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1.
Philip L. Shearman 《Ambio》2010,39(2):181-189
Existing at the interface of land and sea, in regions of low topographic relief, mangroves are likely to be some of the first
ecosystems that undergo spatial modification due to sea-level rise. The mangrove ecosystems of the Gulf of Papua New Guinea
are some of the largest and most pristine in the Asia–Pacific region; they have not been subject to clearance for crustacean
farming nor suffered from land reclamation projects. This article establishes through analysis of a time series of aerial
photography and satellite imagery from the period 1973–2007, that there have been substantial changes in the distribution
of mangroves in this region. These changes include the seaward progradation of the Purari Delta and the regression of the
Kikori Delta by an average of 43 m year−1 at its most seaward point. While these findings are likely to be continuations of long-term trends, it is probable that they
can be explained by a variety of interacting factors including climate change, sea-level rise, subsistence in the northern
Gulf of Papua and changes in sediment dynamics. 相似文献
2.
Background, aim, and scope
Ever since the discovery of the mutagenic properties of ionizing radiation, the possibility of birth sex odds shifts in exposed human populations was considered in the scientific community. Positive evidence, however weak, was obtained after the atomic bombing of Japan. We previously investigated trends in the sex odds before and after the Chernobyl Nuclear Power Plant accident. In a pilot study, combined data from the Czech Republic, Denmark, Finland, Germany, Hungary, Norway, Poland, and Sweden between 1982 and 1992 showed a downward trend in the sex odds and a significant jump in 1987, the year immediately after Chernobyl. Moreover, a significant positive association of the sex odds between 1986 and 1991 with Chernobyl fallout at the district level in Germany was observed. Both of these findings, temporality (effect after exposure) and dose response association, yield evidence of causality. The primary aim of this study was to investigate longer time periods (1950–2007) in all of Europe and in the USA with emphasis on the global atmospheric atomic bomb test fallout and on the Chernobyl accident. To obtain further evidence, we also analyze sex odds data near nuclear facilities in Germany and Switzerland. 相似文献3.
Effects of Natural Disasters on Conservation Policies: The Case of the 2008 Wenchuan Earthquake,China 总被引:1,自引:0,他引:1
Conservation policies are increasing in response to human-induced ecosystem degradation, but little is known about their interplay
with natural disasters. Through an analysis of satellite imagery and field data we evaluated the impacts of a devastating
earthquake on forest recovery and avoided forest loss estimated to have been obtained by two of the largest conservation programs
in the world. Results show that more than 10% of the forests in Wenchuan County, Sichuan province, China were immediately
affected by the 2008 earthquake, offsetting some gains in forest cover observed since the enactment of the conservation programs.
But without the enactment of these conservation programs, the combined effects of human disturbance and earthquake-induced
landslides could have severely reduced the region’s forest cover. The continuation—and enhancement—of incentives for participation
in conservation programs will be important for reducing the environmental impacts of the combined effects of human disturbance
and natural hazards not only in the study area but also in many disaster-prone regions around the world. 相似文献
4.
A decision framework for possible remediation of contaminated sediments in the River Kymijoki, Finland 总被引:1,自引:1,他引:0
Verta M Kiviranta H Salo S Malve O Korhonen M Verkasalo PK Ruokojärvi P Rossi E Hanski A Päätalo K Vartiainen T 《Environmental science and pollution research international》2009,16(1):95-105
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 × 106 m3 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 m3). 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 m3) 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
5.
Liu J Yan C Macnair MR Hu J Li Y 《Environmental science and pollution research international》2007,14(5):345-349
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
6.
REDD+ remains a critical tool for dealing with increasing levels of atmospheric carbon dioxide. Like other global-level initiatives, REDD+ has strong supporters and critics. Despite the division over its merits, little has been done to understand how a national-level audience responds to the program’s arrival in a partner country and which players drive a program’s implementation. Here we coded the archives of two Guyanese newspapers to identify the policy actors, institutions, and concepts (players) that drove the implementation of the country’s Low Carbon Development Strategy (LCDS). Two groups of players—super-key and key—dictated the direction of the LCDS implementation. Super-key players used the state-owned media to advocate their positions, while players who felt they would be punished by the LCDS implementation published their positions in the privately-owned media. Therefore, like responses to other global-level environmental challenges, views around the LCDS were divided. 相似文献
7.
