JPII 9 (4) (2020) 574-582 Jurnal Pendidikan IPA Indonesia http://journal.unnes.ac.id/index.php/jpii SEDIMENTS QUALITY BASED ON GEO-ACCUMULATION INDEX IN HEAVY METALS (Pb, Cu, and Cd) OF CENGKOK COASTAL WATERS, BANTEN BAY N. K. Wardani 1 , T. Prartono 2 , Sulistiono* 3 1,2 Department of Marine Science and Technology, Faculty of Fisheries and Marine Sciences, IPB University 3 Department of Aquatic Resource Management, Faculty of Fisheries and Marine Sciences, IPB University DOI: 10.15294/jpii.v9i4.24908 Accepted: June 12 th 2020. Approved: December 28 th 2020. Published: December 31 st 2020 ABSTRACT This area, which is located near the Banten Bay, is quite active with anthropogenic activities such as industry, fish- eries, settlements, and shipyards that have the potential to pollute the environment with heavy metals. This study aims to determine the chemical environmental conditions of the waters and the concentration of heavy metals in the sediments of Banten Bay. Sediment samples were taken at five stations consisting of river and bay sections in April, May, July, August, and September 2019. Heavy metal content in sediments was analyzed according to APHA 2012 using hydrochloric acid and nitric acid destruction methods. The results of heavy metal concentra- tions in sediments were compared with ANZECC 2000 regulations and sediment quality was determined using the Geo-accumulation Index. The sediment at the observation site is dominated by the silt fraction. The concen- tration of heavy metals in this study was obtained in the form of lead (Pb) ranging from <0.05 to 6.408 mg / Kg, copper (Cu) ranging from 0.059 to 8.791 mg / Kg, and cadmium (Cd) ranging from 0.042 to 0.605 mg / K. While based on the level of heavy metal contamination in sediments using the Geo-accumulation index (I Geo), the value of all metal types in each month has a value <0.000 at all observation stations. Thus it is concluded that the concentration of heavy metals in the sediment is lower than the threshold determined during the observation. So that the metal concentration weight in the sediment has no significant effect on the environment. © 2020 Science Education Study Program FMIPA UNNES Semarang Keywords: Banten Bay; heavy metals; sediments *Correspondence Address E-mail: onosulistiono@gmail.com INTRODUCTION Banten Bay is one of the active areas with industrial activities such as the Suralaya power plant, plastic raw material, chemical, steel, sugar, and shipping transportation activities that emit waste such as lead (Pb), cadmium (Cd), and cop- per (Cu). The presence of heavy metals in aquatic environments is a serious threat to ecosystems be- cause of their toxicity, which cannot be destroyed naturally, and the ability to accumulate biologi- cally in food chains. Heavy metals that get into the water can be in the form of dissolved metals or in the form of particles. Heavy metals have low solubility, are easily absorbed, and accumulate in basic sediments (Wuana & Okieimen, 2011; Zah- ran et al., 2015). The distribution of suspended and sedi- mentary heavy metals depends on physical and chemical interactions in the environment. When the heavy metal that is suspended in water has ex- ceeded the carrying capacity, the heavy metal will be deposited into the sediment. However, in some conditions, heavy metals in sediments can be re- leased into the water. Therefore, the sediment serves as a carrier as well as a good heavy metal reservoir. Sediments are rock particles, organic charts, and minerals formed due to the deposition process. Sediments are believed to act as filters for many metals originating from the mainland befo- re settling on the seabed and accumulating.