Judul: Heavy Metal Content (Hg, Cd, Pb, and Cu) in Mud Crab (Scylla serrata) in Banten Bay
Abstrak: Perkembangan industri dan pemukiman penduduk di sekitar perairan Teluk Banten dapat meningkatkan masukan limbah logam berat dan menyebabkan akumulasi pada biota perairan, khususnya pada kepiting bakau (Scylla serrata). Penelitian ini bertujuan menentukan tingkat akumulasi kandungan logam berat (Hg, Cd, Pb, dan Cu) yang terdapat pada daging kepiting bakau di perairan Bojonegara, Teluk Banten. Pengambilan sampel kepiting bakau dilakukan selama tiga bulan yaitu bulan Agustus hingga Oktober 2020 di perairan tersebut. Pengukuran kandungan logam berat dilakukan dengan menggunakan AAS (Atomic Absorption Spectrophotometer). Kandungan logam berat Hg, Cd, dan Pb pada daging kepiting bakau berada di bawah nilai sensitivitas AAS yang digunakan yaitu sebesar <0,001 mg kg-1, <0,005 mg kg-1, <0,030 mg kg-1, sedangkan untuk logam berat Cu berkisar antara 4,44 sampai 13,52 mg kg-1. Nilai tersebut masih berada di bawah baku mutu yang ditetapkan. Tingkat akumulasi kandungan logam berat kepiting bakau dalam air tergolong akumulasi tinggi. Ukuran sampel tidak berpengaruh secara signifikan terhadap logam berat yang terkandung pada daging kepiting bakau. Batas aman konsumsi daging kepiting bakau yang didapatkan dari perairan tersebut adalah 12,9348 kg daging/minggu (dewasa) dan 3,8831 kg daging/minggu (anak-anak)., The development of industry and residential areas around the waters of Banten Bay can increase the input of heavy metal waste and cause accumulation in aquatic biota, especially in mud crab (Scylla serrata). This study aims to determine the level of accumulation of heavy metals (Hg, Cd, Pb, and Cu) contained in mud crab meat in Bojonegara Coastal Waters, Banten Bay. Sampling of the mud crabs was carried out monthly for three months, from August to October 2020 in the waters. Analysis of heavy metal content was carried out using AAS (Atomic Absorption Spectrophotometer). According to the analysis, content of heavy metals Hg, Cd, and Pb in mud crab was under the AAS sensitivity value used, which was <0.001 mg kg-1, <0.005 mg kg-1, <0.030 mg kg- 1, respectively, while for heavy metal Cu ranged from 4.44 to 13.52 mg kg-1. Based on the results, this value was still below the quality standards. The accumulation level of heavy metal content of mud crab in water is classified as high accumulation. The sample size did not significantly affect the heavy metals contained in the mud crab meat. The safe limit for consumption of the mud crab meat taken in the waters was 12.9348 kg meat/week (adults) and 3.8831 kg meat/week (children).
Keyword: accumulation, Banten Bay, heavy metals, mud crab

Judul: Heavy Metal (Hg, Cd, Pb and Cu) in Long Whiskered catfish Mystus gulio (Hamilton, 1822) in Bojonegara Waters
Abstrak: Aktivitas antropogenik seperti industri, domestik dan pelayaran merupakan penyumbang utama masuknya logam berat di perairan Bojonegara dan sekitarnya. Penelitian ini dilaksanakan pada bulan Agustus hingga Oktober 2020 di perairan Bojonegara, Teluk Banten. Penelitian ini bertujuan untuk menentukan tingkat akumulasi logam berat (Hg, Cd, Pb dan Cu) yang terkandung dalam daging ikan lundu Mystus gulio (Hamilton, 1822) di perairan Bojonegara, Teluk Banten. Lokasi penelitian ditentukan menggunakan teknik purposive sampling. Konsentrasi logam berat Hg, Cd, Pb, Cu pada daging ikan lundu berturut-turut <0,001 mg kg-1 (Hg), <0,005 mg kg-1 (Cd), <0,030 mg kg-1 (Pb) dan 0,699-10,920 mg kg-1 (Cu), nilai tersebut berada di bawah baku mutu menurut PerBPOM RI (2018) dan SK Departemen Kesehatan RI tahun 1989. Akumulasi Cu>Pb>Cd>Hg terjadi pada daging ikan lundu ukuran kecil maupun besar. Bioakumulasi ikan lundu yang ditangkap di perairan Bojonegara, Teluk Banten tergolong dalam akumulasi sedang hingga tinggi untuk logam berat Cu. Bioakumulasi logam berat Hg, Cd, dan Pb termasuk ke dalam kategori akumulasi rendah., Anthropogenic activities such as industrial, domestic, and shipping are the main contributors to the entry of heavy metals into the Banten Bay and the surrounding areas. This research was conducted from August to October 2020 in the coastal waters of Bojonegara, Banten Bay. This study aim to estimate the accumulation of heavy metals (Hg, Cd, Pb and, Cu) contained in long whiskered catfish Mystus gulio (Hamilton, 1822) in the Bojonegara coastal waters. The research location was determined using a purposive sampling technique. Based on the analysis, the heavy metal content in the fish meat were <0,001 mg kg-1 (Hg), <0,005 mg kg-1 (Cd), <0,030 mg kg-1 (Pb) and 0,699-10,920 mg kg-1 (Cu); the values were less than BPOM (2018) and Regulation of the Minister of Health Republic of Indonesia 382/1989 standard. The accumulation of Cu>Pb>Cd>Hg occurred in the small and large fish. The fish caught in Bojonegara Coastal Waters of Banten Bay have moderate to high accumulation levels of Copper (Cu). The accumulation level of Hg, Cd, Pb is included in the low category.
Keyword: accumulation of heavy metals, Banten Bay, heavy metals, Mystus gulio

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology