Interaction Effect of Seasonal Variations on the Presence of Heavy Metals in the Environment and Ready-to-Eat Food in Parts of Port Harcourt Metropolis

Abstract

The presence of heavy metals in the environment and ready-to-eat street food were investigated to determine the interaction effect of seasonal variations on food safety in parts of Port Harcourt city. The study was carried out using complete randomization design in factorial experiment. The experiment was conducted in dry and wet seasons along the 3 locations (Makoba- 1, Elekahia- 2 and Rivers State University-3). The Six Food products studied were roasted plantain, fish, yam, suya, meat pie and doughnuts. Lead, Cadmium, Nickel, Mercury and Arsenic in Foods and Environment were examined. Heavy metal distribution in ambient air from stations 1-3 showed Cadmium (Cd) ranged from <0.01mg/100g – 0.2154mg/100g, with significantly high value of 0.2154mg/100g observed at Elekahia during the raining season. Arsenic was detected from Makoba at raining season and stations 1 and 2 during the dry season, with values of 0.0057mg/100g, 0.0104mg/100g and 0.0099mg/100g, respectively. Nickel values were negligible (<0.001). Lead values 0.0492mg/100g and 0.0650mg/100g were seen only at Makobar during the raining and dry seasons. The presence of Lead during the dry season was significantly different (P<0.05) higher value of 0.0650mg/100g at Makoba than the raining season. Cadmium (Cd) value of 0.0023mg/100g each were detected in roasted Yam (RY1) and Doughnut (DN1) from Makobar, while Lead, Arsenic, Nickel and Mercury were not detected in any of the Ready-to eat food samples during the raining season. Cd values of 0.003mg/100g, 0.003mg/100g and 0.004mg/100g were detected in roasted plantain (RP1, RP3), and roasted fish (RF2), respectively. Arsenic was noticed in suya (SY1-3) values of 0.025, 0.010 and 0.005mg/100g, respectively. While, Ni was only detected in meat pie (MP1 and MP2) (0.06mg/100g each). Lead and Mercury were not detected at dry season. The interaction effects of season and location on heavy metal deposit in ready –to-eat-street foods showed that while Cd was detected at levels of 0.0023mg/100g in roasted yam and doughnut from Makobar during the raining season, Cd was not present in same foods during the dry season. Arsenic was high during the dry season at Makobar, but not detected during the raining season. Nickel was present at level of 0.006mg/100g in meat pie during the dry season but not detected during the raining season. Further work on the comprehensive outdoor air quality and street food quality in Port Harcourt metropolis to serve as a protection to public health and consumer interest is hereby suggested.