Decreasing concentrations of PCDD/Fs in pork based on Korean monitoring in years 2002 and 2005

The congener-specific profiles of PCDD/Fs in domestic and imported pork monitored in South Korea in years 2002 and 2005 were compared. Total concentrations of PCDD/Fs decreased from 2002 to 2005, but displayed a similar pattern of congeners. In neither 2002 nor 2005 were either 2,3,7,8-TCDD or 2,3,7,8-TCDF detected. The mean concentrations of PCDD/Fs in domestic and imported pork were 8.29 pg g^?1 fat from 106 samples in 2002 and 4.03 pg g^?1 fat from 90 samples in 2005. However, the contribution of PCDDs increased about four times with respect to toxic equivalent (TEQ) level and about 1.5 times in terms of concentration in the monitoring results from 2005 compared with 2002, and the PCDF contribution decreased substantially. This suggests that the main source of dioxins in pork probably changed to a larger portion coming from animal feeds than environmental sources of exposure. The estimated human intakes of PCDD/Fs originating from pork in the South Korean diet were calculated as 0.029 and 0.019 pg TEQ kg^?1 body weight day^?1 for the upper bound exposure in 2002 and 2005, respectively. The values represent low intakes when compared with the both Korean tolerable daily intake (TDI) (4 pg TEQ kg^?1 body weight day^?1) and World Health Organization TDI (1–4 pg TEQ kg^?1 body weight day^?1).     

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).     

Dietary intakes of polychlorinated dibenzo- p -dioxins, dibenzofurans and polychlorinated biphenyls in Finland

Samples of cow milk, pork, beef, eggs, rainbow trout, flours and vegetables were analysed for 17 polychlorinated dibenzo- p -dioxins and dibenzofurans (PCDD/F) and 36 polychlorinated biphenyls (PCB). Daily dietary intake of PCDD/Fs as toxic equivalent (I-TEq) and PCBs (PCB-TEq) was assessed using food consumption data from a 24-h dietary recall study for 2862 Finnish adults. The calculated intake of PCDD/F was 46pg I-TEq day -1 . The current level was about half of the earlier estimation of intake in Finland made in 1992. The assessed PCB intake was 53pg PCBTEqday -1 . Thus, the total intake of PCDD/Fs and PCBs was 100pg TEqday -1 (1.3pg TEqkg -1 b.w.day -1 ), which is within the range of tolerable daily intake (TDI) proposed by the WHO (1-4pg TEqkg -1 b.w.day -1 ).     

Studies made to assess risk concerning a 'dioxin' contamination incident near Bolsover, Derbyshire, UK

During 1990 and 1991, milk samples were collected from farms in Derbyshire, a county in the UK, as part of a study designed to establish background concentrations of polychlorinated dibenzo- p -dioxins and furans (PCDD/Fs) in cows' milk produced in the area. The concentrations found in two samples, both taken from farms near the town of Bolsover, were significantly elevated (40.0-42.0ng TEQ kg -1 fat) when compared with the normal range for these compounds in milk from the surrounding area (1.1-7.1 ng TEQ kg -1 fat). An immediate intensive programme commenced in April 1991 to test milk from a further 27 dairy farms close to those where the original 'high' samples were obtained. A maximum tolerable concentration (MTC) was calculated to be 17.5 ng/TEQ kg -1 fat. This was derived by using the tolerable daily intake (TDI) for 2,3,7,8-TCDD of 0.01 ng kg -1 body weight day -1 set by the World Health Organization in 1990 and accepted by the UK government (this figure has since been revised to 1-4 pg kg -1 body weight day -1 ). MTC is defined as the amount of PCDD/Fs that could be present and still ensure that high-level (97.5 pecentile) consumers of milk would not exceed the TDI. Milk originating from dairies supplied by these farms and others contained PCDD/F in the range 1.8-3.1 ng TEQ kg -1 fat, which indicated there was no risk to health for consumers purchasing milk in the normal manner. Milk from the two dairy farms was removed from the food supply until concentrations of PCDD/Fs were consistently below the MTC. The UK Department of Health monitored the blood concentrations of PCDD/Fs in individuals who had consumed milk produced on the affected farms and the Department of the Environment initiated a programme of work to identify and reduce the source of pollution.     

