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251.
广州市是酸雨、可吸入颗粒物污染严重的地区之一,这与其能源结构以煤为主有关.广州发电厂以燃煤为主,其周围大气采样数据分析显示燃煤电厂可对周围大气环境造成较大影响,是酸雨前体物、可吸入颗粒物的主要排放源.酸雨破坏了生态环境,也阻碍了经济的发展;燃煤排放的烟尘细颗粒物属于可吸入颗粒物,其上附着的As、Cr等微量元素多为致癌物质和致基因毒性诱变物质,对周围居民的健康危害极大.最后, 对当前的环境保护工作及存在的问题进行了阐述. 相似文献
252.
Lobpreis T Vrana B Dominiak E Dercová K Mills GA Greenwood R 《Environmental pollution (Barking, Essex : 1987)》2008,153(3):706-710
Passive sampling of pollutants in water has been gaining acceptance for environmental monitoring. Previously, an integrative passive sampler (the Chemcatcher) was developed and calibrated for the measurement of time weighted average concentrations of hydrophobic pollutants in water. Effects of physicochemical properties and environmental variables (water temperature and turbulence) on kinetic and thermodynamic parameters characterising the exchange of analytes between the sampler and water have been published. In this study, the effect of modification in sampler housing geometry on these calibration parameters was studied. The results obtained for polycyclic aromatic hydrocarbons show that reducing the depth of the cavity in the sampler body geometry increased the exchange kinetics by approximately twofold, whilst having no effect on the correlation between the uptake and offload kinetics of analytes. The use of performance reference compounds thus avoids the need for extensive re-calibration when the sampler body geometry is modified. 相似文献
253.
Hossain MB Jahiruddin M Panaullah GM Loeppert RH Islam MR Duxbury JM 《Environmental pollution (Barking, Essex : 1987)》2008,156(3):739-744
Spatial distribution of arsenic (As) concentrations of irrigation water, soil and plant (rice) in a shallow tube-well (STW) command area (8 ha), and their relationship with Fe, Mn and P were studied. Arsenic concentrations of water in the 110 m long irrigation channel clearly decreased with distance from the STW point, the range being 68-136 μg L−1. Such decreasing trend was also noticed with Fe and P concentrations, but the trend for Mn concentrations was not remarkable. Concerning soil As, the concentration showed a decreasing tendency with distance from the pump. The NH4-oxalate extractable As contributed 36% of total As and this amount of As was associated with poorly crystalline Fe-oxides. Furthermore only 22% of total As was phosphate extractable so that most of the As was tightly retained by soil constituents and was not readily exchangeable by phosphate. Soil As (both total and extractable As) was significantly and positively correlated with rice grain As (0.296 ± 0.063 μg g−1, n = 56). Next to drinking water, rice could be a potential source of As exposure of the people living in the As affected areas of Bangladesh. 相似文献
254.
Jaji MO Bamgbose O Odukoya OO Arowolo TA 《Environmental monitoring and assessment》2007,133(1-3):473-482
The quality of Ogun river in South-West, Nigeria was studied by a field survey for a period of 1 year (covering dry season
and rainy season). Water samples were collected from thirteen sites and analysed for physico-chemical and bacteriological
parameters as well as heavy metals using standard methods. Generally, the values obtained for turbidity, phosphate, oil and
grease, iron and faecal coliform from all the sites in both seasons were above the maximum acceptable limit set by the World
Health Organization (WHO) for drinking water. Also, the manganese content from all the sites in the dry season, lead concentrations
from three sites in the dry season and cadmium concentrations from some sites in both seasons were above the WHO limit. The
values obtained for total dissolved solids, dissolved oxygen and chloride at site M in the dry season and nitrate at site
J in the rainy season were also above the WHO limit. Pollution of Ogun river water along its course is evidenced by the high
concentrations of pollution indicators, nutrients and trace metals above the acceptable limit. This poses a health risk to
several rural communities who rely on the river primarily as their source of domestic water. The study showed a need for continuous
pollution monitoring programme of surface waters in Nigeria. 相似文献
255.
Water is key element in human life. All forms of life upon the earth depend upon water for their mere existence. Life & water
may be aptly said to be two facets of the same coin. Most of the water bodies are getting polluted due to domestic waste,
sewage, industrial waste and agricultural effluent. The present study is designed to ascertain the effectiveness of artificial
aeration cum Ozonizer unit installed at Lower Lake, Bhopal for assessment of water quality. Various physico- chemical parameters
like pH, Dissolved oxygen, Biochemical Oxygen demand, Chemical oxygen demand, nitrate, phosphate and bacteriological status
were studied to assess the extent of deterioration in water quality of Lower lake and at the same time to assess the performance
of the dual aeration system in improvement of water quality. 相似文献
256.
