A study on the quality of water abstracted for potable use was conducted in the Selangor River basin from November 2008 to July 2009. Seven sampling sites representing the intake points of water treatment plants in the basin were selected to determine the occurrence and level of 15 organochlorine pesticides (OCPs), six phthalate esters (PAEs) and bisphenol A (BPA). Results indicated OCPs were still detected regularly in 66.1 % of the samples with the Σ15OCPs ranging from 0.6–25.2 ng/L. The first data on PAEs contamination in the basin revealed Σ6PAEs concentrations were between 39.0 and 1,096.6 ng/L with a median concentration of 186.0 ng/L while BPA concentration ranged from <1.2 to 120.0 ng/L. Although di-n-butyl phthalate was detected in all the samples, concentrations of di-ethyl(hexyl)phthalate were higher. Sampling sites located downstream recorded the highest concentrations, together with samples collected during the dry season. Comparison of the detected contaminants with the Department of Environment Water Quality Index (DOE-WQI) showed some agreement between the concentration and the current classification of stream water. While the results suggest that the sites were only slightly polluted and suitable to be used as drinking water source, its presence is cause for concern especially to the fragile firefly “Pteroptyx tener” ecosystem located further downstream. 相似文献
Hypoxic events frequently occur in the aquatic environment in association with micro pollutants, including heavy metals. Only a few studies are however available on the uptake and biological responses of heavy metals under hypoxic conditions. To elucidate the phenomenon, mirror carp Cyprinus carpio L. (16.13-16.22 g) were exposed chronically to dietary copper (Cu; 250 and 500 mg kg dry wt.−1) for 30 d under normoxic (8.25 mg O2 L−1) and hypoxic (∼3 mg O2 L−1) conditions and adopting an integrated approach, sub-lethal biomarker responses were determined at different levels of biological organisation. Level of oxidative DNA damage (as determined by modified Comet assay) showed strong significant difference following exposure to dietary Cu level under normoxic (1.6-fold) as well as under hypoxic condition at both Cu levels (2.1 and 2.5-folds respectively). Significant difference was also observed for haematological parameters (i.e. increased red and white blood cells, haematocrit value and haemoglobin concentration). Quantitative histology revealed alterations in tissues (i.e. liver and gills) for hypoxic and all dietary Cu treatment groups under both normoxic and hypoxic conditions suggesting a compensatory response to these organs (p < 0.05). The order of Cu accumulation in tissues (as determined by ICP-OES) was liver > intestine > kidney > gill. Interestingly, SGR under both normoxic and hypoxic conditions reduced with elevating Cu levels (p = 0.019). Overall, the results provide evidence for enhanced toxicological responses in fish following exposure to Cu either alone or in combination with hypoxic condition and lends support to the evolving viewpoint that many water quality guidelines should be revisited in terms of new ecotoxicological criteria. 相似文献
Marine and terrestrial ecosystems are so fundamentally different in some aspects that many of the issues concerning biodiversity
cannot be interpreted using a single theory of common application to all ecosystems. Their limitation is evident when it comes
to highly biodiverse and interconnected marine ecosystems such as coral reefs. Trophic links are a major factor, but space,
breeding, shelter from predators, environmental cues, behavior ingrained in genotypes, genetic variability, mutations, and
connectivity of marine critical habitats are also important. The importance of the connectivity of habitats such as coral
reefs, seagrasses, and mangrove in biodiversity preservation should be recognized. Migratory species require corridors for
gene flow and that influences diversity. The existing theories do not address the biodiversity issues related to life in the
abyssal plains and deep sea trenches and the challenge posed by climate change. An accurate understanding of marine biodiversity
requires comprehensive knowledge of ecological interrelationships and new perspectives that reflect the reality of global
environmental change. 相似文献
