Muara sungai adalah ekosistem transisi vital yang rentan terhadap pencemaran, seringkali dari limbah domestik dan industri. Penelitian ini menganalisis kualitas air Sungai Muara Asam-Asam berdasarkan parameter fisika (suhu, TSS), kimia (DO, pH, BOD, COD, minyak/lemak), dan menentukan status mutunya menggunakan Metode STORET. Pengambilan sampel dilakukan selama dua minggu di dua stasiun, mencakup kondisi pasang dan surut. Hasil menunjukkan bahwa suhu, pH, DO, dan minyak/lemak umumnya memenuhi baku mutu Kelas II (PP No. 22 Tahun 2021). Namun, TSS (hingga 142 mg/L) dan BOD (hingga 14,84 mg/L) secara konsisten melampaui baku mutu. Analisis STORET mengklasifikasikan Sungai Muara Asam Asam sebagai cemar sedang (skor -10 hingga -15). Beban pencemaran organik dari limbah domestik dan pengadukan sedimen akibat pasang surut diidentifikasi sebagai penyebab utama degradasi. Studi ini menekankan urgensi mitigasi pencemaran untuk keberlanjutan ekosistem dan pemanfaatan sungai.

Kata kunci: Kualitas air, Muara sungai, STORET, TSS, BOD, Pencemaran

Estuaries are vital transitional ecosystems highly susceptible to pollution, often originating from domestic and industrial waste. This research analyzed the water quality of the Muara Asam-Asam River based on physical parameters (temperature, TSS), chemical parameters (DO, pH, BOD, COD, oil/grease), and determined its quality status using the STORET Method. Sampling was conducted over two weeks at two stations, covering both tidal (high and low tide) conditions. Results generally indicated that temperature, pH, DO, and oil/grease met the Class II water quality standards (Government Regulation No. 22 of 2021). However, TSS (up to 142 mg/L) and BOD (up to 14.84 mg/L) consistently exceeded these standards. STORET analysis classified the Muara Asam-Asam River as moderately polluted (scores ranging from 10 to -15). Organic pollution loads from domestic waste and sediment resuspension due to tidal dynamics were identified as the primary causes of degradation. This study emphasizes the urgency of pollution mitigation for the sustainability of the ecosystem and the utilization of the river.

Keywords: Water quality, Estuary, STORET, TSS, BOD, Pollution.