EUTROFIKASI NITROGEN DAN FOSFOR SERTA PENGENDALIANNYA DENGAN PERIKANAN DI WADUK SERMO (Eutrophication by Nitrogen and Phosphorous and Its Control Using Fisheries in Sermo Reservoir)

Abstract

ABSTRAK

Penelitian mengenai konsentrasi nitrogen (N) dan fosfor (P) dilakukan dengan tujuan untuk mengevaluasi tingkat eutrofikasi dan pencemaran air, menghitung neraca N total dan P total serta melakukan pengendaliannya menggunakan perikanan. Penelitian dilakukan menggunakan metode survai, yaitu melakukan pengambilan sampel dan pengamatan air secara purposive. Pengambilan sampel air di daerah waduk (hulu, tengah dan hilir waduk) dan daerah sungai (sungai masuk dan sungai keluar). Di daerah waduk diamati pada jeluk air: 0 m, 2 m, 4 m dan dasar. Pengambilan sampel air dilakukan tiap bulan, mulai Juni 2006 sampai Mei 2007. Vanabel penelitian meliputi: amonia, amonium, nitrit, nitrat dan fosfat; N total dan P total, suhu air, kekeruhan, TDS, TSS, O, terlarut, pH, CO, bebas, alkalinitas dan plankton. Eutrofikasi air oleh N dan P dianalisis secara diskriptif dan tingkat pencemaran air dihitung menggunakan Indeks Pencemaran (lP) yang disyaratkan PP RI Nomor 82. Neraca N total dan P total dihitung dengan input-output, sedangkan pengendaliannya menggunakan metode simulasi. Hasil penelitian menunjukkan bahwa eutrofikasi pada tingkat eutrofik sampai hipereutrofik, pencemaran air masih tergolong ringan di daerah budidaya ikan dan waktu konsentrasi P maksimum; budidaya ikan menggunakan KJA jaring ganda, penebaran dan pemanenan ikan di luar KJA dapat mengurangi residu dan beban N total dan P total.

ABSTRACT

The research of nitrogen (N) and phosphorus (P) in Sermo reservoir aimed to evaluate water eutrophication and pollution, to calculate N total and P total budget and to control its concentration using fisheries. The research was conducted by direct observation and measurement on water samples taken from inflow and outflow rivers, upstream, middle and downstream areas of reservoir. The samples is reservoir were taken at water depth: 0-2,4 m and the bottom. Observation was done monthly from June 2006 up to May 2007. the variables were ammonia, ammonium, nitrite, nitrate and phosphate concentration, N total and P Total, water temperature, transparency, turbidity, total dissolved and suspended solids, dissolved O₂, alkalinity and plankton. The research conclude that eutrophication level varies from eutrophic to hypereutrophic, light pollution was found in fish culture area and when the highest concentration of P, controlling of N and P by fish culture using double nets, fish stocking and harvesting in outside net cage may eliminate residue and decrease loading of N total and P total in the water