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

Nigeria is ranked first among the countries affected by Pb poisoning since it was reported in 2010 inZamfara State. The Pb poisoning epidemic in Zamfara received global attention from variousstakeholders and dietary Pb intake through rice which was identified as a major exposure route. Thereis a need to understand the extent to which different rice varieties accumulate Pb and whether varietalselection could be used to reduce dietary Pb exposure.Whilst the Pb poisoning is having a truly devastating consequence, the dietary transfer of othercontaminants in Nigeria also needs to be understood. One group of contaminants that have receivedvery little attention to date in Nigeria is anthropogenic radionuclides. Nigeria is developing nuclearpower generation as part of its energy mix, there is a need to understand the potential food-chain transferof radionuclides released into the environment. Two radionuclides of importance in both operationaldischarges 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 stablecaesium (Cs) and stable strontium (Sr); stable isotopes are assumed to show the same environmentalbehaviour 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 forthe rice varieties’ field trial; local rice samples were collected from four selected rice farms to examinePb accumulation and partitioning in different parts of the rice plant (experiment 1). This was followedby the field trial for the 10 most commonly grown Nigerian rice varieties (experiment 2). The field trialwas 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 samplesand analysed.Experiment 1; Pb accumulation in the rice plant was in the order of root>shoot>seed. Pb accumulationin shoots and rice seeds exceeded the FAO/WHO permissible limits of 10 mg/kg and 0.3 mg/kgrespectively. Bisalayi rice, ncro-49, ita-315 and art3-7l demonstrated low uptake and accumulation ofPb in both experiment 2 and 3, whereas nerica-l34, nerica-l19, wita-4 and sipi rice varieties were foundto 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 theirpercentage contribution to the recommended daily intake (RDI).

Level dc:type.qualificationlevel

Doctoral (Level 8)

Year dc:date.issued

2021

Author dc:creator

• Bakare, WA

Language dc:language

en

Identifier

oai:salford-repository.worktribe.com:1339841

Author Identifier

0000-0002-7736-043X

OAI identifier oai:identifier

oai:salford-repository.worktribe.com:1339841