Edible Mushrooms from Niger Delta, Nigeria with Heavy Metal Levels of Public Health Concern: A Human Health Risk Assessment.

Background: Mushrooms (US6759049B2, CA2372185A1, DE60108325D1) can be contaminated by heavy metals as described in various patents.

Objective: This study has determined the potential human health risk associated with the consumption of mushroom in Niger Delta, Nigeria. Concentrations of Pb, Cd, Sn, Cu, Ni, Al and Zn in both wild/cultivated mushroom and background soil/substrate were determined using Atomic Absorption Spectrometer (AAS).

Methods: Heavy metal pollution was calculated using Bio-Concentration Factor (BCF) and Pollution Load Index (PLI) while human health risk assessment employed Estimated Daily Intake (EDI), Target Hazard Quotient (THQ), Hazard Index (HI), Carcinogenic Risk (CR) and Total Cancer Risk (TCR). The mean concentration of metals in mushroom and soil/substrate ranged from 0.021 mg/kg - 29.16 mg/kg and 0.01 mg/kg - 56.11 mg/kg. When compared with standards by WHO, EU, SON, DPR, USEPA and NAFDAC, 100% violation was observed in Ni, Cu, Cd, Zn and partial violation by Pb in the mushroom sample although soil heavy metal concentrations were within safe limits.

Results: There was bioconcentration and heavy metal enrichment as PLI ranged from 3.39 - 23.58. Estimated daily intakes were (0.00 - 0.47, 0.00 - 0.51 and 0.00 - 1.17) mg/kg/day and THQ were (0.01 - 0.46, 0.01 - 0.31 and 0.03 - 1.51) for adults, adolescents and children respectively. There was a violation of Permissible Tolerable Daily Intakes (PTDI) set by JECFA. Hazard indices were all >1, another indication of health concern.

Conclusion: Nickel showed the highest carcinogenic risk with values of 4.83E-04 - 1.43E-01, 5.31E-04 - 1.00E-01 and 1.20E-03 - 2.29E-01 for adults, adolescents and children respectively. About 80% of TCR ranged from x10-1 - x10-3. Consumption of mushroom in Niger delta-Nigeria may pose significant health risk.