Beragamnya aktivitas manusia sepanjang aliran sungai menyebabkan pencemaran terhadap sungai semakin meningkat, salah satunya yakni buangan limbah domestik. Sungai merupakan tempat buangan limbah dari berbagai aktifitas daratan. Tujuan dari penelitian ini untuk mengetahui kondisi kualitas air dari aspek parameter fisika dan kimia di Sungai Sesayap Kabupaten Tana Tidung. Metode penelitian yang digunakan adalah metode Storet. Hasil penelitian menunjukkan bahwa kondisi kualitas air pada Sungai desa Tideng Pale parameter suhu berkisar antar 25-32 C, salinitas berkisar 7-15 ppt, kekeruhan berkisar 1,15-4,43 mg/L, kecerahan berkisar 95-125 cm, pH berkisar 7,2-7,7, fosfat berkisar 0,006-0,063 mg/L, amonia berkisar 0,038-0,449 mg/L, nitrat berkisar 0,22-0,28 mg/L, DO berkisar 3,10-4,52 mg/L, BOD berkisar 1,12-2,17 mg/L dan pada Sungai Desa Sesayap parameter suhu berkisar 20-30 C, salinitas berkisar 8-15 ppt, kekeruhan berkisar 1,99-3,75 NTU, kecerahan berkisar 100-135 cm, pH berkisar 6,2-7,4, fosfat berkisar 0,025-0,038 mg/L, amonia berkisar 0,063-0,409 mg/L, nitrat 0,23-0,26 mg/L, DO berkisar 3,254,57 mg/L, BOD berkisar 1,23-2,23 mg/L sedangkan pada Sungai Desa Bebatu parameter suhu berkisar 22-36 C, salinitas berkisar 10-25 ppt, kekeruhan berkisar 2,13-4,19 NTU, kecerahan berkisar 110-130 cm, pH berkisar 6-7,8, fosfat berkisar 0,010-0,30 mg/L, amonia berkisar 0,065-0,525 mg/L, nitrat berkisar 0,26-0,30 mg/L, DO berkisar 3,10-4,60 mg/L, BOD berkisar 1,17-2,23 mg/L. berdasarkan penelitian tersbut bahwa kondisi kualitas air masih tergolong baik.
Kata Kunci: Kualitas air, Kabupaten Tana Tidung, Sungai

The diversity of human activities along the river causes pollution to the river is increasing, one of which is domestic waste disposal. A river is a place of waste disposal from various land activities. The purpose of this study was to determine the condition of water quality from the physical and chemical parameters in the Sesayap River, Tana Tidung Regency. The research method used is the Storet method. The results showed that the condition of water quality in the tideng pale village river temperature parameters ranged between 25-32 oC, salinity ranged from 7-15 ppt, turbidity ranged from 1.15-4.43 mg / L, brightness ranged from 95 to 125 mg / L, pH ranged from 7.2 to 7.7, phosphate ranged from 0.006 to 0.063 mg / L, ammonia ranged from 0.038 to 0.449 mg / L, nitrate ranged from 0.22 to 0.28 mg/L, DO ranged from 3.10 to 4.52 mg / L, BOD ranges from 1.12 to 2.17 mg / L and in village streams with temperature parameters ranging from 20-30 oC, salinity ranges from 8-15 ppt, turbidity ranges from 1.99 to 3.75 NTU, brightness ranges from 100 -135 cm, pH ranges from 6.2-7.4, phosphate ranges from 0.025- 0.038 mg / L, ammonia ranges from 0.063-0.409 mg / L, nitrates 0.23-0.26 mg / L, DO ranges from 3.25- 4.57 mg / L, BOD ranges from 1.23-2.23 mg / L whereas in the river rocks the temperature parameters range from 22-36 oC, salinity ranges from 10-25 ppt, turbidity ranges from 2.13-4.19 NTU, brightness ranges from 110- 130 cm, pH ranges from 6-7.8, phosphate ranges from 0.010 to 0.30 mg / L, ammonia ranges from 0.065 to 0.525 mg / L, nitrates range from 0.26 to 0.30 mg / L, DO ranged from 3.10 to 4.60 mg / L, BOD ranged from 1.17 to 2.23 mg / L. based on this research, the condition of water quality is still relatively good. Keywords: Water Quality, Tana Tidung Regency, River