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1.
The concentrations of five metals in oysters from ten locations along the Northern Territory coastline were determined during the dry season of 1989. The measured concentrations of iron, cadmium, zinc, manganese and copper in oysers were 11.6–274, 0.17–9.1, 4.79–735, 0.25–69.85 and nd-70.2 µg g–1 wet weight. The level of cadmium exceeded the National Health and Medical Research Council (NHMRC) recommended limit at five sites. The largest fluctuation occurred in zinc and cadmium while the other metals displayed much less variation.  相似文献   

2.
The concentrations of cadmium, chromium, copper, iron, lead, manganese, nickel, and zinc in water and bed sediments of river Gomti have been studied in a fairly long stretch of 500 km from Neemsar to Jaunpur. Grab samples of water (October 2002–March 2003) and bed sediments (December 2002 and March 2003) were collected from 10 different locations following the standard methods. The river water and sediment samples were processed and analyzed for heavy metals viz., Cd, Cr, Cu, Fe, Pb, Mn, Ni, and Zn, and using ICP-AES. The heavy metals found in the river water were in the range: Cd (0.0001–0.0005 mg/L); Cr (0.0015–0.0688 mg/L); Cu (0.0013–0.0.0043 mg/L); Fe (0.0791–0.3190 mg/L); Mn (0.0038–0.0.0973 mg/L); Ni (0.0066–0.011 mg/L); Pb (0.0158–0.0276 mg/L); and Zn (0.0144–0.0298 mg/L) respectively. In the sediments the same were found in the range: Cd (0.70–7.90 g/g); Cr (6.105–20.595 g/g); Cu (3.735–35.68 g/g); Fe (5051.485–8291.485 g/g); Mn (134.915–320.45 g/g); Ni (13.905–37.370 g/g); Pb (21.25–92.15 g/g); and Zn (15.72–99.35 g/g) of dry weight respectively. Some physico-chemical parameters viz., pH, total solids, total dissolved solids, total suspended solids, dissolved oxygen, biological oxygen demand, chemical oxygen demand, hardness etc. were estimated as these have direct or indirect influence on the incidence, transport and speciation of the heavy metals. Based on the geoaccumulation indices, the Gomti river sediments from Neemsar to Jaunpur are considered to be unpolluted with respect to Cr, Cu, Fe, Mn, and Zn. It is unpolluted to moderately polluted with Pb. In case of Cd it varies from moderately polluted to highly polluted. As far as Ni is concerned the sediment is very highly polluted at Barabanki and Jaunpur D/s. No correlation was found between enrichment factor and geoaccumulation index.  相似文献   

3.
A comprehensive speciation scheme was proposed for the speciation of iron in river water (0.45 microm filtrate). The speciation was based on the catalytic determination of reactive iron as Fe3+ and Fe(III)Li/(3 -in)+, where i = 1 or 2 for a unidentate and i = 1 for a bidentate ligand, Ln-. The scheme incudes size fractionation and acid decomposition of the sample and determination of the coexisting species. The proposed scheme was applied to natural and artificial samples and acidified preparations of these. Resulting fractionation patterns of reactive and unreactive iron and of coexisting humic acid were useful for the characterization of iron species in the natural samples. The reactive iron in the molecular weight (Mr) > or = 10(4) fraction was associated with humic iron aggregates and estimated as iron complexed with them. The unreactive iron in this fraction dissociated in 0.1 M HCI and was estimated as iron in the aggregates of iron(III) hydroxide (s) and humic iron. From the fractionation results of the artificial sample, the reactive and unreactive iron in the Mr < 10(3) fraction may be formed by complexing simple anions like F- and C2O4(2-) at their naturally-occurring concentration levels. The fractionation results also suggested that humic acid and Si contributed to the formation of reactive and unreactive iron in the Mr > or = 10(4) fraction.  相似文献   

