Inter-varietal variation in elemental uptake by rice and its implications for public health : a case study of Dareta village, Zamfara State, Nigeria

Bakare, WA

Abstract

Nigeria is ranked first among the countries affected by Pb poisoning since it was reported in 2010 in
Zamfara State. The Pb poisoning epidemic in Zamfara received global attention from various
stakeholders and dietary Pb intake through rice which was identified as a major exposure route. There
is a need to understand the extent to which different rice varieties accumulate Pb and whether varietal
selection could be used to reduce dietary Pb exposure.
Whilst the Pb poisoning is having a truly devastating consequence, the dietary transfer of other
contaminants in Nigeria also needs to be understood. One group of contaminants that have received
very little attention to date in Nigeria is anthropogenic radionuclides. Nigeria is developing nuclear
power generation as part of its energy mix, there is a need to understand the potential food-chain transfer
of radionuclides released into the environment. Two radionuclides of importance in both operational
discharges and emergency (accident) situations are likely to be radio-caesium and radio-strontium.
Therefore, in addition to Pb, this thesis provides an evaluation of inter-varietal variation in stable
caesium (Cs) and stable strontium (Sr); stable isotopes are assumed to show the same environmental
behaviour as their radioisotopes. The uptake of nine essential elements was also evaluated.
Site characterisation was conducted first in Dareta village Zamfara Nigeria to select a suitable site for
the rice varieties’ field trial; local rice samples were collected from four selected rice farms to examine
Pb accumulation and partitioning in different parts of the rice plant (experiment 1). This was followed
by the field trial for the 10 most commonly grown Nigerian rice varieties (experiment 2). The field trial
was complemented by a pot trial for the same rice varieties at the University of Abuja, Nigeria
(experiment 3). At maturity, the rice varieties were harvested together with their respective soil samples
and analysed.
Experiment 1; Pb accumulation in the rice plant was in the order of root>shoot>seed. Pb accumulation
in shoots and rice seeds exceeded the FAO/WHO permissible limits of 10 mg/kg and 0.3 mg/kg
respectively. Bisalayi rice, ncro-49, ita-315 and art3-7l demonstrated low uptake and accumulation of
Pb in both experiment 2 and 3, whereas nerica-l34, nerica-l19, wita-4 and sipi rice varieties were found
to have high Pb uptake and accumulation. Statistically, there were no significant differences (p>0.05)
in the uptake and accumulation of the stable Cs and Sr in both trials using the concentration ratio (CR).
All the selected rice varieties were good source of the nine essential elements in terms of their
percentage contribution to the recommended daily intake (RDI).

Citation

Bakare, W. (2021). Inter-varietal variation in elemental uptake by rice and its implications for public health : a case study of Dareta village, Zamfara State, Nigeria. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Aug 4, 2021
• Publicly Available Date: Aug 2, 2023
• Award Date: Jan 1, 2021