Comparison of PCDD/F and dl-PCB levels in Turkish foodstuffs: industrial versus rural,local versus supermarket products,and assessment of dietary intake

Polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) and dioxin-like and non-dioxin-like (indicator) polychlorinated biphenyls (PCBs) were monitored in various foodstuffs of animal origin and edible oil samples obtained from two different cities in Turkey both rural and industrial. Total dioxin+dioxin-like PCBs and indicator PCB concentrations of pooled samples ranged 0.20–4.19 pg World Health Organization-Toxic Equivalency (WHO-TEQ)₍₁₉₉₈₎/g fat and 57.2–1710 pg/g fat, respectively. The dominant congeners were 2,3,4,7,8-PeCDF, 1,2,3,7,8-PeCDD, 2,3,7,8-TCDD and PCB126. Dietary intake of dioxin+dioxin-like PCBs and indicator PCBs from fish, dairy products, edible oil, egg and meat was 0.509 pg WHO-TEQ₁₉₉₈/kg bw (body weight)/day and 839 pg/kg bw/day in Afyon and 0.588 pg WHO-TEQ₁₉₉₈/ kg bw/day and 1070 pg/kg bw/day in Kocaeli, respectively. The major contributors to total exposure were dairy products and fish. Despite the unexplained high contamination level in an individual egg sample from Kocaeli, average concentration levels in Turkey, even in industrialized regions, were low compared to reported concentrations in Western Europe. Exposure levels were well below the tolerable daily intake (TDI) of 2 pg WHO-TEQ₁₉₉₈/kg body weight.     

Severe PCDD/F and PBDD/F pollution in air around an electronic waste dismantling area in China

The presence of chlorinated and brominated compounds in electronic waste (EW) results in the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) during the EW dismantling process. In this study, we investigated the dioxins present in ambient air around the EW dismantling area Guiyu in Guangdong, China. Atmospheric PCDD/F (tetra to octa) abundances and toxic equivalent (TEQ) values were 64.9-2365 pg/m3 and 0.909-48.9 pg of W-TEQ/m3, respectively; these are the highest documented values of these compounds found in ambient air in the world. PBDD/Fs (eight 2,3,7,8-substituted congeners) were also found at high pollution levels (concentrations of 8.124-61 pg/m3 and 1.6-2104 pg of I-TEQ/m3). Profiles of the 2,3,7,8-PCDD/F homologues in the air of Guiyu differed from typical urban air patterns reported in the literature, and the concentration of homologues increased with the chlorination degree of 2,3,7,8-PCDD/Fs except for OCDF. The severe dioxin pollution present in Guiyu substantially influences the adjacent area of Chendian, where atmospheric PCDD/F and 2,3,7,8-PBDD/F levels are higher than those of common urban areas in the world. Our tentative inhalation risk assessment showed that residents in Guiyu are at a high risk of exposure to dioxins. The total PCDD/F intake doses far exceed the WHO 1998 tolerable daily intake limit of 1-4 pg of W-TEQ kg(-1) day(-1).     

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.     

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.     

Dietary uptake of dioxins (PCDD/PCDFs) and dioxin-like PCBs in Spanish aquacultured turbot (Psetta maxima)

The human population is exposed to dioxins (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) mainly through diet; bioaccumulation and biomagnification in aquatic environment results in fishery products and by-products being an important vector to humans. The determination of PCDD/Fs and dl-PCBs in fillets of young turbots (Psetta maxima) (0-2 years) from aquaculture plant (Galicia, Spain) (N = 21) and in feeding stuffs were carried out, and dietary accumulation values and lipid-normalized biomagnification factors (BMF) relating concentration in fish and in feed were calculated. Levels found in feeding stuffs (0.5 pg TEQ-PCDD/F/g and 1.6 pg TEQ-dl-PCB/g), and turbots (0.13-0.27 pg TEQ-PCDD/F/g fresh weight and 0.35-1.2 pg TEQ-dl-PCB/g fresh weight) were below maximum permitted levels set by EC. Levels of toxic compounds in feeding stuff are reflected in fish fillets; predominant isomers are 2,3,7,8-TCDF, OCDD, 1,2,3,7,8-PeCDF, 2,3,4,7,8-PeCDF and 1,2,3,4,6,7,8-HpCDD, and PCBs 118, 105, 156 and 167. Relevant compounds accounting for total toxicity are the same congeners in feeding stuff and turbots: 2,3,4,7,8- PeCDF; 2,3,7,8-TCDF; 2,3,7,8-TCDD and 1,2,3,7,8-PeCDD, and PCB 126. Higher accumulation efficiency values were obtained for dl-PCBs (30-46%); tetra- and penta-chloro substituted PCDD/Fs showed the highest values (27-34%) of the PCDD/F group. Biomagnification was shown for these compounds (BMF around 1.5).     

