This study investigates mercury concentrations in fish samples purchased from a traditional market in Palangka Raya City, Indonesia. Mercury was quantified using the AAS technique, which had detection limits of less than 0.00004 mg/kg. The method’s accuracy was tested against a certified reference material of fish protein from the 2016 Indonesian National Standard no.2354.6 (SNI). The species under examination inhabited rivers in the peatland basin (e.i. wild-pangasfish - Pangasius pangasius, hemibragus - Bagrus nemurus, kriptoterus - Cryptopterus palembangensis, mad barb - Leptobarbus hoevenii, flatfish - Chitala lopis, rasbora - Rasbora argyrotaenia, anglefish - Pangasius microneme, wallago - Wallago leeri, prawn - Penaeus monodon); pond fish (e.i. nilefish - Nile tilapia, goldfish - Cyprinus carpio, pangasfish - Pangasius pangasius); sea (e.i. macarel scad - Decapterus, short macarel - Rastrelliger kanagurta, Spanish macarel - Acanthocybium solandri, pomfret - Parastromateus niger; squid - Loligo chinensis; sea - shrimp); swamp (snakehead – Canna marulius, catfish – Clarias batrachus, kissing gourami – Helastoma temminckii). The mercury concentrations, measured in wet sample weight, ranged from 8 to 3500 grams. The Target Hazard Quotient (THQ), Maximum Safe Consumption Amount (MSCQ), and Estimated Weekly Intake (EWI) were used to look at the health risk assessment analysis. The results were carefully looked over and discussed. We’ve concluded that eating 50 g of these fish types every day is harmful to people’s health in the study area.