Geochemical Distribution of Copper and Zinc in the Aquatic Sediment of Nyolo Spring Water at Karangploso Malang, East Java

Aquatic sediment has a role for heavy metals sink. Understanding the geochemical fractions of heavy metals in the aquatic sediment can predict the mobility and reactivity of heavy metals fractions that can induce environmental problem. The aim of this study was to determine the distribution of geochemical fractions of copper and zinc in aquatic sediment of Nyolo spring. Sediments samples were taken from five locations along the spring. Geochemical fractions of copper and zinc were extracted using BCR (Community Bureau of Reference) sequential extraction method. Concentration of these metals in each extract was analysed using AAS. The result showed that overall the sediment consisted zinc at higher concentration than copper. Amongst the geochemical fractions, Zn was dominant found as oxidizable fraction at 32.67 mg/g (23% ± 39.11) while copper was found dominantly at concentration of 5.09 mg/kg (20% ± 2.21). As the first fraction, Zn was more bioavailable than copper for biological uptake. Furthermore, based on the Risk Assessment Code (RAC) value, the aquatic sediment of Nyolo Spring was low risk to the Zn and Cu contaminations. This metals fraction will potentially available for organism uptake with the changing of pH and redox potential of sediment or overlying water.