Levels and homologue profiles of PCDD/Fs in sediments along the Swedish coast of the Baltic Sea

Background, aim, and scope  The primary aim of this study was to explore the variations in PCDD/F levels and homologue profiles of Baltic surface sediments by comprehensively analyzing polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in samples from a large number of sites, encompassing not only previously known hotspot areas, but also sites near other potential PCDD/F sources, in pristine reference areas (in which there was no industrial activity) and offshore sites. Materials and methods  Surface sediment samples (146 in total) were collected at various points along the Swedish coast and offshore areas. In addition, bulk deposition was sampled, monthly, at a single site in northern Sweden during 1 year. The concentrations of tetra- through octa-substituted CDD/Fs were determined in both matrices. Results  Highly elevated concentrations of PCDD/Fs were found at many sites in coastal areas and concentrations were also slightly elevated in some offshore areas. Homologue profiles varied substantially amongst samples from coastal sites, while those from offshore and other pristine sediments were relatively similar. The offshore sediments showed different profiles from those observed in the deposition samples. Sediment levels of PCDD/Fs were not generally significantly correlated to organic carbon levels, except in some pristine areas. Comparison of data obtained in this and previous studies suggest that both their levels and profiles are similar today to those observed 20 years ago in coastal and offshore areas. The only detected trend is that their levels appear to have decreased slightly in the offshore area of the Bothnian Sea. Discussion  The localization of hotspot areas along the coast, the lack of consensus between PCDD/F profiles of sediments and general background, and their weak correlations with organic carbon suggest that PCDD/Fs in the study area largely originate from local/regional emissions. However, due to complicating factors such as sediment dynamics and land upheaval, it is not possible to conclude whether these pollutants derive from recent emissions or from a combination of recent emissions and re-distribution of previous inputs. Conclusions  The results show that: elevated levels of PCDD/Fs are present in both coastal and offshore areas of the Baltic Sea, the major hotspots are close to the shore, and there are large variations in profiles, indicating that local emissions are (or have been) the major causes of pollution. Recommendations and perspectives  In order to identify other hotspot areas and trace sources, comprehensive analysis of PCDD/Fs in surface sediments is needed in all areas of the Baltic Sea that have not been previously investigated. The high levels of PCDD/Fs observed in surface sediments also indicate a need to elucidate whether they are due mainly to current emissions or a combination of recent pollution and re-distribution of historically deposited pollutants. To do so, better understanding of sediment dynamics and present-day inputs, such as riverine inputs, industrial effluents, and leakage from contaminated soil is required. There are indications that contaminated sediments have a regional impact on fish contamination levels. However, as yet there is no statistically robust evidence linking contaminated sediments with elevated levels in Baltic biota. It should also be noted that the Baltic Sea is being massively invaded by the deep-burrowing polychaete Marenzielleria ssp., whose presence in sediments has been shown to increase water concentrations of hydrophobic pollutants. In awareness of this, it is clear that high levels in sediments cannot be ignored in risk assessments. In order to investigate the emission trends more thoroughly, analysis of PCDD/Fs in offshore sediment cores throughout the Baltic Sea is also recommended. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Sources of PCDD/Fs, non-ortho PCBs and PAHs in sediments of high and low impacted transboundary rivers (Belgium-France)

PAHs, PCDD/Fs and non-ortho PCBs have been assessed in Yser and Upper-Scheldt river sediments. Higher contamination levels were observed in the Upper-Scheldt sediments: maximum concentrations for the 16 US-EPA PAHs, PCDD/Fs and non-ortho PCBs respectively amount to 8.9 mg kg⁻¹, 12 ng TEQ kg⁻¹ and 5.1 ng TEQ kg⁻¹. Diagnostic PAH ratios in sediments and atmospheric samples suggest that the PAH compounds are from pyrolytic origin, more specifically combustion processes. The huge consumption of coal in cokes-ovens and smelters and its use for house-heating in Northern France, although decreasing during the last decades, are in support of that suggestion. PCDD/F fingerprints in sediments and deposition material indicate that OCDD is the dominant congener. In addition use of pentachlorophenol (PCP) in the past led to a minor contribution of PCDD/Fs in our sediment samples. Non-ortho PCBs form a substantial fraction of the total TEQ concentrations observed in the sediments. Since the 1980s and 1990s a substantial reduction of the PCDD/F sediment concentrations is observed, but this is not the case for the PAHs.     

