共查询到20条相似文献,搜索用时 546 毫秒
1.
Sediment accumulation of organic halogen was studied in two forest lakes, one pristine and one which received 30 m 3 of biologically purified bleaching wastewater from a kraft pulp mill in 1979 equivalent to ca. 2 kg of adsorbable organic halogen (AOX). Lake sediments were dated with 210Pb, 134Cs and 137Cs and the annual deposition rates of organic halogens and organic matter were calculated. Organic bound halogen contents of the sediment aged 150 years was 180 μg Cl g ?1 d.w. in both lakes. The concentration of organic bound halogen at the topmost 6 cm of the sediments (less than 20-years-old) ranged from 45 to 80 μg Cl g ?1 d.w. This suggests that solvent extractable halogen had enriched in the older sediment layers. The deposition of extractable organic halogen (EOX) in the lakes in 1950’s was 4 to 5 mg Cl m ?2 a ?1. Since then, the depositon of EOX doubled in both lakes. The deposition of organic matter increased concomitantly from 50 g m ?2 a ?1 to 110 g m ?2 a ?1 in Lake Mustalampi and from 35 g m ?2 a ?1 to 62 g m ?2 a ?1 in Lake Pyylampi suggesting that the increase in the deposition of organic halogen followed the increase in the deposition of organic matter. Of the 2 kg of organic halogen discharged into the lake, 5 % or less was detected in the sediment in tetrahydrofuran extractable form 15 years later. 相似文献
2.
The crustacean Monoporeia affinis Lindström was exposed to two different concentrations of bleached kraft mill effluent (BKME) containing, originally, 8.3 mg/g organic chlorine determined as adsorbable organic halogen (AOX). The swimming activity of the animals was recorded by pairs of infra-red sensitive photocells attached to 5.6 1 aquaria having a seawater inflow rate of 12 ml/min. The test sequence included a control phase, an exposure phase and a recovery phase. During the exposure phase the total swimming activity decreased in three of the four test aquaria containing effluent, indicating that the animals had retreated into the sediment. Total activity increased during the recovery phase and, in the case of the lower organic chlorine concentration, activity almost achieved the original control-phase level. Statistical differences in swimming activity changes during experiment were evaluated using ANOVA. Experimental methods are explained in detail. 相似文献
3.
Background Acid-volatile sulfide (AVS) is operationally defined as sulfides in sediment, which are soluble in cold acid, and is reported
as the most active part of the total sulfur in aquatic sediments. It is a key partitioning phase controlling the activities
of divalent cationic heavy metals in sediment.
Methods In order to examine this in mangrove environments, six sites were selected along the Jiulong River Estuary in Fujian, China,
which had previously been reported to be polluted by heavy metals. Sediments were sampled from 0–60 cm depth at each site,
and the spatial distribution of AVS and SEM (simultaneously extracted metals: copper, cadmium, zinc, and lead) were determined.
Results and Discussion The results indicate that the AVS concentrations had a spatial variation, ranging from 0.24 to 16.10 μmol g −1 sediment dry weight. The AVS concentration in the surface layer is lower than that of the deeper sediment, with peak values
in the 15–30 cm horizon. There was no correlation between the AVS value and organic matter content or total dissolved salts,
but a significant positive correlation of AVS with surface sediment (0–5 cm) moisture content was found. This indicates that
water logged sediments tend to have a high AVS value. The amount of SEM was within the range of 0.33–2.80 μmol g −1 sediment dry weight and decreased with sediment depth.
Conclusions There was a marked variation in AVS and SEM among different sites studied. AVS concentrations were generally lower in the
surface sediments, while SEM concentrations slightly decreased with the depth. Higher concentrations of SEM found in the upper
layers of the sediments confirm the earlier suggestions that this study area may suffer from increasing heavy metal pollution.
Recommendations and Perspectives When monitoring environmental impacts by using AVS, the micro and large-scale spatial variation as well as vertical distribution
need to be estimated to avoid misleading results. Both AVS and SEM concentrations in different sediment layers should be taken
into account in assessing the potential impact of heavy metals on the biotic environment. 相似文献
4.
“Freely-dissolved” aqueous concentrations of 9 trichlorothrough heptachlorobiphenyls are reported, alongside those in sediments
and fish from the R. Severn. For most congeners, BSAFs and lipid-normalised BAFs for pike exceed those for eels. Whilst R.
Severn BSAFs are comparable with those for L. Ontario trout and New Bedford Harbour flounder, R. Severn BAFs are 1–2 orders
of magnitude lower. This discrepancy may be due to inter-species variability, as well as inter-laboratory differences between
operational definitions of “freely-dissolved” aqueous PCB, underlining that the same operational definition must be employed
if R. Severn BAFs are extrapolated elsewhere. For eels, correlation of Log K ow with Log BAF is better (R 2 = 0.66) than with BSAF (R 2 = 0.13), whilst similar correlation coefficients (R 2 = 0.81 and 0.82) were observed for pike. When Log K ow is plotted against BSAF and Log BAF for both species combined, better correlation is observed for Log BAF (R 2 = 0.65), than BSAF (R 2 = 0.36). For both species combined, the observed relationship between Log BAF and Log K ow for trichloro-through heptachlorobiphenyls is: Log BAF = 0.96 * Log K ow −0.24. 相似文献
5.
