In this study, in the removal of macro (P, S, Na, K, Ca, Mg) and micro (Sb, Ba, Co, Cu, Fe, Pb, Mn, Hg, Mo, Se, Ag, Zn) elements in the effluent of Elazig Wastewater Treatment Plant, the efficiency of Lemna minor L. and Lemna gibba L. has been studied comparatively. For this aim, fronds of these plants have been adapted to the effluent of the treatment plant that feeds pilot scale reactors. The concentrations of elements in fronds harvested during the working period were analyzed by ICP/MS. The analytical results show that Lemna minor L. has a high accumulation potential for P, Sb, Ba, Co, Fe, Pb, Mn, Hg, Ag and Zn while Lemna gibba L. has a high accumulation potential for S, Na, Ca, Mg, Cu, Mo and Se. The results show that Lemna minor L. and Lemna gibba L. can be used as phytoremediators of wastewater.

Urban soil pollution has become a major concern in megacities around the world. Due to their non-degradable characteristic, toxic metals are among the most notorious pollutants. In this study determination of total and bioavailable fraction of toxic metals Ni, Cu, Cr, Zn, Co, Cd, Pb and Mn, in surface soils of district 16th in Tehran municipality is considered. Furthermore, metals uptake potential of a variety of endemic plants is also investigated. Forty one surface soil samples and eleven composite leaf samples were collected within the study area in winter 2015. Except for Cd and Pb, other toxic metals showed generally lower concentrations in comparison with shale and mean earth crust values. Intensified traffic load within the district may be considered as the main reason for such augmented concentrations. The order of bioavailable fraction from total metal concentrations detected to be as: Zn(2.78%) > Cd(2.71%) > Co(1.92%) > Mn(1.79%) > Cu(1.59%) > Pb(.89%) > Ni(.7%) > Cr(.4%). Concentration of different metals in leaf samples revealed that berry, eucalyptus, plane and acacia are more capable in comparison with others in translocating toxic metals from soil. Paying more attention to pollution removal capability of urban plants may play a key role in sustainable municipal management of megacities like Tehran.

Jajarm Alumina Plant, the only Alumina powder producer in Iran, generates 500,000 tons of red mud annually. The commonest method for final disposal of red mud in Iran is Tailing dam which is neither cost-effective nor environmentally-friendly. The main objective of this study is to evaluate the possibility of red mud recovery to be used for stabilization of loose soils. Red mud samples have been collected from tailing dam of Jajarm Alumina Plant to be characterized, using X-Ray Fluorescence (XRF). The soil stabilizer has been made by mixing red mud, steel slag, sodium metasilicate, and sodium hydroxide. In order to study the effect of soil stabilizer, five soil samples have been prepared which contain clay, sand, and wind-blown sand ranging from zero to 4 millimeters. Findings show that adding soil stabilizer with red mud significantly enhances compressive strength of soil samples (4.2, 18.2, 5.4, 4, and 4.1 in S1 to S5 samples, respectively). Also the results demonstrate that the red mud, produced from Aluminum industry in Iran, might be successfully used to stabilize loose soils, thereby enhancing their compressive characteristics, reducing environmental issues associated with uncontrolled disposal of such wastes as well as promoting integrated solid waste management strategies.

Due to its wide range of hazardous hydrocarbons and even heavy metal ions, oily sludge has become a great environmental challenge which must be dealt with quite quickly. As a result, ther have been numerous efforts during recent years to develop an efficient method for sludge recovery. The current research studies the effectiveness of solvent extraction with toluene and Fe2O3 nanoparticles for recovery and upgrading of oily sludge. Having employed Design of Experiment (DOE), it has found optimum conditions for sludge recovery with solvent extraction, namely a temperature of 55°C and mixing time of 17 minutes with solvent to sludge ratio of 6.4/4.2. Under these conditions, the sludge recovery has been 37%, which is the maximum available with toluene. Furthermore, it has studied the effectiveness of Fe2O3 nanoparticles for improvement of sludge pyrolysis efficiency in order to upgrade the oily sludge, wherein it has been observed that nanoparticles can significantly decrease the temperature and time of reaching maximum conversion during sludge pyrolysis process. The temperature and time of reaching to the maximum conversion, by means of gamma Fe2O3 nanoparticles, is about 200°C and 1200 s, respectively, which is lower than the condition in which pure sludge is being pyrolyzed.

