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1.
以南湖水体中的水、表层沉积物、生物膜和悬浮物为研究对象,对美国EPA规定的16种优控PAHs中13种PAHs的分布与富集特征进行了研究。结果表明,表层沉积物中检出12种PAHs,生物膜和水相中均检出11种PAHs,而悬浮物中只检出7种PAHs;生物膜和悬浮物富集PAHs的能力相近,比表层沉积物的富集能力大一个数量级;相关分析表明,生物膜和悬浮物富集PAHs的能力归因于其有机质（TOC）的含量高于表层沉积物中有机质的含量。根据菲/蒽比值和PAHs环数相对丰度对南湖表层沉积物中PAHs的来源进行了分析,发现南湖沉积物中的PAHs主要来自于化石燃料燃烧释放的污染。  相似文献   

2.

Purpose  

River bed sediments are often colonized by microorganisms which can produce large amounts of extracellular polymeric substances (EPS) forming biofilms that may increase the resistance of the bed sediment towards erosion and affect the nutrient and pollutant exchange between water and sediments. The objective of this work was to study the influence of organic carbon, ionic concentration (NaCl) and N/P ratio on the growth of autochthonous biomass and the production of EPS in autotrophic biofilms by measuring the extracellular carbohydrates produced, a specific component of the EPS.  相似文献   

3.
Surface and core sediments from Lake Maryut, Egypt, one of the most polluted lakes in Egypt, were analyzed for polycyclic aromatic hydrocarbons (PAHs) using gas chromatography?Cmass spectrometry. This investigation represents the first extensive study of the distribution and sources of PAHs in sediments from Lake Maryut. The total PAHs concentrations (sum of 39 PAH compounds) in surface sediments varied greatly depending on the sampling location and ranged from 106 to 57,800 ng/g dry weight with a mean concentration of 6,950 ng/g. The most polluted areas are distributed in areas which are mainly influenced by municipal sewage and industrial effluent discharges, suggesting a direct influence of these sources on the pollutant distribution patterns. PAH concentrations were one to two orders of magnitude higher in comparison with those reported for riverine/estuaries systems around the world. Molecular indices, such as pyrogenic index (PI), methylphenanthrenes to phenanthrene ratio, HMWPAH/LMWPAH, A-PAHs/P-PAHs, FL/FL?+?PY, BaP/BaP?+?C, IP/IP?+?BgP, and Per/??(penta-aromatics) were calculated to evaluate different hydrocarbon origins and their relative importance. In general, sediments from the main basin and northwest basin of Lake Maryut showed the highest PAH concentrations with petrogenic signatures, indicating major sources of petrogenic PAHs in the city. On the other hand, lower levels of PAHs with a pyrogenic signature were widely recorded in areas that are distant from anthropogenic sources. At other locations, both petrogenic and pyrogenic inputs were significant. The concentrations of perylene relative to the penta-aromatic isomers are dominant especially in locations associated with terrestrial inputs and in the deepest core sediments, indicating diagenetic origin for the presence of perylene. Temporal trends of PAH concentrations in both cores sediments were influenced by input pathways and followed the economic development and the environmental policies of the Egyptian Government in the last 15 years. Finally, PAH levels in sediments were compared with Sediments Quality Guidelines (effects range median?Ceffects range low) for evaluation probable toxic effects on organism. Results suggest an ecotoxicological risk for benthic organisms mainly in the main basin area, where high concentrations of PAHs were found in sediments influenced by anthropogenic activities.  相似文献   

4.

Purpose

A multi-compartment monitoring study was performed to characterize the effect of environmental variables, such as temperature and water flow as well as sediment characteristics, on the distribution and transport of persistent organic pollutants (POPs) in a dynamic river system during 1 year in an industrial region in central Europe.

Materials and methods

Waterborne polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) were assessed over a period of 1 year at five sampling sites in the Morava River in the Czech Republic. Contaminants were measured monthly in riverbed sediments, freshly deposited sediments, water samples and passive samplers.

Results and discussion

Sediments are the main carrier of POPs in the river. Distinguishable patterns of PAHs, OCPs and PCBs in sediment indicate that their origin is from distinct sources and different transport pathways. The PAHs were identified as the dominant contaminant group of compounds with a mean concentration in sediment of 5,900 μg kg?1. Such concentrations are up to 10 times higher than in the Danube River, into which Morava drains. In contrast, mean concentrations of PCBs, hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethane and its breakdown products (DDTs) and hexachlorobenzene (HCB) of 6.0, 0.4, 4.2 and 6.0 μg kg1, respectively, are similar to those in the Danube. With some exceptions, no significant difference in composition of surficial riverbed sediments and those collected using sediment traps was observed. Despite the presence of potential local pollutant sources, the differences in contaminant concentrations between sites in the region were in most cases not significant. Variations in POP concentrations in sediments are mainly induced by high flow events, whereas seasonal variability was not observed.

Conclusions

The changes in contaminant concentrations in Morava River sediments are induced by episodic high flow events that cause erosion of contaminant-containing particles and their deposition at suitable downstream sites.  相似文献   

5.
近年来黄河兰州段的多环芳烃污染日渐严重。为研究黄河兰州段水体中多环芳烃类有机污染物对人体产生的潜在健康危害风险,根据黄河兰州段2004年11个采样点水质监测数据,应用美国环境保护局（USEPA）的健康风险评价方法对黄河兰州段多环芳烃类有机污染物通过饮水和皮肤接触途径进入人体的健康风险进行了初步评价。结果表明：黄河兰州段多环芳烃类有机污染物的非致癌风险指数值均小于1,其中萘的非致癌风险指数值在10^-3数量级,偏高于其他污染物。苯并（a）芘的致癌风险指数值在10^-4数量级以下。从位于西固八盘峡的1号采样点（S1）采集的水样中萘的非致癌风险指数值偏高。在所有采样点中,西固八盘峡的1号采样点（S1）污染较重,具有较高的健康风险。与国内其他地区相比,黄河兰州段萘的非致癌风险亦较高。常规的自来水处理工艺不能有效地去除源水中微量PAHs等有机污染物,因此地面水特别是饮用源水PAHs污染具有较大的健康风险。  相似文献   

6.
生物膜能够从群落水平上表征水生态系统的状态,研究应用生物膜的生态快速监测方法具有重要意义和应用前景。本研究以白洋淀湿地为例,综合运用原位生物膜法、群落分析法和生理生态学方法,通过分析生物膜的生物量、叶绿素、藻类群落组成、胞外酶活性和多糖等指标,对形成于不同人工和天然基质上的生物膜进行比较研究,筛选出了适于草型湖泊湿地的原位生物膜基质。结果表明：不同的基质类型对生物膜的结构和功能产生显著影响。活性炭纤维上形成的生物膜与天然基质芦苇杆的生物膜在结构和功能上相似度高,差异度小于5%,而竹竿上生物膜的结构与前两者明显不同。活性炭纤维作为基质培养生物膜,经过10 d培养即可达到稳定,可应用于白洋淀这类草型湖泊湿地的快速生态监测中,需进一步在不同水体单元进行研究,建立标准化方法并推广应用。  相似文献   

7.
We examined the sorption of heavy metals and polycyclic aromatic hydrocarbons (PAHs) to surface-oxidized activated carbon (AC) and its effect on the distribution of those compounds in sediments. Created surface oxygen groups on AC enhanced the sorption of copper, which is superior in sorption competition, in the marine sediments. In case of cadmium, aqueous chemistry altered by AC addition, such as pH, has greater impact on the bioavailability according to the result of a sequential extraction combined with the pore water concentration measurements. Oxidized AC exhibited 2.3 times more adsorption of reduced bioavailable copper while 23% of bioavailable cadmium was adsorbed onto unmodified AC. No significant changes in BET surface area, pore volume, and AC/water distribution coefficient (K AC) of PAHs were observed with surface-oxidized AC. The largest difference in K AC after the oxidation was only 0.14 log unit. Consequently, freely dissolved aqueous concentrations of PAHs were reduced by more than 96% for all tested ACs in a week despite the increased Cu sorption on AC. This indicates that enhanced metal sorption by surface oxidation of AC is less significant in controlling bioavailability of PAHs in sediments than particle size or sorbent dose.  相似文献   

