Shadegan Wetland Research Articles

Determination of Polychlorinated Biphenyl Congeners in Water and Sediment in North West Persian Gulf, Iran

Polychlorinated biphenyl (PCB) was detected as isomer groups (congener numbers 28, 52, 101, 118, 138, 153 and 180) in the coastal water and sediment of four stations around Shadegan wetland protected area in the northwestern part of the Persian Gulf. Total PCB concentration range was 8-375 ng/L in water and 3.4-50.2 μg/g in sediment. Concentration of different congeners and chromatogram indicates that the source of PCB in this area can be Clophen A60; it used for long time in Iranian electronic industries. Other chlorinated hydrocarbons such as lindane, DDT and their metabolites were also present in the samples.

Water quality variability and eutrophic state in wet and dry years in wetlands of the semiarid and arid regions

Wetland ecosystems are particularly vulnerable due to flow of nutrients from the surrounding watershed. The study was performed in the Shadegan wetland, a Ramsar-listed wetland located in the south-west of Iran at the head of the Persian Gulf. The wetland plays a significant hydrological and ecological role in the natural functioning of the northern Gulf. The proposed wetland has different water quality characteristics in wet and dry years of study during 1994–2006. To determine the variables, sampling was carried seasonally for each year at six stations. The results indicate that wetland in wet years had high concentrations of nitrate and silicate, leading to oligo–meso eutrophic conditions. Wetland in dry years had high phosphate concentrations, resulting in meso-eutrophic conditions. Forcing functions, such as climatic patterns, water residence time, reduce runoff and increasing density of wastewaters from the surrounding urban, agricultural and industrial area are probably the main variables that explain the observed patterns.

Biodegradation of Polycyclic Aromatic Hydrocarbons by Aerobic Mixed Bacterial Culture Isolated from Hydrocarbon Polluted Soils

In this study, the degradation potential of five polycyclic aromatic hydrocarbons (PAHs) by aerobic mixed bacterial cultures was investigated. Microorganisms were isolated from hydrocarbon contaminated soils of Shadegan wetland located in southwest of Iran. The degradation experiments were conducted in liquid cultures. PAH or PAHs concentration was 100 mg/L at the beginning of degradation experiments. After ten days incubation, the mixed culture was capable of degrading phenanthrene completely and anthracene 80%, pyrene 60%, fluorene 30%, and fluoranthene 20%, individually. Optimal temperature and pH were as 30 °C and 7.0 respectively. Results showed that in samples containing a mixture of the five PAHs, fluoranthene could degrade cometabolically and the rate of degradation increased from 20 to 44%. It was observed also that PAHs degradation could be enhanced by the individual addition of yeast extract or glucose. The isolated mixed culture is valuable in bioremediation of PAH-contaminated environments.