Mercury in fish from the Madeira River and health risk to Amazonian and riverine populations

• Published in: Food research international Vol. 109; pp. 537 - 543
• Main Authors: Soares, José Maria, Gomes, José M., Anjos, Marcelo R., Silveira, Josianne N., Custódio, Flavia B., Gloria, M. Beatriz A.
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01-07-2018
• Subjects: Amazonia; Gold amalgamation-atomic absorption spectrometry; Location of capture; Methylmercury; Risk; Season; Tissue distribution; Gold amalgamation-atomic absorption spectrometry; Location of capture; Methylmercury; Amazonia; Risk; Tissue distribution; Season
• ISSN: 0963-9969; 1873-7145
• DOI: 10.1016/j.foodres.2018.04.069

The objective of this study was to quantify total mercury in highly popular Amazonian fish pacu, curimatã, jaraqui, and sardinha from the Madeira River and to estimate the exposure to methylmercury from fish consumption. The samples were obtained from two locations - Puruzinho Igarapé and Santa Rosa - near Humaitá, Amazonia, Brazil in two seasons of 2015 (high and low waters). The fish were identified, weighed and measured, and lipids were quantified. Total mercury was determined by gold amalgamation-atomic absorption spectrometry. Mean levels were used to calculate exposure of Amazonian and riverine populations. There was significant correlation (p < 0.05) between length × weight for all fish; length × lipid and weight × lipid were significant only for pacu. Total mercury levels varied along muscle tissue for the fish, except for sardinha; therefore muscle from the dorsal area along the fish were sampled, homogenized and used for analysis. The levels of total mercury varied from 0.01 to 0.46 mg/kg, with higher median levels in sardinha (0.24 mg/kg), followed by curimatã (0.16 mg/kg), jaraqui (0.13 mg/kg) and pacu (0.04 mg/kg), corresponding with the respective feeding habits along the trophic chain. Total mercury levels were not affected by the location of fish capture and by high and low waters seasons. Total mercury correlated significantly with length and weight for jaraqui and with length for sardinha (negative correlation). Total mercury levels in fish complied with legislation; however, exposures to methylmercury from fish consumption overpassed the safe intake reference dose for sardinha for Amazonians; however, for the riverine communities, all of the fish would cause potential health risk, mainly for children and women of childbearing age.
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•Total mercury levels in fish from Madeira River complied with legislation.•Due to high fish consumption methylmercury exposures overpassed the safe intake.•Estimated exposure confirms that mercury is still a potential health risk.•Total mercury levels were not affected by the location of fish capture and by seasons.•Total mercury content varied along the muscle of the fish, except for sardinha.