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2.
Hornbuckle KC  Green ML 《Ambio》2003,32(6):406-411
A predictive model for gas-phase PCBs and trans-nonachlor over Lake Michigan has been constructed and the resulting data examined for trends. In this paper, we describe the model results to show how the magnitude and variability of a plume of contaminants from the Chicago area contributes to a highly variable region of net contaminant deposition over the entire lake. For the whole lake, gross annual deposition of PCBs is approximately 3200 kg, although the net annual gas exchange is not significantly different from zero. The data-driven model illustrates that on a daily basis, the net exchange of persistent organic pollutants (POPs) can change from net deposition to net volatilization depending on the area of plume impact. These findings suggest that i) control of urban areas can accelerate the rate of volatilization from lakes; and ii) release of POPs from urban areas is largely a result of volatilization processes.  相似文献   

3.
The current status of global marine pollution by TBT (tributyltin), TPT (triphenyltin) and polychlorinated biphenyls (PCBs) was examined by determining their concentrations in squid livers. TBT and TPT concentrations in squid livers were higher in coastal waters than in open oceans. The highest values of TBT and TPT of 279 and 519 ng g(-1), respectively, were detected off Japan. TBT concentrations were higher in the northern hemisphere than those of the southern hemisphere organisms. TPT was not detected in squid livers collected in the southern hemisphere. The variation in TBT and TPT concentrations between the northern and the southern hemisphere was greater than those recognized for PCBs distribution in the world oceans. This global distribution pattern of TBT, TPT and PCB seemed to reflect their usage (amount, period and manner of utilization). Approximate TBT concentrations in seawater estimated from bioaccumulation factor in the squid liver were 0.1-5.8 ng litre(-1) in waters around Japan, tr-0.8 ng litre(-1) in oceanic waters in the northern hemisphere, and tr-0.4 ng litre(-1) in the southern hemisphere oceans.  相似文献   

4.
During the last decade, a number of studies have been devoted to the sources and emissions of Persistent Organic Pollutants (POPs) at regional and global scales. While significant improvements in knowledge have been achieved for some pesticides, the quantitative understanding of the emission processes and emission patterns for "non-pesticide" POPs are still considered limited. The key issues remaining for the non-pesticide POPs are in part determined by their general source classification. For industrial chemicals, such as the polychlorinated biphenyls (PCBs), there is considerable uncertainty with respect to the relative importance of atmospheric emissions from various source categories. For PCBs, temperature is discussed as a potential key factor influencing atmospheric emission levels and patterns. When it comes to the unintentional by-products of combustion and industrial processes (PCDD/Fs), there is still a large uncertainty with respect to the relative contribution of emissions from unregulated sources such as backyard barrel burning that requires further consideration and characterisation. For hexachlorobenzene (HCB), the relative importance of primary and secondary atmospheric emissions in controlling current atmospheric concentrations remains one of the key uncertainties. While these and other issues may remain unresolved, knowledge concerning the emissions of POPs is a prerequisite for any attempt to understand and predict the distribution and fate of these chemicals on a regional and global scale as well as to efficiently minimise future environmental burdens.  相似文献   

5.
Detailed soil screening data from the Czech Republic as a typical Central European country are presented here. Determination of a wide selection of organic and inorganic pollutants as well as an assessment of specific soil parameters allowed us to study the soil contamination in relation to the land use and soil properties. While HCHs and HCB were found at highest levels in arable soils, the higher concentrations of PCDDs/Fs, PCBs, PAHs and DDTs were observed in high altitude forest soils. Concentrations of these compounds strongly correlated with the soil organic carbon content. Several possible reasons have been suggested for the observed higher concentrations in mountain forest soils but the impact of each of these influencing factors remains to be identified. An inventory of the soil contamination is needed as a first step in our effort to estimate an extent to which the secondary sources contribute to the enhanced atmospheric levels of POPs.  相似文献   

