This research investigates heavy metal concentrations in soil around Lopburi Municipality open dumping site and to evaluate the possibility of their migration to adjacent areas. Soil samples from a control group (no leachate received), leachate affected, and sediments from a ditch around an open dumping site were collected and analysed for their copper, lead and zinc contents.  The study results show that leachate affected soils contain 42.91±5.23 mg Cu kg^-1, 19.68 ± 3.68 mg Pb kg^-1, 28.28±6.33 mg Zn kg^-1.  The metals observed are significantly higher than those found in a control group soil samples (36.70±5.08 mg Cu kg^-1, 15.72±4.11 mg Pb kg^-1, 22.01±5.97 mg Zn kg^-1).  This finding indicates that Lopburi Municipality waste disposal site is indeed a source of heavy metals to soils around the site through the migration of landfill leachate. The concentrations found, however, is lower than the standard values of Thailand’s Soil Quality Standard for Housing and Agriculture.  Statistical analysis also shows that the metal contents in sediments are significantly higher than those in leachate affected soil samples, particularly for lead and zinc that yielded  p value  as low as <0.000.  This suggests that dredging a ditch around a dumping site can immobilise and prevent the migration of heavy metals from a waste disposal site to adjacent soils.