Background, aim, and scope The pulp and paper industry is the sixth largest polluter discharging a variety of gaseous, liquid, and solid wastes into
the environment. Effluents from bleached Kraft mill effluents (BKME) are polluting waters to a great extent These effluents
cause considerable damage to the receiving waters if discharged untreated since they have high levels of biological oxygen
demand (BOD), chemical oxygen demand (COD), chlorinated compounds (measured as AOX), suspended solids (mainly fibers), fatty
acids, tannins, resin acids, lignin and its derivatives, sulfur and sulfur compounds, etc. This study aimed to remove adsorbed
organic halogen (AOX), total nitrogen, and lignin-degrading products in the wastewater (4,500 m 3/h) from the paper mill in the pulp and paper industry, which is discharged to sea from a plant located in western Turkey.
Materials and methods The photocatalytic degradation of AOX, total nitrogen, and chlorinated lignin in BKME have been investigated in different
parameters, such as time, H 2O 2 and TiO 2 concentration. In addition, for investigating the effect of chlorine on the removal of lignin, pure lignin solution was prepared
in equal amounts to chlorinated lignin degradation products found in BKME. The same experiments were conducted for this solution.
Experiments were carried out in photocatalytic reactor made of Pyrex glass. The mercury lamp was used as a radiation source.
All irradiation was carried out under constant stirring. The existence of dissolved O 2 is an important factor which increases the photocatalytic degradation. Hence, we used an air pump for the aeration of the
wastewater solutions. The temperature of the wastewater was controlled and adjusted to 25°C by thermostat pump in conjunction
with a cooler. At the end of all experiments, AOX, total nitrogen and lignin concentrations were analyzed according to standard
methods. All experiments were performed in duplicate and average values were used.
Results and discussion When the effect of H 2O 2 and time were investigated, it was observed that the AOX concentration increased from 3.0 to 11.0 mg/L by only UV. However,
when H 2O 2 was added, AOX concentration decreased from approximately 3.0 to 0.0 mg/L. The optimal conditions for the removal of AOX
appear to be an initial H 2O 2 concentration of 20.0 mL/L and reaction time of 50 min. In addition, at the same experiment conditions, it was seen that
the total nitrogen concentration decreased from 23.0 to 15.0 mg/L by only UV and by increasing H 2O 2 concentration, the concentration of 20.0 mL/L H 2O 2 appears to be optimal (9.0 mg/L). The AOX, total nitrogen and lignin degradation products and pure lignin go through a minimum
when the concentration of H 2O 2 and TiO 2 increases at constant pH and UV intensity. The kinetics for the degradation of AOX, total nitrogen and lignin degradation
products followed a pseudo-first order law with respect to the products, and the degradation rates (min −1) for the UV/TiO 2/H 2O 2 system were higher than that of the corresponding values for the UV/H 2O 2 system.
Conclusions The AOX, total nitrogen and lignin concentration go through a minimum when the concentration of H 2O 2 and TiO 2 increases at constant pH and UV intensity. It was found that the UV/TiO 2/H 2O 2 system has proved capable of the degradation of total nitrogen as well as chlorinated and degraded lignin in BKME.
Recommendations and perspectives The photocatalytic process can be considered a suitable alternative for the remove of some compounds from the BKME. Nevertheless,
further studies should be carried out to confirm the practical feasibility of BKME. Another result obtained from the study
is that pre-purification carried out with UV/TiO 2/H 2O 2 photocatalytic process may constitute an important step for further purification processes such as adsorption, membrane processes,
etc. 相似文献
6.
Background, Aims and Scope Despite the large number of studies on the forms of sulfur in marine deposits, investigations on sulfur organic compounds
are still rare. It is known that the processes leading to formation of intermediate and final sulfur compounds (including
organic ones) in modern deposits are the results of microbiological transformation of sulfur containing proteins, as well
as the microbiological reduction of sulfate ions. The latter are finally reduced by anaerobic sulfate-reducing bacteria to
H 2S, HS − and S 2−; the total sum of these is referred to as ‘hydrogen sulfide’ in chemical oceanography. Further, the formation of reduced
sulfur organic derivatives (sulfides and polysulfides) is the result of interaction of the organic substance destruction products
with the sulfide ions. In such cases, the main source of organic substances, as well as sulfates for the sulfur reducing processes,
is the pore water in the sediments. The choice of the target of our study is based on the fact that the eastern part of the
Gulf of Finland water area receives the bulk of the anthropogenic load of the St. Petersburg region. Low vertical intermixing
of the water thickness is observed there (thus creating a deficiency of oxygen near the bottom), and the bottom sea current
transfers the polluted salty water of the Baltic Sea into the Neva Bay. The whole of the above are the preconditions for the
formation of sulfur-bearing organic compounds.
