ILMU KELAUTAN September 2017 Vol 22(3):126-136 ISSN 0853-7291 *) Corresponding author © Ilmu Kelautan, UNDIP ijms.undip.ac.id DOI: 10.14710/ik.ijms.22.3.126-136 Received : 15-06-2017 Accepted : 20-08-2017 Fate of Heavy Metals Pb and Zn in the West Season at Jeneberang Estuary, Makassar Najamuddin 1* , Tri Prartono 2 , Harpasis S. Sanusi 2 and I. Wayan Nurjaya 2 1 Marine Science Department, Khairun University, Ternate Jl. Raya Pertamina, Ternate, Indonesia 97719 2 Marine Science and Technology Department, Bogor Agricultural University, Bogor Jl. Agatis, Kampus IPB Dramaga Bogor, Indonesia 16680 Email:najamuddin313@gmail.com Abstract The pollutant quantity of heavy metals entering water environment does not give complete answer toward the generated effect and risk, however it needs thoroughly study related to the pollutant dynamic. The aim of this research was to investigate the fate of Pb and Zn in water, such as: distribution, behavior, and reactivity (case study: Jeneberang Estuary, Makassar). Pb and Zn concentrations were determined using Atomic Absorption Spectrophotometry (AAS). The distribution of dissolved Pb and Zn showed a pattern that the lowest concentration was in the fresh water (the river zone), whereas the highest concentration was in the salt water (the marine zone). The distribution pattern of particulate Pb and Zn showed that the highest concentration was in the fresh water (the river zone) and the salt water (the marine zone), whereas the lowest concentration was in the estuary zone. The behavior of dissolved Pb and Zn tended to increase the concentration (desorption) along the increased salinity gradient. The residual fraction was the dominant component of geochemical fractions in the sediment that indicated the sources of Pb and Zn mainly derived from a natural process and the reactivity was low in the water. Keywords: distribution, behavior, reactivity, lead, zinc, pollution Introduction Recent studies of heavy metals are dominantly focused on the quantity analysis of dissolved elements and in the sediments of waters bottom. Several studies have been published, such as: from around coastal waters of Makassar (Samawi, 2007; Rastina, 2012), around coastal of Java (Hamzah and Setiawan, 2010; Lestari, 2011; Suryono and Rochaddi, 2013), Maluku (Rumahlatu, 2012), around of Sumatera (Arifin, 2011; Ahmad 2013; Purwiyanto, 2015), and Kalimantan (Arifin 2008). The complexity of environmental problems could not sufficiently be answered only toward the information of the dissolved element concentration and in the sediment. However, it needs further investigation related to the dynamics of elements in water environment. Martin and Whifield (1983) proposed that the existence and effects of elements in the water system should be associated with four main factors, such as: 1) the quantity of metals in the waters, 2) the composition of dissolved fraction and particulate in the waters, 3) the fate of elements in the mixing zone, and 4) the quantity and amount of heavy metals transferred from estuary to marine waters. Occurrence of elements in the waters is in two forms: dissolved and particulate forms. The dissolved metals are constantly in the water column and spread toward the pattern of water flow, while the particulate matter will be soon deposited and part of it will spread to water column, particularly the very small particles, and afterwards settle in the slow water movement. Both the metal forms play a role in the geochemical cycle of water environment. The dissolved and particulate elements took a role in the mechanism of adsorption-desorption, deposition-resuspension, and dispersion, thus determined the fate of the chemical element of heavy metals in the estuary (Sanusi, 2006; Kontas, 2012). In addition, the studies of heavy metals in the environment were also found limited, particularly on the geochemical fractionation of elements of sediment. The geochemical fractionation will characterize the chemical bond