The Spatial Distribution of Heavy Metal Lead and Cadmium Pollution and Coliform Abundance of Waters and Surface Sediment in Demak

Various activities such as farming, industry, household waste, fish pond, and fishery can possibly affect the estuarine and coastal ecosystem. Demak waters, located to the east of Tanjung Emas Semarang, become an influential element of fishery industry that mostly produces anchovies and shrimps. This research was aimed at (1) analyzing the spatial distribution of heavy metal Pb and Cd in the surface water and sediment; and (2) investigating the abundance of coliform in Demak waters. Moreover, in this research, water pollution index was also analyzed and compared to other polluted water areas. It was found that the Pb content ranged from 0.6037 to 0.6647 mg·1^–1 whereas the Cd content ranged from 0.064 to 0.1707 mg·1^–1. Both lead and cadmium contents had surpassed the water quality standard. The Pb content in sediment ranged from 0.563 to 0.6823 mg·kg^-1 whereas the Cd content reached 0.0047 to 0.0577 mg·kg^-1. It showed that this sediment was not polluted by Pb and Cd. The analysis of water pollution index revealed that the pollution level found in Morosari, Rejo, Tuntang, and Lohbener estuary was low. On the other hand, Wedung and Serang estuary were heavily polluted. Compared to some previous studies, most of Pb and Cd contents in Demak waters were greater. However, lead and cadmium content in sediment was lower.