No abstract

Intense pressure from both onshore and offshore oil exploration and exploitation activities, together with the accompanying urbanization and industrialization has resulted in massive contamination of land and water resources in Niger Delta, Nigeria. Whereas crayfish is very sensitive to contaminant in the aquatic environment and constitute an important part of human diet, its quality and safety from environmental pollutant is of serious health concern. Evaluation of dietary intake, potential carcinogenic and non-carcinogenic risk of lead, cadmium, mercury and arsenic exposure via consumption of dried crayfish purchased from major markets in Calabar, Nigeria was carried out between June and August 2021. Thirty-six composite samples of dried crayfish purchased from 180 vendors were used for the study. Heavy metals concentrations were determined using Atomic Absorption Spectrophotometer (Model AA-6800, Japan) after wet digestion. Metals concentrations (Mg/kg) were of the ranges 0.02 -0.24, 0.14 -0.86, 0.32 -0.72, 0.04 -0.19 for Pb, Cd, Hg and As respectively. The mean content of cadmium and mercury exceeded FAO/ WHO and Commission of European Communities maximum levels for crustaceans. Average Estimated Daily Intake for each of the metals was found to be above the recommended daily intake level except for arsenic. The average estimated daily intake values for Cd and Hg were also above the tolerable upper intake level.

Background: Heavy metals contamination has been reported at petrol station environments. There is a possibility of contamination foods around petrol stations. Objectives: In this study, the concentrations of Pb, Cd and Cr, long term exposure and daily consumption of ready-to-eat food foods sold at Petrol station’s Atmospheric conditions (AF) in Calabar Metropolis was evaluated. Methods: Foods samples, including such prepared ready-to-eat foods were collected at the point of sale at the fuel stations in Calabar Nigeria, about 7:00am in the morning before they were opened for sale (and exposed to the environment of the filling stations). These were labelled “Before”. At about 2:00pm to 3:00pm same day, the same ready-to-eat food samples were collected again at the same spots, for a duration of 3 months. Results: In this study, the levels of Pb, Cd and Cr were determined in some ready-to-eat foods that are sold around the filling station environments in Calabar metropolis. The results obtained showed that the levels of Pb and Cd were significantly (p<0.05) increased in garri, afang soup, melon soup, white rice, beans, stew and meat pie, while the level of and Cr was significantly (p<0.05) increased in afang soup, melon soup, white rice, beans, stew and meat pie after 6 hours of exposure to petrol station’s atmospheric conditions. Conclusion: From this study, it may be concluded that exposure of ready-to-eat foods at the filling station’s atmospheric conditions may cause heavy metal contamination to the foods, particularly Pb, Cd and Cr.