Determining the heavy metal pollution in Denizli (Turkey) by using Robinio pseudo-acacia L

The leaves of Robinia pseudo-acacia L. (Fabaceae) were evaluated as a biomonitors of heavy metal contamination in Denizli city, Turkey. Concentrations of Fe, Zn, Pb, Cu, Mn and Cd were determined in washed and unwashed leaves and soils collected from a wide range of sites with different degrees of metal pollution (industry, urban roadside, suburban) and from a rural (control) site by atomic absorption spectrometry. All the elements that measured were found to be at high levels in samples collected at industrial sites, except for lead and copper which were found at high levels in samples collected from urban roadsides that associated with the road traffic. The strong correlation between the degree of contamination and concentrations in all plant leaves assessed display that the leaves of R. pseudo-acacia reflect the environmental changes accurately, and that they seem as an effective biomonitor of environmental quality in areas subjected to industrial and traffic pollutions.     

Earthquake-related chemical and radioactivity changes of thermal water in Kuzuluk-Adapazan,Turkey

The movements of the North Anatolian Fault Zone (NAFZ) caused two devastating earthquakes within an 87-day interval, epicentered on G?lcük-Izmit (17 August, 1999) and Düzce-Bolu (12 November, 1999). The Kuzuluk geothermal area (KGA) is located in the middle of the epicenters and the distance between the geothermal area and the fault zone is less than 5 km. Hot water samples were collected from two thermal boreholes that supply hot water to the Kuzuluk thermal complex. The water samples taken prior to and after earthquakes were analysed by Neutron Activation and Atomic Absorption Spectroscopy. Particularly, increase in total a and total beta activities, in the content of Pb, Cr, Ni, Cu and decrease in the content of Fe, Zn, Cd, Mn, and Co are significant. The highest values are 75, 35, 12 and 65 ppb for Pb, Cr, Ni and Cu, respectively. The lowest values are 45, 55, 15, 135 and 6 ppb for Fe, Zn, Cd, Mn and Co, respectively.     

Arsenic adsorption from aqueous solutions by activated red mud

Heat treatment and acid treatment methods have been tested on red mud to increase its arsenic adsorption capability. The results indicate that the adsorptive capacity of red mud can be increased by acid treatment. This treatment causes sodalite compounds to leach out. As(III) and As(V) adsorption characteristics of activated red mud have similar tendencies with raw red mud. Batch adsorption studies have shown that activated red mud in dosages ranging from 20 to 100 g l(-1) can be used effectively to remove arsenic from aqueous solutions. The process is pH dependent, the optimum range being 5.8-7.5 for As(III) and 1.8-3.5 for As(V). The maximum removals are 96.52% for As(V) and 87.54% for As(III) for solutions with a final pH of 7.25 and 3.50, respectively, for the initial arsenic concentration of 133.5 micromol l(-1) (10 mg l(-1)), activated red mud dosage of 20 g l(-1), contact time of 60 min and temperature of 25 degrees C. The adsorption data obtained follow a first-order rate expression and fit the Langmuir isotherm well. Isotherms have been used to obtain the thermodynamic parameters. It was found that the adsorption of As(III) was exothermic, whereas As(V) adsorption was endothermic.     

Bioaccumulation of cesium-137 by biota in different aquatic environments

Macroalgae, isopods and fish species were exposed to 137Cs in brackish and sea water conditions for 18 days to determine radionuclide concentration factors. The concentration factors of 137Cs in brown shrimp and polychaete species were also investigated under brackish water conditions. At equilibrium, the concentration factors in macroalgae, isopod, fish, brown shrimp and polychate samples were found to be 2.5, 33, 2, 16 and 11 at 16 degrees C in brackish water conditions, respectively. The accumulation rate in macroalgae species was influenced by temperatures between 6 degrees C and 16 degrees C. The bioaccumulation of 137Cs in isopods at low salinity regime was increased significantly. At the same time, the bioaccumulation rate in macroalgae species also showed slight increase at low salinity. On the other hand, the bioaccumulation rate of 137Cs in the fish species in sea water was higher than in brackish water.     

Experimental studies on the biokinetics of 134Cs and 24Am in mussels (Mytilus galloprovincialis).

The biokinetics of 134Cs and 241Am in mussel species contaminated through water pathway has been studied under laboratory conditions. At equilibrium, the concentration factors for 134Cs and 241Am in small and large mussels were 2.80 and 2.57 and 200 and 150, respectively. The concentration factor of 134Cs in soft parts of the mussels was significantly high than whole body and shell tissue. However, the concentration factors of 241Am in soft parts and shell tissue samples were found to have similar rates. The depuration kinetics of the radionuclides were described by two-component exponential models. The biological half-lives at slow components between small and large mussels did not change significant, and were found to be 46.8-46.5 and 72.2-75.3 days for 134Cs and 241Am. The depuration kinetics of 134Cs and 241Am in soft parts described a single-component exponential model and the biological half-lives were found to be 29.4 and 41.1 days, respectively.     

