Carry-over of dioxins and PCBs from feed and soil to eggs at low contamination levels - influence of mycotoxin binders on the carry-over from feed to eggs

Laying hens were fed with compound feed containing six different levels of dioxins, dioxin-like PCBs and indicator PCBs for a period of 56 days. This was followed by a period of 56 days on clean feed. Dioxin levels in feed varied from background levels to three times the current EU tolerance limit of 0.75 ng TEQ/kg. At all dose levels a rapid increase was observed in the dioxin levels in eggs. There was a clear linear dose-response relationship between the dioxin levels in eggs and feed. The feed containing 0.4 ng TEQ dioxins per kg resulted in egg levels just above the EU limit of 3 pg TEQ/g fat. Dioxin-like and indicator PCB residues followed a pattern very similar to that of dioxins. Exposure to the highest indicator PCB level of 32 µg/kg resulted in egg levels around 300 ng/g fat. Exposure to dioxins through contaminated soil, mixed at 10% into the feed, resulted in a similar carry-over as from feed. Mycotoxin binders, mixed at 0.5% into the feed, had little effect on the carry-over of dioxins from the feed to the egg. It can be concluded that consumption of feed or soil with even moderate levels of dioxins and dioxin-like PCBs rapidly results in increased levels in eggs. The current EU dioxin limit for feed cannot guarantee egg dioxin levels below the EU-limit.     

Probabilistic intake assessment and body burden estimation of dioxin-like substances in background conditions and during a short food contamination episode.

The objective was to perform a dioxin body burden estimate based on a probabilistic intake assessment of PCDDs, PCDFs and dioxin-like PCBs because of the so-called 1999 'Belgian dioxin incident'. Monte Carlo simulation techniques were used to combine detailed 7-day food intake data on the individual level from a sample of 14-18-year-old adolescents with 'background' and 'incident-related' food contamination data. In background conditions, 3% of the adolescents had an intake <1 pg TEQ kg(-1) bw day(-1), while 85% had <4 pg TEQ kg(-1) bw day(-1). Milk and other dairy products were the basic source of dioxin-like contaminants, while fish constituted the main source at the higher percentiles of intake. During the dioxin incident, the estimated median dioxin intake showed a moderate increase. At the 99th percentile, the highest intake level, and the 95% upper bound uncertainty level, peak body burden-23.73 ng TEQ kg(-1) bw-remained below body burdens that in the experimental animal or in man are accompanied by a population-based observable increase in the incidence of adverse effects. The 1999 Belgian dioxin incident most likely did not affect public health in Belgium in a measurable way, although exceptions remain possible on the individual level.     

Sex, BMI and age in addition to dietary intakes influence blood concentrations and congener profiles of dioxins and PCBs

Scope: The aim of this study was to i) characterize dietary polychlorinated biphenyls (PCBs) and dioxin exposure in consumers of fish from the PCB contaminated Lake Mjøsa in Norway ii) examine the influence of demographic factors on blood concentrations and congener composition of dioxins and PCBs, iii) characterize dietary sources and possible exposures above tolerable intake. Methods and results: Blood samples were analysed for dioxin‐like (dl) compounds (PCDD/Fs and dl‐PCBs) and non‐dl‐PCBs (ndl‐PCBs). Dietary exposures were calculated using food frequency questionnaires (n=64). Men had higher median intake of dl‐compounds than women (1.2 and 0.85 pg TEQ/kg bw/day), but similar blood concentrations (23.3 and 25.8, pg TEQ/g lipid weight (lw)). For non‐dl‐PCBs, intakes (6.5 and 4.5 ng/kg bw/day) and blood concentrations (381 and 224 ng/g lw) were higher in men than in women. Blood concentrations correlated with dietary intakes in men only. Increasing BMI and age elevated blood concentrations mainly in women. Men and women had different blood congener profiles, with a higher share of PCB‐126 in women, despite similar dietary congener profiles. Eleven participants exceeded the tolerable intake for dl‐compounds. Fish from Lake Mjøsa was the main dietary source. Conclusion: The higher influence of BMI and age for women than for men may have implications for risk assessment.     

Dietary intakes of polychlorinated dibenzo-p-dioxins, dibenzofurans and dioxin-like polychlorinated biphenyls in Spain.