Rapid and unplanned urbanization and industrialization are the main reasons of environmental problems. If urban growth is not based on resource sustainability criteria and urban plans are not applied, natural and human resources are damaged dramatically. In this study, land use change and urban expansion in Edremit region of Turkey is determined by means of remote sensing techniques between 1971 and 2002. To improve the accuracy of land use/cover maps, the contribution of SAR images to optic images in defining land cover types was investigated. To determine the situation of land use/cover types in 2002 accurately, Landsat-5 images and Radarsat-1 images were fused, and the land use/cover types were defined from the fused images. Comparisons with the ground truth reveal that land use maps generated using the fuse technique are improved about 6% with an accuracy of 81.20%. To define land use types and urban expansion, screen digitizing and classification methods were used. The results of the study indicate that the urban areas have been increased 1,826 ha across the agricultural fields which are in land use capability classes of I and II, and significant environmental changes such as land degradation and degeneration of ground water quality occurred. 相似文献
Concentrations of heavy metals (Ag, Cd, Cr, Cu, Fe, Ni, Pb ve Zn) were measured in running water and in tissues (muscle, liver, gill, skin and gonads) of one commercially valuable fish species (Carasobarbus luteus) from the Orontes (Asi) River (Güzelburç region) in Hatay (Southeastern Turkey). Results for levels in water compared with national and international water quality guidelines were found at the highest concentrations in international criteria’s WHO, EC and EPA, but Cd, Cu, Ni and Pb were found to exceed permissible level of drinking water in national criteria TSE-266 whereas Fe, Zn and Cr concentrations were within the permissible levels for drinking. The present study showed a significant seasonal variation (p?0.05) in the concentration of the studied metals in the selected tissues, except gonads (p?>?0.05), which showed seasonal variation of only Zn (p?0.05). Maximum concentrations of Ag, Cd, Cr and Pb were detected in gonads followed by liver, gill, skin and muscle while maximum concentrations of Cu, Fe, Ni and Zn were detected in liver followed by other tissues. Concentrations of heavy metals in the muscle of C. luteus were below the permissible limit for human consumption, level of Cu being very close to the permissible limit. Consequently, continuous monitoring of heavy metal concentration in edible freshwater fish will be needed in Orontes River. 相似文献
The aim of this study was to evaluate the incidence of total aflatoxin (AF), ochratoxin A, T-2 toxin, deoxynivalenol (DON), zearalenone (ZEA), and fumonisin (FB) in dairy cattle, beef cattle, and lamb–calf feeds. A total of 180 dairy cattle, beef cattle, and lamb–calf feeds (60 samples each) were randomly collected from farms, feed mills, and villages in Burdur province, between September 2006 and August 2007. All samples were analyzed by the competitive Enzyme Linked Immuno Sorbent Assay (ELISA). The most frequent mycotoxin detected was total AF, which was found in 108 samples (60 %) in concentrations ranging from 3.82 to 116.83 μg?kg?1, followed by DON that was detected in 87 samples (48.3 %), in concentrations ranging from 18.50 to 500 μg?kg?1. Ochratoxin A (OTA), T-2 toxin, ZEA, and FB were found in 84 (46.7 %), 85 (47.2 %), 57 (31.7 %), and 19 (10.6 %) samples, respectively, in concentrations of 1.01 to 15.85 μg?kg?1 for OTA, 3.85 to 52.36 μg?kg?1 for T-2 toxin, 2.10 to 29.30 μg?kg?1 for ZEA, and 2.69 to 4.96 mg?kg?1 for FB. It was concluded that feed samples in Burdur province were contaminated by mycotoxins, and the levels of total aflatoxin in the samples were considered a risk to animal health. 相似文献
Transfer station, incineration plant, and landfill site made up the major parts of municipal solid waste disposal system of S city in Eastern China. Characteristics of volatile compounds (VCs) and odor pollution of each facility were investigated from a systematic perspective. Also major index related to odor pollution, i.e., species and concentration of VCs, olfactory odor concentration, and theoretic odor concentration, was quantified. Oxygenated compounds and hydrocarbons were the most abundant VCs in the three facilities. Different chemical species were quantified, and the following average concentrations were obtained: transfer station, 54 VCs, 2472.47 μg/m3; incineration plant, 75 VCs, 33,129.25 μg/m3; and landfill site, 71 VCs, 1694.33 μg/m3. Furthermore, the average olfactory odor concentrations were 20,388.80; 50,677.50; and 4951.17, respectively. The highest odor nuisance was detected in the waste tipping port of the incineration plant. A positive correlation between the olfactory and chemical odor concentrations was found with R2 = 0.918 (n = 15, P < 0.01). The result shows odor pollution risk transfer from landfill to incineration plant when adopting thermal technology to deal with the non-source-separated waste. Strong attention thus needs to be paid on the enclosed systems in incineration plant to avoid any accidental odor emission.
