Heavy metals content in playground topsoil of some public primary schools in metropolitan Lagos, Nigeria
Assessing the concentration of potentially harmful heavy metals in playground topsoil from public primary schools in metropolitan Lagos, is imperative in order to evaluate the potential risks to the children in the schools. The study was conducted in order to determine if the concentrations of heavy metals in the soil is high enough to constitute a risk to children. Samples were collected from 20 schools in the Lagos metropolis and were subjected to microwave aqua regia digestion. Subsequently, the concentrations of the metals in the samples were measured using Graphite Furnace Atomic Absorption Spectrometry (GFAAS). The investigation revealed that Pb has the highest concentrations of all the metals. Mean metal concentration in playground soils were PbHD 23.08 ( 11.11, PbLD 23.54 ( 14.55; CrHD 5.99 ( 5.79, CrLD 3.80 ( 3.83; CdHD 0.33 ( 0.33, CdLD 0.39 ( 0.31; MnHD 1.60 (0.14, MnLD 1.61 ( 0.05 íg/g. Univariate analysis of variance showed that the metal concentrations in the high or low population density areas were not significantly different (p>0.05). Thus, pollution by metals in the dusts and soils is minimal for Pb and Cr and negligible for Mn and Cd while geographic location of the schools in high and low population density areas of Lagos state, Nigeria was not a determinant in the evaluation of children’s exposure to heavy metals.