Congener-specific analyses of seventeen 2,3,7,8-substituted PCDD/Fs, three non-ortho and 8 mono-ortho dioxin-like polychlorinated biphenyls (PCBs) were performed on 258 Spanish foodstuff samples, mainly of animal origin, for 2000--03. Daily dietary intakes of PCDD/Fs and PCBs, expressed as toxic equivalents (WHO-TEQs), were estimated by combining food consumption data from the Spanish National Institute Statistics survey and concentration levels measured in individual samples, using upper bound determination values (not detectable = limit of detection). The calculated dietary intake of PCDD/Fs for a person weighing 70 kg was 1.35+/-0.11pg WHO-TEQs kg(-1) bw day(-1), and 3.22+/-0.75 pg WHO-TEQs kg(-1) bw day(-1) if dioxin-like PCBs (non- and mono-ortho PCBs) were included, showing the importance of their inclusion in monitoring studies. Both values were within the range of tolerable daily intake (TDI) proposed by the WHO (1-4pg WHO-TEQs kg(-1) bw day(-1)). The current levels are lower than earlier intakes estimates conducted in Spain. Meat and meat products accounted for more than 35% of the intake, followed by milk and milk products (29%), vegetables oils (19%), fish and seafood (11%) and eggs (4%). Dioxin-like PCBs are an important component in the total WHO-TEQs in foodstuffs. This is particularly true for the fish food group, where the total WHO-TEQs is dominated by dioxin-like PCBs (up to 80% of WHO-TEQs in some cases).     

Surveillance of dioxins and polychlorinated biphenyls (PCBs) in food commercialized in Barcelona,Spain

This study explored the potential use of seven congeners of polychlorinated biphenyls (PCBs-7) as indicator compounds for the presence of dioxins and PCBs in food samples, as part of the routine surveillance programme of a public health agency. Samples of 24 foodstuffs with high fat content were collected (ten fresh fish, six dairy products, five meat and three eggs). Duplicate analyses were performed. A research laboratory tested samples for seven polychlorinated dibenzo-p-dioxin (PCDDs), ten dibenzofurans (PCDFs) and twelve dioxin-like PCBs, with limits of detection in the range of ng kg^?1 (ppt). The public health services official control laboratory tested samples for PCBs-7, with a limit of quantification of 5 µg kg^?1 (ppb). The research laboratory detected the presence of dioxins and dioxin-like PCBs in all samples; fish samples had the highest levels (0.04–10.3 pg WHO-TEQ g^?1). The public health service official control laboratory detected PCBs-7 only in five samples, which were all fish. Comparing the results in the two laboratories there seems to be an association between the detection of PCB-7 and the presence of higher levels of PCDD/Fs and dioxin-like PCBs. The use of PCB-7 as an indicator compound may be a practical surveillance strategy for those foodstuffs with higher concentrations of dioxin-like congeners.     

Changes in concentrations of dioxins and dioxin-like PCBs during processing of fish

Fish among meat and dairy products mainly contribute to the human exposition with dioxins and dioxin-like PCBs. Contaminant levels of fish are mainly determined in the edible part of the raw material. In Germany fish are not consumed raw but industrially processed to manifold products and cooked, fried or deep-fried in household. To study the influence of processing on the contaminant levels, changes of dioxins and partly of dioxin-like PCBs were followed during canning of herring fillets, hot smoking of mackerel fillets and Greenland halibut cutlets and during sugar salting of beheaded whole herring. The hot smoking process and sugar salting of herring led to an increase of the dioxin content in the edible part of the final product. The increase was related to the loss of water during processing whereas the fat and thus the lipophilic dioxins remained in the muscle meat. For sugar salting also changes of dioxin-like PCB levels were followed and the same effect was observed. Otherwise the production of canned herring fillets in tomato sauce led to a “dilution” of the dioxin content due to the addition of the sauce.     

