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1.
Buyukcekmece Lake located north of the Marmara Sea coast of Turkey is the third largest water resources among the six main reservoirs of a megacity Istanbul, providing 17% water demand. This study aims to investigate the water quality changes in Buyukcekmece Lake and to classify it in accordance to Turkish Water Pollution Control Regulation for inland surface waters, and assess the impacts of the land-use practices, population density, and settlement in the Buyukcekmece watershed. Physical, chemical, and biological quality of Büyükçekmece Lake has been investigated between December 2007 and June 2008 by collecting samples from the Lake and four streams that feed Büyükçekmece Lake. Land use profile maps of the water basin were created by using ARC-GIS to ensure the quality of drinking water. It was determined that the water quality of Büyükçekmece Lake was still of overall second class, implying that it can be used as a safe drinking water resource following a conventional water treatment scheme; however, it is moving toward the third class. Remarkable portion of the pollution in water basin was attributed to domestic wastewater discharges. Agricultural areas that occupy more than half of the water basin have also adversely affected the water quality. 相似文献
2.
Mahesh Mohan M S Shylesh Chandran K K Jayasooryan E V Ramasamy 《Environmental monitoring and assessment》2014,186(6):3321-3336
Mercury, a global pollutant, is popping up in places where it was never expected before and it burdens in sediments and other non-biological materials. It is estimated to have increased up to five times the pre-human level due to anthropogenic activities. Vembanad backwaters, one of the largest Ramsar site in India, which have extraordinary importance for its hydrological function, are now considered as one of the mercury hot spots in India. In this study, surface sediment samples of Vembanad Lake and nearshore areas have been seasonally analysed for total mercury and methyl mercury concentrations while the core sediment samples were analysed for total mercury. The results showed that the northern part of the lake was more contaminated with mercury than the southern part. The mercury concentration was relatively high in the subsurface sediment samples, indicating the possibility of historic industrial mercury deposition. A decreasing trend in the mercury level towards the surface in the core sediment was also observed. The geochemical parameters were also analysed to understand the sediment mercury chemistry. Anoxic conditions, pH and organic carbon, sulphur and Fe determined the presence of various species of mercury in the sediments of Vembanad Lake. The prevailing physical and geochemical conditions in Vembanad Lake have indicated the chances of chemical transformation of mercury and the potential hazard if the deposited mercury fractions are remobilised. 相似文献
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Measuring Water Storage Fluctuations in Lake Dongting, China, by Topex/Poseidon Satellite Altimetry 总被引:1,自引:0,他引:1
Zhang J Xu K Yang Y Qi L Hayashi S Watanabe M 《Environmental monitoring and assessment》2006,115(1-3):23-37
Although satellite radar altimetry was developed and optimized for open oceans, it has been used to monitor variations in the level of inland water-bodies such as lakes and rivers. Here, for the first time, we have further used the altimetry-derived variation of water level for estimating the fluctuation of water storage as an addition to the present in situ water storage estimation systems to be used in remote areas and in emergency situation such as in the events flooding monitoring and for studying the effect of climate change. Lake Dongting, the second largest lake in China, influenced frequently by flooding, was, therefore, chosen to demonstrate the potential of the technique. By using the concept of an “assumed reference point”, we converted Topex/Poseidon satellite altimetry data on water level variations in Lake Dongting to “water level” data. The “water level” time-series data and in situ water storage were used to establish a rating curve. From the rating curve, we converted data on “water level” derived from seven years (1993–1999) of Topex/Poseidon data to actual water storage in Lake Dongting. The result reveals that the seasonal and annual fluctuations of water storage occurred during the 1990s with a more frequent flooding at the late 1990s' especially the flooding in whole catchment level in 1998 and 1999. The study supports the usefulness of satellite altimetry for dense and continuous monitoring of the temporal variations in water dynamic in moderate to large lakes. 相似文献
5.
Spatial distribution and multiple sources of heavy metals in the water of Chaohu Lake,Anhui, China 总被引:4,自引:0,他引:4
Li G Liu G Zhou C Chou CL Zheng L Wang J 《Environmental monitoring and assessment》2012,184(5):2763-2773
In this study, a survey for the spatial distribution of heavy metals in Chaohu Lake of China was conducted. Sixty-two surface
water samples were collected from entire lake including three of its main river entrances. This is the first systematic report
concerning the content, distribution, and origin of heavy metals (Cu, Cr, Cd, Hg, Zn, and Ni) in the Chaohu Lake water. The
results showed that heavy metals (Cu, Cr, Zn, and Ni) concentrations in the estuary of Nanfei River were relatively higher
than those in the other areas, while content of Hg is higher in the southeast lake than northwest lake. Moreover, Cd has locally
concentration in the surface water from the entire Chaohu Lake. The heavy metal average concentrations, except Hg, were lower
than the cutoff values for the first-grade water quality (China Environment Quality Standard) which was set as the highest
standard to protect the social nature reserves. The Hg content is between the grades three and four water quality, and other
heavy metals contents are higher than background values. The aquatic environment of Chaohu Lake has apparently been contaminated.
Both the cluster analysis (CA) and correlation analysis provide information about the origin of heavy metals in the Lake.
Our findings indicated that agricultural activities and adjacent plants chimneys may contribute the most to Cd and Hg contamination
of Chaohu Lake, respectively. 相似文献
6.
This report describes a study to identify reference lakes in two lake classifications common to parts of two level III ecoregions in western Arkansas—the Arkansas Valley and Ouachita Mountains. Fifty-two lakes were considered. A screening process that relied on land-use data was followed by reconnaissance water-quality sampling, and two lakes from each ecoregion were selected for intensive water-quality sampling. Our data suggest that Spring Lake is a suitable reference lake for the Arkansas Valley and that Hot Springs Lake is a suitable reference lake for the Ouachita Mountains. Concentrations for five nutrient constituents—orthophosphorus, total phosphorus, total kjeldahl nitrogen, total nitrogen, and total organic carbon—were lower at Spring Lake on all nine sampling occasions and transparency measurements at Spring Lake were significantly deeper than measurements at Cove Lake. For the Ouachita Mountains ecoregion, water quality at Hot Springs Lake slightly exceeded that of Lake Winona. The most apparent water-quality differences for the two lakes were related to transparency and total organic carbon concentrations, which were deeper and lower at Hot Springs Lake, respectively. Our results indicate that when nutrient concentrations are low, transparency may be more valuable for differentiating between lake water quality than chemical constituents that have been useful for distinguishing between water-quality conditions in mesotrophic and eutrophic settings. For example, in this oligotrophic setting, concentrations for chlorophyll a can be less than 5 μg/L and diurnal variability that is typically associated with dissolved oxygen in more productive settings was not evident. 相似文献
7.
Evaluation of anthropogenic effects on water quality and bacterial diversity in Rawal Lake,Islamabad 总被引:2,自引:0,他引:2
Water quality and bacterial diversity in the surface water of Rawal Lake was investigated for a period of 8 months to evaluate the pollution load from anthropogenic effects of surrounding areas. Rawal Lake in Islamabad, Pakistan is an artificial reservoir that provides the water needs for the residents of Rawalpindi and Islamabad. Grabbed water samples were collected according to standard protocols from ten different locations of the lake and tributaries keeping in view the recharge points from adjacent areas. Temperature, pH, electrical conductivity, dissolved oxygen, total dissolved solids, hardness, alkalinity, and turbidity of water samples were determined to study the water quality characteristics. The physicochemical parameters showed higher values at the tributaries as compared to the sampling locations within the lake such as values of hardness and alkalinity were 298 and 244 mg/L, respectively, at the tributary of the Nurpur stream. Bacterial strains were isolated by streaking on differential and selective growth media by observing colony morphology and other biochemical tests such as Gram reaction, oxidase, and catalase test. Template DNA was prepared from pure cultivated bacteria and 16S rRNA gene analysis was performed using universal primers for bacteria. Sequencing was performed by using BigDye terminator cycle sequencing kit. Sequences of nearest relative microbial species were identified by using basic local alignment search tool and used as reference sequences for phylogenetic analysis. Phylogenetic trees were inferred using the neighbor-joining method. Sequencing and phylogenetic characterization of microbes showed various phylotypes, of which Firmicutes, Teobacteria, and Proteobacteria were predominant. 相似文献
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Distinguishing and quantifying anthropogenic trace metals and phosphorus accumulated in sediment is important for the protection
of our aquatic ecosystems. Here, anthropogenic proportion and potential sources of trace metals and phosphorus in surface
sediments of Chaohu Lake were evaluated based on the exhaustive geochemical data. The analysis shows that concentrations of
major and trace metals, and phosphorus, displayed significant spatial diversity and almost all elements were over the pre-industrial
background value, which should be related to the variations of sediment composition partially. Therefore, conservative element
normalization was introduced and calculated enrichment factors (EFs) of the elements were referenced highlighting the human
contamination. EFs of the major and trace metals, except Zn, Pb, and Cu, were all nearly 1.0, indicating the detrital origin.
The EFs of Zn, Pb, Cu and phosphorus were 1.0–10.4, 1.0–3.8, 1.0–4.9, and 1.0–7.6, respectively, showing moderate to significant
contamination. Higher EFs of Zn, Pb and Cu occurred in the mouth areas of Nanfei River and Zhegao River, and they decreased
to the lake center in the northwest and northeast lake areas, respectively. We deduced that anthropogenic Zn, Pb, and Cu were
mainly from urban and industrial point sources and the non-point sources of atmospheric deposition contributed little to their
contamination. The EFs of phosphorus showed similar spatial degradation with that of Zn, Pb, and Cu. Moreover, higher EFs
(>1) of phosphorus also occurred in other areas adjacent to the river mouths besides Nanfei River and Zhegao River. This indicated
that the non-point agricultural source may also be responsible for the contamination of phosphorus in Chaohu Lake in addition
to the urban sewage sources. Anthropogenic phosphorus was mainly concentrated in the speciation of NaOH-P, which had higher
potential biological effects than the detrital proportion. Concentrations of Zn, Pb and Cu surpassed the threshold effect
concentrations (TEC) of consensus-based sediment quality guidelines of freshwater ecosystems, especially in the contaminated
northwest area of Chaohu Lake. This highlighted the contributions of anthropogenic contamination to the elevated potential
biological effects of trace metals. Though there had been no obvious human contamination of Cr and Ni in Chaohu Lake, concentrations
were all over the TECs, which may be due to higher background levels in the parent materials of soils and bedrocks in Chaohu
Lake catchment. 相似文献
10.
Evangelos P. Tziritis 《Environmental monitoring and assessment》2014,186(7):4553-4568
The Micro Prespa basin is a trilateral catchment area of significant importance with a unique ecosystem closely related to the homonymous lake. In this frame, a fully operational monitoring project was carried out including continuous real-time measurements in Micro Prespa Lake with the use of a multi-sensor probe, as well as periodical sampling and analyses of all available water systems for an extended set of 85 parameters. Four main interacting water systems were identified, including alluvial and karstic aquifers, Micro Prespa Lake and adjacent drainage network. The results outlined that general environmental conditions are satisfying in respect to the relative legislation and the hydrogeochemical signatures. However, trends of environmental pressures were ascertained as a result of natural (geogenic) factors, embracing seasonal peaks for Ni, Pb, and NH4 mainly in groundwater systems. Based on chlorophyll a records, Micro Prespa is classified as oligotrophic to slightly mesotrophic, subjected to seasonal variations. Heavy metal concentrations are low, except Ni which appears to have elevated values during the dry hydrological period. Finally, the hydrogeochemistry of drainage network is primarily influenced by surface runoff of the surrounding mountainous areas, hence elevated phosphorus values of the Aghios Germanos stream are possibly linked with the leaching of the granitic formations on the east. 相似文献