## 3 Results and Discussion
### Heavy Metal Assessment through Various Indices
Arsenic, particularly noted for its toxicity, bioaccumulation, and potential to propagate through trophic levels [56], emerges as a conspicuous concern given its consistently high Igeo values, implying a pressing need for strategic intervention. A conspicuous disparity in the Igeo values among various metals underscores the complex contamination and sedimentation dynamics. Mercury, for instance, consistently manifested negative Igeo values across all samples, emblematic of comparatively unpolluted conditions. Contrasting sedimentation and dilution mechanisms might be influential, as proposed by [57], who emphasized the role of sediment particle size, organic matter, and redox conditions in modulating Hg distribution and bioavailability in sediments. The elevated levels of certain metals, such as Cd and Pb, even at localized hotspots such as Sample 10, warrant a comprehensive evaluation considering their ecotoxicological implications. Cd, renowned for its nephrotoxic, carcinogenic, and mutagenic properties [46], and Pb, noted for its neurological and developmental toxicity, elevate the ecological and health risk spectrums associated with the investigated tributary [58]. Zonal differences in heavy metal accumulation, evidenced by the spatial variability in Igeo values, suggest divergent contamination sources or transport mechanisms. Investigating the disparate contaminant profiles and scrutinizing the potential sources and pathways using isotopic fingerprinting or spatial distribution modeling, akin to methodologies adopted by [59], can discernibly elucidate contamination origins and trajectories. Implementing rigorous pollution source controls, enforcing stringent discharge norms, and adopting sustainable land-use practices will mitigate further contamination. Furthermore, community-centric approaches that amalgamate local knowledge, stakeholder engagement, and participative management will bolster the effectiveness and inclusivity of contamination management strategies. The Ecological Risk Index (Ei) and Potential Ecological Response Index (Ri) illuminated a noticeable presence and an alarming level of certain heavy metals across all sampling sites (Figure 5). Remarkably, Cd showcased elevated Ei values across all sites, reaching 245.7 in Sample 10. Similarly, As and Hg also demonstrated pronounced Ei, although not as critically elevated as Cd. A perceivable augmenting trend was discerned in Ri values, cascading from 280.94 (Sample 1) to 386.68 (Sample 10), potentially suggesting an augmenting ecological risk along the sampled path. The infiltration of heavy metals, notably Cd, As, and Hg, in the tributary sediments underscores a tangible ecological problem, revealing a scenario of pronounced metal contamination. The significantly high Ei values for Cd  
\begin{table}
\begin{tabular}{l l l l l l l l l} \hline \hline
**Igeo** & **Arsenic** & **Cadmium** & **Chromium** & **Copper** & **Lead** & **Nickel** & **Zinc** & **Mercury** \\ \hline Sample 1 & 1.05 & 2.04 & 1.44 & 1.39 & \(-\)0.06 & 0.69 & \(-\)0.07 & \(-\)1.902 \\ \hline Sample 2 & 1.06 & 1.92 & 1.24 & 1.49 & 0.01 & 0.71 & \(-\)0.11 & \(-\)2.13 \\ \hline Sample 3 & 1.05 & 2.03 & 1.27 & 1.57 & \(-\)0.13 & 1.09 & \(across all sampling sites burgeon above the typical range observed in uncontaminated sites, rendering it an element of critical concern. The previous literature documented Cd as a potent toxicant, even at minimal concentrations, imposing severe repercussions on aquatic life and potentially spiraling up the trophic chain [38; 60]. As and Hg also disturbed the sediments with notably high Ei values, entailing potential detrimental consequences. Arsenic is renowned for its non-threshold toxicity, culminating in severe ecological ramifications [56]. Concurrently, Hg's potential for bioaccumulation and biomagnification poses tangible threats to aquatic ecosystems and human health via seafood consumption [42].