Brominated and chlorinated dioxins, PCBs and brominated flame retardants in Scottish shellfish: methodology, occurrence and human dietary exposure

The most commonly consumed shellfish species produced in Scotland - mussels, oysters and scallops - were investigated for the occurrence of a range of brominated and chlorinated contaminants in order to establish current levels and estimate human dietary exposure. Flesh from individual sub-samples was representatively pooled and 35 composites were analysed for brominated and chlorinated dioxins (PBDD/Fs, PCDD/Fs), brominated and chlorinated biphenyls (PBBs, PCBs), polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs) and tetrabromobisphenol A (TBBPA). The analytical methodology used (13)C(12) labelled surrogates of the target compounds, with GC coupled to (usually) high resolution MS, and LC-MS/MS for HBCD and TBBPA analysis. Positive identifications were made in the majority of samples for most analytes with the exception of TBBPA and most PBDD congeners measured. None of the levels detected for PCDD/F and PCB were above the maximum permitted levels specified in European Union regulations. The levels of brominated furans predominated over brominated dioxins, reflecting the environmental distribution and source emission profiles of these contaminants, and relatively high levels of the tri-brominated congeners were observed. Levels of the flame retardant chemicals reflected current and legacy use, with appreciable concentrations of PBDEs and HBCDs (predominantly alpha-HBCD) but far lower levels of PBBs. TBBPA was not detected in any of the species. In general, mussels and oysters displayed relatively higher levels of contamination than scallops, although the gonad tissue of the latter showed significant levels of brominated dioxins. The estimated adult dietary intakes of PCDD/Fs and PCBs arising from the consumption of a typical portion of these foods in combination with an otherwise average UK diet were in the range 0.5-0.6 pg World Health Organisation (WHO)-toxic equivalent (TEQ)(2005)/kg bodyweight per day. These estimated dietary intakes are well within the Tolerable Daily Intake for dioxins and dioxin-like PCBs of 2 pg WHO-TEQ(2005)/kg bodyweight/day endorsed by the independent expert Committee on Toxicology of Chemicals in Food, Consumer Products and the Environment. The corresponding intakes for sumPBDEs and sumHBCDs were 5.6-6.1 and 5.9-7.9 ng/kg bodyweight/day respectively.     

Levels of dioxins in Japanese fruit in 1999 to 2002 and estimation of their intake

A total of 148 samples of nine species of fruit were collected between 1999 and 2002 and analyzed for PCDDs, PCDFs (PCDD/Fs) and Coplanar PCBs. Sampling points within about 1 km of operational municipal waste incinerators that were considered sources of dioxins were defined as "near-source" areas, and all other sampling points were defined as "general" areas. The TEQ of apples collected from near-source areas was significantly higher than that from general areas (p < 0.05). 3,3',4,4',5-PeCB (#126) was the main contributor to this difference in TEQs between apples collected from near-source areas and from general area. A principal component analysis performed to estimate the source of this congener revealed that not only the municipal waste incinerators, but also PCBs in the environment were associated with the high TEQ in apples collected from near-source areas. The daily intakes of PCDD/Fs and Coplanar PCBs from the fruits including skin were estimated to be 0.0082 pg-TEQ/kg b.w./day (ND = 0) and 0.072 pg-TEQ/ kg b.w./day (ND = 1/2 LOQ). Though these values are likely to be overestimates, they are far lower than the tolerable daily intake set in Japan for PCDD/Fs and Coplanar PCBs (4 pg-TEQ/kg b.w./day). It is thought that fruit intake is not an important pathway of human exposure to PCDD/Fs and Coplanar PCBs.     

Determination of polychlorinated dibenzo-p-dioxins and dibenzofurans and comparison of extraction methods for edible freshwater fish and frogs in South Korea by using a high-resolution GC/MS.

Three different extraction methods were evaluated: Soxhlet extraction, accelerated solvent extractor extraction and alkali digestion with high-resolution gas chromatography/high-resolution mass spectrometry, for the analysis of edible freshwater fish and frogs. The recovery efficiencies for the different extraction methods were also compared. Using these extraction methods, the concentrations and spatial distributions of these compounds in freshwater fish and frogs (n = 99), collected from 31 locations on four major river systems (Han, Nakdong, Kum and Youngsan) and two wetlands in South Korea, were examined. The concentrations of total polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in all the freshwater fish and frog samples were analysed. The toxic equivalency (TEQ) concentration of PCDD/Fs in fish ranged from 0 (n.d.) to 1.309 pg I-TEQ g(-1) wet weight. Detailed concentrations for different types of fish were as follows (pg I-TEQ g(-1) wet weight): 0 (n.d.)-1.309 for crucian (mean 0.331, n = 28), 0.004-0.743 for carp (0.244, n = 10), 0.004-0.592 for dace (0.198, n = 8), 0.187-0.400 for cornet fish (0.287, n = 3), 0.164-0.410 for Korean piscivorous chub (0.303, n = 6), 0.105-0.516 for bass (0.310, n = 2), 0.451-0.812 for mullet (0.631, n = 2), 0.082 for long-nosed barbell, 0.100 for common Korean bitterling and 0.995 for dark chub. The total TEQ concentration ranged from 0 (n.d.) to 1.258 pg I-TEQ g(-1) wet weight for the two kinds of frogs (n = 36) investigated: 0 (n.d.)-1.258 pg I-TEQ g(-1) (mean 0.346, n = 29) for the bullfrog and from 0 (n.d.)-0.474 pg I-TEQ g(-1) (0.185, n = 7) for the mountain frog.     