Relationship of PCDD/Fs congener profiles between beef and raw milk in South Korea

The relationship between profiles of residual PCDD/Fs in beef and raw milk was examined by measuring concentrations and detected frequencies. Unrelated samples of beef and raw milk were collected from nine regions in South Korea. Congener-specific profiles of PCDD/Fs in beef and raw milk were very similar. PCDFs, particularly 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, and 2,3,4,6,7,8-HxCDF, were dominant congeners in both beef and raw milk suggesting that sources of contamination may not significantly differ nationwide. The profiles of PCDD/Fs in domestic beef and raw milk in this study were closer to the profiles of emission from metal industries although Korea imports over 75% of feedingstuffs. The ratios of PCDF/PCDD in TEQ concentration were more than 5 and 15 in beef and raw milk, respectively. The mean concentrations of PCDD/Fs in 60 samples of beef and 60 samples of raw milk were 0.80 pg WHO-TEQ/g fat and 0.65 pg WHO-TEQ/g fat, respectively. The residual profiles of PCDD/Fs in raw milk resembled that in beef although the congener profiles might change throughout the food chain. This indicated that monitoring of dioxins in milk could provide information for contamination of milk itself or other associated food.     

Levels and congener profiles of PCDD/Fs, PCBs and PBDEs in seafood from China

A nationwide investigation into polychlorinated dibenzo-p-dioxins/furans (PCDD/Fs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) in market seafood was conducted for the first time in this study. Total PCDD/F concentrations in fatty fish ranged from 0.13 to 8.64 pg g⁻¹ wet weight (mean 2.05 pg g⁻¹ wet weight), total PCB concentrations ranged from 38.9 to 3514 pg g⁻¹ wet weight (mean 1133 pg g⁻¹ wet weight), and total PBDE concentrations ranged from 42.8 to 913 pg g⁻¹ wet weight (mean 322 pg g⁻¹ wet weight). Corresponding mean toxicity equivalent (TEQ) values for total PCDD/F and dioxin-like PCB were 0.25 pg g⁻¹ wet weight (WHO 98-TEQ) and 0.32 pg g⁻¹ wet weight (WHO 98-TEQ), respectively. OCDD, PCB-138 and PBDE-47 were the dominant compounds according to their respective congeners. WHO 98-TEQ _{PCDD/PCDF/PCB} for fatty fish and shell fish were 0.60 and 0.070 pg g⁻¹ wet weight, respectively, lower than the standard set by the European Commission. The contamination levels and profiles were compared with those documented in previous publications.     

Identifying source regions for the atmospheric input of PCDD/Fs to the Baltic Sea

PCDD/F contamination of the Baltic Sea has resulted in the European Union imposing restrictions on the marketing of several fish species. Atmospheric deposition is the major source of PCDD/Fs to the Baltic Sea, and hence there is a need to identify the source regions of the PCDD/Fs in ambient air over the Baltic Sea. A novel monitoring strategy was employed to address this question. During the winter of 2006–2007 air samples were collected in Aspvreten (southern Sweden) and Pallas (northern Finland). Short sampling times (24 h) were employed and only samples with stable air mass back trajectories were selected for analysis of the 2,3,7,8-substituted PCDD/F congeners. The range in the PCDD/F concentrations from 40 samples collected at Aspvreten was a factor of almost 50 (range 0.6–29 fg TEQ/m³). When the samples were grouped according to air mass origin into seven compass sectors, the variability was much lower (typically less than a factor of 3). This indicates that air mass origin was the primary source of the variability. The contribution of each sector to the PCDD/F contamination over the Baltic Sea during the winter half year of 2006/2007 was calculated from the average PCDD/F concentration for each sector and the frequency with which the air over the Baltic Sea came from that sector. Air masses originating from the south–southwest, south–southeast and east segments contributed 65% of the PCDDs and 75% of the PCDFs. Strong correlations were obtained between the concentrations of most of the PCDD/F congeners and the concentration of soot. These correlations can be used to predict the PCDD/F concentrations during the winter half year from inexpensive soot measurements.     

