Urban soil assessment caused by heavy metals contamination in Yogyakarta City, Indonesia

The effect of urbanization and industrialization in the urban city is soil contamination by heavy metals. This study was conducted to assess Pb, Cu, Zn, and Cd, in the soil of Yogyakarta city and its surrounding, Indonesia. The assessment was done by analyzing 45 surface soil samples in the study area, divided into three-zone. They are divided based on the distance of each zone to the center of the city. The zone III is located in the outermost of the study area, and zone I is inside the city. The results of the study showed that generally, the highest concentration of metals was located in zone I, which is located near or directly situated in a city center. The result indicated that Pb and Cd had the highest pollution index compared to Cu and Zn. The pollition load indeks (PLI) and geoaccumulation indeks (Igeo) calculations in the whole study area showed that the values demonstrated a moderate class in average. Special attention was needed to be given to the zone I, which has a higher PLI and Igeo index to reduce the source of emission for Pb and Cd.