Health risk assessment of heavy metals in Coptodon zillii and Parachanna obscura from a tropical reservoir

Abstract

In this study, the concentrations of trace metals were examined in commercially important fish, Coptodon zillii and Parachanna obscura from Osu reservoir. These were with a view to providing baseline information on the levels of heavy metals and its associated risks to human health through fish consumption. Fish samples were collected fortnightly for five months using fish traps and gill nets with the assistance of local fisherman. They were brought into the laboratory in an ice chest for identification. The fish samples were dissected and the gills, fillet and liver kept in freezer and later analyzed for heavy metals based on Atomic Absorption Spectrophotometric (AAS) method. The data collected were subjected to appropriate statistical software packages. The results revealed that the concentration of the heavy metals in P. obscura and C. zillii across the tissues were not significantly different (p > 0.05) from each other. Also, the mean concentration of heavy metals in the fish were below the recommended limits of FAO and WHO. The target hazard quotient (THQ) for each heavy metals were below one (1) while the estimated hazard index (HI) for C. zillii and P. obscura showed no threat to human health risk through the consumption of the fish species. However, continuous consumption of the fish could probably cause health risk to the consumers of the fish. According to the study's findings, human consumption of fish species with low concentration of heavy metals at the current accumulating level is safe.