This study was conducted in the Swedish sub-Arctic, near Abisko, in order to assess the direction and scale of possible vegetation
changes in the alpine–birch forest ecotone. We have re-surveyed shrub, tree and vegetation data at 549 plots grouped into
61 clusters. The plots were originally surveyed in 1997 and re-surveyed in 2010. Our study is unique for the area as we have
quantitatively estimated a 19% increase in tree biomass mainly within the existing birch forest. We also found significant
increases in the cover of two vegetation types—“birch forest-heath with mosses” and “meadow with low herbs”, while the cover
of snowbed vegetation decreased significantly. The vegetation changes might be caused by climate, herbivory and past human
impact but irrespective of the causes, the observed transition of the vegetation will have substantial effects on the mountain
ecosystems. 相似文献
8.
Yueyue Li Shengli Wang Huiling Sun Wen Huang Zhongren Nan Fei Zang Yepu Li 《Environmental science and pollution research international》2020,27(7):6950-6959
Fluoride (F) is a necessary trace element in the human body, which would lead to some diseases if human body lacks or accumulates it excessively (1–1.5 mg d−1). Fluoride contamination in sediments has become more and more serious, which has potential hazards to human body. In this paper, a novel sorbent (loess) was proposed to immobilize trace element F in sediment. The effectiveness of loess on F stabilization was evaluated by decreasing F bioavailability in contaminated sediment. The loess and the sediment were mixed at different proportions for stabilization. About 70 days after the application of loess, the soil column was subject to simulate acid rain leaching test to observe the leaching-migration of F, which can be used to predict the leaching migration of F in the study area. The results showed that when the loess dose was 5 kg, the loess converted highly effective fractions of F (i.e., water-soluble and exchangeable fractions) into a more stable state (i.e., residual state). After 30 days of leaching with HNO3 solution with pH at 3.0, the lowest concentration of F was found in the leachate of soil column with 2 kg loess application. Correlation analysis showed that the F concentration in soil column profile was affected by CaCO3, EC, pH, and OM, of which, pH and CaCO3 have greater influence than other factors. 相似文献
9.
Hofmann T Wendelborn A 《Environmental science and pollution research international》2007,14(4):223-224
PCDD/Fs are hydrophobic organic substances and strongly sorbing to soil particles. Once adsorbed to soil particles they are
believed to be virtually immobile. However, research in the last decades confirmed that strong sorbing contaminants may reach
the groundwater via colloid-facilitated transport. This pathway has not been investigated before in Vietnam. Ma Da area, 100
km north of Ho Chi Minh City, was repeatedly sprayed during the Vietnam War (1962–1971) with herbicides like Agent Orange
containing, beside others, the teratogenic contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). 11 surface soil samples and 12 water samples were collected in Ma Da area for analysis of PCDD/Fs in solids.
Soil TCDD concentrations ranged from 1–41 ppt with a mean of 8.8 ppt and a mean I-TEQ of 9.7 ppt. Two surface water samples
showed colloid bound TCDD (7 and 19 ppt). Groundwater samples showed elevated colloid bound PCDD concentrations (mean 770
ng/kg), mainly octachlorodibenzo-p-dioxin. Groundwater colloids separated by filtration did not show any TCDD. The results support that TCDD/Fs can be relocated
from the top soil to the groundwater by colloidal pathway. They did not provide evidence that the dioxins bound to groundwater
colloids are leftovers from the Second Indochinese War. However, this study reinforces that the colloidal transport pathway
has to be included investigating the relocation of strong sorbing organic contaminants. 相似文献
10.
Quantifying phosphorus levels in soils, plants, surface water, and shallow groundwater associated with bahiagrass-based pastures 总被引:1,自引:1,他引:0
Gilbert C. Sigua Robert K. Hubbard Samuel W. Coleman 《Environmental science and pollution research international》2010,17(1):210-219
Background, aim, and scope
Recent assessments of water quality status have identified eutrophication as one of the major causes of water quality ‘impairment’ not only in the USA but also around the world. In most cases, eutrophication has accelerated by increased inputs of phosphorus due to intensification of crop and animal production systems since the early 1990s. Despite substantial measurements using both laboratory and field techniques, little is known about the spatial and temporal variability of phosphorus dynamics across landscapes, especially in agricultural landscapes with cow-calf operations. Critical to determining environmental balance and accountability is an understanding of phosphorus excreted by animals, phosphorus removal by plants, acceptable losses of phosphorus within the manure management and crop production systems into soil and waters, and export of phosphorus off-farm. Further research effort on optimizing forage-based cow-calf operations to improve pasture sustainability and protect water quality is therefore warranted. We hypothesized that properly managed cow-calf operations in subtropical agroecosystem would not be major contributors to excess loads of phosphorus in surface and ground water. To verify our hypothesis, we examined the comparative concentrations of total phosphorus among soils, forage, surface water, and groundwater beneath bahiagrass-based pastures with cow-calf operations in central Florida, USA. 相似文献11.
以古运河镇江段为研究对象,研究了表层沉积物中碱性磷酸酶活性、硝酸还原酶活性和亚硝酸还原酶活性的时空变化以及3种酶活性与河流表层沉积物中氮磷阴离子浓度及上覆水水质的相关性。结果表明,镇江古运河表层沉积物中碱性磷酸酶活性、硝酸还原酶活性和亚硝酸还原酶活性具有显著的时间和区域性差异,枯水期(12月)各酶活性较高,分别介于0.29~0.32 mg/(g·24 h)、0.13~0.19 mg/(g·24 h)、3.05~5.21 mg/(g·24 h);丰水期(5月)各酶活性较低,变化范围分别为0.18~0.29 mg/(g·24 h)、0.08~0.14 mg/(g·24 h)、2.95~3.64 mg/(g·24 h)。冗余分析结果显示,古运河表层沉积物酶活性在枯水期差异较大,丰水期差异较小,各酶活性与其相关离子浓度呈显著正相关(P0.05),硝酸还原酶和亚硝酸还原酶与上覆水的水质呈正相关。3种酶活性可被作为判断古运河镇江段沉积物富营养化负荷的参考性指标,硝酸还原酶和亚硝酸还原酶还可作为评价古运河镇江段水质的参考性指标。 相似文献
12.
《国际环境与污染杂志》2011,22(5):628-633
The natural radiation levels were measured in about 50 residential houses of Tehri Garhwal, Uttaranchal, using an environmental radiation dosimeter in both the indoor and the outdoor atmosphere. The total gamma ray activity was found to vary from 29.74 µR/h to 41.19 µR/h with a mean of 36.5 µR/h for the indoor environment, whereas for outdoors it varied from 28.76 µR/h to 43.46 µR/h with a mean of 30.1 µR/h. The resulting gamma ray dose at 20 traditional rural houses was also measured. The values varied from 38.91 µR/h to 77.68 µR/h with a mean of 66.6 µR/h. Measurements of the diurnal variation of the dose rates showed that they are higher in the rural traditional houses than in modern houses. The variations of dose rate with the type of building material, the mode of construction and the age of houses are also discussed. 相似文献
13.
Corsolini S Borghesi N Schiamone A Focardi S 《Environmental science and pollution research international》2007,14(6):421-429
Background, Aims and Scope Fish-eating seabirds are recognized to be at risk of accumulating toxic contaminants due to their high position in the trophic
web and to their low ability to metabolize xenobiotic compounds. Penguins are widely distributed in Antarctica and represent
an important fraction of the Antarctic biomass. They feed mainly on krill and, depending on krill availability, also on fish.
It has been reported that predators may be a sink for volatile and toxic chemicals and this may pose a serious environmental
problem. Polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-dioxins (PCDDs),-furans (PCDFs), and-biphenyls (PCBs),
including non-ortho congeners, hexachlorobenzene (HCB) and p,p′-DDE, were quantified in three species of Antarctic Pygoscelids in order to evaluate their accumulation patterns. The potential
toxicity of twenty-two dioxin-like congeners was assessed and expressed as 2,3,7,8-tetraCDD equivalents (TEQs). Differences
between males and females were investigated.
Methods Blood samples of the Adélie penguin Pygoscelis adeliae, Chinstrap penguin Pygoscelis antarctica and Gentoo penguin Pygoscelis papua were collected at Admiralty Bay, King George Is (62°10′39″ S, 58°26′46″ W) in February 2004. Halogenated hydrocarbons were
identified and quantified using gas chromatography coupled with gas chromatography mass spectrometry analyses. Results are
expressed on a wet weight basis.
Results and Discussion HCB, p,p′-DDE and ΣPCBs were higher in Adélie penguins (6.7±6.1, 8.2±3.3 and 9.8±3.8 ng/g, respectively) than in Chinstrap and Gentoo
penguins, both of which showed values in the same order of magnitude, but approximately 40% lower than Adélie penguins. Hexa-CBs
ranged 35–45% of the residue. Low-chlorinated PCBs (nos. 70+76+95+56+60+101) accounted for 40–60% in the three species. PCB101
made up 15% of the residue in Adélie penguins. PBDEs were 291±477, 107±104 and 116±108 pg/g in Adélie, Chinstrap and Gentoo
penguins, respectively; the most abundant congeners were BDE47 in Adélie and Chinstrap penguins and BDE17 in Gentoo penguins.
PCDDs were 22±32, 6.5±7.4 and 18±23 pg/g in Adélie, Chinstrap and Gentoo penguins, respectively. PCDFs were higher in Adélie
penguins and lower in Chinstrap penguins. PCDDs/Fs and PBDEs were higher in males than in females of Gentoo and Chinstrap
penguins; differences in concentrations were likely related to the partial detoxification that occurs in females during egg
formation. Of the four non-ortho PCBs measured, PCB126 occurred at the highest concentrations and contributed the majority of the non-ortho PCB-TEQ in Gentoo and Chinstrap penguins. The highest TEQs were found in the Gentoo penguin and due mainly to PCDDs and non-ortho PCBs.
Conclusions POP concentrations in penguins were lower than those found in seabird species from other areas of the world. Different chemical
accumulation patterns were observed in relation to species and sex; the Adélie penguin showed the highest POP levels. Dissimilar
ecological or metabolic features may be involved; the diverse timing of reproduction steps can be responsible for those differences;
moreover, Adélie penguins feed on krill (a fatty resource) more abundantly than the other two species during the rearing period.
Recommendation and Outlook The South Shetland Islands might be subjected to a higher chemical impact with respect to the rest of Antarctica, due to their
being near South America. Because penguins are fish-eating birds showing low detoxifying capacities and key-species in Antarctic
ecosystems, further studies on their xenobiotic metabolism should be carried out. 相似文献
14.
Amory B. Lovins 《Ambio》2010,39(3):236-248
Protecting the climate is not costly but profitable (even if avoided climate change is worth zero), mainly because saving
fuel costs less than buying fuel. The two biggest opportunities, both sufficiently fast, are oil and electricity. The US,
for example, can eliminate its oil use by the 2040s at an average cost of 15 per barrel (200015 per barrel (2000), half by redoubled efficiency
and half by alternative supplies, and can save three-fourths of its electricity more cheaply than operating a thermal power station. Integrative design permits this by making big energy savings cheaper than small ones, turning traditionally assumed diminishing returns into empirically observed expanding returns. Such efficiency
choices accelerate climate-safe, inexhaustible, and resilient energy supply—notably the “micropower” now delivering about
a sixth of the world’s electricity and 90% of its new electricity. These cheap, fast, market-financeable, globally applicable
options offer the most effective, yet most underestimated and overlooked, solutions for climate, proliferation, and poverty. 相似文献
15.
Estimation of Nitrogen and Phosphorus in Effluent from the Striped Catfish Farming Sector in the Mekong Delta,Vietnam 总被引:1,自引:0,他引:1
In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish
(Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8°33′–10°55′N, 104°30′–106°50′E), South Vietnam. The sector accounted for 687,000 t
production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial
and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were
similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge
levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish).
Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged
31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned
directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish
farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta
compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P
discharged in the production of a tonne of production was estimated. 相似文献
16.
Bettinetti R Quadroni S Crosa G Harper D Dickie J Kyalo M Mavuti K Galassi S 《Ambio》2011,40(4):341-350
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
17.
Georg Steinhauser Stefan Merz Dieter Hainz Johannes H. Sterba 《Environmental science and pollution research international》2013,20(4):2527-2534
Several environmental media in Austria were monitored for artificial radionuclides released during the Fukushima nuclear accident. Air (up to 1.2 mBq/m3 particulate 131I) and rainwater (up to 5.2 Bq/L 131I) proved to be the media best suited for the environmental monitoring, allowing also a temporal resolution of the activity levels. Significant regional differences in the wet deposition of 131I with rain could be observed within the city of Vienna during the arrival of the contaminated air masses. Forward-trajectory analysis supported the hypothesis that the contaminated air masses coming from the northwest changed direction to northeast over Northern Austria, leading to a strong activity concentration gradient over Vienna. In the course of the environmental monitoring of the Fukushima releases, this phenomenon—significant differences of 131I activity concentrations in rainwater on a narrow local scale (8.1 km)—appears to be unique. Vegetation (grass) was contaminated with 131I and/or 137Cs at a low level. Soil (up to 22 Bq/kg 137Cs) was only affected by previous releases (nuclear weapon tests, Chernobyl). Here, also significant local differences can be observed due to different deposition rates during the Chernobyl accident. The effective ecological half-lives of 137Cs in soil were calculated for four locations in Austria. They range from 7 to 30 years. No Austrian sample investigated herein exceeded the detection limit for 134Cs; hence, the Fukushima nuclear accident did not contribute significantly to the total radiocesium inventory in Austrian environmental media. The levels of detected radioactivity were of no concern for public health. 相似文献
18.
This study was performed to investigate the possible enantioselective metabolism of the four chlorinated bornanes: #26, #32, #50 and #62 (according to the Parlar nomenclature) by rats. Rats were exposed to a mixture of these toxaphenes by a single intravenous injection. Enantiomer ratios (ER) as well as the enantiomer fractions (EF) were determined in brain, adipose tissue and liver samples at six time intervals by high resolution gas chromatography (HRGC) coupled to negative ion chemical ionization (NICI) mass spectrometry (MS). Capillaries coated with heptakis-(2,3,6-O-tert-butyldimethylsilyl)-beta-cyclodextrin (TBDMS-CD) or octakis-(2,3,6-tri-O-ethyl)-gamma-cyclodextrin (TEG-CD) were used for the enantioselective separations. Significant time-dependent changes of ER and EF were found in all the three tissues for #26, #50 and #62. Greatest deviations from racemic composition were found in the liver, which is known to be the major metabolizing organ for toxaphenes. #32 was metabolized the fastest, but showed no changes in ER. Brief information is also included about the possible reasons for the different behaviors of the four congeners in the studied tissues. 相似文献
19.
Manaca MN Grimalt JO Gari M Sacarlal J Sunyer J Gonzalez R Dobaño C Menendez C Alonso PL 《Environmental science and pollution research international》2012,19(3):756-762
Introduction
We report on the analysis of 4,4′-dichlorodiphenyltrichloroethane (4,4′-DDT) and its metabolites in thatch and branch samples constituting the wall materials of dwellings from South African subtropical areas. This approach was used to assess the exposure to DDT in the residents of the dwellings after indoor residual spraying (IRS) following recommended sanitation practices against malaria vectors. 相似文献20.
Surface water concentrations of dissolved organic carbon ([DOC]) are changing throughout the northern hemisphere due to changes
in climate, land use and acid deposition. However, the relative importance of these drivers is unclear. Here, we use the Integrated
Catchments model for Carbon (INCA-C) to simulate long-term (1996–2008) streamwater [DOC] at the four Swedish integrated monitoring
(IM) sites. These are unmanaged headwater catchments with old-growth forests and no major changes in land use. Daily, seasonal
and long-term variations in streamwater [DOC] driven by runoff, seasonal temperature and atmospheric sulfate (SO4
2−) deposition were observed at all sites. Using INCA-C, it was possible to reproduce observed patterns of variability in streamwater
[DOC] at the four IM sites. Runoff was found to be the main short-term control on [DOC]. Seasonal patterns in [DOC] were controlled
primarily by soil temperature. Measured SO4
2− deposition explained some of the long-term [DOC] variability at all sites. 相似文献