KUALITAS PERAIRAN SUNGAI BANGER PEKALONGAN BERDASARKAN INDIKATOR BIOLOGIS

Abstract

ABSTRAK
Pembuangan limbah pabrik/industri, pertanian, maupun limbah domestik dapat menyebabkan degradasi kualitas air. Kualitas air dapat ditentukan melalui studi analisis biologi menggunakan biota akuatik fitoplankton sebagai bioindikator. Penelitian dilaksanakan di sungai Banger Pekalongan pada bulan Agustus - September 2006, bertujuan menilai kualitas perairan berdasarkan indikator biologis. Stasiun penelitian berjumlah 3 stasiun, stasiun A adalah daerah pangkal sungai Banger yang merupakan percabangan dan mendapatkan masukan air dari sungai Pekalongan, dimana di sekitar DAS Pekalongan terdapat aktivitas industri tekstil skala rumah tangga, stasiun B merupakan daerah pembuangan limbah beberapa industri tekstil, dan stasiun C adalah daerah sesudah area industri tekstil. Parameter biologi yang diukur meliputi Indeks Keanekaragaman (H`), Indeks Kemerataan (E), dan Koefisien Saprobik (X). Secara umum proporsi terbesar penyusun komunitas fitoplankton adalah kelas Bacillariophyceae dan Chlorophyceae. Kelimpahan individu fitoplankton berkisar antara 8535 - 22.972 individu/L. Indeks keanekaragaman berkisar antara 1,945 - 2,540 dan koefisien saprobik berkisar antara 0,17 - 1,31. Berdasarkan pendekatan indeks keanekaragaman dan koefisien saprobik, tingkat pencemaran dan kualitas perairan sungai Banger termasuk dalam kategori tercemar ringan sampai sedang.
Kata kunci : Fitoplankton, indeks keanekaragaman, koefisien saprobik, kualitas air

ABSTRACT
Disposal wastes from industrial, agricultural and domestic could degrade water quality. Water quality can be assessed by biological analysis using aquatic biota as a bio-indicator. Research took place at Banger River Pekalongan on August to September 2006, with the aims to examine water quality based on biological indicators. There are three research stations : station A is at the upland of the river where intake waters is from a branch of Pekalongan river in catchment’s areas of home based textile industries. Station B is in surrounding area where the textile industries dispose their waste; and station C is in the following area after the textile industries. Biological parameters that be calculated include diversity index, evenness index and saprobic coefficient. In general the biggest proportion of phytoplankton community is from class of Bacillariophyceae and Chlorophyceae. Phytoplankton individual abundance is around 8535 to 22.972 indv/l. Diversity index is around 1.945 to 2.540 and saprobic coefficient is 0.17 to 1.31. Based on diversity index and saprobic coefficient approaches, pollution level and water quality of the Banger River is categorized in little to middle pollution.
Key Word : Phytoplankton, diversity index, saprobic coefficient, water quality