4.
Samples of PM(2.5) were collected to measure the concentrations of its chemical constituents at two rural locations, Potsdam and Stockton, NY from November 2002 to August 2005. These samples were collected on multiple filters at both sites, every third day for a 24-h interval with a speciation network sampler. The Teflo(R) filters were analyzed for PM(2.5) mass by gravimetry, and elemental composition by X-ray fluorescence (XRF). Nylasorb(R) filters and Teflo(R) filters were leached with water and analyzed for anions and cations, respectively, by ion chromatography (IC). Fine particulate matter (PM(2.5)) mass and its inorganic component measurements were statistically characterized, and the temporal behavior of these species were assessed. Over the entire study period, PM(2.5) mass concentrations were lower at Potsdam (8.35 mug/m(3)) than at Stockton (10.24 mug/m(3)). At both locations, organic matter (OM) was the highest contributor to mass. Sulfate was the second highest contributor to mass at 27.0% at Potsdam, and 28.7% at Stockton. Nitrate contributions to mass of 8.9 and 9.5% at Potsdam and Stockton, respectively, were the third highest. At both locations, fine PM mass exhibited an annual cycle with a pronounced summer peak and indications of another peak during the winter, consistent with an overall increase in the rate of secondary aerosol formation during the summer, and increased partitioning of ammonium nitrate to the particle phase and condensation of other semi-volatiles during the winter, respectively. An ion-balance analysis indicated that at both locations, during the summers as well as in the winters, the aerosol was acidic. Lognormal frequency distribution fits to the measured mass concentrations on a seasonal basis indicated the overall increase in particle phase secondary aerosol (sulfate and SOA) concentrations during the summers compared to the winters at both locations.  相似文献   

5.
The inorganic nitrogen transformations occurring at a municipal waste leachate treatment facility were investigated. The treatment facility consisted of a collection well and an artificial wetland between two aeration ponds. The first aeration pond showed a decrease in ammonium (from 3480 (± 120) to 630(± 90) mg ⋅ L−1), a reduction in inorganic nitrogen load (3480 to 1680 mg N ⋅ L−1), and an accumulation of nitrite (< 1.3 mg-N ⋅ L−1 in the collection well, to 1030 mg-N ⋅ L−1). Incomplete ammonium oxidation was presumably the result of the low concentration of carbonate alkalinity (∼2 mg ⋅ L−1), which may cause a limitation in the ammonium oxidation rate of nitrifiers. Low carbonate alkalinity levels may have been the result of stripping of CO2 from the first aeration pond at the high aeration rates and low pH. Various chemodenitrification mechanisms are discussed as the reason for the reduction in the inorganic nitrogen load, including; the reduction of nitrite by iron (II) (producing various forms of gaseous nitrogen); and reactions involving nitrous acid. It is suggested that the accumulation of nitrite may be the result of inhibition of nitrite oxidizers by nitrous acid and low temperatures. Relative to the first aeration pond, the speciation and concentration of inorganic nitrogen was stable in the wetlands and 2nd aeration pond. The limited denitrification in the wetlands most probably occurred due to low concentrations of organic carbon, and short retention times.  相似文献   

6.
A field study was conducted around two thermal power plants of India to quantify the changes in foliar elemental concentrations due to emission in a low rainfall tropical area. Sulphur dioxide and particulates were at high levels which may cause serious ecological effects. Emission from the power plants has altered the elemental concentrations in the leaves of evergreen and deciduous plants. The foliar total-S and SO4 2–-S levels were significantly higher in all the plants growing at polluted sites. However, the organic-S content was more or less unaltered. In evergreen plants, the SO4 2–-S content increased gradually from summer through winter, whereas in the deciduous plants there was a higher magnitude of increase after onset of new leaves during summer. With the increasing pollution load, foliar Ca2+ and K+ contents increased, whereas N content decreased. The reduction in N content was greater during summer in evergreen plants and during winter in deciduous plants. The plants growing closer to the power plants accumulated more trace elements (Mn, Fe, Cd, Pb and Ni) as compared to those growing at distant sites. In deciduous plants the leaf fall during winter lowered down the trace element  相似文献   

7.
利用西安市环境监测站超级站2013年9月1日—2015年5月31日黑碳气溶胶(BC)的监测数据,研究空气中BC浓度特征及其与气象因素和常规污染物相关性。结果表明:BC小时平均浓度均值在春季、夏季和冬季的变化趋势呈"W"型,秋季呈"V"型,且冬季的第一个最低值和峰值比春季和夏季的分别延迟1 h和2~3 h,且20:00~次日6:00秋季BC小时平均浓度均值高于当年冬季。BC浓度在秋季和冬季较高,夏季较低。冬季BC/PM_(2.5)基本最低,秋季BC/PM_(2.5)相对最高。BC日平均浓度与气温、降水和风速的日平均值为极负显著相关,且风速小于1.0 m/s时,其与风速呈最显著的负相关。除O_3外,BC日平均浓度与其他常规空气污染物浓度呈显著相关,表明其同源性很强,且受机动车尾气排放的影响更大。  相似文献   