With the growth and development of chemical plants, the amount of mercury released in wastewater has increased. Mercury in wastewater contains harmful compounds which are hazardous to the human health and living organisms. Therefore, its removal from wastewater is significant. There are various techniques or methods available for removing mercury from aqueous solutions. This study focused upon the removal of mercury from aqueous solution with commercial activated carbon and activated carbon from sugarcane bagasse.  Activated carbon produced from sugarcane bagasse was used as adsorbent. This adsorbent was used to remove mercury from aqueous solution. For this purpose, first, the optimal mercury solution pH for mercury removal was obtained. Effective parameters such as contact time, initial concentration of mercury, adsorbent dose and agitation speed were investigated. The mercury adsorption was increased when the mass of activated carbon was increased. Increasing the initial mercury concentration leads to decrease in mercury adsorption efficiency. The results of experiments indicated that the speed of the stirrer was not considered to be an effective factor in the mercury adsorption. Experiments were also carried out on a commercial activated carbon. Adsorption results obtained for sugarcane bagasse activated carbon were compared with commercial activated carbon.  The adsorption efficiency was increased as the contact time was increased.  Finally, the experiment was carried out on water samples released from South Pars platforms. In addition to the mercury removal, other heavy metals removal such as lead and cadmium were also carried out.

The present investigation has been conducted to assess the status of physico-chemical parameters as well as the concentrations of some selected heavy metals to understand the present scenario of water quality at Perak River basin, Malaysia. The temperature, turbidity, pH, EC and DO values of all the examined samples have been within the range of 25.0 to 30.5 0C, 39.5 to 168.00 NTU, 6.8 to 7.33, 30.3 to 113.8 μs/cm and 3.62 to 7.01 mg/L, respectively. The concentrations of trace metallic constituents have been determined by means of Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), giving the following ranges: Cr: 0.01 to 0.052 mg/L; Pb: 0.01 to 0.03 mg/L; Zn: 0.11 to 0.92 mg/L; Fe: 1.38 to 5.55 mg/L; Mn: 0.10 to 0.25 mg/L and Ca: 2.55-23.23 mg/L, respectively. The concentrations of heavy metals at downstream of Perak River water were higher than the concentrations of upstream. The order of heavy metallic constituents in the water samples was Fe > Zn > Mn > Cr > Pb. R mode Cluster Analysis (CA) suggests that multiple anthropogenic activities like urban runoff, agricultural runoff, discharges of vehicles washing and workshops, land use changes, unplanned settlements, domestic effluents, wastewater of livestock husbandry farms etc., are influencing the physico-chemical parameters and heavy metals concentrations of Perak River water. The present study is highly significant for providing baseline information of potential hazardous level of heavy metals to human health, environment, and sustainable water resources management for economically and environment friendly uses of Perak River.

In this study, the concentrations of Zn and Cr in downstream waters from Uzunçayır Dam (Tunceli, Turkey) were monitored during spring (March, April, May) and summer (June, July, August) season. Zinc and Cr concentrations in surface water samples were detected using the ICP-MS device. According to the data obtained the lowest Zn and Cr concentrations in the spring season were 65.43±3.2 μg/L in March at 10th day for Zn and 0.28±0.02 μg/L in March at 10th and 20th day for Cr, the highest Zn and Cr concentrations were determined to be 83.12±4.1 μg/L in May at day 30 for Zn and 0.48±0.02 μg/L in May at day 30 for Cr. The lowest Zn and Cr concentrations in summer season were 55.48±2.7 μg/L at 30th day in August for Zn and 0.54±0.03 μg/L at 10th day in June for Cr. The highest Zn and Cr concentration in summer season were found as 69.48±3.5 μg/L in June at day 10 for Zn and 1.23±0.06 μg/L in August at day 30 for Cr. The Zn and Cr concentrations in the downstream of Uzunçayır Dam were found to be smaller than the Zn and Cr concentrations given by the Surface Water Quality Regulation (SWQR). As a result, it was determined that there was no harm in using water from the Uzunçayır Dam as irrigation water or drinking water in terms of Zn and Cr concentrations.

