Assessment of Health Risk Associated with Heavy Metal Contamination of Edible Vegetables in Cement Contaminated Area
Edmund Richard Egbe
Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, College of Medical Sciences, University of Calabar, Nigeria.
Augusta Chinyere Nsonwu-Anyanwu *
Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, College of Medical Sciences, University of Calabar, Nigeria.
Sunday Jeremiah Offor
Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, College of Medical Sciences, University of Calabar, Nigeria.
Chinyere Adanna Opara Usoro
Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, College of Medical Sciences, University of Calabar, Nigeria.
Maise Henrietta Etukudo
Department of Medical Laboratory Science, Faculty of Allied Medical Sciences, College of Medical Sciences, University of Calabar, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
Aim: Heavy metal (HM) content of some vegetables in the vicinity of a cement factory can be a useful index for assessment of HM contamination of the environment associated with cement production.
Study Design: This cross sectional study was conducted at the United Cement Company at Mfamosing, Akamkpa local government area, Cross River State, Nigeria between February to November 2016.
Methods: One hundred and forty edible vegetables of Telfairia occidentalis (fluted pumpkin), Vernonia amygdalina (bitter leaf), Amaranthus viriditis (green leaf), Talinum triangulare (water leaf), Lavantheca africanum, Heinsia crinata and Gnatum africana were collected at varying distances and directions from the cement factory site and an area remote to the site serving as control. The lead (Pb), copper (Cu), manganese (Mn), iron (Fe), cadmium (Cd), selenium (Se), chromium (Cr), zinc (Zn) and arsenic (As) content of the vegetable samples were determined using atomic absorption spectrophotometry. Data were analyzed using analysis of variance at P = .05.
Results: The Pb, Cu, Mn, Fe, Cd, Se and Zn content of vegetables in all the locations studied were within the safe limits except for Cr and As levels of some vegetables from location closest to the factory which were higher than the safe limits. The HM content of all vegetables from location closest to the factory were significantly higher than those from other locations (P <0.001). The hazard quotient (HQ) of all HM in all the vegetables were <1 except for Mn in T. occidentalis which was >1. The hazard index (ƩHQ) for all HM in all the vegetables were >1.
Conclusion: Cement production is associated with chromium and arsenic contamination of edible vegetables and increase in hazard index of HM levels in vegetables closest to the factory which may be implicated in increased risk for development of deleterious health consequences to consumers.
Keywords: Cement dust, heavy metals, vegetables, contamination.