The Levels of Selected Heavy Metals in Solid Wastes and Their Environmental Pollution Effects in Bungoma Town, Kenya

The levels of Pb, Cd, Cr and Zn were analysed from classified solid wastes samples from a dump site in Bungoma town, Kenya. Soil samples from surrounding farm lands were also analysed for pH and heavy metal levels. The soil samples were digested by wet ashing and then subjected to flame atomic absorption spectrometry (FAAS) analysis. The results showed that the municipal solid wastes comprised more than 50 % of each waste sample and on average 60.90 % of all the wastes from the dump site. The mean concentrations (mg kg-1) of heavy metals in the dumpsite samples determined using the most reliable method of standard addition were 5.532.96, 6.602.45, 13.411.62 and 5.943.34 for Pb, Cd, Zn, and Cr respectively. While the mean concentrations in farm soil samples were 4.630.023, 5.080.005, 12.570.011, and 3.92 0.006 for Pb, Cd, Zn, and Cr respectively. The mean concentrations (mg kg-1) for Pb, Cd, Cr and Zn in the dump site samples obtained by less reliable but easy to perform external standard method were 1.150.27, 0.130.06, 0.0970.09 and 11.602.89 respectively while the mean concentrations (mg kg-1) in farm soils were 0.260.34, 0.00630.0026 and 7.825.79 for Pb, Cd and Zn respectively. The pH values range was 5.250.13 to 6.800.08 for sample D and reference sample respectively. However, there was no significant correlation between farm soil heavy metal contents and their pH. All the heavy metal concentrations were found to be below the maximum acceptable levels set by United States Environmental Protection Agency (U. S. EPA) regulations. The analysis of variance (ANOVA) F-test at p-0.05 (95 % confidence level) showed a significant difference between the two methods used in the analysis.