Systematic\nReview and Spatiotemporal Assessment of\nMercury Concentration in Fish from the Tapajos River Basin:\nImplications for Environmental and Human Health

This study reviews the literature on mercury (Hg) pollution\nin\nthe Tapajós River basin from 1992 to 2022, focusing on the\nbioaccumulation in fish and the associated health risks to humans\nvia ingesting contaminated species. Variability in Hg bioaccumulation\nwas analyzed from both spatial (sub-basins) and ecological (trophic\nlevels) perspectives. Mercury concentrations in fish muscle tissue\nand spatial differences in Hg levels were analyzed using nonparametric\nKruskal–Wallis ANOVA and mapped with Inverse Distance Weighting.\nAdditionally, a risk assessment of mercury contamination was conducted\nusing the Target Hazard Quotient (THQ) and Maximum Safe Consuming\nQuantity (MSCQ) indices. Results indicate that Hg contamination is\npervasive across the basin, with piscivorous fish showing the highest\nHg levels, particularly in the middle Tapajós, upper Tapajs\nóand Teles Pires sub-basins, identified as contamination hotspots.\nPiscivorous species exhibited high Target Hazard Quotients (THQ),\nsuggesting health risks for local consumers. The MSCQ values indicated\nthat 75% of the fish species analyzed should be consumed in quantities\nlower than the current consumption daily average to avoid health risks.