6.
The 6th Intergovernmental Negotiating Committee (INC 6), under the Stockholm Convention on POPs, gave an expert group the mandate to develop guidelines for the application and implementation of best available techniques (BAT) and best environmental practices (BEP) for the prevention and reduction of unintentionally produced and emitted POPs, including polychlorinated dibenzodioxins/-furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB). Measures to reduce or eliminate the release of these POPs to the environment can be found in Article 5 of the Convention. BAT and BEP are already being applied as emission reduction instruments in a number of industrialised countries and are elements of other major international treaties, e.g. the UN ECE Protocol on POPs and the Marine Convention's OSPAR and HELCOM, and of the EU Directive for Integrated Pollution Prevention and Control (IPPC Directive). Existing concepts are presented and compared with the requirements of the Stockholm Convention. Consequences, perspectives and questions for the future intersessional work of the above-mentioned Expert Group are discussed.  相似文献   

7.
The concept of maximum reservoir capacity (MRC), the ratio of the capacities of the surface soil and of the atmospheric mixed layer (AML) to hold chemical under equilibrium conditions, is applied to selected persistent organic pollutants (POPs) in the surface 'skin' (1 mm) of soils. MRC is calculated as a function of soil organic matter (SOM) content and temperature-dependent K(OA) and mapped globally for selected PCB congeners (PCB-28; -153; -180) and HCB, to identify regions with a higher tendency to retain POPs. It is shown to vary over many orders of magnitude, between compounds, locations and time (seasonally/diurnally). The MRC approach emphasises the very large capacity of soils as a storage compartment for POPs. The theoretical MRC concept is compared to reality and its implications for the global cycling of POPs are discussed. Sharp gradients in soil MRC can exist in mountainous areas and between the land and ocean. Exchanges between oceans and land masses via the atmosphere is likely to be an important driver to the global cycling of these compounds, and net ocean-land transfers could occur in some areas.  相似文献   

8.
Located in the center of the Asian continent, the Waliguan Baseline Observatory (WBO) is the highest and the most inland Global Atmospheric Watch (GAW) station in the world. In the present study, organochlorine pesticides (OCPs) and polybrominated biphenyl (PBDEs) were analyzed in the daily collected samples at the WBO from 2 April to 23 May 2005, in an attempt to investigate the long-range atmospheric transport (LRAT) of persistent organic pollutants (POPs) in northwest China. The mean concentrations of OCPs at WBO were slightly higher than the Arctic regions, and the concentrations of total PBDEs (8.3±4.0 pg m−3) was comparable with other remote areas. The low temperature dependence of the POP concentrations in the air, and the absence of local use of these compounds implied LRAT to WBO. As suggested by backward air trajectory analysis, the high concentrations of γ-HCH, DDTs and PBDEs, during the sampled spring period, were mainly related to air mass passing over the neighboring countries (e.g., Russia, Kazakhstan). Additional evidence was also obtained by the lead isotopic composition analysis, which showed similar 206Pb/207Pb and 208Pb/207Pb ratios as those of ores in these countries. The present results indicate that the WBO may serve as an excellent GAW station for monitoring the LRAT of POPs in the Asian continent.  相似文献   

9.
Weber K  Goerke H 《Chemosphere》2003,53(6):667-678
Organochlorine compounds were analysed in three fish species of different feeding types from the area of Elephant Island in the Antarctic. In 1996, hexachlorobenzene (HCB) (means: 15-20 ng/g lipid), p,p'-DDE (5-13 ng/g lipid) and mirex (1-7 ng/g lipid) predominated, while PCBs were minor components (PCB 153: 0.4-2 ng/g lipid). Concentration patterns were species-dependent: PCB 180, PCB 153, mirex, nonachlor III, trans-nonachlor and the toxaphene compound B8-1413 were highest in the bottom invertebrate feeder Gobionotothen gibberifrons and lowest in the krill feeder Champsocephalus gunnari. Levels of p,p'-DDE, PCB 138 and heptachloro-1'-methyl-1,2'-bipyrrole (Q1), a natural bioaccumulative product, were highest in the fish feeder Chaenocephalus aceratus, whereas HCB was present in about equal concentrations in all species. Most compounds were taken up preferentially via the benthic food chain, the chlorinated bipyrrole via the pelagic food chain and HCB from the water. In antarctic fish, biomagnification was generally more important than bioconcentration. Between 1987 and 1996, most persistent organic pollutant (POP) levels showed significant increases in the benthos feeder and the fish feeder, while they remained nearly constant or increased less in the krill feeder. Hence, the former species represent indicator species for changing POP levels in Antarctica. Ratios (1996/1987) of average concentrations in G. gibberifrons were: PCB 138 0.7, HCB 0.8, B8-1413 1.5, PCB 180 1.7, PCB 153 1.8, p,p'-DDE 2.0, nonachlor III 2.9, trans-nonachlor 3.3, mirex 6.7. By comparison with trends in the northern hemisphere it is concluded that global distribution of HCB is close to equilibrium. Changing levels of other POPs reflect global redistribution and increasing transfer to antarctic waters probably due to recent usage in the southern hemisphere and climate changes.  相似文献   

