Pengukuran Kadar COD, TDS, dan Logam Kromium Heksavalen Sebagai Pemantauan Kualitas Badan Air Sungai Bengawan Solo di UPT Laboratorium Dinas Lingkungan Hidup Gresik

This research was conducted to determine the levels of Chemical Oxygen Demand (COD), Total Dissolve Solid (TDS) and Metal Chromium Hexavalent (Cr VI) from Bengawan Solo River water as monitoring and supervision to determine the condition of water quality. Analysis of COD levels was carried out using closed reflux method using UV-Vis spectrophotmetry, the results obtained were 188.4 mg / L. Analysis of TDS levels using the gravimetric method obtained results of 5,134 mg / L and analysis of Cr-VI levels by UV-Vis spectrophotometry with diphenylcarbazide reagent in acidic conditions obtained results of -2.645 mg / L. Obtained negative levels because the results were below the MDL so that the sample could not be detected because the Cr-VI content was too low. Based on the East Java Provincial Regulation No. 02 of 2008, the standard class III river water quality standard for COD parameters is 100 mg / L. while the TDS parameter was 2000 mg / L and the Cr-VI parameter was 1 mg / L. It was found that COD and TDS levels exceeded the water quality standards so that the Bengawan Solo River water could not be used as freshwater fish cultivators, livestock, irrigation and / or other uses