Monitoring and modeling of heavy metal contents in vegetables collected from markets in Imo State, Nigeria

Abstract

Vegetable consumption is one major exposure route of heavy metals to humans, but few data exist for Imo State, Nigeria. We assessed the contamination levels and associated health risk of cadmium (Cd), cobalt (Co), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn) in vegetables (Telfairia occidentalis, Pterocarpus mildbraedii, Gongronenina latifolium and Vernonia amygdalina) that are consumed frequently from markets (n=16) in three zones of Imo State, Nigeria. After wet-digestion of samples, the supernatant were analyzed using atomic absorption spectrophotometry. The mean concentrations in the four vegetables ranged from 0.006±0.003 mg/kg to 0.011±0.007 mg/kg for Cd, 0.064±0.012 mg/kg to 1.225±0.226 mg/kg for Co, 10.711±1.968 mg/kg to 25.088±13.975 mg/kg for Cu, 0.062±0.013 mg/kg to 0.307±0.210 mg/kg for Ni, 0.006±0.005 mg/kg to 0.012±0.002 mg/kg for Pb and 63.55±4.055 mg/kg to 104.126±24.080 mg/kg for Zn. Except for Zn, all heavy metals in the various vegetables were below the joint standard of Food and Agriculture Organization and World Health Organization. Although, overall load of heavy metal was very low, Zn had the highest contamination factor in vegetables. Heavy metals concentrations in vegetables generally showed low to high variations and statistically different (p<0.05). Average daily intake was below the provisional tolerance limit except for Zn. The target hazard quotient of metals in vegetables for both children and adults were below 1, indicating no potential risk to the public. Overall, heavy metals hazard index were below 1, indicating acceptable level of non-carcinogenic adverse health effect. However, potential multi-element contamination from ingestion is possible as revealed by the correlation profiling of heavy metals.

Determination and Human Health Risk Assessment of Heavy Metals in Floodbasin Soils in Owerri, Southeastern Nigeria

“…The adverse effects caused due to heavy metals agglomeration in plants eventually enter the food chain in the form of food and dust posing types of health hazards [2]. In humans, they are essential nutrients that are required for various physiological and biochemical functions in the body and may result in deficiency diseases or syndromes if not in adequate amounts but in large doses, they may cause acute or chronic toxicities [3,4].…”

Superparamagnetic polyvinylpyrrolidone/chitosan/Fe3O4 electrospun nanofibers as effective U(VI) adsorbents

“…Water sources are contaminated by different toxic pollutants, which are ubiquitous and affect water quality and as a result, the ecosystem and subsequently human health 2 . Therefore, there is an increased interest in the removal and recovery of toxic metals from process and waste waters using effective water treatment technologies.…”

Bioaccumulation and health risk assessment of heavy metals in Musa paradisiaca, Zea mays, Cucumeropsis manii and Manihot esculenta cultivated in Onne, Rivers State, Nigeria

“…One gram (1.0 g) of the powdered leaf and soil samples were weighed into separate corresponding test tubes and digested in 24 mL of aqua regia (HCl:HNO 3 = 3:1 v/v ) for three days as previously described [ 16 , 18 ]. The concentrations of Pb, Co, Cd, Zn, Ni, Cu, and Mn in the leaf and soil samples were measured triplicate using atomic absorption spectrophotometer (Buck Model 210) according to the methods previously reported [ 19 ].…”

“…where C HM is heavy metal concentration in plant leaf (mg/kg), D FI is daily consumption of M. paradisiaca , Z. mays , C. manii , and M. esculenta by adults and children based on related studies [ 19 , 21 ], which was put at estimated averages of 0.345 and 0.232 kg-person/day, respectively, and BAW is average body weights of the consumers based on field estimations using a mobile weighing scale (Hana instrument; China), which was put at 55.9 kg and 32.7 kg for adults and children, respectively [ 21 ].…”