Study the mercury biosorption by unicellular diatom Nitzschia capitellata Hustedt

Present study was conducted to investigate the ability of Nitzschia capitellata in accumulation of heavy metal, together with investigating the concentration of the heavy metals absorbed by N. capitellata. The diatom samples of the study collected from Taleghan River in the west of Alborz Province, Iran. The isolated and purified diatom was transferred to the liquid culture medium (F/2) and Mercury test concentrations were 90, 285 and 300 μg/L of HgCl2 in three replications. Cold Atomic Absorption Spectrometry method was used to measure mercury concentration.  The precipitation of 30 ml of diatoms’ culture with cell density of 350 × 103 cell/cm2 was added to each mercury concentration. After inoculation, the DTE 0.01 molL-1 solution was used to separate the mercury bonded to the cell wall. The N. capitellata cells were killed when they were exposed to 1000 μgL-1 HgCl2 concentration. The highest intracellular absorbance (416.50 μgL) was related to the first day of treatment in 285 μgL-1 concentration of mercury, and the highest discharge of mercury to environment was 256 μgL-1 concentration in the fourth day. and also the concentrations of intracellular solution mercury and bonded mercury was significantly different.