10.
The spatial distribution of persistent organic pollutants (POPs) was examined in soils surrounding the Tanggu Chemical Industrial District in Tianjin, China. The concentrations of hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs), hexachlorobenzenes (HCBs), and polychlorinated biphenyls (PCBs) were determined in 70 surface soils using accelerated solvent extraction and gas chromatography with electron capture detection. The results showed that the ranges of ∑HCH, ∑DDT, ΣHCB, and ∑PCB concentrations in soils were 2.1–12,549 μg?kg?1 (average, 965 μg?kg?1), n.d.–2,033 μg?kg?1 (average, 88.4 μg?kg?1), n.d.–1,924 μg?kg?1 (average, 349 μg?kg?1), and n.d.–373 μg?kg?1 (average, 46.2 μg?kg?1), respectively. Of these, HCHs were the dominant POPs, accounting for 75 % of the total organochlorine pesticide (OCP) residues. Overall, the spatial distribution of OCP concentrations showed a decreasing trend from the center of the Tanggu District to the surrounding areas. Two major pollution sources were Tianjin Dagu Chemical Co., Ltd. in the district center and the Tianjin Chemical Plant in Hangu District. In contrast, PCB concentrations were relatively high in the Haihe estuary to the east and low to the west of the study area. Component analysis of OCPs in these soils showed that they mainly came from industrial point sources. Compared with soils in other regions, soil DDT pollution was at a medium level in the Tanggu Chemical Industrial District, but associated HCH, HCB, and PCB pollution was relatively heavy. By multivariate statistical analyses, Tianjin Dagu Chemical Co., Ltd. was recognized as the main source of POPs, and soil properties were clarified to play an important role on the distribution and composition of POPs, especially the organic carbon content.  相似文献   

11.
Concentrations of persistent organic pollutants (POPs) such as hexachlorobenzene (HCB), dichlore diphenyl trichloretane (DDT), polychlorinated biphenyls (PCBs), and gamma-hexachlorocyclohexane (gamma-HCH or lindane) were determined in tissue of marine benthic invertebrates such as Mytilus galloprovincialis, Chamelea gallina, Venus verrucosa, Lithophaga lithophaga and Paracentrotus lividus. Species were selected due to their habitat, trophic level, feeding behaviour and their consumption. Invertebrate species were systematically sampled from December 1996 to December 2005 from several sites along the Balearic Islands. The highest concentrations of PCBs (785ng/g lipid) were found in M. galloprovincialis while the lowest concentrations were found in the sea-urchin P. lividus (193ng/g lipid). Among the 7 PCB quantified congeners the higher values are mainly obtained for CB138 and CB153. All bivalves presented higher PCBs contents than the sea-urchin P. lividus are possibly linked with the bioaccumulation process of POPs throughout the food web and to differential detoxifying mechanisms. The concentration of SigmaDDT exceeds that of HCB and gamma-HCH at all species and sampling stations. DDT concentrations ranged from 0.4ng/g ww at the bivalve C. gallina in 2002, to values of 15.8ng/g ww at the bivalve L. lithophaga in 1998. The values obtained for the organic compounds (HCH, HCB, PCBs, DDT) depend upon the place and year of sampling and are compared to values found by other authors for the mussel M. galloprovincialis in other Mediterranean areas. gamma-HCH and HCB were found in lower concentrations than the other POPs.  相似文献   

