Evaluation of Selected Heavy Metals in Indoor Dust and Interior Painted Walls of Nursery Schools in Nairobi County, Kenya

Abstract

School playgrounds found in painted environments have become death chambers for millions of innocent children who unknowingly ingest toxic metals. The objective of this study is to determine the levels of the heavy metals in paint chips from painted interior walls and indoor dust samples from 14 selected nursery schools in Nairobi County. The paint chips and indoor dust samples collected were digested using the Environmental Protection Agency method SW846 3050B then analyzed using Flame Atomic Absorption Spectrometry. Iron (Fe) had the highest concentrations in both the paint chip from interior walls and the indoor dust while Cadmium (Cd) had the lowest concentration followed by Chromium (Cr), Lead (Pb) and Zinc (Zn) respectively. 50% of the nursery schools had Lead (Pb) concentrations that exceeded the 90 µg/g limit set by KEBS. For Cadmium (Cd) and Chromium (Cr), the concentration in the nursery schools and the indoor dust was below the 200 µg/g used in Germany. Generally, the correlation between the various metal pairs for the samples analyzed showed a non-significant correlation with exception of Lead - Iron (Pb-Fe) and Chromium - Cadmium (Cr-Cd) for the indoor dust samples from pre-schools. The t-tests carried out show that levels of the heavy metals in the paint chip did not differ significantly with the levels in the indoor dust for nursery schools at 95% confidence level.