ASSESSMENT OF HEAVY METALS IN OKRO (ABELMECHUS ESCULENTUM) CULTIVATED THROUGH IRRIGATION, IN MAIDUGURI, NIGERIA

OJN Preprints | Environmental Research | OJNPPer20043001 > This version is not peer-reviewed

Abstract

The contamination of the environment with heavy metals is one of the challenges that constitute Nigeria’s environmental problem with urbanization as one of the major causes due to unavailability of proper waste dumpsites and the act of landfills for infrastructural development thereby polluting rivers and streams around them. Cultivation of vegetables along channels and rivers that transcend major cities have been a concern globally in the recent decades due to accumulation of heavy metals and introduction of heavy metals into the food chain. Assessment of concentrations of heavy metals namely Aluminum, Iron, Lanthanum, Manganese, Chromium, Rubidium, Antimony, Scandium, Barium, Samarium and Zinc were carried out in Okro samples obtained on farmlands along the bank of river Ngadda and Alau dam and cultivated through irrigation The samples were analyzed using instrumental neutron activation analysis (INAA) analytical technique with the aim to assess their levels of accumulation with heavy metals and with the objective to ascertain the food safety status of the vegetable by  comparing the values obtained with maximum permissible limit (MPL) recommended by FAO/WHO for vegetables. The result showed that the concentration levels ranged from below detection limit (BDL) for Aluminum, Chromium, and Antimony to 843 ± 16ppm, 1.3 ± 0.2ppm and 0.26 ± 0.03 ppm respectively, Barium 7 ± 1.0 to 12 ± 1.0 ppm, Iron 11 ± 0.4 to 303 ± 36 ppm, Lanthanum 0.203± 0.03 to 1.93± 0.05 ppm, Manganese 22.9 ± 0.2  to 40.2 ± 0.2 ppm, Rubidium  7 ± 1 to 13± 1 ppm, Scandium  0.02 ± 0.00  to 0.05 ± 0.01 ppm, Samarium  0.02 ± 0.00  to 0.24± 0.01ppm, and Zinc 8 ± 1.0 to 24±0.1ppm. This result also indicates that the maximum concentration value of Manganese exceed the MPL recommended by FAO/WHO for vegetables therefore the consumption of Okro cultivated from the study site has a potential health risk due to the presence of Manganese above recommended value