A great number of bottom sediment samples for analytical surveys were collected in the Eastern Gulf of Finland during research
expeditions in the years of 1997 and 2001. These were screened for structures of sulfur organic microcontaminants, including
organic forms of sulfur, using advanced instrumentation and experienced personnel in our two, cooperating laboratories. This
work is a part of the research being carried out on organic micro-admixtures present in bottom sediments, and is the summary
of our findings on previously unstudied sulfur organic substances there.
Materials and Methods A number of sulfur organic compounds present in nineteen bottom sediment samples from the Eastern Gulf of Finland (EGF) were
characterized by high performance gas chromatography connected to low and high resolution mass spectrometers (GC/LRMS and
GC/HRMS). The structure screening was carried out as compared with literature and library mass spectra, and taking the GC
retention times into account. In the cases of an absence of mass spectra not in the literature, interpretation of the most
probable structures was performed with the help of high resolution mass-spectrometric data, fragmentation rules for sulfur-bearing
organic substances and ICLU simulation of spectra. These data were registered to form a conclusive ‘fingerprint’ for identification
and confirmation of the structure of each novel compound found, e.g. by later syntheses of authentic model compounds. The
relative contents of sulfur organic compounds were determined from MS response ratios of each compound to 2-fluorine naphthalene
(internal standard).
Results This paper is a completion of work, which has been published in part as three papers in the European Journal of Mass Spectrometry.
As the total study result, 43 sulfur-bearing compounds were characterized. The mass spectra of 20 of them were found in the
literature. The most probable structures for the 23 compounds whose mass-spectra were not available in the literature data
were proposed. All of those 23 compounds were detected in bottom sediments for the first time, and 5 of them were described
as originating from plants or being generated by chemical synthesis products, while the remaining 18 substances were previously
unknown. The structures of these were deduced to be most probably the following (in order of their GC retention): dichloromethyl
thiylsulfenylchloride, chloromethyl dichloromethyl disulfide, 3,4-dithiacyclohexene, 1,2,4-trithiacycloheptane, 1,2,3-trithiacyclohexane,
tetrathiacyclopentane, 3,4,5-trithiacyclohexene, 1,2,4-trithiacyclohexane, cyclopropylhydrotrisulfide, 1,2-dithiane-3-thiol,
1,3-dithiane-2-thiol, bis(trichloromethyl)-tri-sulfide, 1,2,4,5-tetrathiacyclohexane, 1,2,3,4-tetrathiacycloheptane, 1,2,3,4-tetrathiacycloheptane,
1,2,3,4-tetrathia-cyclo-hexane, pentathiacyclohexane, and 1,2,4,6-tetrathiacyclooctane. The highest amounts of sulfur organic
compounds were found in the deepest, bottom areas in the open part of the sea, where the salinity was highest, and oxygen
deficiency occurred as well. Also, some coastal places with a high solid matter deposition rate had elevated contents of sulfur
organic compounds.
Discussion From the 43 sulfur organic compounds found, the HRMS data provided the atomic composition of the molecular ions for 16 compounds
with a high confidence (see Table 3). The LRMS spectra could be identified with catalogue or literature spectra in 29 cases.
The MS information obtained was insufficient in two cases: 1) The obvious molecular ion (at m/z 110) of compound 1 was not
visible in LRMS. 2) For compound 43, the HRMS measurement, due to the low intensity (2%) of the molecular ion (m/z 210), could
not exclude the presence of 2 oxygen atoms (instead of one sulfur atom) in the molecule. Major fragments, however, of our
43, certainly contained no oxygen atoms according to HRMS. The limited LRMS data in the literature, for an isomer of 43, had
m/z values of all fragments different from those of the compound found by us.
The retention times (RT) formed one more evidence for identity between compounds in different samples. The use of different
non-polar columns in GC and similar, but not identical, temperature programs produced eluted peaks of novel and known compounds
in each sample (mixture) in GC/HRMS and GC/LRMS. These gave sets of RTs which were in a very significant linear correlation
(measured example R = 0.999866, p = 1.85E-06, N = 5). Therefore, the RTs in the HRMS analysis systems could be converted to
values comparable with those from the LRMS device.
