Estimation of suspended sediment concentration in rivers using acoustic methods

Acoustic Doppler current meters (ADV, ADCP, and ADP) are widely used in water systems to measure flow velocities and velocity profiles. Although these meters are designed for flow velocity measurements, they can also provide information defining the quantity of particulate matter in the water, after appropriate calibration. When an acoustic instrument is calibrated for a water system, no additional sensor is needed to measure suspended sediment concentration (SSC). This provides the simultaneous measurements of velocity and concentration required for most sediment transport studies. The performance of acoustic Doppler current meters for measuring SSC was investigated in different studies where signal-to-noise ratio (SNR) and suspended sediment concentration were related using different formulations. However, these studies were each limited to a single study site where neither the effect of particle size nor the effect of temperature was investigated. In this study, different parameters that affect the performance of an ADV for the prediction of SSC are investigated. In order to investigate the reliability of an ADV for SSC measurements in different environments, flow and SSC measurements were made in different streams located in the Aegean region of Turkey having different soil types. Soil samples were collected from all measuring stations and particle size analysis was conducted by mechanical means. Multivariate analysis was utilized to investigate the effect of soil type and water temperature on the measurements. Statistical analysis indicates that SNR readings ob tained from the ADV are affected by water temperature and particle size distribution of the soil, as expected, and a prediction model is presented relating SNR readings to SSC mea surements where both water temperature and sediment characteristics type are incorporated into the model. The coefficients of the suggested model were obtained using the multivariate anal ysis. Effect of high turbidity conditions on ADV performance was also investigated during and after rain events.     

A complex investigation of the extent of pollution in sediments of the Sava River. Part 1: Selected elements

The Sava River is the biggest tributary to the Danube River. As a part of the 6th FW EU project, Sava River Basin: Sustainable Use, Management and Protection of Resources (SARIB), ecological status of sediments was investigated. In order to assess the geographical distribution in sediment contamination of the Sava River, inorganic and persistent organic pollutants were analyzed in sediments at 20 selected sampling sites along the Sava River from its spring to its outfall into the Danube River. For comparability of data to other river basins the sediment fraction below 63 μm was studied. Due to complexity of the work performed, the results are published separately (“Part I: Selected elements” and “Part II: Persistent organic pollutants”). In the present study, the extent of pollution was estimated by determination of the total element concentrations and by the identification of the most hazardous highly mobile element fractions and anthropogenic inputs of elements to sediments. To assess the mobile metal fraction extraction in 0.11 mol L^???1, acetic acid was performed (first step of the Community Bureau of Reference extraction procedure), while anthropogenic inputs of elements were estimated on the basis of normalization to aluminum (Al) concentration. According to the Water Framework Directive, the following elements were investigated in sediments: cadmium (Cd), lead (Pb), nickel (Ni), and mercury (Hg). Furthermore, copper (Cu), zinc (Zn), chromium (Cr), arsenic (As), and phosphorous (P) were determined. The analyses of sediments demonstrated slightly elevated values for Hg, Cr, and Ni in industrially exposed sites (concentrations up to 0.6, 380, and 210 mg kg^???1, respectively). However, the latter two elements exist in sparingly soluble forms and therefore do not represent an environmental burden. P concentrations were found in elevated concentrations at agricultural areas and big cities (up to 1,000 mg kg^???1).     

The 210Po and 210Pb levels in surface sediment samples in the Izmir Bay (Aegean Sea-Turkey)

Bottom sediments reflect in general the relative contamination of a sea area. Therefore, a great deal of monitoring work has been dedicated to the analysis of bottom sediments. Izmir Bay is a very important pollution centre in Turkish Aegean coast region due to a densely populated community, industrial complex and maritime transportation, and there are many streams flowing into the bay that pass through a number of industrial and agricultural areas. It had received the majority of domestic and industrial wastewaters until the wastewater treatment plant was constructed. It is well known that sediments play an important role as reservoirs of a fraction of the pollution in aquatic systems. Therefore, sediment samples were collected monthly from three stations which are located in the inner part of the bay during the period January to December 2003. Temporal variations and seasonal changes on their ²¹⁰Po and ²¹⁰Pb contents were examined, and the activity concentrations of ²¹⁰Po and ²¹⁰Pb were found to vary from 43±6 to 132±12 and 27±5 to 91±9 Bq kg^???1 dry wt, respectively. The highest values of those natural radionuclides were measured at Kar??yaka Station because of the current systems of the bay. Seasonally, the ²¹⁰Pb levels were found to increase during the winter time for all the stations.     

Assessment of natural radiation exposure levels and mass attenuation coefficients of lime and gypsum samples used in Turkey

The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K in lime and gypsum samples used as building materials in Turkey were measured using gamma spectrometry. The mean activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were found to be 38 ± 16, 20 ± 9, and 156 ± 54 Bq kg^???1 for lime and found to be 17 ± 6, 13 ± 5, and 429 ± 24 Bq kg^???1 for gypsum, respectively. The radiological hazards due to the natural radioactivity in the samples were inferred from calculations of radium equivalent activities (Ra_eq), indoor absorbed dose rate in the air, the annual effective dose, and gamma and alpha indices. These radiological parameters were evaluated and compared with the internationally recommended limits. The experimental mass attenuation coefficients (μ/ρ) of the samples were determined in the energy range 81–1,332 keV. The experimental mass attenuation coefficients were compared with theoretical values obtained using XCOM. It is found that the calculated values and the experimental results are in good agreement.     

