Health Risk Assessment of Some Heavy Metals from Canned Tuna and Fish in Tijuana, Mexico

A main route of heavy metal exposure is the consumption of contaminated food or water, resulting in negative health effects. The objective of this study was to assess the health risk related to consumption of canned tuna and fresh fish by evaluating chromium (Cr), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations. Forty-eight samples of tuna canned in water and 20 samples of different fish species sold in the city of Tijuana were used. Samples were digested by microwave-assisted digestion. Mercury was measured using the cold vapor atomic absorption spectrometry (CVAAS) method (United States Environmental Protection Agency (USEPA) method 7419b) and Pb, Cd, and Cr were measured using graphite furnace atomic absorption spectroscopy (GFAAS) (USEPA method 7010). Health risk assessment was conducted calculating the total hazard quotients (THQs) using the USEPA region III risk-based concentration table for adults. The wet weight heavy metal concentrations in the canned tuna for Hg were 0.005 to 1.17 mg/kg, for Pb were 0.07 to 0.32 mg/kg, for Cd were from not detected (ND) to 0.007 mg/kg, and for Cr were 0.02 to 0.65 mg/kg. In the fresh fish samples, concentrations of Hg were 0.14 to 2.14 mg/kg, for Pb were 0.04 to 0.32 mg/kg, for Cd were 0.001 to 0.003 mg/kg, and for Cr were 0.07 to 0.38 mg/kg. The highest Hg concentrations were found in species of mako shark (Isurus oxyrinchus) and soupfin shark (Galeorhinus galeus). THQ values calculated were below one for all the samples. The results suggest that the consumption of canned tuna and fish in Tijuana does not represent a health risk for the general population in terms of exposure.