The RT values, HRMS m/z values, LRMS spectra, and ICLU simulation results for each organic sulfur compound form an identification
‘fingerprint’. The interpretation of these experimental data, with supporting use of fragmentation rules, allow the giving
of a provisional name and structure to the ‘suspect’. In this study and in environmental surveys of micropollutants in general,
the compounds suspected of anthropogenic or natural origin occur at low levels in complex mixtures. Therefore, no bulk amount
of an authentic, pure model substance for the suspect is available quite often. The most probable name and structure from
the fingerprint data are very useful in guiding the preparation of the model substance for a conclusive identification. Similarly,
the unknown criminal can be identified in advance by forensic science and his fingerprint, DNA, etc. as registered before
the arrest. The analogy can be found in the literature and CAS register of organic polysulfides, which in great part consists
of the results of sensitive mixture analysis methods.
Conclusions Sediment of the Eastern Gulf of Finland is over large areas anaerobic, as indicated by the existence of novel, non-oxygenated
sulfur organic microcontaminants. These substances were most abundant in anoxic and saline, deep bottom regions, and, in addition,
in one coastal area near industrial discharges. This occurrence, and also the limited information about sulfur organic compounds
in scientific literature, is considered evidence for the dominantly natural processes in their formation.
Recommendations and Perspectives The importance and necessity of investigating the sulfur organic compounds in the bottom sediments, result from the fact that
their presence can be an indicator of stable anaerobic processes. Similarly, the oxygen disappearance (anoxia) in the marine
water, due to a high concentration of the sulfate ions and relatively high content of organic matter, is practically always
connected with the appearance of hydrogen sulfide and sulfides. The generation of sulfur organic compounds precedes the formation
of the new, or expansion of the existing anaerobic (‘hydrogen sulfide’) zones, which lead to such environmental disasters
as mass destruction of hydrobionts. Many organic compounds of sulfur, including sulfides and polysulfides, are toxic to the
aquatic organisms. Therefore, in addition to the danger of mass wholesale deaths of marine fauna in the bottom sediments region,
there exists a probability of secondary pollution of the water thickness as well, due to the entry of those substances from
bottom sediments in the water when the environmental conditions are changed (stormy weather, floods, geological activity of
the earth’s crust, etc.). 相似文献
7.
Background, aim, and scope The paper describes the spatial contamination of the River Kymijoki, South-Eastern Finland, and the coastal region of the
Gulf of Finland with PCDD/Fs and mercury. The findings of ecotoxicologial and human health studies are also reported, including
environmental and human risk assessments. Sediments from the River Kymijoki, draining into the Gulf of Finland, have been
heavily polluted by the pulp and paper industry and by chemical industries. A wood preservative, known as Ky-5, was manufactured
in the upper reaches of the river between 1940 and 1984 causing severe pollution of river sediments with polychlorinated dibenzo- p-dioxins (PCDD) and dibenzofurans (PCDF). Moreover, the sediments have been polluted with mercury (Hg) from chlor-alkali production
and the use of Hg as a slimicide in pulp and paper manufacturing.
Materials and methods An extensive sediment survey was conducted as well as sediment transport modeling, toxicity screening of sediment invertebrates,
and a survey of contaminant bioaccumulation in invertebrates and fish. Studies on human exposure to PCDD/Fs and the possible
effects on hypermineralization of teeth as well as an epidemiological study to reveal increased cancer risk were also conducted.
An assessment of the ecological and human health risks with a null hypothesis (no remediation) was undertaken.
Results The sediment survey revealed severe contamination of river and coastal sediments with PCDD/Fs and Hg. The total volume of
contaminated sediments was estimated to reach 5 × 10 6 m 3 and hot spots with extremely high concentrations (max 292,000 ng g −1 or 1,060 ng I-TEQ g −1 d.w.) were located immediately downstream from the pollution source (approximately 90,000 m 3). Sediment contamination was accompanied by changes in benthic assemblages, but direct effects were masked by many factors.
The fish showed only slightly elevated PCDD/F levels in muscle, but orders of magnitude higher in the liver compared with
reference freshwater sites and the Baltic Sea. The concentrations in human fat did not reveal high human exposure in the Kymijoki
area in general and was lower than in sea fishermen. The relative risk for total cancer among farmers was marginally higher
(RR = 1.13) among those living close to the river, compared with farmers living further away, and the possibility of increased
cancer risk cannot be ruled out. A conservative risk assessment revealed that the present probability of exceeding the WHO
upper exposure limit of 4 pg WHO-TEQ kg −1 d −1 for PCDD/Fs and DL-PCBs was 6%. The probability of exceeding the WHO limit value of 0.23 μg kg −1 d −1 for methyl mercury was estimated to be notably higher at 62%. Based on these studies and the estimated risks connected with
different remediation techniques a general remediation plan with cost benefit analysis was generated for several sub-regions
in the river. Dredging, on-site treatment, and a close disposal of the most contaminated sediments (90,000 m 3) was suggested as the first phase of the remediation. The decision regarding the start of remediation will be made during
autumn 2008.
