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
