk assessments highlighted arsenic as the most significant contributor to non-carcinogenic and carcinogenic risks. For children, the hazard index (HI) for arsenic was 7.35E-01 (ingestion: 7.26E-01; dermal: 9.00E-03), remaining below the safety threshold of 1, indicating no significant non-carcinogenic risk. Similarly, the carcinogenic risk (CR) for arsenic was 2.92E-04, within the acceptable range (1E-06 to 1E-04). The Monte Carlo Simulation quantified variability and uncertainty in health risks, highlighting arsenic as the main contributor, with 16.15 % of scenarios for children exceeded the acceptable non-carcinogenic risk threshold. This study is the first to integrate PMF with MCS for a comprehensive evaluation of pollution sources and health risks in the Abdal River System, offering a novel approach to environmental management in semi-urban watersheds. The findings confirm the water quality is safe under current conditions but highlight the need for ongoing monitoring and targeted mitigation to ensure sustainable management of the Abdal River System.