Long-term daily intake estimates of polychlorinated dibenzo-p-dioxins and furans,polychlorinated biphenyls and polybrominated diphenylethers from food in Finnish children: risk assessment implications

Food is contaminated by polychlorinated dibenzo-p-dioxins and furans (PCDD/F), polychlorinated biphenyls (PCB) and polybrominated diphenylethers (PBDE) worldwide. Previous data show elevated intakes in children. We determined intakes of POPs in Finnish children. Because no children-specific safe limit values exist, we used tolerable daily intakes (TDIs) set for adults by international expert bodies to examine the proportion of the study population that exceed those limits. We utilised dietary monitoring data with food consumption of Finnish boys and girls aged 1–6 years, measured the contaminant concentrations in all the main food items and calculated age-specific contaminant sum and congener-specific long-term daily intake levels. Our food intake and contaminant data correspond to years 2002–2005. The long-term upper-bound dioxin intakes ranged between 0.1 and 12.8?pg WHO_PCDD/F-PCB-TEQ/kg bw/d (min and max). An immediate TDI for WHO_PCDD/F-PCB-TEQs of 4.0?pg/kg?bw/d were exceeded by 2.5%–7.5% of the children. PBDE long-term upper-bound intake was between 0.1 and 5.8?ng/kg bw/d (min and max). Congener-specific analyses indicated a typical Finnish adult exposure pattern of the children to PCDD/Fs, PCBs and PBDEs. The highest POP intakes were observed in children aged 3 years. Long-term daily PCDD/F, PCB and PBDE intakes among Finnish children varied greatly between individuals and ages. In each age group of the study population, there was a proportion of children with their WHO_PCDD/F-PCB-TEQ intake exceeding considered safe limits set for adults. Based on the exposure profile reported herein, children should be clearly considered as a specific sub-population in food-mediated contaminant risk assessment.     

Role of dietary patterns for dioxin and PCB exposure

Dietary patterns were related to intake and blood concentrations of polychlorinated dibenzo‐p‐dioxins and dibenzofurans (PCDD/PCDFs), dioxin‐like polychlorinated biphenyls (dl‐PCBs) and selected non‐dioxin‐like‐PCBs (ndl‐PCBs). Intake calculations were based on an extensive food frequency questionnaire and a congener‐specific database on concentrations in Norwegian foods. The study (2003) applied a two‐step inclusion strategy recruiting representative (n=73) and high consumers (n=111) of seafood and game. Estimated median intakes of sum PCDD/PCDFs and dl‐PCBs of the representative and high consumers were 0.78 and 1.25 pg toxic equivalents (TEQ)/kg bw/day, respectively. Estimated median intakes of ndl‐PCBs (sum chlorinated biphenyl (CB)‐28, 52, 101, 138, 153, 180) were 4.26 and 6.40 ng/kg bw/day. The median blood concentrations of PCDD/PCDFs/dl‐PCBs were 28.7 and 35.1 pg TEQ/g lipid, and ndl‐PCBs (sum of CB‐101, 138, 153 and 180) 252 and 299 ng/g lipid. The Spearman correlations between dietary intake and serum concentration were r=0.34 (p=0.017) for dl‐compounds and r=0.37 (p<0.001) for ndl‐PCBs. Oily fish was the major source of dl‐compounds and ndl‐PCBs in high and representative consumers. Four dietary patterns were identified by principal component analysis. Two were related to high intakes, one dominated by oily fish ((Ω‐3)), the other by fish liver and seagull eggs (“northern coastal”). Only the latter was closely associated with high blood concentrations of dioxins and PCBs.     

Polychlorinated biphenyls (PCBs), dioxins and furans (PCDD/Fs): Occurrence in fishery products and dietary intake

Concentrations and congener specific profiles of PCBs, PCDDs and PCDFs were determined in various edible fish from the Adriatic Sea. PCBs were the dominant chemicals (116–1980 ng g⁻¹ lipid wt), followed by PCDFs (ND-58.3 pg g⁻¹ lipid wt) and PCDDs (ND-20 pg g⁻¹ lipid wt). The levels of these contaminants varied among species. Benthic organisms possessed the highest concentrations, followed by demersal and pelagic fish species. PCB and PCDD/F accumulation pattern in the samples analysed showed a distribution typically reported for marine samples. The mean weekly intake of toxic equivalency (TEQ) was estimated to be 0.84 pg TEQs/kg bw/week. The dioxin-like PCBs accounted for more than 77% of this intake, followed by PCDDs (15.5%) and PCDFs (13.1%). In general, the samples analysed in this survey can be considered safe with regard to the levels obtained and the in-force legislation, nevertheless the consumption of some species may be of significance importance for consumer health.     

