Occurrence of trace metals in food crops grown on the Mbale dumpsite, Uganda and human health risks.

Abstract

Food crops can be used as bio-monitors to assess potential food safety hazards to public health from contaminated agricultural environments. Globally, over 800 million people grow fruits, vegetables and grains on urban garden soils with unknown health risks. This worldwide practice has exposed consumers to pathogenic and carcinogenic risks from locally grown and imported contaminated foodstuffs such as Amaranthus cruentus and Zea mays - traditional and widely consumed crops across the globe. This study used Zea mays and Amaranthus cruentus crops to investigate the occurrence and spatial variations of aluminium (Al), chromium (Cr), iron (Fe), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), arsenic (As), selenium (Se), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations across the Mbale dumpsite, Uganda. Mean concentrations for Fe, Al, Zn, Mn and Cu were high in both crops whereas Pb, Cr, Co, Cd, As, Hg, Se and Ni occurred in trace amounts. Using the two crops as bio-monitors, significant variations for Al, Zn, Fe, Cr, and Co concentrations in individual crops were identified across the dump centre, hill slope and riverbank. The variations in Al, Zn, Fe, Cr and Co concentrations were specific for crop types, crop parts and location. The highest overall accumulation of metals was at the dump centre and in crop leaves. Except for Pb concentrations in Zea mays seeds, Cr, Pb, Zn and Al concentrations in other crop parts were above World Health Organization/Food and Agricultural Organization (WHO/FAO) consumer food safety limits. Therefore, Zea mays and Amaranthus cruentus consumption could pose health risks to consumers. Further health assessments and potential regulations are recommended to reduce potential health risks from metals in crops for human consumption. This article is protected by copyright. All rights reserved.