Natural radioactivity in various surface waters in stanbul, Turkey

Gross-α and gross-β, activities of eight well and five tap water samples taken in stanbul were determined. Ra²²⁶, Rn²²², Pb²¹⁴, Bi²¹⁴, K⁴⁰, Cs¹³⁷ activity concentrations in four lake, four sea water, one snow and one rain water samples were also analyzed in order to determine their radioactivity. The results obtained showed that, in general, natural activities in drinking water samples did not exceed WHO and ITS guidelines. In sea and lake water, four samples were over WHO and TSI guidelines. Concentrations ranging from 0.007 to 0.04 Bq l⁻¹ and from 0.02 to 0.1 Bq l⁻¹ were observed for drinking water and the gross-α and gross-β activities, respectively. For all samples the gross-β activities were higher than the corresponding gross-α activities. In order to evaluate the annual effective dose equilavent of ingestion of these waters, a conservative dosimetric calculation was carried out using dose conversion factor suggested by the ICRP. An average annual effective dose equivalent of 0.84 μSv y⁻¹ for Ra²²⁶ was calculated.     

Some elements comprising particulate matter during summer in waters of various environments in British Columbia, Canada

Multi-elemental traces comprising particulate matter in natural water collected during summer in 1978 and 1979 from British Columbia, Canada, were analyzed by α-particle excited X-ray fluorometry. Common elements from all waters examined were Si, Cl, Ca and Fe. The similarity of their distribution in different aquatic environments was statistically analyzed. They were distributed homogeneously in the marine environment but heterogeneously in the freshwater environments. No heavy metals concerned with the environmental standards were detected for all waters examined.     

Microbial Cell Wall Constituents in Indoor Air and their Relation to Disease

Abstract This presentation reviews the relation between damp buildings, mold growth and symptoms and disease among persons living or working in such buildings. Epidemiological studies on these relationships date back to 1924 and at present there are almost 30 large-scale investigations. There is an almost general concordance between studies on the relation between damp buildings and symptoms of the airways. Most of the studies show also a relation between symptoms and reported or measured mold growth. The symptoms reported are remarkably similar in the different studies: nose or throat irritation, wheezing, dry cough and fatigue. It is suggested that this symptom profile reflects a non-specific airways inflammation and that antigen-mediated allergy is rare. Regarding agents capable of inducing airways inflammation, data on bacterial endotoxin demonstrate a causal relationship, whereas information on another microbial wall agent - (1→3)-β-D-glucan - is suggestive but not conclusive of a causal relationship. From a practical point of view, dampness and previous mold growth represent conditions in buildings where renovation should be undertaken, particularly if there are symptoms of airways inflammation among the occupants.     

Stochastic modelling of mean monthly flows of Karasu River,in Turkey

Stochastic modelling of streamflows is vital for planning water resource systems. In this study, a stochastic model of the mean monthly streamflows at 2154 A?a?ιka?dariç Gauging Station on Karasu River was constructed. Studies were carried out using data from the water yearbooks published by chk later onEIE. The modelling procedure for streamflows with constant coefficient autoregressive moving average (ARMA) models was given in detail and indicated models were constructed. Analysis with streamflows at 2154 A?a?ιka?dariç Gauging Station showed that the autoregressive (AR) (1) model is the most appropriate model among the competing models. While selecting the most efficient model the Akaike information criterion (AIC) was used. The Port–Manteau test showed that residuals are white noise series. Using the AR(1) model, 100 synthetic series were generated and the time series generated were found to have the same statistical parameters (monthly mean, monthly standard deviation and autocorrelation) as historic time series within 95% confidence intervals.     

The identification of highly chlorinated ethers and diethers in river sediment near an epichlorohydrin plant

In harbour sediment samples taken near an epichlorohydrin production plant, a series of highly chlorinated ethers and diethers were detected viz. three isomeric bis(dichloropropyl)ethers, several structurally closely related ethers with 9 carbon atoms (C₉ ethers), a number of C₁₂ ethers and diethers, and finally several C₁₅ ethers. The formation of this new class of ether compounds can be explained on the basis of the chemistry of the addition of HOCl to allylchloride. After initial addition of Cl⁻, a reactive intermediate is formed which may react with the product dichloropropanol, to give the C₆ ethers, or may polymerize with the starting compound allylchloride followed by reaction with the product, to give the C₉, C₁₂ and C₁₅ ethers.     