Polychlorinated dioxins, furans, and biphenyls, and polybrominated diphenyl ethers in a U.S. meat market basket and estimates of dietary intake

Persistent environmental contaminants including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), non-ortho-polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs) were analyzed in 65 meat samples collected from supermarkets across the U.S. in 2001. The samples included hamburger, sirloin steaks, pork chops, bacon, and whole chickens from nine different cities. The average PCDD/F/non-ortho-PCB toxic equivalency (TEQ) for all the samples was 0.55 pg/g of lipid (nd (nondetect) = DL (detection limit)/2) with a range from nondetectable to 3.21 pg/g of lipid. For PBDEs, eight congeners were routinely found in the meat samples with an average sum of 1.71 ng/g of lipid (nd = DL/2) and a range from nondetectable to 16.6 ng/g of lipid. While average TEQs were similar to recent values reported in Europe and Asia, the sums of PBDEs in chicken and pork were 3-20 times higher than levels reported in Spain and Japan for these foods. The presence of a few outliers raised the average PBDE sums and indicated that isolated sources of contamination may exist that, if identified, could be removed from the U.S. animal production chain. Using these TEQ and PBDE values and USDA food consumption data, the estimated dietary intake ranges from meat products were 5.3-16.0 pg TEQ and 14.9-44.7 ng of PBDEs/d or 0.1-0.3 pg TEQ and 0.3-0.5 (ng of PBDEs/kg of body mass)/d for an average individual, similar to intakes in other countries.     

Dioxins, furans and dioxin-like PCBs: Occurrence in food and dietary intake in France

PCDD/Fs and DL-PCBs contamination data in food products consumed in France collected from national monitoring programmes (2001-04) and representing analytical results for almost 800 individual food samples were combined with food consumption data from the French national dietary survey to estimate PCDD/Fs and DL-PCBs dietary intakes, expressed as toxic equivalents (WHO-TEQs). The mean PCDD/Fs and DL-PCBs intakes were estimated as 1.8 and 2.8 pg WHO-TEQ kg^-1 b.w. day^-1, respectively, for adults (aged 15 years and over) and children (aged 3-14 years). The main contributors to total intake were fish and milk products for both children and adults (48 and 31% for adults and 34 and 43% for children, respectively). DL-PCBs constituted the largest contributor to contamination in most foodstuffs. A life-long intake estimate showed that a non-negligible part of the French population (between 20 and 28%) had an intake above the tolerable monthly intake for dioxins and dioxin-like PCBs of 70 pg WHO-TEQ kg^-1 b.w. month^-1.     

Body loadings and health risk assessment of polychlorinated dibenzo-p-dioxins and dibenzofurans at an intensive electronic waste recycling site in China

This study is one of the very few investigating the dioxin body burden of a group of child-bearing-aged women at an electronic waste (e-waste) recycling site (Taizhou, Zhejiang Province) (24 +/- 2.83 years of age, 40% were primiparae) and a reference site (Lin'an city, Zhejiang Province, about 245 km away from Taizhou) (24 +/- 2.35 years of age, 100% were primiparae) in China. Five sets of samples (each set consisted of human milk, placenta, and hair) were collected from each site. Body burdens of people from the e-waste processing site (human milk, 21.02 +/- 13.81 pg WHO-TEQ1998/g fat (World Health Organization toxic equivalency 1998); placenta, 31.15 +/- 15.67 pg WHO-TEQ1998/g fat; hair, 33.82 +/- 17.74 pg WHO-TEQ1998/g dry wt) showed significantly higher levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/ Fs) than those from the reference site (human milk, 9.35 +/- 7.39 pg WHO-TEQ1998/g fat; placenta, 11.91 +/- 7.05 pg WHO-TEQ1998/g fat; hair, 5.59 +/- 4.36 pg WHO-TEQ1998/g dry wt) and were comparatively higher than other studies. The difference between the two sites was due to e-waste recycling operations, for example, open burning, which led to high background levels. Moreover, mothers from the e-waste recycling site consumed more foods of animal origin. The estimated daily intake of PCDD/Fs within 6 months by breastfed infants from the e-waste processing site was 2 times higher than that from the reference site. Both values exceeded the WHO tolerable daily intake for adults by at least 25 and 11 times, respectively. Our results implicated that e-waste recycling operations cause prominent PCDD/F levels in the environment and in humans. The elevated body burden may have health implications for the next generation.     

