All samples were digested and analyzed at Center of excellence for environmental and hazardous waste management, Chulalongkorn University by microwave digestion machine and inductively coupled plasma optical emission spectrometry, VISTA-MPX Axial (ICP-OES) respectively. Digestion method can digest the target heavy metals in this the study including lead (Pb). Moreover, ICP can analyze several metals per one time so include all of the six heavy metals (Cao et al, 2010) and (Wcislo et al, 2002). The concentrations of heavy metal were calculated in milligram per liter (mg/L) and milligram per kilogram (mg/kg) or ppm and the detection limit of lead was 0.001 mg/kg