Understanding Plankton Community in the Post-mining Lake of Paringin District for Environmental and Reclamation Assessment

Paringin District is one of the coal mining areas in South Kalimantan with the exploitation method of open pit mining. This activity opens rock layers containing sulfur, reacting with water and oxygen, spreading sulfide acid into the environment. Analysis of the water quality of the Post-mining Lake in Paringin District is needed based on the biological parameters. The objective aims to analyze the water quality of the Post-mining Lake, Paringin District, based on plankton’s abundance, diversity, and dominance. This research was located in Post-mining Lake, PT. Adaro Indonesia. Data were taken at three sampling points in the pit pond and three depths. Data was taken from 2019 to 2021 using plankton net and analyzed using the enumeration method. The data was processed using the diversity index, dominance index, and saprobic index. Phytoplankton and Zooplankton abundance were dependent on three different depths (p-value>0.05). The most abundant phytoplankton species in all stations was Oscillatoria sp. (>90%) while Nauplius sp. (>30%) for zooplankton. Rainfall in the study area affected the number of individual species very weakly. The highest dominance value of phytoplankton and zooplankton was recorded around the end of 2019 to early 2020 as well as a saprobic index and diversity. Crustacea class considerably exists in all sites, which is Nauplius sp. and Daphnia sp. This situation proved there was a recovery of the plankton population in the lake, no algae blooming and a balance between nutrients and plankton population. In fact, the aquatic habitats are ready to accommodate large ecosystems.