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Simultaneous Growth Of Spirulina Platensis And Removal Of Hardness In Van Lake Water
MakalelerAbstract
In this study, batch experiments were carried out to investigate simultaneous growth of Spirulina platensis and removal of hardness in the Van Lake Water (VLW). Laboratory-scale studies showed ample Spirulina growth observed in VLW when exposed to light. Spirulina was the only algal specimen inoculated in the water during the study. VLW percentages were varied between 0.1 and 100% while pH values were 8.7–10.42 in the flasks. On a dry-weight basis the biomass concentration was 1.18 g L−1 at pH 10 after 17 days of incubation in the VLW. The increase of pH to above 10.38 associated with Spirulina growth resulted in the precipitation of hardness causing compounds while providing 70% hardness removal from the VLW medium. Experimental results indicated that the proposed method can be used to design batch systems for producing S. platensis and removal of hardness from the VLW.
Keywords
- Algae biomass
- Batch system
- Cyanobacteria
- Spirulina
- Water hardness
Heavy Metal Content And Distribution In Surface Sediments Of The Seyhan River, Turkey
MakalelerAbstract
Chemical fractionation of seven heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) was studied using a modified three-step sequential procedure to assess their impacts in the sediments of the Seyhan River, Turkey. Samples were collected from six representative stations in two campaigns in October 2009 and June 2010, which correspond to the wet and dry seasons, respectively. The total metal concentrations in the sediments demonstrated different distribution patterns at the various stations. Cadmium was the only metal that was below detection at all stations during both sampling periods. Metal fractionation showed that, except for Mn and Pb, the majority of metals were found in the residual fraction regardless of sampling time, indicating that these metals were strongly bound to the sediments. The potential mobility of the metals (non-residual fractions) is reflected in the following ranking: Pb > Mn > Zn > Cu > Ni > Cr in October 2009 and Mn > Pb > Zn > Cu > Ni > Cr in June 2010. The second highest proportion of metals was bound to organic matter/sulfides, originating primarily from anthropogenic activities. Non-residual metal fractions for all stations were highest in June 2010, which may be linked to higher organic matter concentrations in the sediment samples with 1.40% and 15.1% in October 2009 and June 2010, respectively. Potential sediment toxicity was evaluated using the Risk Assessment Code (RAC). Based on RAC classification, Cd and Cr pose no risk, Cu and Ni pose low risk, Pb and Zn were classified as medium risk metals, while the environmental risk from Mn was high. In addition, based on the sediment quality guidelines (SQG), the Seyhan River can be classified as a river with no, to moderate, toxicological risks, based on total metal concentrations
Keywords
- Seasonal distribution
- Sequential extraction
- River sediment
- Sediment quality
Assessment Of Metal Pollution In Water And Surface Sediments Of The Seyhan River, Turkey, Using Different Indexes
MakalelerAbstract
The aim of this study was to assess the level of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination and enrichment in the surface sediments of the Seyhan River, which is the receiving water body of both treated and untreated municipal and industrial effluents as well as agricultural drainage waters generated within Adana, Turkey. Sediment and water samples were taken from six previously determined stations covering the downstream of the Seyhan dam during both wet and dry seasons and the samples were then analyzed for the heavy metals of concern. When both dry and wet seasons were considered, metal concentrations varied significantly within a broad range with Al, 7210–33 967 mg kg−1 dw; Cr, 46–122 mg kg−1 dw; Cu, 6–57 mg kg−1 dw; Fe, 10 294–26 556 mg kg−1 dw; Mn, 144–638 mg kg−1 dw; Ni, 82–215 mg kg−1 dw; Pb, 11–75 mg kg−1 dw; Zn, 34–146 mg kg−1 dw in the sediments while Cd was at non‐detectable levels for all stations. For both seasons combined, the enrichment factor (EF) and the geo‐accumulation index (I geo) for the sediments in terms of the specified metals ranged from 0.56 to 10.36 and −2.92 to 1.56, respectively, throughout the lower Seyhan River. The sediment quality guidelines (SQG) of US‐EPA suggested the sediments of the Seyhan River demonstrated “unpolluted to moderate pollution” of Cu, Pb, and Zn, “moderate to very strong pollution” of Cr and Ni. The water quality data, on the other hand, indicated very low levels of these metals suggesting that the metal content in the surface sediments were most probably originating from fine sediments transported along the river route instead of water/wastewater discharges with high metal content.
