ANALISIS KUALITAS PERAIRAN BERDASARKAN TOTAL BAKTERI COLIFORM DI SUNGAI PLUMBON, SEMARANG An Analysis of Waters Quality Based on Coliform Bacteria in Plumbon River, Semarang

ABSTRAK Sungai Plumbon merupakan sungai yang berada di daerah Mangkang Kulon, terletak di pemukiman padat penduduk. Terdapat sumber pencemar yang masuk ke dalam perairan diantaranya limbah industri rumahan maupun limbah rumah tangga Kegiatan ini dapat menurunkan kualitas perairan. Salah satu cara untuk mengetahui kualitas perairan adalah berdasarkan total bakteri Coliform. Tujuan dari penelitian adalah untuk mengetahui total bakteri Coliform, hubungan total bakteri Coliform dengan nitrat serta bahan organik total dan mengetahui beban pencemaran beserta indeks pencemaran di sungai Plumbon, Semarang. Penelitian ini dilaksanakan pada bulan Maret 2019 dilakukan setiap seminggu sekali dalam waktu dua minggu. Metode yang digunakan pada penelitian adalah metode observasi. Teknik pengambilan sampel menggunakan metode purposive sampling pada 3 stasiun dengan 3 titik di setiap stasiunnya. Analisis data yang digunakan meliputi analisis kepadatan bakteri Coliform, analisis kualitas air berdasarkan baku mutu dan indeks pencemaran, analisis beban pencemaran serta analisis korelasi pearson. Hasil penelitian menunjukan bahwa kepadatan rata-rata total bakteri Coliform berkisar antara 5.566 – 1.203.333 MPN/100 ml. Keberadaan total bakteri Coliform memiliki hubungan yang lemah dengan nitrat dan bahan organik total di Sungai Plumbon, Semarang. Kepadatan rata-rata total bakteri Coliform dan beban pencemaran bakteri Coliform yang diperoleh pada setiap stasiun tidak memenuhi baku mutu kelas II menurut Peraturan Pemerintah No. 82 tahun 2001, sedangkan status pencemaran di sungai Plumbon dikategorikan sebagai tercemar ringan hingga sedang. ABSTRACT Plumbon River is a river in Mangkang Kulon, It is located in densely populated settlements. There are pollutant resource such as home industry waste and household waste in the water. It can decrease water quality. The waters quality can be predicted with the total number of coliform bacteria. This research was aimed to obtain total Coliform bacteria, find the correlation between total Coliform bacteria with nitrate and organic matter, and pollution load with pollution index in Plumbon River, Semarang. This research was conducted on March 2019 and it was held every week in two weeks. The method used in this research was observation method. The sample of this research was taken purposively in 3 stations with 3 points in every station. The data analysis included the analysis of Coliform bacteria density, the analysis of water quality based on quality standards and waters index, the analysis of pollution load, and the analysis of pearson correlation. The result of this research was showed that average density of total Coliform bacteria in the range between 5.566 - 1.203.333 MPN/100 ml. The existence of total Coliform bacteria has low relation with nitrate and total organic matter in Plumbon River, Semarang. The average density of total Coliform bacteria and bacterial pollution load in every station was not fulfill the quality standards class II. Based on Government Regulation No. 82 of 2001,  whereas pollution status of Plumbon River has been categorized as mild to moderate polluted.