Cadmium and lead were determined simultaneously in seawater by differential pulse stripping voltammetry (DPSV) preceded by
adsoptive collection of complexes with 8-hydroxyquinoline (oxine) on to a hanging mercury drop electrode (HMDE). In preliminary
experiments the optimal analytical condition for oxine concentration was found to be 2.10−5 M, at pH 7.7, the accumulation potential was −1.1 V, and the initial scannig potential was −0.8 V. The peak potentials were
found −0.652 V for Cd and −0.463 V for Pb At the 60 s accumalation time. The limit of detection (LOD) and limit of quantitatification
(LOQ) were found to be by voltammetry as 0.588 and 1.959 μg l−1 (RSD, 5.50%) for Cd and 0.931 and 3.104 μg l−1 (RSD, 4.10%) for Pb at 60 s stirred accumulation time respectively. In these conditions the most of the seawater samples
are amenable for direct voltammetric determination of cadmium and lead using a HMDE. An adsorptive stripping mechanism of
the electrode reaction was proposed. For the comparison, seawater samples were also analysed by ICP-atomic emission spectrometry
method (ICP-AES). The applied voltammetric technique was validated and good recoveries were obtained. 相似文献
257.
The microbiological contamination of waterways by pathogenic microbes has been, and is still, a persistent public safety concern
in the United States and in most countries of the world. As most enteric pathogens are transmitted through the fecal–oral
route, fecal pollution is generally regarded as the major contributor of pathogens to waterways. Fecal pollution of waterways
can originate from wastewater treatment facilities, septic tanks, domestic- and wild-animal feces, and pets. Because enteric
pathogens are derived from human or animal sources, techniques capable of identifying and apportioning fecal sources have
been intensively investigated for use in remediation efforts and to satisfy regulatory concerns. Pollution of human origin
is of the most concern, since human feces is more likely to contain human-specific enteric pathogens. Fecal indicator bacteria
have been used successfully as the primary tool for microbiologically based risk assessment. However measurement of fecal
indicator bacteria does not define what pathogens are present, or define the sources of these bacteria. Microbial source tracking
(MST) methods that have the ability to differentiate among sources of fecal pollution are currently under development. These
methods will ultimately be useful for risk assessment purposes and to aid regulatory agencies in developing strategies to
remediate microbiologically impaired waterways. 相似文献
258.
The methodology of materials accounting is presented and applied to developing nutrient balance (nitrogen and phosphorus)
in a river basin. The method is based on the balance principle: inputs and outputs of each nitrogen and phosphorus related
sub-systems were balanced. The application of the methodology strategies was illustrated by means of a case study of the Krka
river, Slovenia. Different pathways of emission to surface waters were taken into account: WWTP discharges, direct discharges,
erosion/runoff and baseflow. Total annual emission into the river Krka was estimated to be 362 tonnes N/year and 73.3 tonnes
P/year. The main sources of nitrogen are diffuse sources, emitted via baseflow (52%). Other important sources are effluents
from WWTP, which account for 36% of total emissions. Other sources like erosion and direct discharges to surface water (animal
manure, industry, households) are of lower magnitude. Erosion is main source of phosphorus emission (55% of total emission),
WWTP effluents account for 37% of total emission, while other sources are less important. Besides reduction of point sources
by means of wastewater collection and implementation of nutrient removal technology, managing agricultural nitrogen and phosphorus
to protect water quality should become a major challenge in the Krka river basin. 相似文献
259.
Eutrophication conditions and ecological status in typical bays of Lake Taihu in China 总被引:4,自引:0,他引:4
Sampling was conducted at three site groups, group E (in East Taihu Bay), G (in Gonghu Bay) and M (in Meiliang Bay) in Lake
Taihu. TN and TP concentrations among site groups was in the increasing order of E < G < M. TP level at G sites is at the
critical threshold for loss of submersed macrophytes. Mean values of DO and Transparence showed different trend, i.e., E >
G > M. The mean phytoplankton fresh-weight biomass at M sites was 5.81 mg/l, higher than that at E sites (4.96 mg/l) and G
sites (5.18 mg/l). Mean zooplankton fresh-weight biomass was in the decreasing order of M (6.4 mg/l) > G (4.9 mg/l) > E (2.7 mg/l).
However, Rotifera density was in the sequence of E > G > M. Both zooplankton biomass and phytoplankton biomass increased with the rise of TN
and TP concentrations. Relationships between zooplankton biomass and phytoplankton biomass showed that zooplankton played
a limited role in the control of algae in eutrophic lakes. Nutrient availability is much more important than zooplankton grazing
pressure in controlling phytoplankton growth in lakes. For most sites in Lake Taihu, reduction of nutrient loading, as well
as macrophyte conservation, zappears to be especially important in maintaining high water quality and regulating lake biological
structure, but for M sites, it’s urgent to control nutrient inputs rather than to restore macrophyte community. 相似文献
260.