Trend of heavy metal contamination: A case study on the soil of Amassoma community, Bayelsa state of Nigeria

Abstract

Presence of heavy metal contamination in agricultural lands, even at low levels is not desirable for human and animal health. Six soil samples were taken from three locations in Amassoma community in Bayelsa state in the months of April from the year 2019 to 2021. These samples were taken from the rhizosphere of pawpaw tree and scent leaf from the depth of 0-30 cm Samples were prepared by wet-ashing in line with the method defined by Smith 1972 and subjected to Atomic Absorption Spectrophotometry (AAS) and readings analysed with SPSS V.23 and IBM Instat GraphPad Prism V.3. Unpaired t test and trend analysis (graph, moving averages and slope)was used to ascertain significant difference between the yearly means and WHO limit at P<0.05, and trends of heavy metal contamination over the study period respectively. Increase in contamination of Lead (Pb), Cadmium (Cd), and Nickel (Ni) from 2019 to 2021 was revealed as 0.050 mg/kg-1 year-1, 0.005 mg/kg-1 year-1, and 0.063 mg/kg-1year-1 respectively. There was no reported increase in Zinc contamination (0.00 mg/kg-1year-1). Yearly analysis revealed statistically significant differences in observed heavy metal concentrations to that of the WHO limit (p<0.05). The 2-tailed p-value between the means of heavy metals studied and that of the WHO limits were all significantly different. Recommendations are that more researches be conducted to determine heavy metal accumulations in soils in Amassoma and other communities in Bayelsa state Nigeria. Government effort is required to initiate concerted remediation processes of the reported heavy metals to curb future health dangers.