8.
Nonylphenol (NP), nonylphenol mono- and di-ethoxylate (NP1EO, NP2EO) and bisphenol A (BPA) were determined in water, suspended particulate matter (s.p.m.) and bed sediment collected from the most polluted stretch of Tiber river (Italy) in the neighbourhood of Rome. Analytes were recovered from water samples by solid-phase extraction (SPE) on Si–C18 cartridges and analysed by HPLC with fluorescence detection. Solid samples were extracted by using an aqueous solution of the non-ionic surfactant Tween 80. Results indicated that 2–42% of NP, 9–45% of NP1EO, 11–18% of NP2EO and 4–62% of BPA respectively occurred in the suspended phase. In general, for all compounds a higher affinity for s.p.m. than for bed sediments was observed, reflecting differences in the nature of particles and in their sorption capacity for organic micro-pollutants. The partition of target compounds in river compartments was affected by differences in hydrological conditions between the two sampling campaigns. Run-off from the basin or resuspension/redissolution from sediments was an important source of nonylphenol and bisphenol A during high discharge regimes. Partition coefficients of compounds (log K oc ) between water and s.p.m. were calculated under stable flow condition. K oc values, experimentally measured in the river, were higher than those predicted by K ow , implying that specific chemical interaction could occur in the sorption mechanisms for these group of compounds.  相似文献   

9.

Purpose

Understanding the fate and behavior of polycyclic aromatic hydrocarbon (PAH) sources in aquatic systems is important for the efficiency of control policies. In this work, a new approach??organic carbon-normalized sediment?Cpore water partition coefficients of PAH source contributions (logK??Osource)??was developed to study the sediment?Cpore water partition of PAH source contributions. The focus of this study was the Yellow River, which is the second largest river in China and one of the largest rivers in the world.

Materials and methods

Sixteen priority US Environmental Protection Agency PAHs were analyzed in 14 surface sediments and 11 pore water samples. Principal component analysis?Cmultiple linear regression (PCA-MLR) and Unmix models were employed to estimate the source contributions of PAHs in sediments and pore water samples. Finally, logK??Osource values were calculated according to the modeled source contributions of PAHs.

Results and discussion

??PAHs (sum of the 16 PAH concentrations) in 14 sediment samples and 11 pore water samples from the Yellow River were 1,415?±?726?ng?g?1 dry weight (dw) and 123?±?57.4???g?l?1, respectively. The source apportionment results indicate the following: (1) for sediment samples, the contributions to ??PAHs from vehicular emissions, coal combustion, and petrogenic sources were 41.07?C61.05, 38.83?C45.56, and 11.18?C14.92?%, respectively, and (2) for pore water samples, vehicular emissions were the most significant contributor (45.51?C69.39?%), followed by petrogenic sources (29.80?C34.22?%) and coal combustion (7.35?C21.59?%). Coal combustion had the highest logK??Osource values (4.15?C4.26) among the three categories, followed by vehicular emissions (3.51?C3.57) and petrogenic sources (3.30?C3.43).

Conclusions

The possible categories of PAH sources identified by hierarchical cluster analysis, PCA-MLR, and Unmix models were consistent, indicating that vehicular emissions, coal combustion, and petrogenic sources were three important categories. The logK??Osource values indicate that contributions from coal combustion had a higher partition for the sediment phase compared with the other two source categories.  相似文献   

10.
Sixteen EPA chosen polycyclic aromatic hydrocarbons (PAH) were studied in the sediments and the suspended matter of the River Seine to determine existing pollution. Analyses were carried out by HPLC with coupled fluorimetric and UV detectors. PAH contents were found to be highly variable depending on many factors such as anthropogenic activities, weather and flow rate of the river, and occasionally they rose to alarming levels. Contents of 16 PAH ranged from 1.5 to 7.4 μg g?1 in the sediments, but a peak at 60.7 μg g?1. In the suspended matter the contents were usually below 10 μg g?1. From these results and taking into account the mean content of suspended matter in the river downstream from Paris, the total adsorbed PAH concentration in the river Seine should be about 60 ng l?1. Evidence has been established that storm drain discharges are a major source of pollution.  相似文献   

