ABSTRAKPenelitian penentuan penyebaran konsentrasi logam berat Cd pada sedimen di muara sungai Way Kuala telah dilakukan. Tujuan penelitian ini adalah untuk melihat penyebaran konsentrasi logam berat pada sedimen di muara tersebut. Konsentrasi Cd ditentukan dengan menggunakan spektrofotometer serapan atom (SSA), dengan menggunakan empat validasi metode yaitu batas deteksi, presisi, akurasi, dan linieritas. ABSTRACTThe determination of heavy metal cadmium concentration distributed in Sediment of Way Kuala Estuary Bandar Lampung has been conducted. The aim of the research is to determine the concentration of Cd which is distributed in the sediment. The concentration of Cd was determined using atomic absorption spectrophotometer (AAS). There are four validation methods in these research: limit of detection, precision, accuracy and linearity. The results showed that the concentrations of heavy metal Cd in sediment samples at the upper course, body and downstream in sediments of the Way Kuala Estuary is in the range of 20.73 ± 0.18 to 23.00 ± 0.81 ppm. The result is at above the sediment quality standards (0.65 to 2.49 ppm) which has been established by National Sediment Quality Survey USEPA (2004). Validation method on the determination of heavy metals Cd in sediments showed that the precision has RSD values <5%; Accuracy 80-120%; limit of detection and correlation coefficients for each of the metal Cd are 0.01 and 0.998 respectively.

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Telah dilakukan kajian sebaran logam berat Timbal (Pb) dan Kromium (Cr) pada sedimen di sekitar perairan Teluk Lampung. Konsentrasi logam Pb dan Cr ditentukan dengan menggunakan spektofotometer serapan atom (SSA) dengan menggunakan tiga validasi metode yaitu limit deteksi, presisi (ketelitian) dan linieritas. Hasil analisil menunjukan konsentrasi logam Pb pada sedimen di sekitar Perairan Teluk Lampung berada pada rentang 77,6673 ± 0,1549 ppm hingga 80,1263 ± 0,944 ppm.Konsentrasi logam berat Cr pada sampel sedimen di perairan Teluk Lampung berada pada rentang 48,7350 ± 0,3638 ppm sampai 66,0250 ± 0,1900ppm. Nilai konsentrasi logam berat Pb dan Cr yang di peroleh dalam penelitian ini berada diantara baku mutu logam berat pada sedimen yang telah di tetapkan oleh National Sediment Quality Survey (USEPA) yaitu 47,82 – 161,06 ppm untuk logam berat Pb dan 26 – 110 ppm untuk logam berat Cr.Validasi metode pada penentuan konsentrasi logam berat Pb dan Cr pada sedimen menunjukan nilai koefisien korelasi yaitu 99,9 %; limit deteksi untuk masing-masing logam Pb dan Cr adalah 0,0000 dan 0,4016; serta presisi dengan nilai RSD < 5%.

Influence of cyanide on the photoreduction of Hg(II) catalyzed by TiO 2 had been studied. Photoreduction process was carried out in a closed reactor equipped with UV lamp The process was done by radiated and stirred a mixture of Hg(II) solution, TiO 2 , and cyanide for a certain period of time. The amount of reduced Hg(II) by photoreduction was calculated by the substracting initial Hg(II) concentration with unreduced one, which was determined by used cold vapor atomic absorption spectrophotometer method. In this research influences of solution concentration and pH solution in the presence cyanide were also evaluated.The result of this research indicated that the presence of cyanide lead to decrease Hg(II) photoreduction, and a drastical drop was observed when more than 2 mmole cyanide was added for each mmole of Hg(II). Increased pH solution from 2 to 4 in the presence of cyanide can improve photoreduction process, but further increased of pH solution higher than 4 lead to decrease photoreduction of Hg(II).