Impact and Health Risk Assessment of Heavy metals on Contaminated Tomatoes (Lycopersicum esculentum) Consumed in Gombe Metropolis

Abstract

Tomatoes consumed in Gombe are contaminated with traces and heavy metals due to accumulation of these metals in soil that absorbed by crop plants, which is the most serious environmental problem with significant implications on human health. This study focused on the comparative studies on concentrations of carcinogenic and non- carcinogenic heavy metals analyzed based on WHO Permissible limits. Sample T1 Tomatoes showed mean concentrations in decreasing order of Zn = 0.094 ± 0.045 mg/kg followed by Mn = 0.0744 ± 0.0031 mg/kg then Ni = 0.0394 ± 0.0014 mg/kg, Fe = 0.0163 ± 0.00113 mg/kg, Cd = 0.0063 ± 0.00106 mg/kg, Pb = 0.0031 ± 0.0062 mg/kg, Co = 0.00152 ± 0.00126 mg/kg, As = 0 respectively. Sample T2 showed mean concentrations of heavy metals with the highest of Ni = 0.2095 ± 0.27 mg/kg followed by Zn = 0.1761 ± 0.134 mg/kg, Mn = 0.0487 ± 0.0023 mg/kg, Fe = 0.0233 ± 0.00195 mg/kg, Cd = 0.0147 ± mg/kg, Pb = 0.0047 ± 0.0062 mg/kg, Co = 0.0075 ± 0.0065 mg/kg respectively with few above WHO limits of 0.002 – 0.005mg/kg. Sample T3 Tomatoes showed mean concentrations with highest in decreasing order of Mn = 0.0829 ± 0.017 mg/kg followed by Ni = 0.0809 ± 0.00412 mg/kg, Zn = 0.0504 ± 0.0031 mg/kg, Co = 0.0225 ±0.00080 mg/kg, Cd = 0.0179 ± 0.00243 mg/kg, Fe = 0.0143 ± 0.00057 mg/kg. As = 0.0011 ± 0.000265 mg/kg, Pb = 0.0004 ± 0.000058 mg/kg respectively. Hazard Index (HI) of non-carcinogenic Heavy metals analyzed in Tomatoes samples showed highest hazard index in all the three pathways with Co = 3.64 E+ 00 followed by Pb = 2.71E+00 then Cd = 5.51E-01, Ni = 1.07E-02, Mn = 6.81E-03, As = 2.16E-03, Zn = 7.79E-04, while the lowest Hazard index was shown by Fe = 5.62E-05 indicating HI > 1 with adverse health risk in decreasing order of Co > Pb > Cd > Ni > Mn > As > Zn > Fe respectively. Cancer risk effects of carcinogenic heavy metals investigated through ingestion showed the highest cancer risk of Cd = 4.10E-05 followed by As = 3.23E-07 then Pb = 7.14E-06 with order of Cd > As > Pb > Co while cancer risk through inhalation showed the highest in Co = 1.27E-11 followed by Cd = 7.06E-12 then As = 4.76E-13, the lowest of Pb = 4.41E-14 with order of Co > Cd > As > Pb indicating that some heavy metals contaminated the tomatoes analyzed were projecting while hazard and cancer risk on human health will persisted on body systems at certain prolong time, examining of these heavy metals levels will safeguard public health.