Kadar dan Sebaran Pencemaran Merkuri (Hg) di Lokasi Penambangan Tradisional Emas Primer Desa Paningkaban, dan Sekitarnya, Kabupaten Banyumas Provinsi Jawa Tengah

FRAGA LUZMI FAHMI, Dr. Wawan Budianta, M.Sc & Dr. rer. nat. Arifudin Idrus

2014 | Skripsi | TEKNIK GEOLOGI

Penelitian ini berlokasi di Desa Paningkaban dan sekitarnya, Kecamatan Gumelar, Kabupaten Banyumas, Propinsi Jawa Tengah. Daerah penelitian merupakan daerah mineralisasi emas, sehingga banyak aktivitas penambangan emas tradisional di daerah ini. Lokasi penambangan tersebar di daerah lereng perbukitan yang menghadap ke selatan-barat daya dan utara-timur laut. Di daerah tersebut terdapat lembah-lembah perbukitan yang dialiri oleh Sungai Tajum. Penelitian dilakukan untuk mengetahui kadar dan sebaran merkuri (Hg) di sekitar daerah mineraliasasi emas dan lokasi penambangan emas berdasarkan data kadar Hg pada 6 jenis sampel: urat/mineral bijih, tailing, tanah dan batuan permukaan, air sungai, sedimen sungai, dan air tanah. Pengambilan sampel secara acak dan berada di daerah sekitar area mineralisasi dan penambangan emas tradisional. Pengujian kadar merkuri dilakukan dengan Portable X-Ray Fluorescence (XRF) dan uji laboratorium dengan metode Atomic Absorption Spectroscopy (AAS) tipe hidrida. Hasil pengukuran kadar merkuri pada berbagai jenis sampel kemudian dimasukkan ke dalam peta untuk mengetahui sebaran merkuri di daerah penelitian. Secara geomorfologi daerah ini dibagi menjadi 3 satuan geomorfologi, yaitu: satuan perbukitan struktural batulempung-batupasir, satuan perbukitan struktural tuf-batupasir, dan satuan fluvial lembah sungai. Litologi daerah penelitian dari satuan batuan yang tertua hingga termuda terdiri 3 satuan: satuan batupasir graywacke, satuan batulempung-batulanau, dan satuan tuf lempungan. Kondisi struktur geologi di daerah penelitian berupa lipatan, kekar, dan sesar. Kadar merkuri pada berbagai jenis sampel antara lain: sampel urat/mineral bijih dengan rentang 0,005 – 0,012 ppm, rata-rata 0,008 ppm; sampel tailing dengan rentang 7,493 - 604,000 ppm, rata-rata 126,761 ppm; sampel tanah dan batuan dengan rentang 11,748 - 102,000 ppm, rata-rata 72,800 ppm; sampel sedimen sungai dengan rentang 7,673 - 11,886 ppm, rata-rata 9,747 ppm; sampel air sungai dengan rentang 0,479 - 1,928 ppm, rata-rata 1,003 ppm; sampel air tanah dengan rentang 0,219 - 1,574 ppm, rata-rata 0,867 ppm. Kadar merkuri yang tinggi pada tailing, tanah, dan batuan. Kadar merkuri tertinggi pada sampel sedimen sungai dan air tanah ditemukan pada 2 daerah utama, yaitu di Desa Cihonje dan Desa Paningkaban yang berdekatan dengan lokasi pengolahan bijih emas. Dari hasil penelitian ini, kadar merkuri menjadi lebih tinggi di atas baku mutu lingkungan (0,001 ppm) pada air tanah sedikit disebabkan oleh kadar merkuri pada batuan yang mengalami mineralisasi, namun kadar merkuri yang tinggi pada berbagai sampel lebih dominan disebabkan oleh aktivitas penambangan dan pengolahan emas secara tradisional menggunakan merkuri (Hg) yang masuk ke dalam tailing, tanah, batuan, air sungai, sedimen sungai, dan air tanah.

The research area is located in Paningkaban Village and surroundings, Gumelar, Banyumas Regency, Central Java Province. The artisanal-small scale gold mining (ASGM) activity is occured on research area. The mining location is distributed at the slope with south-southwest and north-northeast direction of the hills. It also founded some valleys with Tajum river flows. The aims of this research is to know the rate of mercury (Hg) around gold mineralization area and ASGM area based the data of Hg rate on 6 kind of samples: veins/ore minerals,tailings, soil and surface rocks, river water, stream sediment,and groundwater. Sampling method is randomized surrounding mineralization area and ASGM area. The rate of mercury is measured by Portable X-Ray Fluorescence (XRF) and laboratory tested by Atomic Absorption Spectroscopy (AAS) hydrida method. The result is plotted on the map to know the distribution of mercury in research area. Geomorphologically, this area is divided into 3 units: structural hill with claystone-sandstone unit, structural hill with tuf-sandstone unit, and alluvial valley unit. The lithology is composed of: graywacke sandstone unit, claystone-siltstone unit, and clayey tuff unit, which ordered from the oldest to youngest rock. Folding, jointing, and faulting is occured in this area. The grade of mercury taken from samples as follow: vein/ore mineral sample within the range 0,005 – 0,012 ppm, and 0,008 ppm average; tailings samples at the range 7,493 - 604,000 ppm, and 126,761 ppm average; soil and surface rocks samples at the range 11,748 - 102,000 ppm and 72,800 ppm average; stream sediment samples at the range 7,673 - 11,886 ppm and 9,747 ppm average; river water samples at the range 0,479 - 1,928 ppm and 1,003 ppm average; groundwater samples at the range 0,219 - 1,574 ppm and 0,867 ppm average. The high rate of mercury was found on tailing, and soil and surface rocks samples. The highest rate of mercury on stream sediment and rier water samples was found at 2 main area, located in Paningkaban dan Cihonje village, which is near with ASGM and ore mineral processing area. Based on this research, the rate of mercury that above the environmental quality standard (0,001 ppm)in groundwater is slightly involved by mineralization. At the other hand, the high rate of mercury from other sample dominantly caused by ASGM activity that use a mercury polluted into tailings, soils, rocks, river water, stream sediment, and groundwater.

Kata Kunci : Cihonje, Paningkaban, Artisacanal and Small Scale Gold Mining (ASGM), pollution, Tajum River, AAS, Portable XRF.