Judul: Analisis merkuri (Hg) dan sianida (CN) pada beberapa ikan hasil tangkapan nelayan di Teluk Kao, Halmahera Utara
Abstrak: The disposal of mercury (Hg) and cyanide (CN) in the gold mining activities in North Halmahera Regency Kao Bay can cause habitat damage and contamination or poisoning and death of various types of biota that live around the area, including fish and humans. Therefore the aim of this study is to determine the content of mercury (Hg) and cyanide (CN) in water consumption and some types of fish catches around the Gulf of Kao and the level of appropriateness for consumption. Location of fish sampling conducted near the mouth of the river in the Cape Taolas Kao Bay (station 1) and Tanjung Akesone (station 2). While the analysis of heavy metal content in water and the fish is done at the in laboratory research centers and industrial development Manado and Limnology Laboratory in Bogor Agricultural University Bogor using AAS method. Samples of fish that contain mercury in measuring and sianidanya is white shrimp or fish Panaeus merguensis jackfruit seeds or Upeneus sp, fish red Snapper or Lutjanus sp, and Belanak/Mugil sp. Based on laboratory reults showed that mercury (Hg) and cyanide (CN) in seawater around the Gulf of Kao is still below the threshold limit (0.0002 ppm Hg, and CN 0.001 ppm). Compared with water quality standards according to category C Kep-20/MENKLH/I/1990. The content of mercury (Hg) in the liver into 4 types of fish was higher (0.13 to 0.51 ppm) compared to the flesh (0.02 to 0.19 ppm). The most high fish liver content of mercury is fish jackfruit seeds (from 0.45 to 0.51). The content of cyanide (CN) in the liver was also higher (6.0 to 18 ppm) than in meat (4,2 to 9,7 ppm). Referring to the standard intake of mercury on the human body that have been established by WHO in Darmono (2008) of 0.5 ppm, the red Snapper fish, Belanak fish, fish and shrimp jackfruit seeds safe for consumption. While the content of cyanide into the body already exceed safe levels. ranging from 1.52 ppm - 4.5 ppm, WHO (2004). Thus, red snapper, mullet, and shrimp are caught in the Cape and Cape Akesone Taolas Kao Bay is at a critical level (harmful) when consumed.
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Judul: Heavy Metal Content of Hg, Pb, and Cd in Skipjack Tuna Katsuwonus pelamis (Linnaeus, 1758) in Waters of Bacan Island, North Maluku
Abstrak: Pulau Bacan memiliki sumberdaya perikanan yang sangat potensial. Namun, di Pulau Bacan berlangsung aktivitas antropogenik seperti pertambangan, pertanian, perkebunan, dan pelabuhan yang berpotensi menimbulkan pencemaran logam berat di perairan. Penelitian ini bertujuan menganalisis tingkat bioakumulasi logam berat Hg, Pb, dan Cd pada ikan cakalang (Katsuwonus pelamis Linnaeus, 1758) di perairan Pulau Bacan, Halmahera Selatan, Maluku Utara. Pengambilan sampel air dan pengukuran parameter kualitas air serta pengambilan bagian daging, insang, dan hati ikan cakalang berlangsung pada bulan Februari 2022. Pada air, kandungan logam berat Hg, Pb, dan Cd telah melampaui baku mutu. Kandungan logam berat Hg, Pb, dan Cd tertinggi pada ikan cakalang ditemukan pada hati, sedangkan terendah pada daging. Pada daging ikan cakalang, tingkat akumulasi Hg, Pb, dan Cd tergolong rendah., Bacan Island has a high potential of fishery resources. However, anthropogenic activities such as mining, agriculture, and ports taking place on Bacan Island cause heavy metal pollution in the waters. This study aimed to analyze the bioaccumulation level of heavy metals such as Hg, Pb, and Cd in skipjack tuna (Katsuwonus pelamis Linnaeus, 1758) in the waters of Bacan Island, South Halmahera, North Maluku. Water sampling, measurement of water quality parameters and fish sampling was conducted in February 2022. In the water, the heavy metals concentration of Hg, Pb, and Cd has exceeded the quality standard. The highest concentration of Hg, Pb, and Cd was found in the liver, while the lowest was in the muscle. In skipjack tuna muscle, the accumulation level of Hg, Pb, and Cd is low.
Keyword: Bacan Island, heavy metal, skipjack tuna

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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