Conclusions The sediments in the River Kymijoki are heavily polluted with PCDD/Fs and mercury from earlier chlorophenol, chlor-alkali,
and pulp and paper manufacturing. A continuous transport of contaminants is taking place to the Gulf of Finland in the Baltic
Sea. The highly increased PCDD/F and Hg levels in river sediments pose an ecotoxicological risk to benthic fauna, to fish-eating
predators and probably to human health. The risks posed by mercury exceed those from PCDD/Fs and need to be evaluated for
(former) chlor-alkali sites and other mercury releasing industries as one basis for remediation decision making.
Recommendations and perspectives The studies form the basis of a risk management strategy and a plan for possible remediation of contaminated sediments currently
under consideration in the Southeast Finland Regional Environment Centre. It is recommended that a detailed restoration plan
for the most seriously contaminated areas should be undertaken. Based on current knowledge, the restoration of the whole river
is not feasible, considering the current risk caused by the contaminated sediment in the river and the costs of an extensive
restoration project. The experiences gained in the present case should be utilized in the evaluation of PCDD/F- and mercury-contaminated
sites in other countries. The case demonstrates that the historic reservoirs are of contemporary relevance and should be addressed,
e.g., in the national implementation plans of the Stockholm Convention.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
8.
A re-survey of acid-sensitive lakes in Ireland (initial survey 1997) was carried out during spring 2007 ( n = 60). Since 1997, atmospheric emissions of sulfur dioxide and deposition of non-marine sulfate (SO 4
2−) in Ireland have decreased by ~63 and 36%, respectively. Comparison of water chemistry between surveys showed significant
decreases in the concentration of SO 4
2−, non -marine SO 4
2−, and non-marine base cations. In concert, alkalinity increased significantly; however, no change was observed in surface
water pH and total aluminum. High inter-annual variability in sea salt inputs and increasing (albeit non-significant) dissolved
organic carbon may have influenced the response of pH and total aluminum (as ~70% is organic aluminum). Despite their location
on the western periphery of Europe, and dominant influence from Atlantic air masses, the repeat survey suggests that the chemistry
of small Irish lakes has shown a significant response to reductions in air pollution driven primarily by the implementation
of the Gothenburg Protocol under the UNECE Convention on Long-Range Transboundary Air Pollution. 相似文献
9.
Relationships between sedimentary organic matter (SOM) composition and PAH desorption behavior were determined for vegetated and non-vegetated refinery distillate waste sediments. Sediments were fractionated into size, density, and humin fractions and analyzed for their organic matter content. Bulk sediment and humin fractions differed more in organic matter composition than size/density fractions. Vegetated humin and bulk sediments contained more polar organic carbon, black carbon, and modern (plant) carbon than non-vegetated sediment fractions. Desorption kinetics of phenanthrene, pyrene, chrysene, and C 3-phenanthrene/anthracenes from humin and bulk sediments were investigated using Tenax ® beads and a two-compartment, first-order kinetic model. PAH desorption from distillate waste sediments appeared to be controlled by the slow desorbing fractions of sediment; rate constants were similar to literature values for kslow and kvery slow. After several decades of plant colonization and growth ( Phragmites australis), vegetated sediment fractions more extensively desorbed PAHs and had faster desorption kinetics than non-vegetated sediment fractions. 相似文献
10.
Improved benthic conditions compared to the 1990s were found during benthic investigations, including sediment and benthic
macrofauna in the inner Stockholm archipelago during 2008. In the 1990s, these areas were dominated by black and laminated
surface sediments and very sparse fauna. A clear relationship was found when comparing sediment status with the benthic macrofauna.
Reduced surface sediment and impoverished macroinvertebrate community was only found at one sampling station representing
an enclosed part of the inner archipelago, whereas the other seven stations, with depths ranging from 20 to 50 m, had oxidized
surface sediments and considerable biomasses of benthic macrofauna (6–65 g m −2) dominated by the invading polychaete Marenzelleria neglecta. An extrapolation of the results shows that, within the investigated area, the coverage of reduced surface sediments had decreased
from approximately 17% in the late 1990s to 4% in 2008. 相似文献
11.
In this study, we analyzed the concentrations of metals in sediments and Corbicula fluminea in China’s Dongting Lake to assess the suitability of C. fluminea as an effective biomonitor of metal contamination in sediments and food safety. We analyzed the biota-accumulation capacity by calculating the biota-sediment accumulation factor (BSAF) and assessed the potential human health risk of metals exposure via consumption of C. fluminea using the target hazard quotient (THQ) and total target hazard quotient (TTHQ). The results showed that the average concentrations of As (31.93 mg kg−1), Cd (5.54 mg kg−1), Cr (105.50 mg kg−1), Cu (32.53 mg kg−1), and Zn (207.89 mg kg−1) in sediments were higher than their respective standard set by the General Administration of Quality Supervision, Inspection and Quarantine of the People’s Republic of China. The sediment metals, which were mainly anthropogenic in origin, were at high levels and pose a relatively high ecological risk. Cadium (Cd) showed very high potential ecological risk levels and should be included in the prior pollutants list in the studied area. The mean levels of As (0.81 mg kg−1) in C. fluminea were 1.62-times higher than that set by the National Health Commission of the People’s Republic of China. BSAF values of the soft tissues of C. fluminea were between 0.05 and 2.14, with higher values for Cu (2.14), Cd (1.77), Zn (1.60), and Ni (1.27). Soft tissues of C. fluminea were able to reflect spatial differences in Sr within sediments around Dongting Lake. The results indicated that C. fluminea could be an potential biomonitor for sediment metals assessment in biomonitoring programs, especially for Cu, Cd, Zn, Ni, and Sr. The mean values for THQ and TTHQ of all the analyzed metals were below 1.0, indicating that the intake of metals via comsumption of C. fluminea does not result in an appreciable risk to human health. 相似文献
12.
