Carcinogenic Potentials of Toxic Metals and Polycyclic Aromatic Hydrocarbons in Telfairia occidentalis and Talinum triangulare Impacted by Wastewater, Southern Nigeria

Abstract

Health risks of toxic metals and polycyclic aromatic hydrocarbons (PAHs) associated with the consumption of Telfairia occidentalis and Talinum triangulare impacted by wastewater from water treatment plants within Uyo Metropolis, Southern Nigeria, were investigated using standard methods. The level of toxic metals and PAHs was higher in vegetables impacted by wastewater from food processing industries than in the other investigated sources. The levels of cadmium (Cd), lead (Pb), arsenic (As), and chromium (Cr) in the vegetables exceeded their recommended limits by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO). Wastewater was confirmed as the major source of toxic metals in the vegetables. The estimated chronic daily intake of toxic metals through vegetables for both child and adult populations was lower than their tolerable daily intake. The hazard quotients of noncarcinogenic PAHs indicated higher values for children than adults. The vegetables contained all the priority PAHs except dibenz[a,h]anthracene. The estimated daily intake of PAHs was higher in children than in adults, except for phenanthrene. The threshold screening values for PAHs indicated lower non-carcinogenic health risks for consumers. The carcinogenic health risks of metals and PAHs via vegetables indicated a moderately high risk for both populations. The consumption of vegetables impacted by wastewater could result in serious health problems for both child and adult populations. This study has exposed the environmental and human health problems related to the use of wastewater for the irrigation of vegetable gardens, which hitherto were unavailable in the study area.