11.
Polycyclic aromatic hydrocarbons (PAHs); their derivatives nitro, and methyl-PAHs; n-alkanes; and organic acids were investigated in the aerosol samples collected during two field campaigns conducted at three sampling stations in an industrialized city in southern Italy. The main sources affecting the atmosphere and its toxicity were investigated by means of the diagnostic ratios of: specific particulate-phase PAHs, marker compounds among nitro-PAHs, alkanes, and acids, the dominant wind direction, daily and seasonal abundance of carcinogenic organic substances. The potential importance of the non-regulated pollutants to assess the air quality was confirmed; in fact the carcinogenic organic compounds showed to have scarce correlation with particulate matter (PM) concentration. An exceptionally high variability of toxic compounds at a daily scale was due to meteorological condition causing periods of extremely high pollution levels.  相似文献   

12.
Extracellular DNA in soil and sediment: fate and ecological relevance   总被引：1，自引：0，他引：1  
The review discusses origin, state and function of extracellular DNA in soils and sediments. Extracellular DNA can be released from prokaryotic and eukaryotic cells and can be protected against nuclease degradation by its adsorption on soil colloids and sand particles. Laboratory experiments have shown that DNA adsorbed by colloids and sand particles can be taken up by prokaryotic competent cells and be involved in natural transformation. Most of these experiments have been carried out under artificial conditions with pure DNA molecules and pure adsorbing matrices, but in soils and sediments, pure surface-reactive colloids are not present and DNA is present with other cellular components (wall debris, proteins, lipids, RNA, etc.) especially if released after cell lysis. The presence of inorganic compounds and organic molecules on both soil particles and DNA molecules can influence the DNA adsorption, degradation and transformation of competent cells. Extracellular DNA can be used as C, N and P sources by heterotrophic microorganisms and plays a significant role in bacterial biofilm formation. The nucleotides and nucleosides originated from the degradation of extracellular DNA can be re-assimilated by soil microorganisms. Extracellular DNA in soil can be leached and moved by water through the soil profile by capillarity. In this way, the extracellular DNA secreted by a cell can reach a competent bacterial cell far from the donor cell. Finally, the characterisation of extracellular DNA can integrate information on the composition of the microbial community of soil and sediments obtained by analysing intracellular DNA.  相似文献   

13.
A simple analytic technique — isotope dilution — was used for determination of the contents of total and methilated Hg in water, sediments, soils and biological objects collected in the basin of the river Katun. The inspected region is located on a territory of two mercury-stibium geochemical provinces. Evaluation of the Hg transport, transformation and bioaccumulation in aquatic and terrestrial ecosystems of the region showed that the main Hg transport occurs on suspended solids after Hg has been washed out from soil and bedrock by water of the river Katun and its tributaries and also by underground waters. Bottom sediments of some rivers of the basin content increased Hg concentrations. This effect is also noted in the sediments of a small reservoir formed on one of the tributaries. The investigations showed that Hg originating from natural sources differs considerably in its biochemical characteristics from Hg compounds coming from anthropogenic sources. So, natural Hg compounds have lower bioavailability for the water and terrestrial organisms of the region.  相似文献   

14.

Purpose

River ecosystems are under pressure from several different stressors. Among these, inorganic pollutants contribute to multiple stressor situations and the overall degradation of the ecological status of the aquatic environments. The main sources of pollution include different industrial activities, untreated effluents from municipal waste waters and intensive agriculture. In the present study, water, suspended particulate matter (SPM) and sediments of the Sava River were studied in order to assess the pollution status of this river system.

Materials and methods

Sampling was performed during the first sampling campaign of the EU 7th FW funded GLOBAQUA project in September 2014, at 18 selected sampling sites along the Sava River. In 2014, floods predominated from spring to fall. Water samples were collected to determine the total element concentrations, the dissolved (0.45 μm) fraction and element concentrations in SPM. In order to assure comparative results with other river basins, the fraction below 63 μm was analysed in sediments. The extent of pollution was estimated by determination of the total element concentrations and by the identification of the most hazardous highly mobile element fractions (extraction 0.11 mol L?1 acetic acid) and anthropogenic inputs of elements to sediments (normalization to aluminium (Al) concentration). Concentrations of selected elements were determined by inductively coupled plasma mass spectrometry (ICP-MS).

