Some physico-chemical and Heavy metal levels in soils of waste dumpsites in Port Harcourt Municipality and Environs

Abstract

Various physico-chemical techniques were used to investigate the characteristics and heavy metal concentration of soils in some selected waste dumpsites in Port Harcourt. This is because the soils act asvehicles for the permeability of leachates into various levels of aquifers in the environment. The results show that the soils are moderately acidic with a mean pH value of 5.5 for the 1m subsoil and 5.8 for 30cm soil depth in the various dumpsites, while the total organic carbon (TOC) levels show that it was low with 3.41% and 2.90% for depths 30cm and 1m respectively. The cation exchange capacity (CEC) of the soils showed a range of 21.36 – 28.79 meq/100g for a depth of 30cm and 20.94 – 26.44meq/100g for a depth of 1m soil level acrossthe waste dumpsites. The textural class of the soils was observed to be a mixture of sand, clay and loam in all the sites. Low sand fractions (>40%) was observed for almost all sites except for Elekahia and Eleme roads that had 64.7% and 56.4% respectively. The results of the heavy metal concentration in all the locations of the wastedumpsites were above permissible limits. In this study, the soil did not meet up the moisture requirement for a waste land filling and could therefore be prone to porosity, surface flooding and underground water pollution. It is therefore suggested that the use of impermeable geomembrane is necessary for all dumpsites to minimizeseepage of leachates from causing pollution of both surface and groundwater resources taking into account the possibility that the containment system may be threatened by any disaster.