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961.
Screening level risk assessment models are used by many countries to assess the treatability of organic chemicals during the sewage treatment process, especially those that are new to commerce. The performance of one such model, the sewage treatment plant model, is evaluated in the current study by comparing model predictions with actual measurement data collected at various stages of a typical full-scale activated sludge type sewage treatment plant. A suite of ten polycyclic aromatic hydrocarbons (PAHs) with widely varying physico–chemical properties were monitored for the comparison. Model predicted removal efficiencies were in very good agreement with those measured for all ten PAHs. Observed chemical concentrations and their trends at various stages of the sewage treatment process were also well simulated by the model. Results also suggest that a reasonable first approximation estimate of a range for the biodegradation half-life needed for the model may be obtained by dividing reported aqueous biodegradation half-life by scaling factors of 50 and 150. 相似文献
962.
Sakan S Grzetić I Dordević D 《Environmental science and pollution research international》2007,14(4):229-236
Introduction In this work, sediments of the River Tisa (Tisza) are studied to assess their environmental pollution levels for some major
heavy metals, as well as to predict the investigated elements’ mobility on the basis of their association type with the substrate.
The Tisa River catchments area is a subbasin of the River Danube. Part of this river, 166 km long, belongs to the Serbian
province of Vojvodina, before it flows into the Danube. It has been chosen for our investigation, because it has been exposed
to intense pollution in the last decades.
Materials and Methods The river sediment samples were collected at 32 locations. The proportions of sand, silt and clay fractions were determined.
The sequential extraction procedure following a modified Tessier method was applied for speciation of the metal forms in the
collected samples. The metal concentrations of Zn, Cd, Pb, Ni, Cu, Cr, Fe and Mn in extracts were determined by atomic absorption
spectroscopy.
Results and Discussion Granulometric analysis showed that some 50% of the Tisa River sediments were silt and clay, while the rest was sand with quartz,
as the main constituent. The average metal content of the surface river sediment samples for every fraction of sequential
extraction was presented and discussed in relation to pH, Eh and metal fractionation. The average metal content from the Tisa
River sediments, obtained as an average of the metal’s concentration released in all five sequential extraction fractions
was compared with: average metal contents of the Tisa River sediments in Hungary, metal content in soils formed on the Tisa
River alluvium of Vojvodina, average metal content in soils of Vojvodina, and average metal content in soils of Hungary. An
assessment of metal pollution levels in Tisa River sediments was made by comparing mean values for obtained results for the
Tisa River sediments with the freshwater sediment’s Quality Guidelines as published by US EPA, Environment Canada and soil
standards for Serbia.
Conclusion According to US EPA and Canadian Quality Guidelines for freshwater sediments, the concentration of heavy metals in Tisa sediments
were: (a) much higher than defined concentrations below which harmful effects on river biota are unlikely to be observed,
(b) below defined concentrations above which harmful effects on river biota are likely to be observed. The concentration levels
of Pb, Ni, Cu and Cr in Tisa River sediments are safe when compared with Serbian MAQ (Maximum Allowed Quantity) standards
for soils, but they are unsafe in the case of Zn and Cd.
Recommendations and Outlook The quality of sediments in the Tisa River was on the border line between potentially polluted and polluted. This line could
very easily be exceeded since the quality of sediments in the Tisa River in Hungary was already worse than in Serbia. These
results indicated the need for further monitoring of heavy metals in that locality. 相似文献
963.
Hydrogeochemistry and Groundwater Quality Assessment of Lower Part of the Ponnaiyar River Basin, Cuddalore District, South India 总被引:7,自引:0,他引:7
Jeevanandam M Kannan R Srinivasalu S Rammohan V 《Environmental monitoring and assessment》2007,132(1-3):263-274
The Lower Ponnaiyar River Basin forms an important groundwater province in South India constituted by Tertiary formations
dominated by sandstones and overlain by alluvium. The region enjoyed artesian conditions 50 years back but at present frequent
failure of monsoon and over exploitation is threatening the aquifer. Further, extensive agricultural and industrial activities
and urbanization has resulted in the increase in demand and contamination of the aquifer. To identify the sources and quality
of groundwater, water samples from 47 bore wells were collected in an area of 154 km2 and were analysed for major ions and trace metals. The results reveal that the groundwater in many places is contaminated
by higher concentrations of NO3, Cl, PO4 and Fe. Four major hydrochemical facies Ca–Mg–Cl, Na–Cl, Ca–HCO3 and Na–HCO3 were identified using Piper trilinear diagram. Salinity, sodium adsorption ratio, and sodium percentage indicate that most
of the groundwater samples are not suitable for irrigation as well as for domestic purposes and far from drinking water standards.