8.
The physico-chemical behaviour of iron and manganese has been observed during many surveys covering various hydrodynamic conditions in the Seine river estuary system. The results obtained confirm the non-conservative behaviour of these two metals. Generally, dissolved iron exhibits non-conservative removal and shows a rapid decrease in low salinity; it is moved from fresh waters with high concentrations to saline waters with very low concentrations. This can be attributed to the flocculation processes as confirmed by laboratory experiments. Dissolved manganese versus salinity curves exhibit a peak concentration in the low salinity zone. Laboratory mixing experiments have been undertaken comparing iron and manganese adsorption/desorption from suspended material versus salinity, using a series of water samples collected in the up-river and marine regions in order to assess the importance of particulate material and salinity on iron and manganese distributions. The salinity was controlled by varying the marine to fresh water ratio. The reaction kinetics aspect is developed in more detail for manganese in the last series of remobilization experiments starting from a stock of suspended particles collected in the upstream river site (Caudebec) in mixtures of waters, according to time and salinity. This study has allowed us to show that iron and manganese behaviour in the Seine estuary is strongly influenced: (i) by the high turbidity zone and by the presence of calcium carbonate which could stabilise the Mn(II) form; and (ii) by the increase of salinity, calcium, magnesium and suspended matter concentrations and by complex formation.  相似文献   

9.
The personal exposure of children aged 9 – 11 years to particulate matter (PM10 and PM2.5) was carried out between January and September 1997 in the London Borough of Barnet. Personal sampling along with home, garden and classroom microenvironmental monitoring was completed for all ten children. Each child was monitored for five days during winter, spring and summer. All children completed daily time activity diaries to provide information on any potential activities that could influence their exposure to particulate matter. Each evening a household activity questionnaire was also completed by the parents. Personal Environmental Monitors were used to sample personal exposure to PM10 and PM2.5. Harvard Impactors were used for the microenvironmental sampling of both size fractions. The children's mean personal exposure concentrations for PM10 during winter, spring and summer were 72, 54 and 35 µg/m3 respectively and for PM2.5 22, 17 and 18 µg/m3 respectively. In order to determine the potential sources of particulate matter, analysis of the Teflon filters has been undertaken. The physical characteristics of the particles have been identified using Scanning Electron Microscopy. The relationships between personal exposure concentrations and the different microenvironments will be discussed.  相似文献   

10.
《地下水管理条例》自2021年12月1日起施行,但是由于《地下水质量标准》(GB/T 14848—2017)未明确其中的金属指标是检测可溶态含量还是总量,导致各检测机构在检测过程中的采样和前处理环节存在较多不确定之处。梳理了国内外地下水监测相关标准和规范,并进行了实验比对,经分析得出以下结论:铜、铅、锌、铁、锰的可溶态含量和总量检测结果存在明显差异,其中,铁和铅检测结果的差异最明显,铁和锰检测结果的差异会影响地下水质量类别判定。《地下水质量标准》中的金属指标应检测可溶态,包括汞、砷和硒。充分洗井后采集的地下水样品存在一定的浑浊度是合理的。完成采集的地下水金属指标检测样品中不应包含沉淀相。测定地下水可溶态汞、砷和硒时,如采用原子荧光法,则需对样品进行消解;如采用电感耦合等离子体质谱法,则无需对样品进行消解。在此基础上,对地下水采样及前处理关键环节和地下水检测管理工作提出了相关建议。  相似文献   

11.
Distribution of heavy metals in plants and fish of the Yamuna river (India)   总被引:2,自引:0,他引:2  
The distribution of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb) and zinc (Zn) in the plants and fish of Yamuna river from Delhi to Allahabad, a distance of about 840 km, at five sampling stations was determined in the year 1981. The results have shown wide variations in the heavy metal levels from one sampling station to the other. The concentrations of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn in the plants (Eicchornia crassipes) were found to be 0.02–0.12, 2.7–21.3, 4.6–64.8, 9.8–114.0, 193.0–1835.0, 380.0–1443.0, 4.4–83.0, 4.8–30.2, and 22.1–356.5 g g-1 respectively whereas in the fish (Heteropnuestes fossilis) were found to be ND-0.40, 2.3–13.7, 3.7–26.9, 8.33–58.1, 278.3–1108.0, 81.3–213.8, 2.8–32.7, 1.4–12.8 and 101.8–364.8 gg-1 respectively on dry weight basis.  相似文献   