A landfill leachate affected aquifer was investigated with respect to the geology and sediment geochemistry (solid organic carbon, cation exchange capacity, oxidation capacity, reduced iron and sulfur species) involving 185 sediment samples taken along a 305-m-long and 10–12-m-deep transect downgradient from the landfill. The geology showed two distinct sand layers (upper Quaternary, Weichselian and a lower Tertiary, Miocene) sandwiching thin layers of silt/clay deposits, peat and brown coal. The organic carbon content (TOC) and the cation exchange capacity (CEC) of the sandy sediments were low (TOC, 100–300 μg C (g DW) −1 ; CEC, 0.1–0.5 meq per 100 g DW) and correlated fairly well with the geology. Processes in the contaminant plume caused depletion of oxidation capacity and precipitation of reduced iron and sulfur species. However, some of these parameters were also affected by the geology, e.g. the oxidation capacity (OXC) was significantly higher in the Quaternary layer (OXC, 14–35 μeq g DW −1) than in the Tertiary sand layer (OXC, <5 μeq g DW −1). The intermediate layers (silt/clay and brown coal) have significantly higher values of most of the parameters investigated. This work demonstrates the need for a small scale geological model and a detailed mapping of the geochemistry of the sediments in order to distinguish impacts caused by the contaminant plumes from natural variations in the aquifer geochemistry. 相似文献
13.
The behavior of 20 PAH in the organic layers of a L mull, an Of mull and a mor was assessed by a combined approach of a soil
profile study, and the analysis of particle-size separates. Increasing PAH concentrations with depth in the mor profile (L,
866 μg kg −3; Of, 2902 μg kg −1; Oh, 10489 ug kg −1) were assigned to selective enrichment during organic matter decomposition. PAH were further highly enriched within the finer
separates. For the L horizons, significant positive correlations were established between the enrichment of individual PAH
(as observed from the decomposition gradient between the >2-mm fraction and the < 0.05-mm fraction), and the K OW for each compound. The slope of the regression line, m, described the degree of differentiation between low- and high-molecular
PAH during litter decomposition. Since m was greatest in the most biologically active humus type (L mull, 0.33) and smallest
in the most inactive (mor, 0.20), microbial breakdown was assumed as the dominating process for this differentiation. The
results also indicated that decomposition processes had already taken place in the L horizons, leading to morphological and
chemical changes of organic matter, and to an enrichment of high molecular PAH. 相似文献
14.
Concentrations of polybrominated diphenyl ethers (PBDEs) were determined in water and sediment collected from the artificial Lake Shihwa and surrounding creeks. Total concentrations of 23 PBDE congeners in water and sediment ranged from 0.16 to 11.0 ng L −1 and from 1.3 to 18 700 ng g −1 dry weight, respectively. The concentrations of BDE 209 in water and sediment were 1-2 orders of magnitude higher than the total concentrations of other PBDE congeners. The concentrations of total PBDEs and BDE 209 in sediments were the highest compared to previously reported worldwide levels. The highest concentrations of PBDEs in water and sediments were found in creeks near industrial complexes. The PBDE concentrations gradually decreased with increasing distance from the creeks to the inshore and then offshore regions of the lake. BDE 209 was a major congener, accounting for 80% of the total PBDEs in water and sediment, consistent with a high consumption of deca-BDE for the brominated flame retardant market in Korea. Non-parametric multidimensional scaling ordination showed that surrounding creeks are major pathways of PBDE contamination associated with deca-BDE technical mixtures used in industrial complexes around Lake Shihwa. A significant correlation between total organic carbon and total PBDE concentration was found in sediments, and the correlation coefficients for individual PBDE congeners relatively increased from lower to higher brominated congeners. 相似文献
15.