Dietary intake of dioxins in Japan in 2016 with time trends since 1998

Total diet samples collected from seven regions throughout Japan in 2016 were analysed for polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and dioxin-like polychlorinated biphenyls (DL-PCBs), known collectively as dioxins. This led to estimates of the latest dietary intake of these contaminants for the general Japanese population (≥1 year old). The average daily intake of dioxins for a person weighing 50 kg, calculated at non-detected congener concentrations assumed to be equal to zero, was estimated to be 0.54 pg TEQ (toxic equivalents) kg^?1 body weight (bw) day^?1. This value is well below the tolerable daily intake of 4 pg TEQ kg^?1 bw day^?1 for dioxins in Japan. The average intake was highest from fish and shellfish, followed by meat and eggs. The TEQ contribution of the fish and shellfish group to the total dietary TEQs was significant (89%). The DL-PCBs accounted for about 67% of the dioxin intake. The latest dioxin intake level was compared with previous estimates from total diet study results obtained annually since 1998 to determine the time trends in the dietary intake of dioxins in Japan. Overall, the average dioxin intake appeared to be decreasing gradually during the period of study. The previous average intakes of dioxins ranged from 0.58 to 1.9 pg TEQ kg^?1 bw day^?1. The latest average intake was the lowest since 1998 and was about one-third of the average intake in 1998. This decreasing trend in the dietary intake of dioxins was mainly influenced by the decreased dioxin intakes from two food groups, fish and shellfish, and meat and eggs.     

Polychlorinated biphenyls, hexachlorobenzene, hexachlorocyclohexane isomers, and pesticide organochlorine residues in cod-liver oil dietary supplements

Levels of polychlorinated biphenyls (PCBs), hexachlorobenzene, hexachlorocyclohexane isomers (alpha, beta, gamma), and chlorinated pesticides (DDTs) in cod-liver oil used as a dietary supplement were determined. Total PCB and DDT concentrations varied from 25 to 201 ng g(-1) lipid weight basis and from 25 to 133 ng g(-1) lipid weight basis, respectively. Hexachlorobenzene contributed very little to the overall contaminant burden of dietary supplement oils, whereas hexachlorocyclohexane isomers were below the instrumental detection limits in all samples. The daily intake of PCBs and DDTs derived by the consumption of cod-liver oil at manufacturer-recommended doses varied from 0.004 to 2.01 microg/day and from 0.004 to 1.24 microg/day, respectively. Relative to some dioxin-like PCB congeners (mono-ortho PCB 105, 118, and 156; non-ortho PCB 77, 126, and 169), the intakes calculated varied from less than 0.001 to 0.74 pg of toxic equivalency values (TEQ) per kg of body weight per day. These values, although below the range of 1 to 4 pg of TEQ per kg of body weight per day set by the World Health Organization, emphasize the need for strict and continuous monitoring of fish oil contamination to reduce, as much as possible, the risks to human health.     

Tracing and analytical results of the dioxin contamination incident in 2008 originating from the Republic of Ireland

High levels of dioxins (PCDD/Fs) in pork were discovered in France and the Netherlands at the end of 2008. The contamination was rapidly traced back to a feed stock in the Republic of Ireland (RoI). Burning oil, used for the drying of bakery waste, appeared to be contaminated with PCBs. Consequently, very high levels up to 500?pg?TEQ?g^?1 fat were found in pork. The congener pattern clearly pointed to PCB-oil as a source, but the ratio between the non-dioxin-like indicator PCBs (PCBs 28, 52, 101, 138, 152 and 180) and PCDD/Fs was much lower than observed during the Belgian incident, thereby limiting the suitability of indicator PCBs as a marker for the presence of dioxins and dioxin-like PCBs. This paper describes the tracking and tracing of the incident, the public–private cooperation, the surveillance activities and its results. A major lesson to be learned from this incident is the importance of good private food safety systems. In this incident, it was the private surveillance systems that identified the origin of contamination within 10 days after the first signal of increased dioxin levels in a product. On the other hand, retrospective analyses showed that signals were missed that could have led to an earlier detection of the incident and the source. Above all, the incident would not have occurred when food safety assurance systems had been effectively implemented in the involved feed chain. It is discussed that besides primary responsibility for effective private food safety systems, the competent authorities have to supervise whether the food safety procedures are capable of coping with these kinds of complex food safety issues, while private food companies need to implement the law, and public authorities should supervise and enforce them. Finally, it is discussed whether the health risks derived from consumption of the contaminated batches of meat may have been underestimated during the incident due to the unusually high intake of dioxins.     

