KAJIAN DISPERSI BUANGAN PANAS DAN PENGARUHNYA TERHADAP BIOTA DI PERAIRAN LAUT SEKITAR PT. PUPUK KALIMANTAN TIMUR Tbk, BONTANG, KALIMANTAN TIMUR.

Abstract

This study of water outfall heat dispersion and its effect to the marine biota in the sea surrounds PT. Pupuk Kalimantan Timur Tbk has been done. The aim of this study are (1) Study a heat dispersion model from the heat water outfall source of PT. Pupuk Kaltim to the water receiver and (2) Analyze-the effect of dispersion of thermal water outfall to the marine biotic (plankton, nekton, and bentos) in the sea surrounds PT. Pupuk Kaltim. The location of this research is in the area of thermal water outfall of PT. Pupuk Kaltim at the water body to the radius of 3 km and at intake of PT. Pupuk Kaltim, so that its heat spread pattern can be covered. The used research method was a case study with sampling taking purposively in the research area by paying attention to the ease that can be reached technically. For the temperature checking in the horizontal direction, the sampling density taken follow the gradient of temperature decline from the ouoragmeanwhile the temperature variable in the vertical direction only be conducted in the area having a depth more than 8 meters. Data was analyzed by using a method of contour of heat spread From the result, it can be concluded that PT. Pupuk Kaltim discharged thermal calory is 1,396 x 109 kcal/hour. The temperature spread in the water surface is getting down with the decreasing that follows exponential pattern close to the average temperature of sea water ( 28 - 30°C), the limit of outfall output with its temperature is 39°C to 30° C, is in the furthest radius 3 km of outfall and then the temperature in the sea is about 28°C to 30°C. The vertically pattern of temperature spread in the areas with depth is more than 8 meters ( in the basin and alur area ) its basic temperature is almost 30°C, eventhough its surface temperature reaches above 35°C. The plankton density in the area with radius is less than 1 km, is about 15000 ind/liter, meanwhile in the radius that is more than 1 km mostly is under 10000 ind/liter, meanwhile the bentos condition in the area with surface temperature 33 - 37°C is founded with its average excess is 400/m2 it is not different with the condition outside of it. The fish treatment by using floating keramba in the radius of 600 meters from the outfall indicates a good result with its average weight is 250 grams in the age of 75 days, and the low mortality rate (3 percent). The amount of Belat catch in Lhok Tuan (1500 m of outfall) consists of 10 kinds of fish, the most amount is kind of Bawes (Siganus Vermiculatus). This shows that pollution of outfall from PT. Pupuk Kaltim still can be received by the environment and biota inside. Kajian dispersi buangan panas dan dampaknya terhadap biota laut di perairan laut sekitar PT. Pupuk Kalimantan Timur Tbk telah dilakukan. Penelitian ini bertujuan untuk (1) Mengkaji model dispersi panas dari sumber buangan air panas pabrik PT. Pupuk Kaltim ke badan air penerima dan (2) Menganalisis pengaruh/ dampak dispersi buangan panas terhadap biota laut (plankton, nekton dan bentos) di perairan sekitar PT. Pupuk Kaltim. Lokasi penelitian di area water outfal panas pabrik PT. Pupuk Kaltim pada badan air sampai radius 3 km serta di water intake PT. Pupuk Kaltim sehingga terliput pola penyebaran panasnya. Metode penelitian yang digunakan adalah studi lcasus dengan pengambilan contoh secara purposif pada lokasi penelitian dengan memperhatikan kemudahan yang bisa dijangkau secara teknis. Untuk pemeriksaan suhu pada arah horizontal kerapatan sampling diambil mengikuti gradien penurunan suhu dari outfall, sedangkan variabel suhu pada arah vertikal hanya dilakukan ditempat yang mempunyai kedalaman lebih dari 8 meter. Data dianalisis dengan model peta kontur sebaran panas. Dad hasil penelitian dapat disimpullcan bahwa Pabrik Pupuk Kaltim telah membuang kalor yang cukup besar yaitu 1,396 x 10 kkal/jam. Penyebaran temperatur pada permukaan air laut semakin jauh semakin than dengan penurunan yang mengikuti pola eksponensial mendekati temperatur rata-rata air laut (28 — 30°C), batas keluaran outfall dengan temperatur 39°C sampai 30°C, berada pada radius terjauh 3 km dari outfall dan selanjutnya temperatur di laut lepas berkisar 28°C sampai 30°C. Pola penyebaran temperatur secara vertikal di tempat-tempat dengan kedalaman lebih dari 8 meter (di area basin dan alur) temperatur dasarnya mendekati 30°C meskipun temperatur permukaannya mencapai di atas 35°C. Kelimpahan plankton di area dengan radius kurang dad 1 km rata-rata 15000 ind/liter sedangkan di radius lebih besar dari 1 km kebanyakan di bawah 10000 ind/liter sedangkan kondisi bentos di area dengan temperatur permukaan 33-37 °C ditemukan dengan kelimpahan rata-rata 400/m2 tidak jauh beds dengan kondisi di luar itu. Pemeliharaan ikan dengan karamba terapung di radius 600 meter dari outfall menunjukkan hasil yang baik dengan berat rata-rata 250 gram pada umur 75 hari, dan tingkat kematian yang rendah (3 persen). Hasil tangkapan Belat di daerah lhok than (1500 m dad outfall) tertangkap 10 jenis ikan, terbanyak jenis Bawes (Siganus vermiculatus). Hal ini membuktikan bahwa cemaran dad outfall pabrik PT Pupuk Kaltim masih bisa diterima oleh lingkungan dan biota yang ada di-dalamnya.