Health Risk Assessment of Heavy Metals in some Rice Brands Imported into Nigeria

Communication in Physical Sciences 2020, 5(2): 210-222 Authors: Kelle Henrietta Ijeoma, Ogoko Emeka Chima, Achem Daniel and Ousherovich Shola Ayotunde Received 29 April 2020/Accepted 26 May 2020   Rice is a major staple food in Nigeria and currently, the production capacity of the country cannot meet consumers; demand. Therefore, large quantities of rice are imported into the country without recourse to their heavy metal contents. Several research reports indicated that there is a likely possibility of heavy metal contamination of foreign rice and associated health hazards. Therefore, this study seeks to analyse foreign rice in Nigeria markets and identified their health implications. The result obtained indicated that mean concentrations of the heavy metal ions were Cd (0.0014 ± 0.00005 to 0.4322  ±  0.00005),  Cr  (0.0010  ±  0.00005  to 0.1080 ± 0.00005), As (0.0006 ± 0. 0001 to 0.1711 ±  0.0008),  Ni  (0.0007  ±  0.00001  to  0.8865 ± 0.00005), Hg (0.0024 ± 0.0001 to 0.0935 ± 0.001), Cu (0.0052 ± 0.00001 to 0.3208 ± 0.00005), Pb(0.0047 ± 0.00001 to 0.3974 ± 0.00001). Most of the imported rice brands have mean concentration (mg/kg) of the heavy metals below their maximum permissible limit (MPL) as set by FAO/WHO and Codex Alimentarius Commission (CAC). The hazard quotient (HQ) for the heavy metals in the imported rice brands range from 0.0006 (6 x 10–4)  to 5.0 while their hazard index (HI) range from 1.2 – 9.31. Most of the imported rice brands (62.5 %) and all the rice brands (100%) had HQ and HI for the heavy metals greater than one respectively pointing to the, likelihood and high potential for non-carcinogenic risks. The cancer  risk  assessment  value ranged from  8  x 10–6  to  1  x  103 which  suggest  probability  of cancer risks