Dioxins, dioxin-like PCBs and non-dioxin-like PCBs in dairy products on the German market and the temporal tendency in Schleswig-Holstein

Levels of polychlorinated dibenzodioxins and dibenzofurans, dioxin-like polychlorinated biphenyls (PCBs) and non-dioxin-like PCBs were measured in 140 dairy products collected in 2006 from different regions of Germany. The samples (a total of 66 cheese, 23 butter and 51 curd products) were taken from super markets and retail stores on the basis of production volumes in different states of the Federal Republic of Germany. The dioxin and total WHO-TEQ concentrations of all 140 samples were clearly below the EU limits of 3?pg WHO-polychlorinated dibenzo-p-dioxin (PCDD)/F-TEQ/g fat and 6?pg WHO-PCDD/F-PCB-TEQ/g fat, as laid down in the EU regulation No 199/2006. Dioxin concentrations ranged from low 0.07 to 0.53?pg WHO-PCDD/F-TEQ/g fat with a mean value of 0.19?pg WHO-PCDD/F-TEQ/g fat. The WHO-TEQ concentrations (PCDD/F?+?dl-PCBs TEQ) ranged from 0.21 and 2.1?pg WHO-TEQ/g fat with an average value of 0.76?pg WHO-TEQ/g fat. Significant differences of the WHO-TEQ contamination levels at regional level and between the different product groups could not be identified. The temporal tendency of dioxin concentrations in butter and cheese from Schleswig-Holstein was studied over the past 13?years that showed a decrease by more than 50?% from 0.43 to 0.19?pg WHO-PCDD/F-TEQ/g fat.     

The use of the DR CALUX bioassay and indicator polychlorinated biphenyls for screening of elevated levels of dioxins and dioxin-like polychlorinated biphenyls in eel

The DR CALUX bioassay is a very suitable screening method for dioxins and dioxin-like-PCBs in feed and food. This was, e. g. demonstrated in a survey in the Netherlands to control the dioxin levels in eel. The DR CALUX assay, but also indicator polychlorinated biphenyls (PCB) were evaluated as a screening method. Based on the limit for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/F) [at that time 8 pg toxic equivalents (TEQ)/g eel], and the relation between PCDD/F and dioxin-like-PCB, a decision limit of 30 pg TEQ/g eel was used for screening of 153 field samples. Suspected samples (21) and part of the higher contaminated negative samples (35) were analyzed by GC/MS for dioxins, non-ortho, mono-ortho and indicator PCB, revealing 13 samples exceeding the action limit of 30 pg TEQ/g eel. Only one sample slightly exceeded the dioxin level of 8 pg TEQ/g eel. The relatively low sensitivity for mono-ortho PCB was overcome by the use of reference samples, as shown by the correlation of 0.93 between GC/MS and CALUX determined total TEQ levels. The present data show that the DR CALUX assay can be used for screening of total TEQ levels in eel. The use for dioxins only requires a safe, and therefore relatively low, decision limit. The indicator PCB also showed a good correlation with total TEQ levels, mainly due to the large contribution of the mono-ortho PCB at higher concentrations. The relation with dioxins was very poor and as such indicator PCB seem less suitable than the DR CALUX assay for screening for dioxins only. The present study clearly shows that part of the wild eel samples contains high total TEQ levels and will exceed the future European Union limit of 12 pg TEQ/g eel for dioxins and dioxin-like PCB. Especially at high TEQ levels, dioxin-like PCB contribute most to the total TEQ. In practice, wild eel presents only a minor part of the eel consumed.     

Risk assessments of polychlorinated dibenzo- p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in food

The polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF), and dioxin-like polychlorinated biphenyls (dioxin-like PCB) are ubiquitous in food of animal origin and accumulate in fatty tissues of animals and humans. The most toxic congener is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The toxic responses include dermal toxicity, immunotoxicity, carcinogenicity, and reproductive and developmental toxicity. Toxic equivalency factors have been established for the other PCDD, PCDF and dioxin-like PCB relative to TCDD, and the combined toxicity of a sample can be expressed as toxic equivalent (WHO-TEQ). The EC Scientific Committee for Food evaluated these compounds in 2001. The assessment used the most sensitive adverse toxicological end-points of TCDD in experimental animals. These were developmental and reproductive effects in the male offspring of rats administered TCDD during pregnancy. Because of the large difference between rats and humans in the biological half-life of TCDD, the assessment used a body burden approach to compare across species and derived a tolerable weekly intake of 14 pg TCDD/kg of body weight (bw), which was extended to include all the 2,3,7,8-substituted PCDD and PCDF, and the dioxin-like PCB, and expressed as a group tolerable weekly intake of 14 pg WHO-TEQ/kg bw. The FAO/WHO Joint Expert Committee on Food Additives (JECFA) performed a similar assessment whereas the US Environmental Protection Agency (US EPA) has paid more attention to human data on carcinogenicity.     

Levels of polychlorinated biphenyls in foods from Catalonia,Spain: estimated dietary intake

From June to August 2000, food samples were randomly acquired in seven cities in Catalonia, Spain. Polychlorinated biphenyl (PCB) concentrations were determined for 108 samples of vegetables, fruits, pulses, cereals, fish and shellfish, meats and meat products, eggs, milk and dairy products, and oils and fats. Levels of 11 PCB congeners (IUPAC 28, 52, 77, 101, 105, 118, 126, 138, 153, 169, and 180) were determined by high-resolution gas chromatography-high-resolution mass spectrometry. For toxic equivalent (TEQ) calculations, World Health Organization (WHO) toxicity equivalent factors (WHO-TEFs) were used. The highest levels of most congeners were found in fish and shellfish (11,864.18 ng/kg [wet weight]), and the next highest levels, which were substantially lower, were found in milk and dairy products (674.50 ng/kg [wet weight]). For the general population of Catalonia, the total dietary intake of PCBs was found to be 150.13 pg WHO-TEQ/day. The largest contribution to this intake came from fish and shellfish (82.87 pg WHO-TEQ/day) and dairy products (29.38 pg WHO-TEQ per day). A relatively large contribution was also noted for cereals (11.36 pg WHO-TEQ/day). Among the PCB congeners determined in this study, PCB 126 showed the largest contribution to total TEQ intake (50.56%). The data obtained in this study should be useful in risk assessment with regard to human PCB exposure through food in Catalonia.     

Long-term daily intake estimates of polychlorinated dibenzo-p-dioxins and furans, polychlorinated biphenyls and polybrominated diphenylethers from food in Finnish children: risk assessment implications

Food is contaminated by polychlorinated dibenzo-p-dioxins and furans (PCDD/F), polychlorinated biphenyls (PCB) and polybrominated diphenylethers (PBDE) worldwide. Previous data show elevated intakes in children. We determined intakes of POPs in Finnish children. Because no children-specific safe limit values exist, we used tolerable daily intakes (TDIs) set for adults by international expert bodies to examine the proportion of the study population that exceed those limits. We utilised dietary monitoring data with food consumption of Finnish boys and girls aged 1-6 years, measured the contaminant concentrations in all the main food items and calculated age-specific contaminant sum and congener-specific long-term daily intake levels. Our food intake and contaminant data correspond to years 2002-2005. The long-term upper-bound dioxin intakes ranged between 0.1 and 12.8?pg WHO(PCDD/F-PCB)-TEQ/kg bw/d (min and max). An immediate TDI for WHO(PCDD/F-PCB)-TEQs of 4.0?pg/kg?bw/d were exceeded by 2.5%-7.5% of the children. PBDE long-term upper-bound intake was between 0.1 and 5.8?ng/kg bw/d (min and max). Congener-specific analyses indicated a typical Finnish adult exposure pattern of the children to PCDD/Fs, PCBs and PBDEs. The highest POP intakes were observed in children aged 3 years. Long-term daily PCDD/F, PCB and PBDE intakes among Finnish children varied greatly between individuals and ages. In each age group of the study population, there was a proportion of children with their WHO(PCDD/F-PCB)-TEQ intake exceeding considered safe limits set for adults. Based on the exposure profile reported herein, children should be clearly considered as a specific sub-population in food-mediated contaminant risk assessment.     

