Evaluation of Potential Dietary Toxicity of Heavy Metals of Vegetables

Abstract

Introduction: Consumers are exposed to a diversity of chemicals in all areas of life. Air, water, soil and food are all unavoidable components of the human environment. Each of those elements influences the quality of human life, and each of them may be contaminated.Objective: Levels of cadmium (Cd), lead (Pb), mercury (Hg) and nickel (Ni) in vegetables and soils from Ohaji, Umuagwo and Owerri in southern Nigeria were determined and the potential health risks assessed.Methods: Commonly grown vegetables, fruits and food crops were collected from three different sites in southern Nigeria, washed, oven-dried in a hot air oven at 70-80°C for 24 h. Dried samples were powdered using pestle and mortar and sieved through muslin cloth. Samples (0.5 g each) were digested with perchloric acid and nitric acid (1:4) solution. The presence of lead, cadmium and nickel were analyzed in samples using the Unicam Atomic Absorption Spectrophotometer (AAS) Model 929.Results: Concentrations of Cd, Ni and Pb in Ohaji exceeded maximum allowable concentrations for agricultural soil. Cadmium, Ni, and Pb in vegetables were highest in Murraya koenigii, Piper guineense and Amaranthus viridis Linn, respectively. The estimated yearly intake of Pb, Cd and Ni in commonly consumed vegetables, Green leaf (Amaranthus viridis), fluted pumpkin (Telfaria occidetalis) and Curry leaf (Murraya koenigii) in Nigeria were calculated to be 1,210, 150 and 456 mg.kg -1 , respectively. Conclusion:Taken together it might be concluded that these vegetables may contribute to the body burden of heavy metals especially lead.

Concentrations of Some Trace Elements in Vegetables Sold at Maun Market, Botswana

“…However, when they occur in high concentrations, they may cause acute or chronic toxicity (Das et.al, 2008) . Some metals like Pb, Hg, and Cr are toxic even at low concentrations and have been associated with many health issues like cancers, biochemical disorders and diseases of the nervous system (Orisakwe et al, 2012).…”

Comparative study of bioavailability and transfer of heavy metals from irrigation water and soil to <i>Amaranthus</i> spp. vegetables

“…Estimation of Transfer Factor, Daily Intake Rate and Target Hazard Quotient of Metals, Transfer Factor (Bioaccumulation Factor) was done using standard methods (Naser et al, 2012, Orisakwe et al, 2012, Iwegbue et al, 2013. Length of exposure (ED) was set to 16,936 days for Nigerian based on the average life expectancy of 48.4 years, from 2 years of age (Iwegbue et al, 2013).…”

“…Length of exposure (ED) was set to 16,936 days for Nigerian based on the average life expectancy of 48.4 years, from 2 years of age (Iwegbue et al, 2013). The average adult body weight (BW) was considered to be 55.9 kg, and average daily vegetable intake for adults (SFI) is considered to be 0.345 kg/person/day (Orisakwe et al, 2012). AT = ED for non-cancer risk (IDNR, 2013).…”

Bioaccumulation and associated dietary risks of Pb, Cd, and Zn in amaranth (Amaranthus cruentus) and jute mallow (Corchorus olitorius) grown on soil irrigated using polluted water from Asa River, Nigeria

“…In contrast, the levels of Zn in amaranth and the investigated metals in jute mallow were lower than the WHO daily intake levels. However, health risks can be exacerbated if the individuals are overweight since bodyweight can influence the tolerance to pollutants (Orisakwe et al 2012). Furthermore, increased dietary intake of Pb and Cd through the consumption of amaranth may increase the chance of developing various health disorders such as cardiovascular disease and hypertension.…”

“…Consequently, a number of studies have quantified the amount of heavy metals present in vegetables (Fatoba et al 2012;Orisakwe et al 2012). However, only limited studies have assessed the human health risks arising from dietary consumption of the contaminated vegetables in Nigeria.…”