Direct photolysis of estrogens in aqueous solutions

Direct photolysis of two estrogens 17beta-estradiol (E2) and estrone (E1) in aqueous solutions radiated by UV-light and UV-Vis-light was studied preliminarily. The results suggest that the photolysis of E2 in aqueous solutions occurs under irradiation with UV disinfection lamp (lambda = 254 nm, 30 W), while E1 can also undergo photolysis under irradiation with a high-pressure mercury lamp (lambda > or = 365 nm, 125 W). The photolysis reactions of E2 and E1 at the concentration of 3.0-20 mgl(-1) in aqueous solutions were all in accordance with pseudo-first-order law. The photolysis rate of estrogens in aqueous solutions reached the lowest value at pH approximately 5.0, while the highest at pH 8.0 over the range of 2.0-8.0. The higher the initial concentration of the two estrogens, the lower the rate of photolysis.     

Analysis of dissolved microcystins in surface water samples from Kovada Lake, Turkey

Dissolved (extracellular) microcystin (MC) concentrations were determined at 3 sampling stations on Lake Kovada, Turkey. The dominant species of cyanobacteria found in August and September of 2006 were Microcystis aeruginosa, Synechococcus sp., Phormidium limosum, Phormidium formosa and Planktothrix limnetica. MC concentrations in water were measured by ELISA and MC variants were examined by HPLC-PDA. Quantitative analysis by HPLC indicated that five MC variants (MC-LR, -RR, -LA, -LW, -LF) were identified in water samples from Kovada Lake. The maximum concentration of dissolved MC-LW was 98.9 µg l^− 1 in October. MC-LR was only detected in May at a concentration of 0.5 µg l^− 1. The cross reactivity of the antibody (MC10E7) to variants such as MC-LA MC-LW & MC-LF was low. Hence the results determined by ELISA were lower than those determined by HPLC in September and October samples due to differences in the specificity of the antibody to MC variants. Total extraceullar MCs was quantified by ELISA and ranged from 0.73 to 48.5 µg MC-LR equivalents l^− 1, which in some cases exceeded the WHO provisional Guideline Value for MC-LR in drinking water. This study confirms that the lakes of Turkey should be monitored for toxic cyanobacteria and for MCs to avoid or reduce the potential exposure of people to these health hazards.     

Azolla–Anabaena's behaviour in urban wastewater and artificial media – Influence of combined nitrogen

The results of using the nitrogen fixing symbiotic system Azolla–Anabaena to improve the quality of treated urban wastewater, particularly on what concerns phosphorus removal efficiencies (40–65%), obtained in continuous assays performed during the past few years and presented earlier, were very promising. Nevertheless, the presence of combined nitrogen in some wastewaters can compromise the treatment efficiency. The main goal of this work was to compare plants behaviour in wastewater and in mineral media with and without added nitrogen.Azolla filiculoides's specific growth rates in wastewater and in mineral media without added nitrogen or with low nitrate concentration were very similar (0.122 d⁻¹–0.126 d⁻¹), but decreased in the presence of ammonium (0.100 d⁻¹). The orthophosphate removal rate coefficients were similar in all the growth media (0.210 d⁻¹–0.232 d⁻¹), but ammonium removal rate coefficient in wastewater was higher (0.117 d⁻¹) than in mineral medium using that source of nitrogen (0.077 d⁻¹).The ammonium present in wastewater, despite its high concentration (34 mg N L⁻¹), didn't seem to inhibit growth and nitrogen fixation, however, in mineral media, ammonium (40 mg N L⁻¹) was found to induce, respectively, 18% and 46% of inhibition.     

Periphytic oxygen production in outdoor experimental channels

The contribution of periphytic oxygen was quantified in outdoor artificial streams. A factorial design was employed to determine the effect of stream velocity and light on periphytic growth, measured as chlorophyll α. Results showed that periphytic oxygen production can be estimated by the equation: =0.91 × 10⁻³ × Light Intensity (1x) + 0.061 for light intensities to 5000 ft-candles (53,800 lx). Stream velocity was found to be statistically insignificant in affecting oxygen production, but was a factor in periphyton accural and species composition. Gross oxygen production exceeded respiration by a factor of three.     

A toxicity warning monitor using the weakly electric fish, Gnathonemus petersi

A technically simple fish monitor was developed using the weakly electric fish, Gnathonemus petersi, as the test organism. The test system consists of a plexiglass test chamber (21., 27°C) with a flow-through of 4–5 times the chamber volume per hour. The spontaneous electric organ discharges (EOD) are recorded as activity signals. EODs, which have a potential of about 500 mV, last 0.3 ms and they can be converted to computer-compatible signals by a simple amplifier. The EOD-activity is analyzed by a low-cost desk-top computer. Two different modes of analysis which represent two levels of response sensitivity, are possible either alternatively or simultaneously. The toxicity response of Gnathonemus petersi was measured in experiments with the toxicants Hg²⁺, Cu²⁺, NaAsO₂ and CN⁻. The sensitivity to acutely toxic concentrations was found to be as high as that of trout or minnows.     

