Water quality monitoring of Polder Air Hitam Lake in Samarinda

Abstract

This study aimed to evaluate the water quality status of Polder Air Hitam Lake, Samarinda, through monitoring several key water quality parameters and comparing the results with the Indonesian water quality standard (PP RI No. 22 Tahun 2021, Class II). Sampling was conducted from September to November 2023 at five monitoring stations. The measured parameters included chlorophyll-a, Dissolved Oxygen (DO), pH, temperature, Total Dissolved Solids (TDS), turbidity, salinity, and electrical conductivity. The results showed that chlorophyll-a concentrations ranged from 20.67–148.00 µg/L, indicating relatively high phytoplankton productivity, with several observations exceeding the quality standard threshold. DO concentrations ranged from 3.36–10.45 mg/L, while pH values ranged from 7.49–9.61, indicating slightly alkaline conditions. Temperature (27.2–31.27°C), TDS (172–215 ppm), and salinity (0.01–0.02‰) generally remained within acceptable ranges for freshwater ecosystems. Turbidity values (40–121 NTU) indicated considerable suspended materials that may reduce light penetration and affect aquatic productivity. Overall, the water quality of Polder Air Hitam Lake was generally within acceptable standards for several parameters; however, elevated chlorophyll-a, pH, and turbidity values suggest potential anthropogenic influences and indicate the need for continued monitoring and management efforts.