12.
杭州市环境空气中二噁英类物质检测与分析   总被引:2,自引:0,他引:2  
为了解二噁英类物质(PCDD/Fs)在环境空气中污染现状及不同季节不同时段浓度、组成和存在形式等的变化情况,于夏、冬两季对杭州西湖区空气中PCDD/Fs进行了采样分析。结果表明,空气中PCDD/Fs毒性当量浓度与国内其他城市(北京、上海、广州)相近,夏、冬两季空气中PCDD/Fs质量浓度和毒性当量浓度分别为4.92 pg/m3、0.34 I-TEQ pg/m3和4.51 pg/m3、0.40 I-TEQ pg/m3,夏季PCDD/Fs毒性当量浓度略低于冬季;在分时段采样检测结果中,晚间空气中PCDD/Fs质量浓度和毒性当量浓度均高于白天空气中的PCDD/Fs浓度;夏季样品中TCDD/Fs、PeCDD/Fs主要以气相的形式存在,HpCDD/Fs、OCDD/F主要以颗粒相的形式存在,冬季样品中PCDD/Fs主要以颗粒相形式存在。  相似文献   

13.
In the present study, the BCR (Community Bureau of Reference) sequential procedure has been applied to determine the zinc partition in sediments taken from a river situated in the Southwest of Romania, in a region subject of intense mining activities. The sampling was performed during three sampling expeditions, organized in the spring, summer, and autumn, 2007. The zinc concentration in different fractions was normalized, its concentration being related to the concentrations of some metals (such as Al or Fe) that are naturally present in sediments. The zinc-contaminated sediments from the investigated area have been evaluated by means of combining the analysis data from the BCR sequential extraction with the normalization to the Al content. The most important zinc collector in the samples taken during the three sampling expeditions is the easily soluble fraction, next being amorphous iron and manganese hydrated oxides fraction, followed by organic matter fraction.  相似文献   

14.
A range of organotin compounds including tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) were measured in sediment cores collected from contaminated freshwater and estuarine sites in Essex and Suffolk, U.K. Butyltin compounds were found in significant quantities at depths of up to 60 cm within the sediments of marina and boatyard complexes with TBT concentrations ranging from <3 ng g–1 (the detection limit) to >3000 ng g–1. In general sediment TBT concentrations decreased with depth, but maximum enrichment tended to occur just below the surface. It was evident from these core profiles that the accumulation of organotins in surface deposits was on the decline and coincided approximately, with the implementation in 1987 of the UK retail ban on the sale of TBT based antifouling paints for application on vessels <25 m in length. The degradation rate for TBT in sediments was found to exhibit first order kinetics with half lives ranging from 0.9–5.2 years between different sites. Estimated degradation rates have also been determined for DBT and MBT. These ranged from 1.5–3.0 years for DBT and 1.8–3.7 years for MBT.  相似文献   

15.
通过2018—2019年夏冬季在鄱阳湖布设17个采样点,采样检测浮游藻类和水质参数,并采用典范对应分析法研究该湖浮游藻类群落结构特征及其与环境因子的相互关系。结果表明,两次调查共检测出浮游藻类7门31科58属,浮游藻类丰度范围为3.5×105 L-1~1.15×107 L-1,主要由绿藻门、硅藻门和蓝藻门组成,绿藻门为夏、冬季主要优势种群。典范对应分析结果显示,鄱阳湖冬季湖区水环境空间差异较大,而夏季差异较小;夏季氮磷营养盐和DO是影响浮游藻类群落时空分布的主要环境因子,冬季氮磷营养盐、BOD5和IMn是影响浮游藻类群落时空分布的主要环境因子。  相似文献   

16.
In this paper, COSMO numerical weather prediction model is used to simulate land-sea breeze circulation in the north coast of Oman and to analyze the variability of the PBL depth. Typical summer day 1st August 2009 and winter day 1st January 2009 were simulated and verified by surface observations. The COSMO model was initialized using the German global model which runs as 40 km resolution and 40 vertical layers. The simulations show differences in the onset, strength, and inland penetration of the sea breeze. The high sea-land thermal contrast in the summer season induces earlier onset and progression of the sea breeze with larger horizontal and vertical extents. The summer and winter inland penetration is simulated around 150 and 65 km, respectively. The PBL depth was defined from the verticals profiles of the turbulence kinetic energy (TKE). The simulated PBL height varied at 1,600 m in summer and 700 m in the winter case. These results are in general in good agreement with the simulations of the National Centers for Environmental Prediction Global Data Assimilation System (NCEP-GDAS) model. The dispersive ability of the atmosphere was tested through the vertical mixing coefficient (VMC) generated by NCEP-GDAS simulations. The VMC during the summer simulated case is approximately four times larger than the respective one during the winter case. Consequently, during the advection of winter sea breeze, a shallow dome less than 100 m is shaped and forms an obstacle to the air-pollutant dispersion.  相似文献   

