KOMUNITAS TUMBUHAN RIPARIAN YANG BERADAPTASI TERHADAP LIMBAH PENAMBANGAN EMAS TRADISIONAL DISEKITAR SUNGAI TABOBO DAN KAO KECAMATAN MALIPUT DAN KAO HALMAHERA UTARA

MUHLIS MUKARAM, S.Pd, Dr. Retno Peni Sancayaningsih, M.Sc.

2013 | Tesis | S2 Biologi

Kegiatan Pertambangan Emas Tanpa Izin (PETI), diindikasi telah memperparah kondisi perairan Sungai Tabobo. Salah satu masalah yang paling meresahkan bagi masyarakat di sekitar area PETI adalah penggunaan logam berat merkuri (Hg). Tujuan dalam penelitian ini adalah untuk menentukan kemelimpahan tumbuhan yang mampu beradaptasi terhadap lingkungan tercemar dan mengetahui besarnya konsentrasi logam merkuri (Hg) terserap oleh tumbuhan riparian di sekitar Sungai Tabobo dan Sungai Kao, Kecamatan Malifut dan Kao, Halmahera Utara. Ditentukan sebanyak 3 stasiun penelitian, yakni 2 sungai yang mewakili daerah tercemar kegiatan PETI, dan 1 sungai sebagai pembanding yaitu, sungai luaran Umbul Nilo, Margosuko, desa Daleman, Klaten. Digunakan 18 plot ukuran 1 x 1 m2 untuk setiap sungai. Analisis kandungan merkuri pada sampel tumbuhan dominan, dilakukan dengan Mercury Analyzer menggunakan metode destruksi basah. Famili Poaceae, Commelinaceae, dan Convolvulaceae dijumpai baik di sungai Tabobo dan sungai Nilo, terutama genera Digitaria dan Commelina, sedangkan Panicum dan Paspalum hanya dijumpai di 2 sungai tercemar, diduga berfungsi sebagai akumulator. Kandungan merkuri pada daun tumbuhan jenis Paspalum sp. baik di hulu, dan tengah Sungai Tabobo, masih di bawah standar yang ditetapkan (<0,01 ppb), akan tetapi di bagian hilir Sungai Tabobo menunjukkan kadar merkuri terukur sebesar 11,57 ppb. Kadar merkuri terukur pada daun pohon Macaranga sp. menunjukkan nilai 36,45 ppb. Sebaliknya, hasil analisis merkuri pada daun tumbuhan lantai jenis Panicum repens L. dan daun pohon Macaranga semiglobosa J.J.S. dari Sungai Kao menunjukkan nilai merkuri terukur masih di bawah ambang batas (<0,01 ppb).

The Illegally Gold Mining Activities (PETI), which exacerbated to the water conditions of the Tabobo river. One of the higher problems for the people around PETI area was the use of heavy metal mercury (Hg). The purpose of this study was to determine the abundance of plants that adaptable to the environmental condition and to analyze concentration of mercury (Hg) absorbed by riparian vegetation of Tabobo and Kao river, Malifut and Kao Regencies, North Halmahera. Three rivers were selected, two of them represented the high intensity of gold mining, Tabobo and Kao rivers, and “Umbul Nilo” water spring output at Margosuko, Daleman village, Klaten sub-regency as a control area. In each station were placed six square plots (1 x 1 m2 size) located in the upstream, midstream, and the down-stream of the selected river sites. The mercury content absorbed by dominant plants samples was analyzed using Mercury Analyzer after wet destruction. The research results showed that Poaceae, Commelinaceae, and Convolvulaceae were found both in Tabobo and Nilo river, especially Digitaria dan Commelina genera, while Panicum and Paspalum were only found in 2 polluted rivers, Tabobo and Kao. These assumed that they function as plant accumulator. The mercury content in the leaves of Paspalum sp. both in upstream and midstream of Tabobo River, has lower value compared to the standard (<0.01 ppb ), but in the downstream showed that mercury level absorbed by Paspalum sp leaves was high (11.57 ppb). Mercury levels of Macaranga sp. leaves tree in Beringin village had the value of the 36.45 ppb. On the contrary, mercury analysis of Panicum repens L. leaves representing floor vegetation, and leaves of Macaranga semiglobosa J.J.S. surrounding Kao River showed that the mercury contents were below the threshold value (<0.01 ppb).

Kata Kunci : Merkuri, Tumbuhan Riparian, PETI, Halmahera Utara 1