12.
Cyclic volatile methylsiloxanes (cVMS) such as octamethycyclotetrasiloxane (D4), decamethycyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6) are widely used as intermediates in the synthesis of high-molecular weight silicone polymers or as ingredients in the formulation of personal care products. The global environmental fate, latitudinal distribution, and long range transport of those cVMS were analyzed by two multimedia chemical fate models using the best available physicochemical properties as inputs and known persistent organic pollutants (POPs) and highly persistent volatile organic chemicals (“fliers”) as reference. The global transport and accumulation characteristics of cVMS differ from those of typical POPs in three significant ways. First, a large fraction of the released cVMS tends to become airborne and is removed from the global environment by degradation in air, whereas known POPs have a tendency to be distributed and persistent in all media. Secondly, although cVMS can travel a substantial distance in the atmosphere, they have little potential for deposition to surface media in remote regions. This contrasts with a deposition potential of known POPs that exceeds that of cVMS by 4–5 orders of magnitude. Thirdly, cVMS have short global residence times with the majority of the global mass removed within 3 months of the end of release. Global residence times of POPs on the other hand are in years. The persistent fliers resemble the cVMS with respect to the first two attributes, but their global residence times are more like those of the POPs.  相似文献   

13.
Present status of POP contamination in Lake Maggiore (Italy)   总被引:6,自引:0,他引:6  
In the last decade, Lake Maggiore has been subject to heavy DDT contamination due to a chemical plant located near the main influent of the Baveno Bay. The freshwater bivalve zebra mussel (D. polymorpha) was used as a bioindicator of several POPs (DDTs, PCBs, HCB, HCHs) to follow their concentration trend after a heavy flood in autumn 2000. Sampling of mollusc specimens were carried out monthly from April 2001 to October 2002 at two different stations in and outside the bay. Results showed worsening of DDT pollution due to the transport of insecticide from contaminated sediments and soils still present in the closed chemical plant site. Levels of about 4.5 microg/g lipids in soft tissues of specimens from the most contaminated site and 2.0 microg/g lipids outside it were found, which are twice those measured before the flood. HCHs and HCB values were always very low, but it was noticed since winter 2001-2002 a sharp increase of PCB pollution, with values of about 3-4 microg/g lipids, not due to the 2000 flood, but probably to improper discharge or release of contaminated sediments from numerous dams located in the watershed. Concentrations of total dioxin-like PCBs reached dangerous levels for the water community. Fish consumption may be a risk for human health especially for resident population, bearing in mind that fish usually have a higher POP concentration than zebra mussel.  相似文献   

14.
In the context of a monitoring program, persistent organic pollutants (POPs) were quantified in the blood of 10 year old children at four different demographic regions in Baden-Wuerttemberg, a highly industrialised federal state in South West Germany. DDE, HCB, PCB 138, PCB 153 and PCB 180 were measured in 1996/1997, 1998/1999, 2000/2001 and 2002/2003 in individual samples of about 400 children per year. PCDD/PCDFs and some relevant coplanar PCBs were determined in pooled samples from children in seven cycles from 1993 to 2003. Blood concentrations of the investigated compounds decreased in that time period by a factor of 2-4 with the exception of most PCDFs. The concentrations of POPs in the blood of the children were distinctly lower than the concentrations reported for adults. Breast feeding was associated with about 30% higher median concentrations of DDE, HCB, PCBs and a 30% increase for mean PCDD/PCDF concentrations. Concerning demographic differences, significant lower concentrations of HCB, PCBs and PCDD/PCDFs could be seen in children from Mannheim compared to the region of Aulendorf. About 10-20% higher concentrations were found in boys compared to girls for HCB, indicator PCBs and PCDD/PCDFs. The pattern of non-ortho and mono-ortho PCBs in the blood of children was similar to the pattern reported for mother's milk, and PCB 126 and PCB 156 contributed about 70% to the toxicity of dioxin-like PCBs and about one-third to total TEQ including PCDD/PCDFs.  相似文献   

15.
Persistent organic pollutants, POPs (e.g., polychlorinated biphenyls) can seriously and deleteriously affect environmental quality and human health. These organic pollutants are exhibiting high affinities to solid phases and thus, quickly end up in sediments. To better understand the role of carbonaceous materials in the transport and distributions of POPs in terrestrial and near-shore environments, concentrations of PCBs and carbonaceous materials (including total organic carbon, black carbon and total carbohydrates), were determined in surface sediments of the Danshui River and nearby coastal areas, Taiwan. Total concentrations of PCBs in the sediments ranged from non-detectable to 83.9 ngg(-1), dry weight, with the maximum value detected near the discharge point of the marine outfall from the Pali Sewage Treatment Plant. These results suggest that the sewage treatment plant has discharged PCBs in the past and the concentrations are still high due to their persistence; alternatively, PCBs are still being discharged in the estuarine and near-shore environment of the Danshui River. Organic carbon and black carbon concentrations correlated well with those of total PCBs in the sediments, suggesting that both organic carbon and black carbon significantly affect the distribution of trace organic pollutants through either post-depositional adsorption, or by co-transport of similar source materials. The field results demonstrate that black carbon and plays an important role in the general distribution of PCBs, while concentrations of some specific PCBs are affected by both black carbon and organic carbon concentrations.  相似文献   

16.
Information regarding polychlorinated biphenyls (PCBs) in environmental media in Africa is limited. This paper presents results of a monitoring program conducted in KwaZulu-Natal Province, South Africa designed to characterize levels, trends and sources of airborne PCBs. Particulate and vapor samples were sampled over the 2004-2005 period at three sites. The total PCB concentration averaged 128 ± 47 pg m−3, and levels were highest in winter. Tri- through hexa-congeners predominated, and the vapor fraction was predominant. Several tetra- through hexa-chlorinated congeners had levels comparable to those at urban sites in the northern hemisphere, but hepta- through deca-congeners resembled levels at background sites. PCB source areas, deduced using spatial and temporal patterns, compositional information and trajectory analyses, likely included local, regional and global sources. Soils at three rural sites showed high PCB concentrations, and milk from a local dairy showed PCB concentrations comparable to USA levels in year 2000.  相似文献   

17.
Although there is indisputable evidence that long-range atmospheric transport (LRAT) of organic contaminants occurs on a global scale, uncertainties remain about the detailed mechanism and extent of this phenomenon as well as the physical-chemical properties which facilitate LRAT. In this study, we discuss how mass balance models and monitoring data can contribute to a fuller understanding of the mechanism and extent of LRAT. Specifically we address the issues of "grasshopping" or "hopping" (the extent to which molecules are subject to multiple hops as distinct from a single emission-deposition event) and "global fractionation" (the differing behavior of chemicals as they are transported). It is shown that simple mass balance models can be used to assist the interpretation of monitoring data while also providing an instrument that can be used to assess the LRAT potential and the extent of hopping that organic substances may experience. The available evidence supports the notion that many persistent organic pollutants experience varying degrees of "hopping" during their environmental journey and as a consequence become fractionated with distance from source.  相似文献   

18.
This report gives a summary of the historic use, former management and current release of polychlorinated biphenyls (PCBs) in Germany and assesses the impact of the life cycle of PCBs on the contamination of the environment and of food products of animal origin. In Germany 60,000 t of PCBs were used in transformers, capacitors or as hydraulic oils. The use of PCB oils in these “closed applications”, has been banned in Germany in 2000. Thirty to 50% of these PCBs were not appropriately managed. In West Germany, 24,000 t of PCBs were used in open applications, mainly as additive (plasticiser, flame retardant) in sealants and paints in buildings and other construction. The continued use in open applications has not been banned, and in 2013, an estimated more than 12,000 t of PCBs were still present in buildings and other constructions. These open PCB applications continuously emit PCBs into the environment with an estimated release of 7–12 t per year. This amount is in agreement with deposition measurements (estimated to 18 t) and emission estimates for Switzerland. The atmospheric PCB releases still have an relevant impact on vegetation and livestock feed. In addition, PCBs in open applications on farms are still a sources of contamination for farmed animals. Furthermore, the historic production, use, recycling and disposal of PCBs have contaminated soils along the lifecycle. This legacy of contaminated soils and contaminated feed, individually or collectively, can lead to exceedance of maximum levels in food products from animals. In beef and chicken, soil levels of 5 ng PCB-TEQ/kg and for chicken with high soil exposure even 2 ng PCB-TEQ/kg can lead to exceedance of EU limits in meat and eggs. Areas at and around industries having produced or used or managed PCBs, or facilities and areas where PCBs were disposed need to be assessed in respect to potential contamination of food-producing animals. For a large share of impacted land, management measures applicable on farm level might be sufficient to continue with food production. Open PCB applications need to be inventoried and better managed. Other persistent and toxic chemicals used as alternatives to PCBs, e.g. short chain chlorinated paraffins (SCCPs), should be assessed in the life cycle for exposure of food-producing animals and humans.  相似文献   

19.
Polychlorinated biphenyls (PCBs) were banned in the United States in 1979, and since then a significant decline in their release to the environment has been observed. This decline has now reached a plateau. Several new regulatory programs have been put in place to further reduce PCB emissions/releases. However, our ability to measure the effectiveness of these regulatory/voluntary programs and to support regional fate/transport and source/receptor modeling efforts depend on reliable emission information. In this study, we attempt to improve the emission inventory for PCBs by compiling and analyzing the multimedia total PCB emission/release data reported for the U.S Great Lakes states for each year from 1990 to 2000. Although Toxic Release Inventory (TRI), National Emissions Inventory (NEI), Great Lakes Regional Air Toxic Emissions Inventory (GLRATEI), and Integrated Atmospheric Deposition Network (IADN) data formed the basis of estimating air emissions, we used the TRI, National Response Center (NRC), and PCB transformer inventory data to estimate PCB releases to land. We used the Permit Compliance System and NRC data to obtain estimates of PCB discharges to water systems in the Great Lakes states. The Remedial Action Plans for each area of concern were the primary source for estimating PCB loads of dredged sediments. On the basis of the NEI, IADN, and GLRATEI data, the total air emissions within the decade were approximately 126 t. The regionwide discharges to water systems and releases to land in the form of landfills and accidental spills in 1990-2000 were estimated as approximately 170 and 3225 t, respectively. We estimated that approximately 1.3 million t of PCB-contaminated sediment were removed or targeted for removal in five lakes of the U.S. portion of the Great Lakes basin. We stress that these estimates were based on reported amounts and the unreported PCB releases/emissions could result in significantly higher estimates.  相似文献   

20.
Denys S  Gombert D  Tack K 《Chemosphere》2012,88(7):806-812
Fires might be the source of persistent organic pollutants (POPs) such as dioxins, furans (PCDD/Fs) and/or polychlorobiphenyls (PCBs) in the environment. In the perspective of defining legal responsibilities a thorough characterization of the impact of such an event should be carried out. However, such characterization is not easy as the environment integrates both local and diffuse sources of such molecules. Thus, a combined approach, which includes gathering field surveys, modeling and laboratory experiments, should be conducted. The objective of this work is to illustrate different approaches to give sufficient insight to determine the actual impact of wood fire on the environment. The work was carried out at the vicinity of a burnt down parcel. The fired material was a mixture of wood and PCB-contaminated soils as the site was a former pyralene-disposal site. Modeling, soil and lichen sampling and experimental combustion were carried out to delineate the contamination for each chemical and to define the area within the fire that was responsible for the environmental contamination. Concentrations of PCDD/F and PCBs were very high on the burnt plot. The combined approach determined that the furans were the predominant compounds in the smoke emitted by the fire. Based on this tracer, it was possible to demonstrate that in terms of environmental contamination of PCDD/F, the impact of the fire was restricted to a 2 km radius from the burnt down plot. For PCBs, no specific tracer was identified. In this case, the delineation of the impact could only be empirical, based on the total concentration of the chemicals.  相似文献   

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