## 4 Conclusions  
The comprehensive assessment of heavy metal contamination in the studied tributary's surface water and sediments reveals a complex and concerning scenario. The dominance of Cu and Ni in surface water and Zn and Cr in sediments, coupled with a noticeable increase in concentrations from Sample 1 to Sample 10, underscores a potential contamination gradient and the influence of external contamination sources, possibly linked to anthropogenic activities, such as industrial discharges and agricultural runoff. The hierarchical distribution of heavy metals and their correlation with various physicochemical parameters in both water and sediments elucidates potential sources and pathways of contamination. The strong correlations between certain heavy metals, notably between Cu and Pb, Ni and Cr, and Zn and TP, hint at shared origins or co-occurring release mechanisms, potentially tied to industrial activities, agricultural practices, and other anthropogenic influences. The elevated levels of heavy metals in sediments, surpassing guideline values, and the consistent elevation of PLI values across all sampled sites indicate a pervasive contamination issue and a potential risk to aquatic organisms and, by extension, the broader ecosystem. The elevated Ei values for Cd, As, and Hg and the increasing trend in Ri values from Sample 1 to Sample 10 further highlight the tangible ecological risk and suggest a contamination gradient or variable sources of contaminative input across the sampled sites. PCA uncovered intricate patterns in surface water and sediments, emphasizing the role of agricultural runoff in shaping water quality and sediment composition. The contrasting dynamics between matrices underscore the diverse nature of heavy metal influences. This study calls for continued exploration of PC 2 in sediments to unveil specific factors influencing heavy metal concentrations, contributing to a comprehensive understanding of environmental interactions in the tributary. The observed correlations and trends in heavy metal concentrations and ecological risk indices necessitate a multifaceted approach to managing and mitigating pollution in the tributary. This includes rigorous pollution source controls, stringent discharge norms, sustainable land-use practices, and community-centric approaches that amalgamate local knowledge, stakeholder engagement, and participative management. Future research should encompass a broader temporal scale to decipher seasonal variations in heavy metal concentrations and distributions. Investigating these heavy metals' bioavailability and potential bioaccumulation within the aquatic biota will provide a more holistic view of the ecological impacts. Employing advanced techniques such as isotopic fingerprinting and spatial distribution modeling could elucidate contamination origins and trajectories more precisely. The following supporting information can be downloaded at [[https://www.mdpi.com/article/10.3390/app14020904/s1](https://www.mdpi.com/article/10.3390/app14020904/s1)]([https://www.mdpi.com/article/10.3390/app14020904/s1](https://www.mdpi.com/article/10.3390/app14020904/s1)), Table S1. Classification of Igeo that represents various levels of pollution; Table S2. The background value for the respective metal; Table S3. Toxic response factor quotients for the studied heavy metals; Table S4. Various ER and RI index levels represent risks to the aquatic environment; Table S5. Water quality level determination based on the Nemerow pollution index method. **Author Contributions:** A.R. and X.Z. : conceptualization, analysis, and interpretation of data. E.N. and R.T.M. : sampling, experiments, and quantitative analysis. A.R. and X.Z. : manuscript writing and formatting. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable.