Levels and sources of heavy metals in house dust

The concentration and the sources of heavy metals (Pb, Cd, Zn and Cu) in ho use dust samples of nine selected houses of Jalil Town, Gujranwala, Pakista n are determined and a comparison with the concentration of these metals in respective street dust samples is given. Sources, exterior as well as inte rior are identified. The extent of contribution of lead in house dust from exterior sources and interior sources is calculated by determining the isot opic ratios in house dust, street dust and paint used in the houses. It is noticed in the case of well ventilated houses, that most of the heavy metal contribution is from the exterior sources. However, in less ventilated hou ses, contribution from the interior sources is also significant.