<p>Mercury (Hg) bioaccumulation in fish is a major pathway of human exposure, particularly in regions affected by gold mining. In Mato Grosso state, Juruena National Park (PNJu) overlaps with the Apiaká do Pontal e Isolados Indigenous Land, forming an area of high socioecological relevance under increasing mining pressure. This study assessed Hg contamination across environmental matrices (fish muscle, water, and sediment) within PNJu and evaluated associated human health risks under different fish consumption scenarios. Two non-carnivorous species, <i>Brycon falcatus</i> and <i>Leporinus friderici</i>, were selected for their importance to food security among Indigenous populations. Sampling was conducted at three sites with distinct mining influence. Mercury was present in fish muscle (<i>B. falcatus</i>: 0.18–0.92&#xa0;µg g⁻¹ w.w.; <i>L. friderici</i>: 0.41–0.60&#xa0;µg g⁻¹ w.w.) and in sediments (0.25–0.55&#xa0;µg g⁻¹ d.w.) at two sites. Risk quotient (RQ) values exceeded 1 for specimens with Hg concentrations &gt; 0.5&#xa0;µg g⁻¹. Estimated weekly intake (EWI) indicated that Indigenous and regional populations are exposed to Hg levels of 6.1–29.9 and 2.8–13.9&#xa0;µg kg⁻¹ body weight week⁻¹, respectively. Accordingly, Target Hazard Quotient (THQ) and Risk_Hg values exceeded safety thresholds (THQ &gt; 10; RiskHg &gt; 1) under these scenarios, whereas national consumption levels remained below risk. Maximum safe weekly consumption was more restrictive for <i>B. falcatus</i> (56&#xa0;g week⁻¹) than for <i>L. friderici</i> (96&#xa0;g week⁻¹). Our findings demonstrate species-specific distinct Hg-contamination patterns and a significant Hg exposure risk through fish consumption, even in protected areas, highlighting the vulnerability of high fish-consuming populations under weak Hg regulatory frameworks.</p> Graphical Abstract <p></p>