How Land Stripping Affects Quality of River in Pomalaa Nickel Mining, South East Sulawesi, Indonesia

Land stripping due to mining activity affects the river quality located in Pomalaa. An objective in this study is to analyze a change in water quality of rivers around Pomalaa nickel mining during and post-mining activity. The water samples were taken periodically from the rivers and developed data time series. The instrument to analyze Total Suspended Solid (TSS) was gravimeter. Meanwhile, the iron (Fe) parameter was analyzed by using spectrophotometric and Cr, Cr⁶⁺, Cd, Zn, Cu, Ni, Co and Pb analyzed via atomic absorption spectroscopy (AAS) method. The pH determination was based on SNI 06-6989.11-2004 for evaluating water quality status. There are four class categories to determine water quality, where class A score is 0 (very good and has met the standard for quality), class B score is between -1 and -10 (mildly polluted), class C score is between -11 and -30 (moderately polluted), and class D score is ≥ -31 (severely polluted). The results showed that Huko-huko, Kumoro and Oko-oko rivers in Pomalaa were mildly polluted during the mining activity and moderately polluted as class II water. Total land stripping area between 2011 and 2016 was declining into 17,007 ha so that it was improving rivers quality.