PCBs and PCDD/Fs in lake sediments of Grosser Arbersee, Bavarian Forest, South Germany

Despite their environmental importance, there are still relatively few historical studies of the environmental occurrence of polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), especially in middle Europe. Trends in PCBs and PCDD/Fs were, therefore, assessed in lake sediments of the Grosser Arbersee over the past 130 years (1860-1990). Ballschmiter-PCB concentrations (congeners # 28, 52, 101, 138, 153, 180) increased between 1946 and 1972 from 4.2 to 32.0 microg kg(-1) dry wt, but have since decreased to 25.6 microg kg(-1) dry wt. High chlorinated PCB congeners reached their maxima earlier (1968-1972) than low chlorinated congeners (1985-1991). These trends were consistent with patterns expected from the production and use of PCBs and their precursors. PCDD/F concentrations increased between 1950 from 0.6 microg kg(-1) dry wt to 2.3 microg kg(-1) dry wt in 1977, falling to 1.7 microg kg(-1) dry wt by 1993. PCDF concentrations exceeded those of PCDD until 1968, but afterwards PCDDs (especially OCDD) were predominant. These patterns suggest that domestic heating and waste combustion were the most likely sources, but pollution from local industries, such as metal smelting and glass production, might also have been involved. The data provide a valuable case study from central Europe which confirms the overall declining trends of PCB and PCDD/F contamination shown elsewhere.     

Historical trends of PCDD/Fs and dioxin-like PCBs in sediments buried in a reservoir in Northern Taiwan

Polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofuran (PCDF) and polychlorinated biphenyl (PCB) concentrations were analyzed at 1-2cm intervals in a sediment core collected from a reservoir in Northern Taiwan to evaluate the organic pollution history. The highest PCDD/F (14.4ng TEQ/kg d.w.) and PCB (0.261ng TEQ(WHO)/kg d.w.) concentrations were determined at 13-15cm (estimated year: 1992). The ages of the levels of sediment core were estimated from the sedimentation rate. Analysis results demonstrate that the PCDD/F concentration of the sediment core measured in the reservoir reached their peak when the municipal waste incinerators (MWIs) in the area started to operate. Furthermore, the decrease in sediment core PCDD/F concentration is related to the time of enforcement of the PCDD/F emission limit set by the Environmental Protection Administration (EPA) in Taiwan. Significant distribution of OCDD in homologue profiles was noted in archived soil samples in Taiwan in which the major input of PCDD/Fs was thought to be atmospheric. Major PCB congeners found in the sediment core were the major components of the commercial PCB products. Input fluxes of PCDD/Fs (5.75-158ng-I-TEQ/m(2)-yr) and PCBs (0.248-3.71ng TEQ(WHO)/m(2)yr) into the reservoir of interest are also calculated from the concentration and sedimentation rate of the sediment. The results reveal that considerable amounts of PCDD/Fs and PCBs were carried into the reservoir of interest in the flood stage but not during normal stage.     

二(噁)(口英)样品制备与检测技术进展

环境中存在的二噁是一类严重影响食品安全和人类健康的强毒性有机污染物,为了能正确评价这类化合物的来源与环境中分布情况,二噁的分析检测引起了人们强烈的关注。本文介绍了样品检测前处理纯化过程中所用的各种传统的吸附剂(硅酸盐、佛罗里土和活性炭等)和新发展的几种主要吸附剂(2(1芘基)乙基二甲基硅烷化硅胶(PYE)、炭纳米管和多孔石墨炭等)的性能、在样品前处理过程中所起的作用及存在的问题和发展趋势,并在概括样品制备的基础上,阐述了二纯化技术及其检测方法(包括化学分析法和生物分析法)的进展。     

Levels and congener profiles of PCBs and PCDD/Fs in blue shark (Prionace glauca) liver from the South-Eastern Mediterranean Sea (Italy)

Liver of blue shark (Prionace glauca) specimens from the South-Eastern Mediterranean Sea were analyzed for the presence of polychlorinated biphenyls (PCBs), including coplanar congeners, polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs). PCBs were the dominant chemicals, followed by PCDFs and PCDDs. The pattern of PCB congener concentrations in the hepatic tissue was dominated by higher chlorinated compounds. The specific profile of toxic PCDD/F congeners was characterized mainly by 2,3,7,8-TCDF and 2,3,7,8-TCDD, followed by 1,2,3,6,7,8-HxCDD and 2,3,4,6,7,8-HxCDF. The total 2,3,7,8-TCDD toxic equivalent (TEQs) was 149 pg g⁻¹ lipid wt. The profile of TEQ shows that PCDDs present the greatest risk to this species contributing to total toxicity with a percentage approximately of 60%, while the contribution of PCDFs and DL-PCBs is almost the same being 22.4% and 21.6%, respectively. Further investigations are urgently needed to characterize the PCDD/Fs contamination levels not only in elasmobranch fish but in all Mediterranean marine biota.     

