Judul: Heavy Metal Content (Pb, Cd, Cu) in Sediments in the Tinjil Island Waters, Pandeglang, Banten
Abstrak: Pulau Tinjil yang terletak di Kecamatan Cikeusik, Kabupaten Pandeglang, Provinsi Banten mengalami peristiwa penting pada tahun 2018, yakni kapal tongkang pengangkut batubara mengalami kecelakaan, sehingga batubara tumpah ke perairan. Tumpahan batubara ini akan terakumulasi di dasar perairan dan berpotensi mencemari Perairan Pulau Tinjil. Penelitian ini bertujuan untuk menduga tingkat pencemaran logam berat (Pb, Cd, Cu) pada sedimen di Perairan Pulau Tinjil, Pandeglang, Banten. Penelitian dilakukan pada bulan Juni 2020 dengan pengambilan sampel di Perairan Pulau Tinjil, Pandeglang, Banten. Data yang didapat berupa kandungan logam berat (Pb, Cd, Cu) pada sedimen yang dianalisis menggunakan alat ICP-OES. Hasil pengukuran logam Pb memiliki konsentrasi berkisar 0,005 mg/kg sampai 3,26 mg/kg. Hal tersebut menunjukkan bahwa logam Pb pada ketiga stasiun di bawah baku mutu. Logam Cd memiliki konsentrasi 4,12 mg/kg sampai 5,94 mg/kg. Hasil tersebut menunjukkan logam Cd memiliki konsentrasi melebihi baku mutu. Logam Cu memiliki nilai konsentrasi 2,37 mg/kg sampai 5,34 mg/kg. Hasil tersebut menunjukkan bahwa logam Cu pada ketiga stasiun di bawah baku mutu. Indeks geoakumulasi pada logam Pb dan Cu memiliki nilai negatif. Hal tersebut menunjukkan logam Pb dan Cu ada dalam kategori tidak tercemar. Indeks geoakumulasi logam Cd memiliki nilai 0,966 sampai 1,121 yang menunjukkan bahwa sedimen tercemar oleh logam Cd dalam rentang ringan dan sedang., Tinjil Island, located in Cikeusik District, Pandeglang Regency, Banten Province, experienced an important event in 2018, where a barge carrying coal had an accident, resulting in coal spilling into the waters. This coal spill will accumulate at the bottom of the waters and have the potential to pollute the waters of Tinjil Island. This research aims to estimate the level of heavy metal pollution (Pb, Cd, Cu) in sediments in the waters of Tinjil Island, Pandeglang, Banten. The research was conducted in June 2020 by taking samples in the waters of Tinjil Island, Pandeglang, Banten. The data obtained was in the form of heavy metal content (Pb, Cd, Cu) in the sediment which was analyzed using the ICP-OES tool. The results of measurements of Pb have concentrations ranging from 0.005 mg/kg to 3.26 mg/kg. This shows that the Pb at the three stations is below the quality standard. Cd has a concentration of 4.12 mg/kg to 5.94 mg/kg. These results show that Cd has a concentration that exceeds the quality standard. Cu has a concentration value of 2.37 mg/kg to 5.34 mg/kg. These results show that the Cu at the three stations is below the quality standard. The geoaccumulation index for Pb and Cu has negative values. This shows that Pb and Cu are in the uncontaminated category. The geoaccumulation index for Cd has a value of 0.966 to 1.121, which shows that the sediment is polluted by Cd in the light and moderate range.
Keyword: Logam Berat, Sedimen, Batubara, Pulau Tinjil

Judul: Kandungan Logam Berat Cu, Ni, dan Cd dalam Sedimen di Teluk Jakarta
Abstrak: Teluk Jakarta merupakan wilayah perairan dangkal dengan berbagai aktivitas seperti pelabuhan, perikanan, pariwisata, dan pemukiman padat menjadikannya lingkungan sensitif terhadap keberadaan logam berat. Logam berat adalah salah satu jenis limbah yang dapat terakumulasi di dasar perairan dan berbahaya untuk lingkungan apabila keberadaannya sudah melebihi ambang batas. Tujuan dari penelitian ini adalah menentukan kandungan logam berat Cu, Ni dan Cd dalam sedimen dan menduga pencemaran logam berat. Pengambilan sampel sedimen dilakukan bulan Maret-April 2021 pada tiga stasiun pengamatan di Teluk Jakarta, kemudian dianalisis kandungan logam menggunakan metode Spektrofotometer Serapan Atom (SSA). Selain itu, dilakukan analisis ukuran butir sedimen, bahan organik, kondisi oseanografi, indeks geoakumulasi, faktor kontaminasi, dan indeks beban pencemar. Hasil penelitian menunjukkan bahwa konsentrasi Cu pada kisaran 10,06 – 15,82 mg/kg dan konsentrasi Ni 7,54 – 8,18 mg/kg. Logam Cd tidak terdeteksi pada seluruh stasiun karena konsentrasinya dibawah deteksi limit alat. Logam Cu dan Ni cenderung mengalami penurunan konsentrasi yang cukup signifikan sejak tahun 2007 hingga 2021. Sedangkan logam Cd relatif memiliki konsentrasi rendah pada setiap tahunnya. Logam Cu dan Ni dengan bahan organik memiliki korelasi negatif yaitu -0,9979 dan -0,8301. Status pencemaran menunjukkan sedimen Teluk Jakarta berada dalam kategori tidak tercemar sampai tercemar sedang logam Cu dan Ni., Jakarta Bay is a shallow water area with various activities such as ports, fisheries, tourism, and dense settlements, making it a sensitive environment for the presence of heavy metals. Heavy metal is a type of waste that can accumulate in the bottom of the waters and is harmful to the environment if its presence exceeds the threshold. The purpose of this study was to determine the content of heavy metals Cu, Ni and Cd in the sediment and to predict heavy metal contamination. Sediment sampling was carried out in March-April 2021 at three observation stations in Jakarta Bay, then analyzed for metal content using the Atomic Absorption Spectrophotometer (AAS) method. In addition, an analysis of sediment grain size, organic matter, oceanographic conditions, geoaccumulation index, contamination factors, and pollutant load index. The results showed that the concentration of Cu was in the range of 10,06 – 15,82 mg/kg and the concentration of Ni was 7,54 – 8,18 mg/kg. Cd metal was not detected at all stations because its concentration was below the detection limit of the instrument. Cu and Ni metals tend to experience a significant decrease in concentration from 2007 to 2021. Meanwhile, Cd metals have relatively low concentrations. Cu and Ni metals with organic matter have a negative correlation, namely -0,9979 and -0,8301. Pollution status shows that Jakarta Bay sediments are in the category of unpolluted to moderately polluted Cu and Ni metals.
Keyword: Cadmium, Nickel, Sediment, Jakarta Bay, Copper

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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