17.
The concentration and speciation of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in surface sediments (??≤ 63 μm) of Jinjiang River tidal reach are determined to evaluate the metal behavior. A modified BCR three-step sequential extraction procedure is carried out, and the residual fraction is undertaken by microwave-assisted acid digestion. The index of geo-accumulation indicates that Cd appeared highest among all these heavy metals in surface sediments, Cr, Cu, Zn lower, and Ni, Pb the least. The percentage of Zn, Cd is comparatively higher in the acid soluble fraction, Pb and Cu higher in the reductive fraction, indicating larger potential danger to the environment. So it is essential for developing the future remediation plans and pollution control strategies.  相似文献   

18.
An in-depth study on various locations along the Kuwait Coastdifferentiated by the nature of coastal topography, humanhabitation and industrialization was made during the year1995–1997 in relation to the gills of the gastropod, Cerithium scabridum, a bio-indicator of heavy metal pollution.The maximum concentration of heavy metals in the gills of C. scabridum, seawater and particulate matter was observed inStations III when compared to the metal concentrations in theother seven stations. Co-efficient Variance (CV) revealed anincrease in the accumulation of Cu and Pb in gills, seawater andparticulate matter in winter than in summer. However, the CV wasnoted to be lower in winter than in summer in the case of Cr andV, in gills of C. scabridum and Ni in the case of seawatersamples. Further, by ANOVA, except V, significant relationshipswere noted between the heavy metals (Cu, Cr, Pb and Ni) andvarious locations in the gills of C. scabridum.  相似文献   

19.
Monitoring of atmospheric lead from the Dalbergia sissoo treewas undertaken at Lucknow urban centre of the Ganga Plain, India.Atotal of 26 leaf samples were collected in spring, monsoon and winter seasons from 16 sampling sites and was analysed by Atomic Absorption Spectrophotometry method. Lead concentrations were low in spring season, increased in monsoon to winter seasons and range from 2.1 to 28.2 μg/g (dry wt.). This accumulative response of lead in the tree leaves is directly linked with the exposure time of automobile emission that is considered to be the predominant source for it. Highway localities show higher lead concentrations by a factor of 2 as compared to urban localities. Highest concentration was recorded at Sitapur Road (National Highway No. 24) in winter season. A linear quantitative relationship between urban air-lead levels and lead-in-the Dalbergia sissoo leaves is used to infer the qualitative assessment of present day atmospheric lead pollution. Reported results suggest a drastic reduction in mean lead concentration in Lucknow urban air from 1.32μg/m3 in 1994 to 0.19μg/m3 in 2002. Similarly, mean lead concentration in the tree leaves during winter season also dropped from 17.9 μg/g in 1994 to 8.1 μg/g in 2004. Despite of increasing urban population, urban area, vehicle population and traffic density, the introduction of unleaded-petrol (vehicular fuel) keeps lead level in the urban environment of Lucknow much lower than the past. Like Lucknow, other urban centres of the Ganga Plain are also on way to the exponential increase in pressure of urbanization. An appropriate urban public transport planning is required to provide healthy atmospheric environment for millions of people especially future young generation.  相似文献   

20.
A study was begun in the winter of 2000–2001 and continued through the winter of 2001–2002 to examine air quality at the Green Rock snowmobile staging area at 2,985 m elevation in the Snowy Range of Wyoming. The study was designed to evaluate the effects of winter recreation snowmobile activity on air quality at this high elevation site by measuring levels of nitrogen oxides (NO x , NO), carbon monoxide (CO), ozone (O3) and particulate matter (PM10 mass). Snowmobile numbers were higher weekends than weekdays, but numbers were difficult to quantify with an infrared sensor. Nitrogen oxides and carbon monoxide were significantly higher weekends than weekdays. Ozone and particulate matter were not significantly different during the weekend compared to weekdays. Air quality data during the summer was also compared to the winter data. Carbon monoxide levels at the site were significantly higher during the winter than during the summer. Nitrogen oxides and particulates were significantly higher during the summer compared to winter. Nevertheless, air pollutants were well dispersed and diluted by strong winds common at the site, and it appears that snowmobile emissions did not have a significant impact on air quality at this high elevation ecosystem. Pollutant concentrations were generally low both winter and summer. In a separate study, water chemistry and snow density were measured from snow samples collected on and adjacent to a snowmobile trail. Snow on the trail was significantly denser and significantly more acidic with significantly higher concentrations of sodium, ammonium, calcium, magnesium, fluoride, and sulfate than in snow off the trail. Snowmobile activity had no effect on nitrate levels in snow.  相似文献   

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