Metal pollution, eco-health risks and source apportionment in coastal sediments of Samsun, Türkiye: A receiving zone for the Kızılırmak and Yeşilırmak rivers.

This research examined the levels, sources, ecological risks, and health impacts of metal contamination in the coastal sediments of Samsun province, impacted by the Yeşilırmak and Kızılırmak rivers. Surface sediment samples collected from 18 sites representing various land-use types were analyzed for 13 metals (Ba, Cr, Mn, Ni, Co, Sr, Cu, Fe, Zn, Cd, Pb, As and Hg) using inductively coupled plasma mass spectrometry. Spatial assessment results revealed high Cr and Ni concentrations across all sites, primarily due to natural geological formations, while Cd, Pb, Cu, and Hg showed anthropogenic enrichment, particularly at sites near industrial and agricultural areas. Pollution and ecological risk indices as well as sediment quality guidelines (SQGs) were utilized to determine the contamination levels and ecological hazards associated with the metals. Pollution indices (EF, CF, PLI, NPI and MPI) indicated moderate to high pollution levels, mainly driven by Cr and Ni. Ecological risk indices (Er, RI and NRI) showed that Cd posed a moderate risk in sites influenced by industrial and agricultural activities. SQGs-based indices (mERM-Q, TRI and HQc) revealed that some sites exhibited toxic risk potential due to elevated Ni and Cr contents. Health risk assessments highlighted ingestion as the primary exposure pathway and indicated that children were more vulnerable thand adults. The Absolute Principal Component Score-Multiple Linear Regression model discovered three primary sources for metals: natural weathering (21.56 %), anthropogenic activities (32.35 %), and mixed sources (46.09 %). The findings emphasize the importance of determining local background values and sediment quality standards and reinforce the necessity for integrated management strategies to preserve coastal ecosystem health and public safety.