Secondary organic aerosol from α‐pinene ozonolysis in dynamic chamber system

Abstract Abstract The formation of secondary organic aerosol (SOA) produced from α‐pinene ozonolysis was examined using a dynamic chamber system that allowed the simulation of ventilated indoor environments. Particle‐bound reactive species (ROS) including peroxides, peroxy radicals and ions that could penetrate into the lungs and deliver oxidative stress to the tissue causing damage were quantitatively determined from filters collected from the chamber. ROS was determined using dichlorofluorescin such that resulting fluorescent intensities were converted to equivalent H₂O₂ concentrations. Measured ROS concentrations at α‐pinene and ozone concentrations relevant to prevailing indoor concentrations ranged from 1.1 to 7.2 nmol/m³ of H₂O₂. Particle density was also determined from scanning mobility particle sizer measurements and mass collected onto filters to obtain volume and mass concentration, respectively. Partitioning theory reveals the fact that with increased SOA mass loading, even for more volatile species, partitioning onto particle phase is favored relative to low SOA mass loadings. Other recent studies have found changes in composition of the SOA depending on the precursor VOC concentrations. This behavior was reflected in these experiments in terms of a change of density. Measured densities ranged from 1.07 to 1.69 g/cm³.     

Estimation of closure of a fracture under normal stress based on aperture data

The closure of 41-mm hydraulic fractures under normal stress in both loading and elastic closure (unloading) was estimated according to the formula proposed by Brown and Scholz and based on data measured for the initial aperture. By introducing the concept of an effective/ineffective initial aperture and by assuming Gaussian and χ² probability density functions (PDFs) of the initial aperture, the normal stress versus closure curve was determined from the standard deviation (SD) and the spectral moments of the initial aperture and the ratio of the mean effective initial aperture to the SD of the initial aperture. The results showed that the non-linearity in the normal stress versus closure curve at large normal stresses was reproduced better by the χ² PDF of the initial aperture than the Gaussian PDF for both loading and elastic closure. Furthermore, based on the ratio of the mean effective initial aperture to the SD of the initial aperture determined for the hydraulic fractures, the effect of size on the normal stress versus closure curve was estimated for fracture areas in a tensile fracture of 1 m. The results showed that closure increases with the size of the fracture area, and that the effect of size on the closure of the fracture is governed by the SD of the initial aperture.     

Cryptosporidium and Giardia detection in water bodies of Galicia, Spain

The objective of this study was to determine the mean concentration (per litre) of Cryptosporidium oocysts and Giardia cysts in recreational river areas (n = 28), drinking water treatments plants (DWTPs; n = 52) and wastewater treatment plants (WWTPs; n = 50) in Galicia (NW Spain). Water samples from rivers and from the influent (50–100 l) and the treated effluent (100 l) of the water plants were filtered using Filta-Max filters (IDEXX Laboratories, Inc., Westbrook, ME, USA). A total of 232 samples were processed and the (oo)cysts were concentrated, clarified by IMS and then detected by IFAT. The viability was determined by applying fluorogenic vital dye (PI).In the recreational areas, infective forms of Cryptosporidium and Giardia were detected in 16 (57.1%; 1–60 oocysts per litre) and 17 (60.7%; 1–160 cysts per litre) samples, respectively. In the water flowing into the water treatment plants, oocysts were detected in 21 DWTPs (40.4%; 1–13 oocysts per litre) and cysts were observed in 22 DWTPs (42.3%; 1–7 cysts per litre). In the effluents from the treatment plants, Cryptosporidium oocysts and Giardia cysts were identified in 17 DWTPs (32.7%; 1–4 oocysts per litre) and in 19 DWTPs (36.5%; 1–5 cysts per litre), respectively. The highest concentrations of (oo)cysts were found in the WWTPs; specifically, oocysts were detected in 29 (58.0%; 1–80 oocysts per litre) and cysts in 49 (98.0%; 2–14.400 cysts per litre) WWTP effluents. Cryptosporidium and Giardia were detected in 32 (64.0%; 1–120 oocysts per litre) and 48 (96.0%; 2–6.000 cysts per litre) WWTP effluents, respectively. The percentage viability of the (oo)cysts ranged between 90.0% and 95.0%. In all samples analysed. Moreover, it was found that the effluents from coastal WWTPs were discharged directly into the sea, while inland WWTPs were discharged directly into rivers. The concentrations of both enteropathogens detected in effluents from WWTPs therefore represent a significant risk to human and animal health.These results demonstrate the wide distribution of Cryptosporidium and Giardia in the environment, the ineffectiveness of treatments in DWTPs and WWTPs in reducing/inactivating both protozoa and the need to monitor the presence, viability and infectivity of Cryptosporidium and Giardia in water bodies. In conclusion, the findings suggest the need for better monitoring of water quality and identification of sources of contamination.