No abstract

Information about the strategic mineral balance, published in 2013, presumed a significant amount of iron sand deposited in Sarmi, Papua, Indonesia. However, the magnetic properties of these iron sands have never been studied. Our preliminary study on the distribution of magnetic susceptibility of iron sand from the Sarmi Coast area has revealed that the iron sand from the Tor River estuary had the highest mass-specific magnetic susceptibility values with an χ LF average of 3.083 ×10 −5 m 3 /kg. We extracted the raw sand from the Tor River estuary using a mechanical magnetic extraction method and analyzed the magnetic properties and mineral composition. The magnetic susceptibility values increased significantly with an χ LF average of 27.496 ×10 −5 m 3 /kg. The chemical composition acquired from both the X-ray fluorescence and energy dispersive spectroscopy confirmed that the magnetic properties of the extracted sample originated from the high percentage of iron oxide. The hysteresis curve showed high saturation magnetization about 24.7 (emu/g), remanent magnetization of about 6.1 (emu/g) and a low coercive field of about 20 (Oe). The X-ray diffraction patterns identified a magnesioferrite (MgFe 2 O 4) mineral structure. This result showed the novelty of iron sand from Sarmi, Papua when compared with that from Java Island.

No abstract

Sungai Citarum merupakan salah satu sungai yang menunjang kehidupan sebagian besar masyarakat Jawa Barat. Akan tetapi, dampak kegiatan manusia telah membuat Sungai Citarum sebagai sungai yang tercemar. Penelitian ini dilakukan untuk mengetahui kondisi wilayah hulu Sungai Citarum dengan melakukan pengukuran multi parameter terhadap kondisi air di Sungai Citarum Hulu dan air sumur warga sekitar, terutama Sektor 7. Wilayah penelitian ini secara administratif berada di Desa Pangauban, Kecamatan Katapang, Kabupaten Bandung. Sampel yang diuji pada penelitian ini adalah sampel air sungai dan sampel air sumur milik warga yang tinggal di sekitar Sungai Citarum sebanyak masing-masing enam titik lokasi pengamatan. Hasil pengukuran parameter hidrologi dan kandungan logam berat pada sampel air sungai dan air sumur menunjukan bahwa nilai pH, suhu, dan TDS masih di bawah ambang batas tercemar, sedangkan nilai EC menunjukkan bahwa air sumur dan air sungai telah tercemar. Hal ini dibuktikan dengan analisa kandungan logam berat yang dapat dilihat bahwa terdapat kandungan logam besi (Fe) yang cukup tinggi di atas ambang batas air bersih sehingga air tersebut tidak dapat di konsumsi bagi warga, baik untuk air sungai maupun air sumur. Citarum River is one of the rivers that supports the lives of most of the people of West Java. However, the impact of human activities has made the Citarum River a polluted river in the world. This research was conducted to determine the condition of the upstream area of the Citarum River by conducting multi-parameter measurements to water conditions in the Upstream Citarum River Sector 7 and the wells of the surrounding residents. This research area is administratively located in Pangauban Village, Ketapang District, Bandung Regency.  The samples tested in this study were river water samples at six observation locations and well water samples belonging to the residents living around the Citarum River as many as six observation location points. The results of measurements of hydrological parameters and heavy metal content in river and well water samples indicate that the pH, temperature, and TDS values are still below the polluted threshold, while the EC values indicate that well water and river water have been polluted. This is evidenced by the analysis of heavy metal content which can be seen that there is a high metal content of iron (Fe) above the threshold of clean water so that the water cannot be consumed by residents, both for river water and well water.Kata kunci : hidrologi, logam berat, Sungai Citarum