ANALISIS STATUS MUTU AIR SUNGAI SIANGKER BERDASARKAN INDEKS KUALITAS AIR Water Quality Status Analysis of Siangker River based on Water Quality Index

Abstract

Sungai Siangker merupakan sungai yang terletak di Semarang Barat. Terdapat berbagai aktivitas di sepanjang aliran sungai tersebut, diantaranya pemukiman penduduk, perkotaan, dan pertambakan dimana buangan limbah masuk ke dalam badan sungai. Hal tersebut menyebabkan terjadinya penurunan kualitas perairan. Tujuan penelitian ini adalah untuk mengetahui konsentrasi nitrat, fosfat, BOD, dan COD, mengetahui status mutu air berdasarkan nilai indeks kualitas air (IKA), dan rasio BOD/COD Sungai Siangker. Penelitian  dilaksanakan bulan April 2019. Pegambilan sampel terdiri dari 3 stasiun yang masing-masing dilakukan 3 kali pengulangan. Stasiun I berada di kawasan pemukiman namun masih jauh dari pipa pembuangan limbah domestik, stasiun II berada setelah kawasan pemukiman dan di kawasan pertambakan, serta stasiun III berada di hilir Sungai Siangker. Berdasarkan hasil penelitian, konsentrasi rata-rata nitrat di Sungai Siangker sebesar 0,52 mg/l, konsentrasi rata-rata fosfat di Sungai Siangker sebesar 0,054 mg/l, konsentrasi rata-rata BOD di Sungai Siangker sebesar 28 mg/l, dan konsentrasi rata-rata COD di Sungai Siangker sebesar 113 mg/l. Konsentrasi  nitrat, fosfat, BOD, dan COD di beberapa titik telah melebihi baku mutu, baik baku mutu PP No. 82 Tahun 2001 kelas III untuk perikanan maupun baku mutu air laut untuk biota laut KepMenLH No. 51 Tahun 2004. Berdasarkan nilai IKA, kualitas air Sungai Siangker (IKA: 1,48 - 29,72) termasuk kategori tercemar ringan - tercemar sangat berat (kotor). Hasil rasio BOD/COD pada stasiun I (0,23), stasiun II (0,30), dan stasiun III (0,38) menunjukan bahwa bahan-bahan pencemar yang berada pada stasiun I, II, dan III bersifat biodegradable.

ABSTRACT

Siangker River is a river that located in West Semarang. There are various activities along the river flow, including the existence of settlements, restaurants, and aquaculture where waste effluents enter the river. It causes a decrease in water quality. The purpose of this study was to determine the concentration of nitrate, phosphate, BOD, and COD, also to determine water quality status based on Water Quality Index (WQI). The study was conducted on April, 2019. Samples of water from Siangker were taken from the upstream, midstream, and downstream. The sampling point was consisted of 3 points with 3 repetitions. Station I is located in a residential area but still far away from the domestic sewage pipe, station II is after the residential area and near a fishpond area, and station III is downstream of Siangker River. Based on the result, the average concentration of nitrate was 0.52 mg/l, the average concentration of phospate was 0.054 mg/l, the average concentration of BOD was 28 mg/l, and the average concentration of COD was 113 mg/l. The concentration of nitrate, phosphate, BOD, COD, and DO at some point has exceeded the quality, both quality standard PP No. 82 of 2001 class III and KepMenLH No. 51 of 2004 seawater quality standard for marine biota. Based on IKA, water quality of Siangker River (WQI: 1.48 – 29.72) included in the slightly polluted category - the very heavily polluted category. The BOD/COD ratio at station I (0.23), station II (0.30), and station III (0.38) shows that pollutants at stations I, II, and III are biodegradable.