Keywords
- Enrichment factor
- Geo-accumulation index
- Metals
- River pollution
- Sediments
Modeling The Performance Of Upflow Anaerobic Filters Treating Paper-Mill Wastewater Using Gene-Expression Programming
MakalelerAbstract
This study investigates the predictive ability of gene-expression programming (GEP) in the estimation of methane yield (Ym) and effluent substrate (Se) produced by two anaerobic filters. The modeling study was carried out using the data obtained from two upflow anaerobic filters – one mesophilic (35 °C) and one thermophilic (55 °C) – operated for the treatment of paper-mill wastewater under varying organic loadings. The GEP model was composed of three inputs, hydraulic retention time (Thr), organic loading rate (Rol), and influent substrate (Si), and one output, either Se or Ym. The Stover–Kincannon model was also used for data analysis and to evaluate the prediction ability. Three statistical criteria, root mean square error (RMSE), determination coefficient (R2), and Akaike’s information criteria (AIC), were the means used for comparison. The results showed that the GEP approach predicted the performance of both anaerobic filters much better than the Stover–Kincannon model.
Keywords
- Anaerobic digestion
- Mesophilic
- Thermophilic
- Paper-mill wastewater
- Gene-expression programming
Groundwater Hydrochemistry At The Mediterranean Coastal Plains - The Case Of Silifke, Turkey
MakalelerAbstract
Hydrochemical characterization of the Silifke Plain coastal aquifer was accomplished in this research in order to investigate the water quality of groundwater. The aquifer is located along the Mediterranean coast and forms one of the most productive aquifers in Turkey. Groundwater samples were collected from the aquifer as monthly between December 2007 and November 2008 for 12 months. Twenty one artesian wells were chosen and water sampling was made once a month. The values of electrical conductivity (EC) and pH as well as main anions and cations were determined twice for each month. Based on the observations in the water wells, the EC, sodium adsorption rate (SAR), and chloride (Cl−) concentrations varied between 437 and 3480 µS/cm, 0.13 and 23.1, and 25 and 1661 mg Cl−/L, respectively. Deterioration of water quality was observed in some areas very close to the sea due to seawater intrusion and intense use of groundwater for irrigation.
Keywords
- Groundwater
- SeGroundwater
- Seawater intrusion
- Coastal plain
Speciation And Implications Of Heavy Metal Content In Surface Sediments Of Akyatan Lagoon-Turkey
MakalelerAbstract
Akyatan Lagoon, which is located on the Mediterranean coast of Turkey, is ecologically and economically important due to biological diversity, valuable fish species, and wildlife resources and the area has been declared as a wildlife protection area. The characterization of surface sediments in the Akyatan Lagoon revealed that the surface sediments of the lagoon, on average, contained higher organic matter by about 15% in wet season as compared to dry season. The organic content of the lagoon sediments varied between 4.35% and 11.66% with a mean value of 8.76% for wet season, and 4.24% and 9.49% with a mean value of 7.60% for dry season. The oxidation–reduction potential (ORP) values were mostly below − 300 mV and there was no significant seasonal or spatial change in the pH levels. The spatial distribution for total heavy metals (Cr, Cu, Mn, Ni, Pb and Zn) concentrations of the surface sediments in the lagoon varied from each station to another due to factors such as hydrodynamic conditions, pH, ORP, temperature, water depth, distance to the discharge points and the canal opening to the sea. The heavy metal concentrations were higher at the stations with high silt and clay content in the sediments characterized. The total concentrations of Cr, Ni, and Zn were as high as 95.6, 