Results and discussion

Since during sampling campaign the water level was extremely high, water samples contained high amounts of SPM (in general between 80 and 100 mg L?1). The data of chemical analysis revealed that concentrations of elements in water, SPM and sediments in general increase along the Sava River from its origin to the confluence with the Danube River. Elevated concentrations of chromium (Cr) and nickel (Ni) in SPM and sediments were observed at industrially exposed sites. Concentrations of Cr and Ni in sediments were up to 320 and 250 mg kg?1, respectively. Nevertheless, these elements were present in sparingly soluble forms and hence did not represent an environmental threat. Phosphorus (P) was found in elevated concentrations (up to 1500 mg kg?1) at regions with intensive agricultural activities and cities with dense population.

Conclusions

With respect to element concentrations, the pollution of the Sava River is similar to other moderately polluted European rivers. The data from the present study are beneficial for the water management authorities and can contribute to sustainable utilization, management and protection of the Sava River water resources.
  相似文献   

15.

Purpose

Rivers feeding into the Loskop Dam, South Africa, pass through coal mining and heavily industrialised areas. Previous studies investigating mass mortalities of crocodile and fish in the river system, revealed the presence of organic compounds, including polycyclic aromatic hydrocarbons (PAHs), in their tissues.

Materials and methods

Samples were collected from nine sites within the dam in winter and summer. Liquid-liquid and microwave-assisted extraction was used for preconcentrating PAHs from water and sediment samples, respectively. Extracts were analysed by gas chromatography-mass spectrometry in the selected ion monitoring mode to determine the presence and levels of the 16 United States Environmental Protection Agency (US EPA)-priority PAHs.

Results and discussion

Significant levels of PAHs were found in both water and sediment samples. Concentrations were higher in sediments than in water, as well as in samples collected in winter. Levels of PAHs in sediments were generally higher than those reported by many researchers for other water bodies in industrialised areas. Zebrafish embryos were used to assess potential risks associated with the water and sediment, and to determine the effects of PAHs on aquatic life. Embryos, exposed to intact water and sediment samples, as well as to diluted sediment extracts, were monitored for 120 h post fertilisation. Sediment proved more toxic to zebrafish embryos than water, causing delayed embryo development and malformations.

Conclusions

These findings are alarming as they indicate that this water system is under stress. These findings can be typical of any water system situated in a coal mining and industrial region.
  相似文献   

16.

Goal, Scope and Background

Distribution of hydrophobic organic contaminants in abiotic compartments is essential for describing their transfer and fate in aquatic ecosystems. Taihu Lake is the third largest freshwater lake in China. Water quality of Taihu Lake has deteriorated greatly during the last decades and has threatened the water supply. The aim of the present study was to investigate the partitioning of polycyclic aromatic hydrocarbons (PAHs) among overlying water, suspended particulate matter (SPM), sediments, and pore water in Meiliang Bay, Taihu Lake and to provide useful information for the ecological engineering in this area.

Materials and Methods

Overlying water and surface sediment were sampled from six sites in Meiliang Bay, Taihu Lake, China. Within 72 h of sampling, sediments were centrifuged to obtain the pore water. Overlying water samples were filtered to separate dissolved and SPM samples. After extraction, samples were purified following a clean-up procedure. PAH fraction was obtained by elution with a mixture of hexane: DCM (7:3, V/V) and analyzed by GC/MS.

Results

PAHs concentrations in overlying water varied from 37.5 ng/L to 183.5 ng/L. Concentrations of PAHs in pore water were higher than those in overlying water. The total concentrations of 16 priority PAHs in sediments ranged from 2091.8 ng/g-dw to 4094.4 ng/g-dw. PAHs concentrations on SPM were decreased with suspended solid concentrations (SSC). Total PAHs concentrations on SPM varied in the range of 3369.6 ng/g-dw to 7531.1 ng/g-dw. The partition coefficients between sediment and overlying water (log K oc) for PAHs with log K ow<5 were positively correlated with their octanol-water partition coefficients (log K ow) (n=39, r=0.79, p<0.0001). Partition coefficients between sediment and pore water (log K oc′) for all PAHs were also significantly correlated with their log K ow values (n=48, r=0.82, p<0.0001).

