Judul: Status Kecemaran Tanah oleh Kadmium pada Lahan Budidaya Sawi Putih (Brassica chinensis L.) di Sentra Produksi Hortikultura Lembang, Jawa Barat.
Abstrak: The source of cadmium (Cd) contamination in arable land, among others, is the use of manure and P fertilizer. Therefore, its long-term application at excesive dosage, as those practized by farmers in horticulture production centers, many cause Cd accumulation in soil and plant tissues. It is the main route of Cd intoxication into human body, therefore it poses health risk. The objective of this research was to explore the Cd pollution status in soil and its concentration in leaves of chinese cabbage (Brassica chinensis L.) cultivated in horticulture production center of Lembang, West Java. The study site was parts of an intensively cultivated land area for horticulture commodity. Field observation and soil (composite, 0-20 cm) and plant tissue (leaf) sampling were conducted at 16 points represented uncultivated control land [Lc] and 3 categories of land productivity level (high [Ph], medium [Pm] and low [Pl]). Soil analysis was conducted on texture; pH (H2O 1:1); Corganic; POlsen; Cdaqua regia (HNO3:HCl =1:3) and CdNH4OAc-EDTA (0.5 M NH4OAc + 0.002 M EDTA pH 4.65). Plant tissue analysis was performed for Cdplant concentration (dry ashing, 0.2 M HNO3). Soil Cd pollution level was evaluated based on the value of contamination/pollution (c/p) index according to the Lacatusu (2000) procedure. Average concentration of soil Cdaqua regia (mg/kg) at Pm (2.26) > Lc (2.02) > Ph (2.01) > Pl (1.43), with average soil Cd pollution status from very light pollution at Lc (value of c/p 1.96) to light pollution level at Pl (c/p 2.19), Ph (c/p 2.97) and Pm (c/p 3.26). Soil pollution level at Pl, Pm and Ph that was higher than that of Lc revealed the contribution of anthropogenic factors or sources, among others was the accumulation from the application of Cd-containing fertilizers. The amount of Cd absorbed by plant increased with the increasing concentration of soil Cd active fraction or CdNH4OAc-EDTA. Concentration of Cdplant at Ph was the lowest eventhoug its absorption was the highest. This was due to the occurrence of dilution effect related to the higher biomass yield. Concentration of Cdplant (0.10-0.39 mg/kg) has exceeded the maximum acceptable limit for vegetables (0.2 mg/kg) according to Codex Alimentarius Commision and, hence, its consumption higher than the tolerable dose will pose more health risk. Keywords:Brassica chinensis L., Cd, c/p index, Soil pollution.
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Judul: Erapan Kadmium Pada Tanah Inseptisol Brebes Dengan Tanaman Indikator Bawang Merah
Abstrak: pengendalian pencemaran lingkungan yang berhubungan dengan program keamanan pangan nasional harus segera dilaksanakan. Produk-produk pertanian dituntut mempunyai standar mutu yang baik serta &nan untuk dikonsumsi. Penggunaan pupuk: dan pestisida untuk mcningkatkan basil pertanian tidak dapat dihindari. Petani di daerah Brches. sebagai salah satu pusat produksi bawang merah dUaw8 Tengah, cenderung menggunakan pupuk dan pestisida secaca berlebihan sehingga dapat meningkatkan kandungan logam herat yang termasuk dalam bahan beracun dan berbahaya (83). Adanya logam berat dalam tanab pertanian dapat menunmkan produktivitas tanah dan kua1itas basil pertanian selain dapal membahayakan kesehatan manusia mclalui konsumsi pangan yang dihasilkan dari tanah yang terccmar (OgaIn herat tersebut. Melihat kondisi yang demikian. diperlukan kajian mengenaj kandungan logam berat berbahaya (Cd) yang terserap dalam tanaman sayuran yang biasa dikonswnsi manusia seperti halnya bawang merah. Penelitian ini bertujuan mempelajari erapan kadmium pada tanah Jnseptisol dari Brehes dengan tanaman indikator bawang merah. Metode yang digunakan adalah penentuan erapan Cd pada contoh tanah Inseptisol dengan absorpsi Langmuir, penanaman dan pengamatan tanaman bawang merah dengan berbagai perlakuan Cd. selanjutnya dianalisis Cd-tersedia pada tanah sebelum tanam dan setelah panen, serta Cd total pada daun dan umbi bawang merah varietas Bima Brebes. Oari basil penelitian diketahui bahwa perlalruan kadmium (0400 ppm) pada tanah Inseptisol Brebes tidak berpengaruh nyata pada kenampakan
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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