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 the Blue Swimming Crab (Portunus pelagicus) at Bojonegara Coastal Waters, Banten Bay
Abstrak: Perairan pantai Bojonegara, Teluk Banten merupakan zona industri di wilayah Serang Barat yang dicirikan dengan banyaknya pabrik di sekitar pantai yang berpotensi menghasilkan bahan pencemar seperti logam berat dll. Bahan ini masuk ke dalam perairan dan berakumulasi dalam tubuh organisme perairan termasuk rajungan. Penelitian ini bertujuan menganalisis tingkat akumulasi kandungan logam berat pada rajungan (Portunus pelagicus) di Teluk Banten. Pengambilan sampel dilaksanakan pada bulan Agustus hingga Oktober 2020. Analisis kandungan logam berat dilakukan dengan menggunakan alat AAS (Atomic Absorption Spectrophotometer). Hasil pengamatan menunjukkan kandungan logam berat Hg, Cd, Pb, dan Cu berbeda nyata antara rajungan besar dan kecil (p<0,05). Kandungan akumulasi logam berat Cu pada rajungan kecil berkisar 3,22-4,34 mg kg-1 dan rajungan besar berkisar 6,64-9,52 mg kg-1 sedangkan kandungan logam berat Hg, Cd, dan Pb pada rajungan berada di bawah deteksi alat AAS. Bioakumulasi logam Cu pada rajungan tersebut termasuk akumulasi sedang hingga tinggi sedangkan logam logam Hg, Cd dan Pb tergolong akumulasi yang rendah. Batas aman konsumsi rajungan yaitu 22,0588 kg daging/minggu untuk orang dewasa dan 5,5147 kg daging/minggu untuk anak-anak., Bojonegara coast, Banten Bay is an industrial zone in the West Serang region, which is characterized by the presence of some factories around the coast. These have potential to produce and pour the pollutants such as heavy metals into the water and accumulate into the body of aquatic organisms like blue swimming crab. This study aims to analyze the level of heavy metal accumulation in the blue swimming crab (Portunus pelagicus) of Banten Bay waters. Sampling was carried out from August to October 2020. Analysis of heavy metal content was carried out using AAS (Atomic Absorption Spectrophotometer). During the observation, the heavy metal content of Hg, Cd, Pb, and Cu were significantly different between large and small blue swimming crab (p<0,05). The accumulation of heavy metal Cu in small blue swimming crab ranged from 3,22-4,34 mg kg-1 and large blue swimming crab ranged from 6,64-9,52 mg kg-1 while the heavy metal content of Hg, Cd, and Pb in small crabs was below detection AAS. Bioaccumulation of Cu in blue swimming included moderate to high, while heavy metal Hg, Cd, and Pb it was low accumulation. The safe limit for consumption blue swimming crab is 22,0588 kg of meat/week for adults and 5,5147 kg of meat/week for children.
Keyword: Accumulation, blue swimming crab, Bojonegara coastal waters, heavy metals

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