Intake estimation of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) in salmon: the inclusion of uncertainty

Dioxins and dioxin-like PCBs are given toxic equivalency factors (TEFs) in order to calculate the combined toxic equivalence (TEQ) of these contaminants in a sample of food. This study calculates the probability of an average consumer exceeding the recommended tolerable daily intake of 1-4 pg WHO-TEQ kg^-1 bw day^-1 as the amount of salmon in the diet is increased. Probabilistic risk analysis is used to account for the known uncertainties in this calculation. When the TEF uncertainty was excluded with no salmon consumption, the background dietary intake ranged from 1.36 to 1.78 pg TEQ kg^-1 bw day^-1. A weekly consumption of three standard salmon portions resulted in a 36% chance of exceeding the upper limit of the TDI. Inclusion of the TEF uncertainty increased the background dietary intake range from 2.1 to 4.4 pg TEQ kg^-1 bw day^-1, and the weekly consumption of one salmon portion resulted in a 79% chance of the average consumer exceeding the upper TDI. The most important factors contributing to the uncertainty in these results were, in order of magnitude, the TEF for PCB 126 and the sampling uncertainty (sample size) followed by the measurement uncertainty of PCB 126. We recommend that it is more important to increase sample size and produce more precise estimates in the TEF than to improve analytical accuracy.     

Dietary exposure to dioxins and dioxin-like PCBs of Hong Kong adults: results of the first Hong Kong Total Diet Study

Dioxins and dioxin-like polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs) covered by the Stockholm Convention on POPs. To assess the associated health risk of the Hong Kong population, the dietary exposure of the Hong Kong population and various age–gender subgroups to dioxins and dioxin-like PCBs was estimated in the first Hong Kong Total Diet Study (TDS), where food samples were collected and prepared “as consumed”. A total of 142 composite food samples, mainly foods of animal origin and their products and oily food, were analysed for polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxin-like PCBs by the high-resolution gas chromatograph/high-resolution mass spectrometer (HRGC/HRMS) system. Dietary exposures were estimated by combining the analytical results with the food consumption data of Hong Kong adults. The mean and 95th percentile exposures to dioxins and dioxin-like PCBs of the Hong Kong population were 21.9 and 59.7 pg toxic equivalent (TEQ) kg^?1 body weight (bw) month^?1 respectively, which amounted to 31.3% and 85.2% of the provisional tolerable monthly intake (PTMI). The main dietary source of dioxins and dioxin-like PCBs was “Fish and seafood and their products” (61.9% of the total exposure), followed by “Meat, poultry and game and their products” (20.0%) and “Mixed dishes” (6.95%). The study findings suggest that the Hong Kong population is unlikely to experience the major undesirable health effects of dioxins and dioxin-like PCBs.     

Butter as an indicator of regional persistent organic pollutant contamination: further development of the approach using polychlorinated dioxins and furans (PCDD/Fs), and dioxin-like polychlorinated biphenyls (PCBs)

The potential for use of butter as a widely available, relatively uniform lipid-rich matrix for the determination of spatial distributions of persistent organic pollutants has already been demonstrated. The present study determines the contributions to toxicity equivalence (TEQ) from polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCBs) using butter samples from 24 countries world wide. Concentrations of PCDD/Fs and dioxin-like PCBs ranged from 0.07 to 5.69 pg ΣWHO-TEQ g -1 lipid. For most samples, PCDD/F TEQ fell within ranges reported for European dairy products over the last decade (0.3-2 pg g -1 lipid I-TEQ), though a single sample from Spain was a notable exception. Other than this sample, the highest values were recorded for samples from the Netherlands and Italy, with those from India, China and Tunisia also being relatively high. The contribution from non- ortho -PCBs was particularly significant in samples from Germany, Austria, Italy, the Czech Republic, Tunisia, India and Argentina. Although overall TEQs were generally highest in European and Mediterranean butters, elevated levels were also apparent in industrializing regions of Asia (India, China) and Latin America (Argentina). More detailed regional studies would be necessary to identify likely dioxin and PCB sources in each case. Nevertheless, this study supports the utility of butter as a monitoring matrix that may be especially applicable in regions for which monitoring programmes are currently lacking.