Evaluation of microbial contamination and distribution of sulphate-reducing bacteria in dental units

Although bacterial contamination is widely researched in dental unit water systems, we have been unable to find any published reports to date about the presence and distribution of sulphate-reducing bacteria (SRB) in dental unit waterlines (DUWLs). The aim of this study was to evaluate microbial contamination and to determine the presence and distribution of SRB in DUWLs. One hundred twenty-three water samples were collected from the air–water syringes, high-speed drills and water sources from 41 dental units in Istanbul, Turkey. The counts of aerobic heterotrophic bacteria and SRB were investigated in the water samples. In addition, the presence of free-living amoebae (FLA) was examined. In this work, we evaluated microbial contamination and reported for the first time the distribution of SRB in DUWLs. We determined that only ten out of 123 water samples were able to meet the American Dental Association’s limit (≤200 CFU ml^− 1). SRB were observed in 102 out of 123 samples (82.9%). In addition, SRB were detected in all of the air–water syringes and high-speed drills. FLA were established in 103 out of 123 samples (83.7%).     

Effect of complex shape of pier foundation exposure on time development of scour

Environmental Fluid Mechanics - Local pier scour has been recognized as one of the most significant causes of bridge failures. Despite numerous studies on the subject of local pier scour have been...     

Response of tomato (Lycopersicon esculentum Mill.) to salinity in the early growth stages for agricultural cultivation in saline environments

Salinity is a serious environmental problem. Growing of plants like tomato can be solution for coping with soil salinity. For this purpose, response of tomato to salinity has been tested in the early growth stages. Characteristics of germination (percentage and period; length and fresh-dry weight of radicle and hypcotyl) and seedling (length and fresh-dry weight of root, shoot and whole plant; leaf number and area based on Relative Growth Rate); Na+ and K+ content of leaf; K+/Na+ rate of leaf has been studied at the 0, 50, 100 and 150 mM NaCl levels. Thus, it determined that tomato can be indicator for agricultural cultivation at the salinity environments at the early growth stages.     

DETERMINATION OF AQUIFER PARAMETERS USING REGRESSION ANALYSIS1

ABSTRACT: Transmissivity and storativity of an aquifer are usually determined by analysis of steady or nonsteady pumping test data. The classical methods of nonsteady pumping test analysis are mostly graphical in nature and are, therefore, subject to errors of judgment in curve fitting, interpolating, and reading graphs and charts. A method is described here which does not require construction of graphs or use of charts and tables. The transmissivity and the storativity are calculated using regression analysis of the nonsteady time drawdown field data. The calculations can readily be performed on a hand held calculator. The procedure is described using four examples, and the results are compared with those obtained from graphical techniques. It is shown that the method is a viable alternative to the type curve solution of Theis or Straight line solution of Jacob for nonleaky artesian aquifers. However, the regression method poses problem in the cases of leaky artesian and water table aquifers.     

A Model for Managing Irrigated Agriculture1

ABSTRACT: Irrigation in arid and semiarid regions has led to accumulation of salts, destruction of soil texture, decline in fertility and yield, and eventual abandoning of the land. The problems of irrigated agriculture may be attributed to the fact that managers seldom consider irrigated land as a system consisting of a number of components and that the individual health of each component is vital to the overall health of the entire system. A management model is described here which considers all the important components of an irrigated system and may help maintain a permanent irrigated agriculture. The model optimizes net farm income, maintains favorable hydrologic and salt balance in the irrigated system, meets the concentration requirements of the drainage water for the individual crops, and simulates the impact of the irrigation on the unsaturated and the saturated zone.     

Examining the effectiveness of low-carbon strategies in South Asian countries: the case of energy efficiency and renewable energy

Environment, Development and Sustainability - This paper examines the impact of energy efficiency (EE) and renewable energy (RE) on carbon emissions, using a panel data of South Asian countries...     

Impregnation on activated carbon for removal of chemical warfare agents (CWAs) and radioactive content

Environmental Science and Pollution Research - Nuclear, biological, and chemical warfare (NBC) agents cause an inevitable threat to defense forces and civilians. Exposure to these toxic agents...     

Greenwash and green purchase behavior: an environmentally sustainable perspective

Environment, Development and Sustainability - Consumers’ interest is accelerating toward environmentally sustainable products, which are commonly known as green products. Companies use...     

Hydrochemical characterization and pollution assessment of groundwater in Jammu Siwaliks,India

Physico-chemical groundwater (GW) parameters were evaluated to understand the hydrogeochemical processes in the Siwalik plains of Jammu and Kashmir, India. During the 2012–2013 post-monsoon (POM) and pre-monsoon (PRM) seasons, GW samples (n = 207) from deep bore wells and shallow open wells were chemically analysed. Cations (Ca²⁺, Mg²⁺, Na⁺, K⁺ and Fe²⁺) and anions (HCO₃ ^?, Cl^?, SO₄ ^2? and F^?) showed a wide spatio-temporal variation. Results suggest that weathering and dissolution of carbonates and silicate rocks is the main source of water mineralization. The major hydrochemical facies is characterized by Ca-Mg-HCO₃ and Ca-HCO₃ during the PRM and POM seasons respectively. The presence of sulphate-bearing water in a large number of the samples indicates a significant role of gypsum dissolution and anthropogenic contamination of the GW. Factor analysis (FA) and hierarchical cluster analysis (HCA) revealed that the variability of hydrochemistry is mainly related to rock-water interaction, dissolution of carbonates and other lithological units as well as the influence of anthropogenic activities in the area. Overall, it was found that the GW quality is within the limits of human consumption. The higher concentration of a few chemicals indicates an increasing trend of industrial contamination of the GW. For sustainable development of the portable GW in Siwaliks, it is necessary to minimize the adverse impacts of the anthropogenic and industrial contamination on the GW resources through best management practices and prevent its further contamination to a level that could make GW unsuitable for human uses.     

Determination of urinary levels of Bisphenol A in a Turkish population

Bisphenol A (BPA) is one of the environmental endocrine disrupting chemicals that is widely used in common consumer products. The aim of this study was to report the total urinary BPA concentrations (free plus conjugated) in 200 urine samples (children: 57; male: 74; female: 69) obtained from residents of a Mediterranean city, Mersin. Analyses were performed by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and for assessing environmental exposure to free BPA and its major metabolite bisphenol A glucuronide (BPAG) in human urine were determinated. Our results indicated that the free BPA and BPAG concentrations were in the range of 0.06-0.99 μg/g creatinine and 0.24-615 μg/g creatinine, respectively. No statistically significant difference obtained in BPA concentrations between genders (male and female) or domicile of residence (rural and urban) (p?>?0.05). In our study, the mean level of detected free BPA was 0.46 μg/g creatinine in the urban area and 0.37 μg/g creatinine in the rural area. The average amount of BPAG was 60.56 μg/g creatinine in the urban area and 30.28 μg/g creatinine in the rural area. The data demonstrate that determined amount of total BPA in the present study is lower than the results of similar studies conducted in developed countries. There is no data about the levels of BPA in humans and environment in Turkey. Because of this reason, present study is very important since it is the first study in Turkey which determined the concentrations of free BPA and total BPA in human.