The most serious pollution threat to groundwater is from nitrate ions, which are associated with sewage and fertilizers application.
The present state of the quality of the lower part of Ponnaiyar River Basin is of great concern and the higher concentration
of toxic metals (Fe and Ni) may entail various health hazards. 相似文献
964.
Knowledge of the total concentration of heavy metals is not enough to fully assess the environmental impact of urban soils.
For this reason, the determination of metal speciation is important to evaluate their environment and the mobilization capacity.
Sequential extraction technique proposed by the former European Community Bureau of Reference (BCR) was used to speciate Cd,
Cu, Fe, Mn, Ni, Pb, and Zn in urban soils from Guangzhou into four operationally defined fractions: HOAc extractable, reducible,
oxidizable, and residual. The Cu, Fe, Ni, and Zn were predominately located in the residual fraction, Pb in the reducible
fraction, and Cd and Mn within the HOAc extractable fraction. The order of Cd in each fraction was generally HOAc extractable
> reducible > residual > oxidizable; Cu and Fe were residual > reducible > oxidizable > HOAc extractable; Mn was HOAc extractable
> residual > reducible > oxidizable; Ni and Zn were residual > reducible > HOAc extractable > oxidizable; and Pb was reducible
> residual > oxidizable > HOAc extractable. Cadmium was identified as being the most mobile of the elements, followed by Mn,
Zn, Ni, Cu, Pb and Fe. Iron–Mn oxides can play an important role in binding Cd, Cu, Ni, Pb, and Zn and in decreasing their
proportion associated with the residual fraction in the soils. With total concentrations of Cd, Cu, Ni, Pb, Zn, and Mn increase,
these metals more easily release and may produce more negative effects on the urban environment. 相似文献
965.
Perrino C Canepari S Cardarelli E Catrambone M Sargolini T 《Environmental monitoring and assessment》2007,128(1-3):133-151
A field study was carried out at six locations in the Lazio region (Central Italy) aimed at characterising atmospheric particulate
matter (PM10 and PM2.5) from the point of view of the chemical composition and grain size distribution of the particles, the mixing properties of
the atmosphere, the frequency and relevance of natural events. The combination of four different analytical techniques (ion
chromatography, X-ray fluorescence and ICP for inorganic components, thermo-optical analysis for carbon compounds) yielded
sound results in terms of characterisation of the air masses. During the first three months of the study (October-December
2004), many pollution events of natural (sea-salt or desert dust episodes) or anthropogenic nature were identified and characterised.
More than 90% of the collected mass was identified by chemical analysis. The central role played by the mixing properties
of the lower atmosphere when pollution events occurred was highlighted. The results show a major impact of primary anthropogenic
pollutants on traffic stations and a homogeneous distribution of secondary pollutants over the regional area. An evaluation
of the sources of PM and an identification of possible reliable tracers were obtained using a chemical fractionation procedure. 相似文献
966.
967.
简述了江苏沿江化工园区存在的环境风险,分析了园区区位特征和产业结构矛盾、监控预警体系及应急保障体系等方面存在的问题。提出应加强环境应急队伍建设,完善监控预警体系,强化应急预案管理,提升应急处置能力,以降低环境风险,维护区域环境安全。 相似文献
968.
969.
淄博化工园区大气有机污染应急监测与管理对策 总被引:3,自引:0,他引:3
针对工业聚集区内多种恶臭混杂的情况,以淄博化工园区为例,研究了大气有机污染突发事件中有机物的应急监测方法,并提出了治理对策。利用便携式气相色谱-质谱联用仪,对重点企业事先监测,掌握各企业特征污染物,作为应急监测查找污染源头的依据;现场分析受污染空气中的化合物组成及浓度,通过查询、比对各企业特征污染物,确认责任排污企业。提出了末端监测处罚治理与对重点污染企业推行清洁生产相结合,应急监测与有机污染物在线监测相结合,建立企业污染源特征组分数据库,加强企业无组织排放监测与监管等治理大气有机污染的建议。 相似文献
970.
环境监测实验室重要试剂及耗材的质量验收方法 总被引:1,自引:0,他引:1
阐述了对环境监测实验室重要试剂及消耗性材料进行质量验收的必要性,以实验用水、过硫酸钾、活性炭采样管和滤膜等典型的试剂及消耗材料为例,介绍了常用的重要试剂及消耗性材料质量验收的程序、范围、方法、要求与结果讨论. 相似文献