Public health threats of heavy metals due to the consumption of Achachatina marginata (African Giant Land Snail) from a partially remediated site in Ikot Ada Udo, Akwa Ibom State, South-South Nigeria.

Abstract

The risk of oral intake of metals from the ingestion of contaminated Achachatina marginata was carried-out. Snail samples (n=48) were hand-picked, preserved in ice, then analyzed for zinc (Zn), nickel (Ni), chromium (Cr) using inductively coupled plasma-atomic emission spectrometry (ICP-AES, Yobin Yvon JY-24), then cadmium (Cd), lead (Pb) using graphite furnace atomic absorption spectrometry (GF-AAS, 4110ZL PerkinElmer). The mean levels of metals in snail from each sampling point were higher compared to the control site. SP 1 had the highest significant levels (p<0.05) of Pb, Zn, Ni, Cd, while SP 3 had the highest significant levels (p<0.05) of Cr compared to the control site. The mean heavy metals in the snail were 3.280±0.995mg/kg (Cd), 8.906±2.079mg/kg (Zn), 0.896±0.401mg/kg (Cr), 1.867±0.921mg/kg (Ni), 1.998±0.781mg/kg (Pb). The mean Cd, Cr, Ni, and Pb in A.marginata were above WHO acceptable limits for food. Heavy metals level in A.marginata had a decreasing trend of Zn>Cd>Pb>Ni>Cr. The estimated daily intake (EDI) of Cd (5.61×10-3mg/kg/day) was higher than the reference oral dose (RfD) value of 0.001mg/kg/day. The target hazard quotient (THQ) of Cd (5.61) and the hazard index (HI) of metals (6.80) were greater than 1. The carcinogenic risk (CR) of Ni (5.43×10-3) and Cd (2.13×10-3) from contaminated snails intake were higher than the safe range of 10-6 to 10-4. The THQ, EDI of Cd, HI of the metals, and the CR values of Ni and Cd in snails from the contaminated site reveals a potential future health challenge to consumers and a possibility of contracting cancer over a 70 year lifetime. Furthermore, the findings revealed that the site requires a thorough clean-up for the total restoration of the environment.