The objective of this study was to examine the effects of vegetation change from a native broadleaf forest to a coniferous plantation on selected soil properties, including soil texture, pH, organic matter, total nitrogen (N), total phosphorus (P), exchangeable cations (Ca2+, K+, Na+), and cation exchange capacity (CEC). Results showed that the amount of clay particles, Ca2+, and K+ values significantly increased, whereas Na+, total N, and organic matter and soil pH values decreased on the treatment plot after vegetation change. Soil acidity also increased and soil textural group changed from moderately fine-textured soils (clay loam) to medium-textured soils (loam) under both control and treatment plots. Organic matter, total N, and Na+ values increased, whereas Ca2+ concentration decreased through time on the control plot. Soil pH, total P, K+, and CEC did not show significant changes through time on the control plot. 相似文献
Cadmium is perhaps environmentally the most significant heavy metal in soils. Bioavailability, remobilization and fate of Cd entering in soils are usually controlled by adsorption-desorption reactions on Fe oxides. Adsorption of Cd on soil colloids including Fe oxides has been extensively studied but Cd desorption from such soil minerals has received relatively little attention. Some factors that affect Cd adsorption on goethite include pH, temperature, aging, type of index cations, Cd concentrations, solution ionic strength and presence of organic and inorganic ions. This research was conducted to study the influence of pH, temperature and aging on Cd desorption from goethite. Batch experiments were conducted to evaluate Cd desorption from goethite with 0.01 M Ca(NO3)2. In these experiments Cd desorption was observed at 20, 40 and 70 degrees C in combination with aging for 16 h, 30, 90 and 180 d from goethite that adsorbed Cd from solutions containing initial Cd concentrations of 20, 80 and 180 microM. Following the adsorption step Cd desorption was measured by 15 successive desorptions after aging at various temperatures. At the lowest amount of initially adsorbed Cd and equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 17% with aging from 16 h to 180 d and the corresponding decrease at equilibrium pH 6.0 was from 32% to 3%. There was a substantial decrease in Cd desorption with increasing equilibration temperature. For example, in goethite with the lowest amount of initial adsorption at equilibrium pH 5.5, cumulative Cd desorption decreased from 71% to 31% with increase in temperature from 20 to 70 degrees C, even after 16 h. Dissolution of Cd adsorbed goethite in 1M HCl, after 15 successive desorptions with 0.01 M Ca(NO3)2, indicated that approximately 60% of the Cd was surface adsorbed. Overall, dissolution kinetics data revealed that 23% to 88% Cd could not be desorbed, which could possibly be diffused into the cracks and got entrapped in goethite crystals. At elevated temperature increased equilibrium solution pH favoured the formation of CaCO3 and CdCO3 which reasonably decreased Cd desorption. Cadmium speciation showed the formation of calcite and otavite minerals at 40 and 70 degrees C due to increase in pH (>9.5) during aging. X-ray diffraction analysis (XRD) of these samples also revealed the formation of CaCO3 at elevated temperatures with aging. While mechanisms such as Cd diffusion and/or entrapment into fissures and cracks in goethite structure with increase in temperature and aging are possible. 相似文献