219, and 102 mg/kg, respectively, while Cu and Pb concentrations, on the other hand, varied between 15.4–31.3 mg/kg and 19.5–33.6 mg/kg, respectively. Cd was found to be non-detectable (< 0.005 mg/L). Chemical speciation of heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) and their seasonal and spatial concentration distributions were determined using a modified BCR 3-step extraction procedure for the lagoon sediments during both wet and dry seasons. The speciation study revealed that most of the heavy metals would be immobile due to their mostly high residual fraction (42% of Mn, 87% of Cr, 68% of Cu, 88% of Ni, 61% of Pb, and 82% of Zn, on average) and low reducible and exchangeable/acid soluble fraction (44.7% of Mn, 0.51% of Cr, 0.68% of Cu, 1.1% of Ni, 4.8% of Pb, and 3.7% of Zn, on average). Based on the Risk Assessment Code, Mn, Ni, Pb, and Zn levels pose low risk and Cd, Cr, and Cu pose no risk for the possibility to enter the food chain indicating that the industrial use of the lagoon in terms of fisheries/nurseries may not be impacted. Spearman Rank coefficients obtained for the lagoon sediments indicated adsorption of heavy metals by fine particles such as silt and clay and more than moderate relationship between the metals and sediment characteristics.
Keywords
- Dissolved inorganic carbon
- Heavy metals
- Fractionation
- Point source
- Non-point source
- Correlation
- Three-step sequential extraction
- Ramsar
- Coastal water
Dissolved Nutrient Distributions In Groundwater In The Mediterranean Coastal Plains - The Case Of Silifke, Turkey
MakalelerAbstract
Total carbon, nitrogen, and phosphate parameters were studied for the first time in the groundwater in the Silifke coastal plain, which is a RAMSAR site in Turkey. Seasonal variations of these parameters in the plain were examined based on groundwater data collected from 21 wells during the winter, spring, summer, and fall seasons. Total dissolved organic carbon (DOC), inorganic carbon (DIC), inorganic phosphate (DIP), inorganic nitrogen (DIN), and total alkalinity (TAlk) average values in the groundwater were low in all seasons (<2.2 mg/L for DOC; <54 mg/L for DIC; <0.06 mg/L for DIP; <1.5 mg/L for DIN; <232 mg/L for TAlk). The results showed a strong relationship between DIC and 
as expected. The results indicate that the content of these parameters in the groundwater of Silifke coastal plain pose no or little risk at present. However, computed Langelier Saturation Index (LSI) values indicated that the groundwater has a tendency to form scale and CaCO3 precipitation may occur.
Keywords
- Dissolved inorganic carbon
- Dissolved inorganic nitrogen
- Dissolved inorganic phosphate
- Groundwater
- Silifke coastal plain
- Total alkalinity
Monitoring Of Seasonal Variation Of Heavy Metal Concentrations In Bed Sediments Of Lower Seyhan River, Turkey
MakalelerAbstract
In this study, variation of total heavy metal concentrations in the bed sediments against the flow rate of the lower Seyhan river has been evaluated. Sediment samples were collected at 6 representative sampling stations along the lower Seyhan river, Turkey under low and high flow conditions during four seasons. Concentrations of Cd, Cu, Fe, Mn, Ni, Pb and Zn decreased by increasing river flow rate. Sediment quality assessment according to the “U.S.EPA Sediment Quality Guidelines (SQG)” revealed that there was heavy metal pollution with respect to especially Ni, Cd and Zn. However, mean Cu and Pb levels in the river indicated that the river was non-contaminated. There were several mechanisms suggested for heavy metal distribution in the river such as immobilization by sedimentation, remobilization by pH decrease due to microbial degradation of organic matter and resuspension due to increased river flow rate.
Keywords
- Trace metals
- Seasonal distribution
- Sediment quality
- Immobilization