Abstract

In recent times, heavy metals pollution is a public health concern due to their toxic, bioaccumulative nature and their tendency to persist in aquatic environment for extended periods. Human health ambient water quality criteria (AWQC) are defined as the safe concentration levels of chemicals in water that do not pose a risk to human health and very significant in accurate estimation of health risk of pollutants. Currently, the impact of aquatic vegetables is often overlooked in the formulation of these criteria in most countries. Consequently, this study incorporated the consumption of aquatic vegetables (Brasenia schreberi) into the derivation of AWQC and conducted a health risk assessment for five heavy metals present in Ntawogba Creek. The toxicological data for cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As) and zinc (Zn) were collected from different databases, screened, and used to develop AWQC for these heavy metals. The result revealed that the heavy metal concentration in water was in the order of Zn(30.95mgL^-1) > Cr(2.72mgL^-1) > Cd(1.84mgL^-1) > Pb(0.66mgL^-1) > As(0.005mgL^-1). Furthermore, the AWQC (consumption of water, fish and aquatic vegetables) value of the 5 heavy metals with respect to human health was in the order of As (0.73µg/L) < Cd (8.68µg/L) < Cr(19.1µg/L) < Cd(225.35µg/L) < Zn(2093.37µg/L). The hazard quotients of Pb, Cr, Cd, As and Zn were higher than the safe level (HQ=1), indicating that Pb, Cr, Cd, As and Zn in Ntawogba Creek posed a significant health risk. Therefore, greater attention should be given to the health risks posed by these metals from dietary intake related to surface water.