Discussion

In general, PAHs derived from combustion sources tend to bind strongly to soot particles in natural sediment. Consequentially, K oc values observed in the natural environment could be orders of magnitude higher than those predicted by linear correlation relationships under laboratory conditions. In the present study, the ratio of log K oc values to log K ow values falls consistently above 1, indicating that the sediment soot carbon in the bay was more attractive for PAHs than n-octanol. The log K oc′ was also higher than that predicted under laboratory conditions, suggesting that the measured pore water PAH concentrations were lower than those predicted. That is to say, not all the sediment PAHs can be available to partition rapidly into sediment pore waters. A variation in soot content is a possible reason. Furthermore, concentrations of PAHs on SPM were higher than those in sediments. The compositions of PAHs on SPM and in sediments were similar, indicating the importance of re-suspension process of sediments in the partitioning process of the shallow lake.

Conclusions

The results indicated the equilibrium partitioning model could be used to predict PAHs distribution in various phases of a shallow lake in the stagnation period, but re-suspension processes should be considered to modify the relationship between log K ocs and log K ows.

Recommendations and Perspectives

Concentration, particle size and composition of resuspended particles could affect the relationship between log K ocs and log K ows. Further work should be done under field conditions, especially where a steady thermodynamic equilibrium state could be assumed.
  相似文献   

17.
Intention, Goal, Scope, Background  Environmental pollution caused by oil spills is a major ecological problem. Oil contamination in the environment is primarily evaluated by measuring the chemical concentrations of hydrocarbons. The results of chemical analyses are important for estimating water and sediment quality in the risk assessment to the flora and fauna of oil-contaminated sites. In the world there are lake ecosystems under permanent chemical stress due to urbanization and the oil industry. Studies, however, have been generally limited to petroleum compounds and have not considered other pollutants of the site like PCBs, polychlorinated pesticides and heavy metals. Objective  Water and sediment from stations in the Mecoacán Lake in the Mexican State of Tabasco were analyzed for polycy-clic aromatic compounds (PAHs), aliphatic hydrocarbons (AHs), polychlorinated biphenyls (PCBs), polychlorinated pesticides (PCPs) and heavy metals. The objective of this study was to examine the contaminant levels of the samples collected in February 1993 and 1996 after oil spills at the Mecoacán petroleum region. The goals of this study were to reveal the effect of the spills on the distribution of the hydrocarbons and assess the toxi-cological significance of the levels found. In addition, our aim was to examine the distribution of the PAHs in sediments from Mecoacán originated from both pyrolytic and petrogenic sources. Methods  Samples were collected from 19 stations and prepared according to the CARIPOL (Caribbean Pollution) methodology of the United Nations Environmental Programme (1992) of the Great Caribbean Region for hydrocarbons in marine and coastal water, and sediments. The gas-chromatographic and atomic absorption analysis of the samples was performed after sampling. Results and Discussion  Concentrations of PAHs in water ranged from 0.2 to 0.8 μg/l in 1993 and from 0.3 to 2.8 μg/l in 1996. The concentration of the 16 EPA-PAHs varied from 0.1 to 36 mg/kg dry weight in the lake sediment samples collected in 1996, while those of AHs, PCBs and PCPs ranged from 0.1 to 67 mg/kg, 0.1 to 59 μg/kg and 6 to 370 μg/kg, respectively. The most abundant contaminants in water were benz[a]anthracene and pyrene, in 1993 and 1996, respectively; while in sediments collected in 1996: Pyrene, C24, 2-chlorobiphenyl and endrin predominated. Heavy metals (Cu, Pb and Zn) were found at low concentrations. Benzo[a]pyrene was detected in some sediment samples in varying amounts (0.2 to 0.3 mg/kg). Conclusions  The maximum total PAH concentration in sediments was found at sites near the oil fields and the AH concentration near the urban zone. The mayor pollutants in sediments were PAHs and AHs, and taking into regard the detected PAHs near the oil fields, the source was the oil spilling. The mean total PAH value in Mecoacan sediments of 6.4 mg/kg did not exceed the median range effects value (ERM) for total PAHs of 44.8 mg/kg. The measured organochlorine compounds and heavy metals were present in amounts much inferior to the ERM values. This study confirms that contaminants concentration in sediments did not exceed the environmental quality guideline for the 50% probability and no adverse effect can be expected. Recommendation and Outlook  Analysis revealed no indication of a contribution of PAHs, PCBs, PCPs and heavy metals to acute sediment toxicity. The results of this study demonstrate the importance of continuous monitoring of ecosystems exposed to pollution to make pre-spill data available in order to evaluate the real consequence of the spilling and its effect on flora and fauna.  相似文献   

