Investigation of lead and other heavy metal emission sources and their depositions in indoors

Abstract

Heavymetals such as lead (Pb), nickel (Ni) and cadmium (Cd) are highly toxic metals that originatein the environment with heavy metal dust due to vehicular emissions on roadways andvariousindustrial chemical productionsand operations. This investigation was carried out to study the chemical and physical characteristics of differentsettled indoor dust samples collected from selected residences in suburban western province in Sri Lanka. Selected residences in six different locations which were in Kiribathgoda,Gampaha and Hanwella areas were subjected to this investigation.The toxic heavymetals content in different settled indoor dust samples were evaluated for six months periodtime from August 2007 to January 2008 in selected residences in each location.Indoor dust samples analysed for lead (Pb), nickel (Ni) and cadmium (Cd) indicated remarkably high level of lead and nickel in highly industrialised and urbanised Kiribathgoda area with themaximumlead and nickel content of 65.1:1:1.2mg kg-Iand 30.2:1:0.5mg kg-1respectively. Therefore,indoor deposition of dust is a majorsource of heavy metal pollutants which direct to serious environmental hazards. A statistical approach was employed to investigate the correlationsbetween toxic heavy metals in different dust samples collected from different locations. Analysisof paint chips samples from old houses without being painted for a longer period indicatedthat those paint chip contained higher amount lead up to 701.4:!::8.0mg kg-J.The experimentaldata showed that the amount oflead in paint chip samples collected from newly paintedhouses was relatively low. Therefore, releasing of lead from lead based paint which hadbeenapplied in old houses was also one ofthe majorsourcesfor indoor lead depositions. Analysisof heavy metals in different household paints in the Sri Lankan market indicated thatthe levelsof lead in paints analysedvaried from 12.4:1:0.3mg kg-Ito 666.1:1:13.3mg kg-I. Therefore, high levels of lead pigments and lead adiditives are still used by some paint manufacturersin Sri Lanka with increased risk of lead exposure to people. Those high levels of lead paints cannot be recommended for applications, since they have a potential risk of causinghealth hazards pertainingto lead poisoning in human being