Biomonitoring of Mercury, Cadmium and Selenium in Fish and the Population of Puerto Nariño, at the Southern Corner of the Colombian Amazon.

Abstract

Heavy metals threaten communities near biodiversity hotspots, astheir protein sources come from the environment. This study assessed Hg, Cd, and Seconcentrationsin fish, as well as the magnitudeof exposure and hematological conditions of adult citizens fromPuerto Nariño (Colombian Amazon). Among fish samples, greaterHg concentrations were found inhighertrophic levelspecies, including Rhaphiodon vulpinus (880 ± 130ng/g) and Pseudoplatystoma tigrinum (920 ± 87ng/g). These species presented the highest hazard quotients and lowest Se:Hg molar ratios among thosestudied, showing their consumption representsa health risk to consumers. Moreover, some samples of Mylossoma duriventre and Prochilodus magdalenaehadCd levels greater than the regulated limit (100 ng/g).The average total Hg(T-Hg) concentrations in human hair and blood were 5.31µg/g and 13.7µg/L, respectively. All hair samples exceeded the 1.0μg/g thresholdset by the USEPA, whereas 93% of the volunteers had T-Hgblood levelsgreater than 5μg/L, suggesting elevated exposure. The mean Cd level was 3.1µg/L, with 21% of samples surpassing 5µg/L, valueat which mitigating actions should be taken. Eighty-four percent of participants presented Se deficiencies (<100μg/L). There was a significant association between fish consumption and T-Hg in hair (ρ = 0.323; p = 0.032) and blood (ρ = 0.381; p = 0.011). In this last matrix, Se correlated with Cd content, whereas lymphocytes were inversely linked to Hg concentrations. The results of this study show that there is extensive exposure to Hg in fish, the consumption of which may promote detrimental impacts on hematology parameters within the community.