Principal component analysis for soil contamination with organochlorine compounds

In order to investigate the distribution pattern of individual organochlorine compounds in soil samples collected from the sites (Canary Island – Spain, China, Germany, India, Romania, Russia, Serbia, Swiss, UK) affected by industrial activities to the more remote areas, principal component analysis was performed on the data taken from literature. Loading plots pointed out the strong correlation among the variables. Score plots revealed similar PCB- and OCP-soil patterns for majority of the investigated sites. Nevertheless, the temporal differences of PCB-soil loads have been identified: the late 1990s and early 2000s concentrations are similar to those of the early 1940s, and they are below the levels existed in 1980. The most pronounced PCB concentrations characterized the soil from 1966. For OCPs the influence of sites location on the detected concentration has been revealed: China and India were characterized by comparably higher loads of DDX (DDT and its metabolites) and of HCH-isomers, respectively.     

Heavy metals in soils: distribution, relationship with soil characteristics and radionuclides and multivariate assessment of contamination sources

The study is dealing with the distribution and the origin of heavy metals (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in soils from a priori non-polluted areas. Positive correlations with organic matter and clay content but not with pH have been observed for most of elements analyzed in this study. Correlations of some metals (Cr, Pb and Zn) and radionuclides (238U and 137Cs) observed for analyzed soils could be explained by their common affinity for clay minerals. Enrichment factor (EF) analysis and cluster analysis (CA) highlighted the lithogenic origin of Cr, Cu, Mn, Ni, Pb and Zn and pointed out the primary input of Cd from anthropogenic sources. It also revealed the need for detailed geochemical surveys in the future in order to decrease the uncertainty of discrimination between lithogenic and anthropogenic origin of metals of interest.     

Environmental and Economic Criteria in Ranking of Copper Concentrates

Influence of the economic criterion, called Profit, on the ranking of copper concentrates is investigated. Values of the criterion, which correspond to alternatives, are derived as earning values obtained by the exploitation of individual concentrates. Various scenarios with respect to the weight w ₁₄, corresponding to the additional economical criterion, are defined and solved. A discrete set of results is generated, applying DECISION LAB software implementation of the PROMETHEE-GAIA methodology. Interpolating these results, we derived continuous interpolation functions which compute necessary quantities of concentrates for each real value of w ₁₄ within the interval [0, 100].     

The assessment of the relationship between various waterscapes and outdoor activities: Edirne,Turkey

The environment is very important in terms of the behaviours and actions of human beings, and activity–environment correlation is used frequently in outdoor arrangements. The environment must meet the requirements and expectations of society. Outdoor activities are the activities that contribute to the well-being of human beings in physical (heartbeat, respiration, blood pressure, etc.) (Ulrich, Journal of Environmental Psychology 11:210–230, 1991), psychological (fear, anxiety, depression, loneliness, stress, etc.) (Marcus and Barnes 1999) and behavioural (insomnia, nervousness, restlessness, passivity, etc.) (Ulrich 1999) terms. It is known that human beings are affected significantly by the environments they are in, and more importantly, it is known that the environment they are in affects their happiness status. The causes of this effect are the features and appearances of the spatial elements and components that mainly make up such environments. One of the elements that is used frequently in landscape is water. If one examines designed or natural open spaces, it may be observed that water has very distinctive features. Dynamic (in the form of a leak, with intense flow rate, cascade, foamy, squirting, jet, graded, etc.) and still water elements may be used with sculptures, plants, rocks and elevations (on land). This study aims to reveal which age groups of students enjoy the different types of activities with regards to water features and emotional associations that motion and characteristics of water bring out in human beings and also to reveal the water preferences of human beings, including their reasons for such preference. Thus, 20 different water compositions located in Edirne Province were selected, and in 2-min camera reels, the students of various age groups assessed water with various characteristic features via a survey. As a result, it was revealed that human beings from various age groups wish to perform different activities with water elements having distinctive characteristic features, and the types of water elements that are subject to various age groups’ like and dislike were determined. Kruskal–Wallis test was used during testing the effect of age differences. Chi-square analysis was used in order to examine the effect of age differences on preferences with regards to the activities that shall be performed at locations that include utilization of various water elements. The results reveal that while the use of water should be allowed in landscaping, selections regarding the elements of these water features should be made based on the type of activity and the age group of users in relation to the location.     

Long-term seasonal changes of the Danube River eco-chemical status in the region of Serbia

Seasonal spatial and temporal changes of selected eco-chemical parameters in section of the Danube River flowing through Serbia were analyzed. Data for electrical conductivity (EC), dry and suspended matter, residue on ignition, chemical oxygen demand (COD), biochemical oxygen demand (BOD-5), ultraviolet extinction, dissolved oxygen (DO), oxygen saturation, pH, nitrates, total phosphorus, and nitrogen were collected between 1992 and 2006. The use of monthly medians combined with linear regression and two-sided t test has been proven to be the best approach for resolving trends from natural variability of investigated parameters and for determining trend significance. Patterns of temporal changes between different months were examined. It was also determined that spatial trends of some parameters oscillate in predictable manner, increasing in one part of the year and declining in the other. Regression slope coefficients, an excellent indicator for determining when the water quality is changing the most along the course of the Danube, reach their maximum during summer for temperature (t), electric conductivity, nitrates, and total N, while in the same season suspended matter, COD, BOD-5, DO, and oxygen saturation coefficients reach their minimum. Correlations for used data sets of selected parameters were analyzed for better understanding of their behavior and mutual relations. It was observed that as Danube flows through Serbia, its general eco-chemical status either stagnates or improves, but the rate of river self-purification often depends on the season of the year.