Flourene and phenanthrene are organic compounds with high hydrophobicity and toxicity. Being recalcitrant in nature they are accumulating in the environment at an alarming concentration, posing serious threat to living beings. Thus in the present study, microorganisms were screened for their ability to degrade these contaminants at high concentrations in least period of time. Two out of fifteen isolates screened showed growth in basal medium containing 25 mg/l of fluorene/phenanthrene as the only carbon source. These selected isolates were acclimatised with step wise increased concentrations of flourene/phenanthrene for 165 days in basal medium. The acclimatised strains were identified and characterised on the basis of their morphological and biochemical characteristics and 16S rRNA gene sequence analysis. Results showed close relatedness of the isolates to Pseudomonas aeruginosa sp. and Bacillus safensis sp. Biodegradation studies carried out with these acclimatised strains at optimum conditions (pH 7 and temperature 30°C) showed 62.44% degradation of fluorene and 54.21% of phenanthrene in 10 days by Pseudomonas sp. VB92, whereas, Bacillus sp. JK17 degraded 43.64% of fluorene and 59.91% of phenanthrene in 12 days, at an initial concentration of 200 mg/l, as determined by HPTLC. During fluorene degradation by Pseudomonas sp. VB92, one metabolite was identified as fluorene,1,4-dihydro. An anionic biosurfactant (emulsification index of 80%) produced by strain VB92 during growth with PAHs, improved its degradation rate. This showed strong potential of the acclimatised strains for bioremediation and reclamation of polyaromatic hydrocarbon contaminated sites.

The experiment was performed to evaluate effect of heavy metals on total phytoplankton load (TPL) using water of Turag River adjacent to Ashulia locating on the north-eastern side of Dhaka city, Bangladesh. Total phytoplankton load comprises of Euglena sp., Borodinella sp., Pediastrum biradiatum, Pinnularia sp., Fragillaria sp., Fragillaria crotonensis, Gloeocapsa sp., Navicula sp., Cynedra sp., Crucigenia sp., Chlorella sp., Spirogyra sp., Phacus acuminatus, Phacus circulatus., Nitzschia sp. and Nitzschia clausii. Phytoplankton load showed the abundances Bascillariophyceae (43.75%) > Chlorophyceae (37.50%) > Euglenophyceae (18.75%). The average maximum growth rate (log transformed) of TPL in control culture was -0.25μg/l and treated cultures using 1ppm, 3ppm, 5ppm, 7ppm concentration of heavy metals (Zn and Cu) were 0.03 μg/l, 0.03 μg/l, -0.11 μg/l and -0.26 μg/l, respectively. In treated culture using 1ppm concentration of heavy metals (Zn and Cu) the growth rate of phytoplankton load increased significantly whereas the growth rate decreased at higher concentrations (3ppm, 5ppm and 7ppm) of heavy metals. The implication of this finding can be used to monitor health of riverine ecosystems and management of river pollution.

Present study aims to unravel the hydro geochemical interaction of sediment and water of Saheb bandh lake, West Bengal, India with an emphasis on heavy metal assessment. Lake water belongs to Ca2+–HCO3− type hydro geochemical faces and water-rock interaction primarily controls the lake water chemistry. Based on different Hydro chemical characteristics it is suggested that silicate weathering is the major hydro geochemical process operating in Saheb bandh lake water. Regarding point source contribution of pollutants the average value of NO3-N, TP and Hg are much higher in inlet water (7.5 mg/L, 1.29 mg/L and 8.5 μg/L) than the lake water (1.5 mg/L, 0.05 mg/L and 0.42 μg/L). Risk assessment indices suggest advanced decline of the sediment quality. Water-sediment interaction of heavy metals reveals that Cd, As, Pb and Hg metals enter into lake water as a result of not only natural processes but also of direct and indirect activities of humans. This study recommends that continuous monitoring of these metals in water and sediment and other aquatic biota of Saheb bandh should be directed to assess the risk of these vital heavy metals in order to maintain the safe ecology in the vicinity of this lake.