Heavy Metal Concentrations in Food Crops Grown In Crude Oil Impacted Soils in Olomoro, Delta State-Nigeria and Their Health Implications

Abstract

This research examines the heavy metal concentrations in crude-oil impacted soil (site 1) and un-impacted soils (site 2), in Olomoro, an oil producing community in Delta state. It also examines heavy metal concentrations in cassava tubers (cortex) and in plantain fruits (mesocarp) grown and harvested at both sites and the health implications of consuming these food crops. Heavy metal concentrations of soils pooled from both sites were compared. Results showed higher values of Cr, Cu, Fe, Pb, and Zn at site 1 than site 2, indicating that there is significant difference between both soils (p<0.05). Food crops grown and harvested from both sites were also compared, and results showed higher values in crops harvested at site 1 than those harvested at site 2, indicating a significant difference between food crops grown and harvested from both sites (p<0.05). Crops harvested from site 1 were compared with WHO acceptable limits for food and results showed that only Pb was above permissible limits (0.30mg/kg). Zn and Pb showed high accumulation in both food crops suggesting that there is a likely possibility of Zn and Pb poisoning if contaminated food crops are ingested. Research methods also involved the use of two structured questionnaire. The first questionnaire examined 130 households with 10 numbers of items to identify the common diseases experienced in households among others, while the second questionnaire administered to medical personnel showed the degree of prevalence of these common diseases. Common ailments experienced by household members were acute headache, body pain, stomach disorder, nausea/ vomiting and dizziness (acute symptoms of Pb and Zn poisoning) which were reported to be prevalently high among the people, while cancer, bone malformation in children, mental illness and depression (chronic symptoms) were not as prevalent as the acute symptoms of Pb and Zn toxicity mentioned earlier. The paper recommends among others that agricultural activities be carried out 5km away from petroleum activities/ oil spill sites and that public awareness and enlightenment be done in rural areas to warn the people about the dangers of consuming contaminated food crops and the associated health implications, since most of the populace are illiterates.