Transfer pathways and accumulation of vanadium in the crab Carcinus maenas

The transfer pathways of vanadium in Carcinus meanas (L.) were investigated from February to April 1978 in order to determine the role of the food and environmental medium in the accumulation of this metal. The carbs, purchased from a fish market in Nice, France, in February 1978, were contaminated by food (the polychaete Nereis divesicolor), by environmental medium, and by food plus medium. In the early stages (15 d) of contamination, the accumulation of vanadium was greatest in crabs exposed to the contaminated medium. In later stages (30 d) crabs exposed to contaminated food plus medium exhibited the highest accumulation. Very little accumulation was observed in crabs contaminated by food alone.     

Cadmium accumulation by green algae Cladophora glomerata (L.) Kutz. (Chlorophyta) in presence of Nile tilapia Oreochromis niloticus (L.)

Accumulation of metals by aquatic organisms is mostly affected by other biological components in environments. In this study, cadmium (Cd) accumulation in green algae, Cladophora glomerata (L.) Kutz., exposed to 0.1 and 1.0 mg L^?1 of Cd for 15 and 30 days was examined in laboratory conditions in the presence of Nile tilapia Oreochromis niloticus (L.). The green algae C. glomerata accumulated Cd concentrations as 690 ± 70 and 3430 ± 470 mg kg^?1 on day 15, and 1130 ± 180 and 6830 ± 1540 mg kg^?1 on day 30. There were significant increases (p < 0.05) in metal accumulation by green algae as the exposure time and metal concentration increased. The results also indicated that the presence of Nile tilapia in the medium led to a significant Cd accumulation in the green algae compared to control (p < 0.05).     

The impact of human capital and bio-capacity on the environmental quality: evidence from G20 countries

Environmental Science and Pollution Research - This study investigates the effects of human capital, bio-capacity, energy use, and economic growth on the ecological footprint of G20 countries for...     

Heavy Metal Concentrations in Water, Sediment, Fish and Some Benthic Organisms from Tigris River, Turkey

In this study concentrations of heavy metals, such as Cd, Co, Cu, Fe, Mn, Ni, Pb and Zn were determined in water, sediment, muscle, liver and gill of fish (Silurus triostegus, Mastacembelus simack, Mystus halepensis, Orthrias euphraticus) the muscle and liver of crab (Potamon fluviatilis), the internal organs of fresh water snail (Physa acuta), and mussel (Unio elongatulus), and in whole biomass of green algae (Spirogyra sp.) examples collected seasonally from three selected sites (I, II, and III) of Tigris River and from a reference site on Resan Creek. In general, the average Cd, Cu, Mn, Ni, Zn, and Fe values in Sites I, II, and III were found to be high in spring and summer. The concentrations of heavy metals in the Tigris River are compared with previous studies in the same sites. The results showed that Cu levels have gradually decreased during recent years. In Tigris River, among the living organisms, i.e., those which are living in benthic region and showing biomonitor characteristic, crab, snail, green algae, mussel and fish are seen to be formed in sequence. Cu, Fe, Mn and Zn values obtained from the muscle of fish and from the mass of internal organs of mussel and snail were found to be under the acceptable values suggested.     

弯曲线不重合V形件的模具设计

弯曲线不重合且其精度要求较高的V形件的弯曲,是一较为棘手的问题。本文介绍了一种利用顶板侧壁的斜面,迫使下模框内摆块转动,从而克服工件回弹,并确保弯曲精度的V形弯曲模的设计。     

Determination of Commonly Used Herbicides in Surface Water Using Solid-Phase Extraction and Dual-Column HPLC-DAD

The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C₁₈) Empore extraction disks, octadecyl (C₁₈), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C₁₈ and CN) to confirm identification. Analytical separation was performed simultaneously on C₁₈ and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C₁₈ disks, from 75.1% to 100.0% for C₁₈ cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025–0.4 μg L^?1. The limits of detection were 0.012–0.035 μg L^?1.     

A decision support system for assessing landfill performance

Designing environmentally sound landfills is a challenging engineering task due to complex interactions of numerous design variables; such as landfill size, waste characteristics, and site hydrogeology. Decision support systems (DSS) can be utilized to handle these complex interactions and to aid in a performance-based landfill design by coupling system simulation models (SSM). The aim of this paper is to present a decision support system developed for a performance-based landfill design. The developed DSS is called Landfill Design Decision Support System – LFDSS. A two-step DSS framework, composed of preliminary design and detailed design phases, is set to effectively couple and run the SSMs and calculation modules. In preliminary design phase, preliminary design alternatives are proposed using general site data. In detailed design phase, proposed design alternatives are further simulated under site-specific data using SSMs for performance evaluation. LFDSS calculates the required landfill volume, performs landfill base contour design, proposes preliminary design alternatives based on general site conditions, evaluates the performance of the proposed designs, calculates the factor of safety values for slope stability analyses, and performs major cost calculations. The DSS evaluates the results of all landfill design alternatives, and determines whether the design satisfies the predefined performance criteria. The DSS ultimately enables comparisons among different landfill designs based on their performances (i.e. leachate head stability, and groundwater contamination), constructional stability and costs. The developed DSS was applied to a real site, and the results demonstrated the strengths of the developed system on designing environmentally sound and feasible landfills.     

Monitoring The Turbidity and Surface Temperature Changes and Effects of the 17 August 1999 Earthquake in the İzmİt Gulf,Turkey by the Landsat TM/ETM Data

The temporal turbidity and surface temperature changes and effects of the 17 August 1999 earthquake in the İzmit Gulf, Turkey have been investigated using Landsat TM/ETM data. The gulf is in the Mediterranean–Black Sea transition climatic zone and is partially surrounded by green vegetation cover and degraded and densely urbanized-industrialized areas. Landsat TM/ETM data acquired in 1990–1999 confirms increase in turbidity. Turbidity is always low in the southern part and high in the northern part of the gulf, because the more urbanized and industrialized areas are located in the northern part. The Landsat-7 ETM data acquired in the same year (1999) shows seasonal changes in turbidity. Moreover, the two high turbidity and surface temperature anomalies, one of which is parallel to the 17 August 1999 earthquake surface rupture (east–west) and the other which is in the northwest–southeast direction were mapped from Landsat-5 TM data acquired the day (18.08.1999) following the earthquake in the east end of the gulf. On the basis of turbidity implying the sea bottom movement, it is possible to state that a second rupture in the northwest and southeast direction could have occurred at the sea bottom during the earthquake. The distribution of the seismicity centers and the orientation of the lineaments in the area support this finding.     

Heavy metal pollution in surface sediment and mussel samples in the Gulf of Gemlik

Different sources of pollution in Karasu Creek were investigated to obtain the water quality and ratio of contamination in this region. To achieve the main objectives of the present study, water samples were collected from Karasu Creek, starting from flow pattern at the upstream site of Akkaya Dam to the end of the dam, crossing the place where the Creek drains into. Dissolved oxygen, electrical conductivity, temperature and maximum/minimum pH were measured systematically for 12 months in the stations, where the water samples were collected. Chemical analyses of the water samples were carried out by using Cadas 50 S brand UV spectrometer to find out the Pb, Fe, Cu, Zn, Ni, Cr, Cd, S, F and Cn concentrations. These concentration were determined in μg/lt as 80–850; 180–4,920; 10–6,100; 440–25,530; 130–2,400; 120–280; 20–150; 214,250–1,113,580; 1,560–4,270 and 40–690, respectively. To determine metal levels of the water samples, multivariate analyses (element coefficient correlation, coefficient correlation dendrogram, hierarchical cluster analysis dendrogram, model summary and ANOVA) were used. The analyses yielded highly accurate results. There were positive correlations between some elements and their possible sources were the same. The stations which resembled each other along the creek were divided into three groups. The water quality of the creek was low and had toxic qualities. Eutrophication developed in Akkaya Dam along the creek. The source of pollution was thought to be industrial and residential wastes. Absolute (0–100 m), short distance (100–500 m) and medium distance (500–2,000 m) conservation areas should be determined in pollution areas along Karasu Creek and they should be improved.