Precipitable water modelling using artificial neural network in Çukurova region

Precipitable water (PW) is an important atmospheric variable for climate system calculation. Local monthly mean PW values were measured by daily radiosonde observations for the time period from 1990 to 2006. Artificial neural network (ANN) method was applied for modeling and prediction of mean precipitable water data in Çukurova region, south of Turkey. We applied Levenberg–Marquardt (LM) learning algorithm and logistic sigmoid transfer function in the network. In order to train our neural network we used data of Adana station, which are assumed to give a general idea about the precipitable water of Çukurova region. Thus, meteorological and geographical data (altitude, temperature, pressure, and humidity) were used in the input layer of the network for Çukurova region. Precipitable water was the output. Correlation coefficient (R²) between the predicted and measured values for monthly mean daily sum with LM method values was found to be 94.00% (training), 91.84% (testing), respectively. The findings revealed that the ANN-based prediction technique for estimating PW values is as effective as meteorological radiosonde observations. In addition, the results suggest that ANN method values be used so as to predict the precipitable water.     

Spatial distribution and source identification of trace elements in topsoil from heavily industrialized region,Aliaga, Turkey

Topsoil samples (n?=?40) were collected from a heavily industrialized region in Turkey. The region includes several scrap processing iron–steel plants with electric arc furnaces (EAFs), a petroleum refinery, a petrochemical complex, steel rolling mills, a natural gas-fired power plant, ship-breaking yards and very dense transportation activities. The region has undergone a rapid transition from an agricultural region to a heavily industrialized region in the last three decades. Collected soil samples were analyzed for 48 trace elements using inductively coupled plasma-mass spectrometry (ICP-MS). The elemental distribution pattern in the region indicated that Nemrut area with dense iron–steel production activities was a hotspot for elemental pollution. In addition to crustal elements, concentrations of anthropogenic trace elements (i.e., Fe, Zn, Pb, Mn, Cu, Cd, Cr and Mo) were very high in the area influencing many parts of the region. Elemental compositions of fugitive sources polluting the soil (i.e., paved and unpaved roads, slag piles, EAFs filter dust piles and coal piles) were also determined. The methods (enrichment factors [EFs] and the index of geoaccumulation [I _geo]) used for determination of pollution status of soil showed that Cr, Ag, Zn, As and Pb were the strongly contaminating elements for the region. Principal component analysis (PCA) clearly indicated that anthropogenic sources (steel production, refinery and petrochemical processes and traffic) were important sources in this region.     

道路交通网络与城市土地利用时空耦合关系——以南京市为例

城市的扩张与道路交通的发展是相辅相成的。道路建设造成了城市景观的破碎化，使城市景观呈现不同的空间格局和空间异质性特征，并且这种空间异质性随着时间的变化而发生改变。在RS和GIS技术的支持下，利用1989、1999和2008年的Landsat TM/ETM+数据，以南京市为例对道路交通网络与城市土地利用之间关系进行了不同层次和尺度的空间分析。结果表明：1989～2008年近20 a来，南京市城市空间形态扩展迅速，建设用地面积从1989年的1003 km2增加到2008年的6847 km2；在不同时期，南京市城市化过程表现出不同的道路交通网络结构和城市空间扩展模式；由道路交通建设造成的局部区域的景观破碎度在一定程度上能够反映周边区域的土地利用强度；土地利用强度和由道路交通建设造成的景观破碎度均表现出显著的空间自相关性，随时间推移，这种特征愈加明显，并且二者在表征城市空间拓展方面具有较高的耦合度；受其他辐射中心的作用，交通干线周边地区土地利用强度并未表现出距离指数衰减效应     

Sulphur-oxidising bacteria isolated from deep caves improve the removal of arsenic from contaminated harbour sediments

Acidophilic S-oxidising bacteria isolated from sulphur-rich deep caves (Frasassi, Italy), characterised by relatively low temperature, were tested for their ability to mobilise (semi-)metals from contaminated sediments. Sediment samples from two commercial Italian seaports were used to set up bioleaching experiments. The effect of different growth substrates was also investigated. Our experiments revealed that S-oxidising bacteria isolated from Frasassi caves have a high potential to remove As from contaminated marine sediments, as never reported before. Although As solubilisation efficiency was quite low (i.e. about 30%), only a small amount of As was associated with non-residual fractions of the sediment. On the contrary, the solubilisation efficiencies of Zn and Ni (20% and 10%, respectively) were lower than those previously obtained by the use of other acidophilic bacteria and mainly influenced by the experimental conditions rather than by the presence of the S-oxidising bacteria. Results presented here open new perspectives in bioleaching applications for the remediation of contaminated sediments. Indeed, microbial strains adapted to relatively low-temperature environments could improve sediment bioleaching at temperature regimes where mesophilic and thermophilic strains are not favoured. Such strains could be exploited for developing selective bioremediation procedures for sediments contaminated with As, to be applied in multistep biotreatment processes.