Human Health Risk Assessment of Heavy Metals Contamination and Accumulation in Maga-Pouss Rice Fields, Far North Region of Cameroon

Accumulation of heavy metals in foodstuffs is a matter of concern for human health. In this sense, the present study was conducted in Maga-Pouss rice fields, the major rice-cultivated area in Cameroon, in order to assess the concentrations of iron (Fe), zinc (Zn), copper (Cu), mercuric (Hg), cadmium (Cd) and lead (Pb) in rice grains and their possible human health risks. Metals were measured by atomic absorption spectrophotometer (AAS) in irrigation water, paddy soils and rice plants and grains gathered from Maga, Ziam, Bakasaraï and Pouss villages. All selected heavy metals were detected in different samples, except Hg. The mean concentrations of heavy metals were in this order: Cu < Zn < Cd < Pb < Fe in water, Cd < Zn < Cu < Pb < Fe in the soil, Cd < Pb < Zn < Cu < Fe in rice plants and Cu < Cd < Pb < Fe < Zn in rice grains. The concentrations of Pb and Cd were alarmingly high in edible part of rice and excessively surpassing allowable values in rice grain. Thus, estimate daily intake, target hazard quotient, total hazard index and cancer risk values for Cd and Pb were greater than 1 for children and adults. These results showed that adults and children are at high risk of cancer and non-carcinogenic health risks through ingestion of rice grown in Maga-Pouss rice fields. Our finding shows the necessity to adopt mitigation measures to protect food from rice-growing area in Northern Cameroon.