Distribution patterns of PCDD/Fs in chlorinated chemicals

The purpose of this research was to determine polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) in five chlorinated chemicals (phthalocyanine copper, phthalocyanine green, chloranil-1 and 2, and triclosan), and to compare their 2,3,7,8-tetrachlordibenzo-IpI-dioxin equivalents (TEQ). The distribution patterns of total PCDD/Fs and 2,3,7,8-substituted PCDD/Fs were elucidated in detail. The TEQ values of toxic PCDD/Fs in all chemicals were in the range of 5.03-1379.55 ng I-TEQ/kg. The contribution of OCDD and OCDF in phthalocyanine green was 75% of the total TEQ. For chloranils, the maximum contribution of toxic PCDD/Fs was from 2,3,7,8-substituted HxCDF and 2,3,7,8-substituted HpCDF. The TEQ of HxCDF and HpCDF in chloranil-1 was 90% and in chloranil-2 was 71%. And the toxic contribution increased with the degree of chlorination for PCDFs.     

Optimization of selective pressurized liquid extraction for extraction and in-cell clean-up of PCDD/Fs in soils and sediments

This paper describes the development of methods for selective extraction of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) from soils and sediments, using pressurized liquid extraction with in-cell clean-up (SPLE). Two binary solvent mixtures, viz. dichloromethane/n-heptane (DCM/Hp), and diethylether/n-heptane (DEE/Hp), were evaluated. The SPLE extraction conditions were optimized using central composite face (CCF) design. Three factors were investigated: extraction temperature (60–160 °C), number of extraction cycles (1–3) and time per cycle (2–18 min). The results showed that DCM/Hp (1/1, v/v) and DEE/Hp (1/2, v/v) were the best extraction solvent compositions and that the extraction temperature was a critical factor that needed careful optimization to achieve high extraction efficiency without co-extraction of sulfuric acid. Under the optimal conditions, the SPLE methods provided results with good accuracy and precision. For the sandy soil certified reference material (CRM-529) the quantification results ended up in the range 82–110% as compared to the concentrations obtained by a reference method based on Soxhlet extraction and external column clean-up. Furthermore, for a clay soil (CRM-530) and a sediment reference material (WMS-01), the accuracy (trueness) of the TEQ values were +11% (DCM/Hp) and +8% (DEE/Hp) for CRM-530, +8% and ?7% for WMS-01, respectively. The individual congener concentrations also agreed well with the certified values. These findings show that SPLE is a promising method for combined extraction and clean-up of PCDD/Fs in soil/sediment samples.     

Congener profiles of PCDD/Fs in soil and vegetation samples collected near to a municipal waste incinerator

Recently, we measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in soil and herbage samples collected in the vicinity of a municipal solid waste incinerator (MSWI) from Tarragona (Catalonia, Spain). Since these concentrations could be increased by the presence of other emission sources of PCDD/Fs in the same area in which the MSWI is placed, the main goal of the present study was to determine the PCDD/F congener profiles in the soil and vegetation samples collected in 1996 and again in 1997 near to the facility and to compare with those from samples collected in a close area outside of direct emissions of the plant. From an accurate inspection of the PCDD/F congener profiles, it was concluded that PCDD/F emissions from the MSWI here examined are neither the only nor the main responsible for the presence of PCDD/Fs in the samples of environmental matrices collected in the area under direct influence of the plant.     

Phytoremediation to increase the degradation of PCBs and PCDD/Fs

Phytoremediation is already regarded as an efficient technique to remove or degrade various pollutants in soils, water and sediments. However, hydrophobic organic molecules such as PAHs, PCBs and PCDD/Fs are much less responsive to bioremediation strategies than, for example, BTEX or LAS. PCDD/Fs and PCBs represent 3 prominent groups of persistent organic pollutants that share common chemical, toxicological and environmental properties. Their widespread presence in the environment may be explained by their chemical and biological stability. This review considers their fate and dissipation mechanisms. It is then possible to identify major sinks and to understand biological activities useful for remediation. Public health and economic priorities lead to the conclusion that alternative techniques to physical treatments are required. This review focuses on particular problems encountered in biodegradation and bioavailability of PCDD/Fs and PCBs. It highlights the potential and limitations of plants and micro-organisms as bioremediation agents and summarises how plants can be used to augment bacterial activity. Phytoremediation is shown to provide some new possibilities in reducing risks associated with dioxins and PCBs.     

Sedimentation of PCDD/Fs and PCBs in the Gulf of Finland and the Gulf of Bothnia,the Baltic Sea

Sediment trap material was collected during May–December in the period 1996–2008 in three coastal areas and four open sea stations in the Finnish territory of the Baltic Sea. The highest sedimentation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) with a typical source-related congener profile from chlorophenol production dominated by highly chlorinated dibenzofurans was found close to a historical source in the Kymijoki estuary. This was an order of magnitude higher than in other river estuaries and two orders of magnitude higher than in the open sea stations. The sedimentation of polychlorinated biphenyls (PCBs) was also higher in river estuaries than in other areas. No significant decrease over a 12 year period of monitoring was found in concentration or in sedimentation in the Kymijoki estuary. In the western Gulf of Finland, the Archipelago Sea and the Gulf of Bothnia, the dominating congeners, calculated as toxic equivalent (TEQ) in sedimentation were 1, 2, 3, 7, 8-PeCDD and 2, 3, 4, 7, 8-PeCDF, often reported as the main congeners in deposition.     

Formation and mitigation of PCDD/Fs in iron ore sintering

The sintering of iron ore is presently a significant industrial source of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) worldwide owing to the fundamental requirement of the operation of a high temperature process to pre-treat fines and to recycle plant by-products arising from the integrated iron and steelworks. The process is a noteworthy contributor of PCDD/F indirectly due to decreasing PCDD/F releases from municipal solid waste incineration. Commonly PCDD/F formation from the process is associated with the addition of oily mill scales although raw material containing a combination of C, Cl and specific metal catalyst has been shown to drastically increase PCDD/F formation in the process. The degenerate graphitic structure of carbon present in coke fuel and soot formed and the chemistry of catalytic metals and Cl are important factors. A review on PCDD/F emission in this process has been carried out, including examination of its formation mechanism, congener distribution, contributing factors and mitigation strategies, with emphasis on the use of inhibiting compound to achieve suppression. A detailed analysis of the de novo and precursor theories of formation and the contributing factor is given since the subject of PCDD/F formation is still controversial. The de novo formation pathway identified in sinter plants and controlled studies performed in the laboratory as well as at pilot-scale are discussed; where appropriate, a comparison is drawn between sintering and other thermal processes emitting PCDD/Fs. Summary of the latest developments in PCDD/F downstream abatement strategies presently employed in full scale industrial plants is provided. Potential inhibiting compounds are discussed in terms of their mode of action and merits under sintering conditions.     

PCDD/Fs and PCBs in Baltic herring during the 1990s

Baltic herring samples caught from the Baltic Sea during the spring periods of 1993-1994 and 1999 were analysed for polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and polychlorinated biphenyls (PCB). For analyses, 1570 individual herring were combined to 120 pools. Correlations between concentrations of congeners 1,2,3,7,8-PeCDD, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF, and 2,3,4,6,7,8-HxCDF, and age of herring were the strongest (r>0.8) followed by correlations between PCB congeners PCB 105, 118, 126, 156, 169 and 180 (r>0.7), and age of herring. Due to higher fat percentage in herring in the Gulf of Bothnia the concentrations of PCDD/Fs and PCBs on fresh weight (fw) basis were higher than in herring in the Gulf of Finland. The concentrations of WHO(PCDD/F)-TEQs ranged from 1 to 27 pg/g fw, depending on the age and catchment area of herring, and concentrations of WHO(PCB)-TEQs reached 32 pg/g fw. Between the two studied time points no clear downward trend in concentrations was observed.     

PCDD/Fs in sprat (Sprattus sprattus balticus) from the Gulf of Finland, the Baltic Sea

The concentrations and congeners pattern of the polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were determined in sprat collected by the commercial catches in the Gulf of Finland, Baltic Sea. Based on the toxic equivalent concentrations 2,3,4,7,8-PeCDF prevailed among the congeners of PCDD/Fs. The significance of age- and season-specific relationship between the concentration of lipids and dioxins was demonstrated. On lipid weight basis the concentration of PCDDs was significantly higher in spring than in autumn. This difference was not statistically significant for PCDFs. On lipid weight basis the concentration of dioxins decreased with rising content of lipids. PCDD/Fs toxic equivalent concentration increased with the age of sprat exceeding the EU maximum limit value at more than 5-year-old fish.     

Evaluation of PCDD/Fs characterization in animal feed and feed additives

Safety control of feed and feed additives is necessary to have safe food of animal origin. Based on media reports, nine incidents regarding dioxins and/or PCBs contaminations occurred worldwide during the last decade. Korea is a country which imports feed and feed additives. In this study, various kinds of feed and feed additives were analyzed to monitor the contamination level of dioxins. The level of PCDD/Fs in fish oil was the highest with a concentration of 23.33ngkg(-1), which is equivalent to a toxicological concentration of 4.68ngWHO-TEQ/kg. Feed from animals origin such as chicken meal, animal fat, fish meal, fish oil, and shell powder showed relatively higher concentrations of PCDD/Fs. Feed from plants origin, minerals, and additives ranged from non-detects for bit pulp and ethoxyquin to 8.28ngkg(-1) for dl-methionine. From a toxicological point of view, the highest concentration in vitamins was 0.08ngWHO-TEQ/kg among the feed additives. 2,3,4,7,8-PeCDF was the dominant congener in samples of fish oil, fish meal, and shell powder. Animal fat showed that the pattern of PCDD/Fs depends on the sources of contamination. A sample of animal fat showed 1,2,3,4,7,8-HxCDF and the other sample showed 1,2,3,4,7,8-HxCDD as a primary congener. Generally, low levels of PCDDs were detected in feed additives. Patterns of PCDD/Fs in choline chloride were different with that in choline chloride from an incident in Europe in 2000.     

Survey of PCDD/Fs and non-ortho PCBs in UK sewage sludges

A survey of PCDD/F and non-ortho PCB concentrations in the mesophilic, anaerobically digested sludge of 14 UK wastewater treatment works was carried out. The range of total Cl1-Cl8DD/F concentrations in the sludges was 8880-428000 pg/g dw with a median of 23300 pg/g dw. The concentrations of the three non-ortho PCBs were in the range 272-63000 pg/g dw with a median of 695 pg/g dw. The PCDD/F I-TEQs of the sludges studied were comparable to those published in the literature with a range of 20-225 pg I-TEQ/g dw and a median of 40.4 pg/g dw. The non-ortho PCBs usually added 2-7 pg/g to the total TEQ with one notable exception which increased the TEQ value 20-fold. With three exceptions, the PCDD/F content of the sludges fell well below the draft EU limit values proposed on 27 April 2000. The homologue group pattern of the PCDD/Fs is dominated by the HpCDDs and OCDD and is consistent with that found in most sewage sludges. There appears to be no correlation between the degree of industrial input and the PCDD/F concentration. This suggests that trade effluent is not always the most significant source of PCDD/Fs to wastewater in the UK.     

PCDD/Fs emissions inventory in the Lombardy Region: results and uncertainties

The results of an assessment study of both industrial and non-industrial dioxin and furan (PCDD/Fs) emissions in the Lombardy Region (Italy) are outlined below. The main data source refer to 1997, and are compiled from the Lombardy Emissions Inventory (developed under the framework of the Regional Air Quality Plan) together with documented emissions factors available. Due to the uncertain nature of the emissions assessment, results are provided as a most probable value within a given range. Total PCDD/Fs emissions in Lombardy average 33 g I-TEQ y(-1), ranging from minimum 13 g I-TEQ y(-1) to maximum 88 g I-TEQ y(-1). The main PCDD/Fs sources are waste incineration, electric arc furnace for steel production, vehicle diesel combustion and residential wood combustion. Incineration emission factors are expected to decrease over the period 2005-2010, in compliance with legal requirements. This will prioritize control over the remaining main PCDD/Fs contributors. Due to limited information available concerning this data, the accuracy of which is uncertain, further research is needed to evaluate the future role of these sources.