18.
Distribution of trace metals in the Periyar river has been investigated in detail. The fluvial concentrations of trace metals increase in river water and decrease in sediments during the summer months due to solubilization and concentration by evaporation. The levels, especially of Zn and Cd which are industrial pollutants increase by a factor of 10 both in water and sediments at the industrial zone. The concentration of Cd in the river water approaches the WHO standards for safe limits in drinking water. Solubilization at the backwater zone under high salinity is identified as one of the major mechanisms of trace metal transport to the marine environment. River meandering is responsible for large scale deposition of suspended solids at the industrial zone during the monsoon period. The trace metals exhibit build-up in specific concentration in the suspended solids in proportion to their residence time.  相似文献   

19.
The presence of organotin (OT) compounds was investigated in coastal areas (10 stations), wastewater treatment systems (six stations), rivers (19 stations) and lakes (12 stations) throughout Greece, in three sampling campaigns organized between October 1998 and September 1999. A screening method for the determination of toluene extractable organotins (TEOTs) by Electrothermal Atomic Absorption Spectrometry (ETAAS) was used during the first two sampling campaigns. TEOTs (sum of tributyltin, TBT, dibutyltin, DBT and triphenyltin, TPhT) were detected in most seawater and wastewater samples at concentrations up to 19.4 and 89.9 ng l?1, respectively, while they were detected occasionally in surface water. During the third sampling campaign, OT compounds were extracted in selected stations using direct derivatization with NaBEt4 in acidic medium and analysed by Gas Chromatography–Mass Spectrometry (GC–MS). In seawater, the levels of TBT, DBT and monobutyltin (MBT) were varied between < 2 and 70, 159 and 19 ng l?1, respectively and tend to decrease with increasing distance from the coastline. TPhT was not detected in any of the samples. Significant concentrations of OT species were detected in influent wastewater, up to 384, 76.2 and 67.8 ng l?1 for TBT, DBT and MBT, respectively. OTs were mainly associated with the suspended solids and were totally removed during wastewater treatment.  相似文献   

20.
Determination of Zn in the aqueous, suspended and sedimentary phases of the Rhone River was carried out by differential pulse anodic stripping voltammetry with static mercury drop electrode. For total desorbable Zn (operationally defined as that measured on unfiltered water at pH 1.5 to 2) the concentration was 2.0 ± 0.6 μg L?1 in unfiltered upstream water (8 stations) and in the unfiltered delta water (2 stations) was 1.05 ± 0.25 μg L?1. The delta values are slightly higher than values found recently for estuaries of other rivers such as the Amazon and Yangtse, but non-delta values correspond mainly with those from relatively unpolluted areas. Overall, in non-delta water about 35% of the Zn was in true solution, 25% adsorbed on suspended material and 40% was in the suspended material but not desorbable. The calculatedK d for Zn on the suspended material was about 2.5E4. The Zn content in suspended matter including adsorbed Zn was 69 ± 33 mg kg?1, much lower than other literature values, and is approximately equivalent to the concentration in fine sediment fractions. The Zn in Rhone river sediment was on average 40 times the amount from nearby non-industrialized areas such as the Roya river.  相似文献   

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