The spatial distribution and bioaccumulation of organochlorine pesticides (OCPs) in surface sediments and benthic organisms from Taihu Lake were studied. OCPs were detected in all sediment samples with total concentrations ranging from 4.22 to 461 ng g −1 dry weight (dw). The ratios of certain metabolites to their parent compounds indicated there are still new inputs of parent DDT (dichlorodiphenyltrichloroethane) to Taihu Lake, while the highest residues of HCHs (hexachlorocyclohexanes) mainly came from earlier usage and fresh γ-HCH (lindane). No positive correlation was found between the distribution of OCPs and organic matter contents in sediments. Concentrations of OCPs and lipids in typical large benthic organisms, Bellamya aeruginosa ( B. aeruginosa) and Corbicula fluminea ( C. fluminea) , increased with body weight. HCHs, DDTs, chlordanes and heptachlors were the dominant compounds detected in organisms and C. fluminea accumulated much more OCP than B. aeruginosa. Higher values of biota-sediment accumulation factor (BSAF) were detected in C. fluminea, which was both affected by biological characteristics of the organisms and physicochemical properties of the compounds. 相似文献
16.
To study the influence of mariculture on mercury (Hg) speciation and distribution in sediments and cultured fish around Hong Kong and adjacent mainland China waters, sediment samples were collected from six mariculture sites and the corresponding reference sites, 200-300 m away from the mariculture sites. Mariculture activities increased total mercury, organic matter, carbon, nitrogen and sulfur concentrations in the surface sediments underneath mariculture sites, possibly due to the accumulation of unconsumed fish feed and fish excretion. However, methylmercury (MeHg) concentrations and the ratio of MeHg to THg (% MeHg) in sediments underneath mariculture sites were lower than the corresponding reference sites. The % MeHg in sediments was negatively correlated ( r = −0.579, p < 0.05) with organic matter (OM) content among all sites, indicating that OM may have inhibited Hg methylation in surface sediments. Three mariculture fish species were collected from each mariculture site, including red snapper ( Lutjanus campechanus), orange-spotted grouper ( Epinephelus coioides) and snubnose pompano ( Trachinotus blochii). The average MeHg concentration in fish muscle was 75 μg kg −1 (wet weight), and the dietary intake of MeHg through fish consumption for Hong Kong residents was 0.37 μg kg −1 week −1, which was lower than the corresponding WHO limits (500 μg kg −1 and 1.6 μg kg −1 week −1). 相似文献
17.
The examinations of selected wastes and stream sediments from the vicinity of a chemical plant by sequential extraction procedures
and direct methods, SEM/EDX and XRD, were carried out in order to identify the different forms of chromium, particularly as
they are released to potential mobility. The results show that the top and bottom waste samples contain 37,756 and 53,650
μg g 1 Cr, respectively, but about 7% and 2% of the total chromium type Cr(VI). The chemical extraction results show that the mobility
of Cr in the upper part of the waste pile is significantly higher than in the bottom section; the exchangeable form of Cr
accounts for 25% and < 1%, respectively, the last one irrespective of redox conditions. About 50% of Cr is associated with
the reducible fraction of the top waste, and similar with the residual fraction in the bottom waste. Oxidation of the bottom
waste shift some portion of Cr from residual to the moderately reducible fraction. The major Cr-forms in the river sediments
are compounded with Fe-oxides. The < 2 μm size fraction of the selected sediment sample, particular enriched in chromium contained
up to 73,000 μg g 1 Cr with about 95% of this in the moderately reducible fraction, predominantly bound with oxyhydroxides. SEM/EDX and XRD analysis
of wastes and river sediment indicate that the main insoluble Cr-phase is ferroan — (Mg, Fe) (Cr, Al) 2O 4 which would be dissolved mainly in the residual fraction. 相似文献
18.
Dichlorodiphenyltrichloroethane (DDT) is still used in Africa for the indoor control of malaria and it may represent a potential
hazard for wildlife. The littoral sediments of two alkaline-saline lakes, Natron (Tanzania) and Bogoria (Kenya), in the Eastern
Rift Valley, supporting large populations of lesser flamingos ( Phoeniconaias minor), were analysed for DDT residues. Physical–chemical analyses (temperature, conductivity, pH and dissolved oxygen) were also
performed on the water of the two lakes and in the tributaries of Lake Natron, to evaluate the influence of the environmental
variables on pollutant occurrence. At Lake Natron, around 1 km from the sediment collection sites, tree leaves of Acacia tortilis were also collected. The main metabolite found in all sediment samples was pp’DDE, whilst equal concentrations of pp’DDT
and pp’DDE were measured in acacia leaves. The levels of DDTs measured in the sediments were within 5.9–30.9 ng g −1 d.w., reaching the maximum value in a tributary of Lake Natron. On the whole, the contamination of Lake Natron and Lake Bogoria
basins seems to be quite moderate. Nevertheless, the pp’DDE/pp’DDT ratio equals 1 in the Acacia tortilis leaves, which makes one suppose that the input of the parent compound was rather recent and could have been from aerial transport
or dust from relatively close-by old pesticides storage sites. 相似文献
19.
Background, aim, and scope The Arctic holds large stores of minerals, and extracted materials are provided to the world’s economy; in this sense, the
Arctic issue associated with mining is not local but global. In a part of the Arctic region (the Kola Peninsula, 66–70° N
and 28–41° E), metal levels are generally elevated in the lake sediment. There is a question as to what results in elevated
metal levels—a natural process (naturally abundant minerals) or an anthropogenic process (mining and metallurgy). In terms
of solving this question, Staroe lake located on the Kola Peninsula was researched as a case study.
Materials and methods The following parameters were determined in relation with Staroe lake: (1) the current quality of the lake’s water—each 1,000-ml
sample was collected at a surface point and a deep point (near the bottom layer), and the collected samples were directly
analyzed after filtration; (2) atmospheric bulk deposition—bulk deposition was collected using a set of three rainwater samplers
near the lake. In addition, bulk deposition was collected in a background site (250 km to the southwest of the smelter complex)
as a reference; and (3) sediment profile (plus principal component analysis)—lake-bottom sediment was collected by an open-gravimetric
column sampler equipped with an automatic diaphragm. After collection, the sample columns were cut at a 1-cm interval for
analysis. Eigenvalues and variances by factor were calculated from the correlation coefficients.
Results The obtained data show that (1) naturally poor elements (Cu, Ni, Si, and SO 4
2−) dominantly influence the lake’s water quality; (2) they are transported from the anthropogenic sources to the study lake
through the atmospheric pathway; (3) mainly the contents of Cu, Ni, Sr, and Ca have influenced the sediment quality since
the 1950s, corresponding to the industrial movement; and (4) Cu, Ni, and Sr originate from an anthropogenic source (smelter),
and Ca originates from both natural and anthropogenic sources.
Discussion As compared with the Russian standard (San Pin 2.1.980–00), the contents of NO 3
− (50.3 ± 0.1 mg l −1) and particulates (2.3 ± 0.2 mg l −1) exceeded the standard levels (0.7 mg l −1 NO 3
− and 45 mg l −1 particulates); Staroe lake may be slightly contaminated. However, the contamination factor (comparison with the background
data) implies that Staroe lake is considerably contaminated. There is a strong possibility that fine overburden detritus (<0.1 mm
diameter) may be transported from an open pit to the study lake by natural forces such as wind. Although it is difficult to
suppose that one factor dominantly affects the sediment quality, it follows from a factor analysis that factors 1 and 2 account
for about 70% of the total variance: Factor 1 is the most dominant, and factor 2 is the second most dominant in the variability
of sediment quality. It is considered that Cu, Sr, and Ni in factor 1 originate from anthropogenic sources because they are
poor in sediment rocks.
Conclusions The field survey conducted in Staroe lake can give the following answers to the key objectives: (1) The present water quality
is affected by Cu, Ni, Si, and SO 4
2− in light of the contamination factor, and these elements originate from anthropogenic sources (the smelter and the open pit)
and are transported to the lake through the atmospheric pathway; (2) the sediment profile and statistic analysis show that
the lake quality has been influenced by deposition of metals since the 1950s; and (3) Cu, Ni, Sr, and Ca have influenced the
sediment quality in light of the most dominant factor—Cu, Ni, and Sr originate from an anthropogenic source, whereas Ca comes
from both natural and anthropogenic sources.
Recommendations and perspectives The presented lake survey shows that the dispersion of human-related pollutants via the atmospheric pathway takes place in
the Arctic region. If the current pollution continues without countermeasures, the high-latitude environment may lose its
original characteristics; hence, this subject is important when considering how to implement a wide range of environmental
protection measures in the Arctic. 相似文献
20.
Polybrominated diphenyl ether (PBDE) concentrations in sediment and fish from 12 principal rivers in Taiwan were investigated to determine their association with water quality parameters as well as the biota-sediment accumulation factor (BSAF) in fish with different living patterns. The highest PBDE concentration in sediment was found in the Bajhang River (261 ng g ?1 dry weight (d.w.)) and the lowest in the Beinan River and the Da-an River (0.17 ng g ?1 d.w.). The PBDE concentrations in fish samples ranged from 1.28 ng g ?1 d.w. ( Oreochromis niloticus niloticus) in the Yanshuei River to 33.7 ng g ?1 d.w. ( Varico rhinos barbatulus) in the Da-an River. We conclude that PBDEs contamination in sediment was significantly affected by NH 3–N, pH, and DO. The BSAF results showed a parabolic trend from low- to high-brominated BDEs. Fish easily accumulated the congeners BDE-47, -100, -119, -126, and -154 from sediment. The BSAF decreased in the following order: PeBDE > HxBDE > TeBDE > other BDEs. Principle component analysis showed that demersal fish have different PBDE sources than do pelagic fish. We conclude that living and feeding habits are critical factors affecting PBDE accumulation in fish. 相似文献
|