Elimination of dioxins in milk by dairy cows after the long-term intake of contaminated sugar beet pellets

ABSTRACT

Dried feed materials, such as sugar beet pellets, may be a source of high levels of PCDD/Fs. The studies followed up dioxin congener elimination from contaminated milk (5.02 ± 1.39 pg WHO PCDD/F-PCBs-TEQ g^?1 fat) up to 338 days after withdrawal of polluted feed ingredient (4.37 ± 0.25 ng PCDD/F/DL-PCBs-TEQ kg^?1 feed). The main objectives of the study were to estimate the length of the time needed to achieve an acceptable PCDD/F milk level as set by European Union law, to track the fate of the PCDD/F congeners, and to assess the potential risk for consumers associated with long-term consumption of contaminated milk. After approximately 200 days, the PCDD/F levels reached ML (2.5 pg WHO-TEQ g^?1 fat), then decreased to the action level after more than 300 days (1.75 pg WHO-TEQ g^?1 fat) for most of cows. The potential risk of PCDD/F/DL-PCBs intake was characterised by comparing the theoretically calculated weekly and monthly intakes with the toxicological reference values (TRVs). The dioxin intake for the average adult and high-milk consumers did not exceed half of any of the TRVs applied (TWI, PTMI). The consumption of milk by children in the amount recommended by nutritionists (500 ml day^–1) resulted in an exposure equal to 317% TWI and 275% PTMI.     

Characterizing the emissions of polybrominated dibenzo-p-dioxins and dibenzofurans from municipal and industrial waste incinerators

As yet, very little is known about the polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) characteristics in the stack flue gases of incinerators. In this study, nine large-scale continuous municipal solid waste incinerators (MSWIs), two small-scale batch MSWls, and nine industrial waste incinerators (IWIs) were investigated for 2,3,7,8-substituted PBDD/Fs. The elevated PBDD/F concentrations (18.2 pg/Nm3, 4.17 pg TEQ/Nm3) of the IWIs, which were eight times higher than those of MSWIs (2.28 pg/Nm3, 0.557 pg TEQ/Nm3), are accompanied by PCDD/ Fs that are in the same range as those measured from MSWIs (0.0171-1.98 ng I-TEQ/Nm3). The obtained TEQ ratios (in percentage) of the PBDD/F to the PCDD/F concentration in the stack flue gases of the MSWls (0.72%), batch MWIs (0.18%), and IWIs (5.4%) are useful for the future estimate of PBDD/F emission quantity based on the well-established PCDD/F inventory. In addition, a significantly high correlation was found between the PBDD/F and PCDD/F concentrations, and the PBDD/F and PCDD/F congener profiles of the same emission source were similar, indicating a similar formation and substitution mechanism of bromine and chlorine in the combustion system.     

Evaluation of atmospheric PCDD/F depositions via automated and traditional water surface samplers in Taiwan

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are a group of compounds of major environmental concern. Once emitted into the atmosphere, PCDD/Fs undergo photochemical reactions and enter other environmental compartments via wet and dry deposition. In this study, atmospheric PCDD/F depositions were collected via an automated PCDD/F deposition sampler and traditional cylindrical vessels, respectively, in northern, central, and southern Taiwan from 2008 to 2010. The automated PCDD/F precipitation sampler used in this study can prevent both resuspension and photodegradation of the PCDD/Fs collected and also effectively separates the PCDD/F samples into dry and wet contributions. The results indicate that the average atmospheric PCDD/F concentrations collected by the high-volume sampling trains were 13.6 ± 10 (n = 10), 15.6 ± 5.2 (n = 7), and 10.9 ± 6.3 (n = 6) fg I-TEQ/m(3) in northern, central, and southern Taiwan, respectively. In addition, the results also indicate that the PCDD/F deposition flux collected with an automated PCDD/F sampler (1.84 ± 0.90-8.68 ± 5.1 pg I-TEQ/m(2)/day, n = 23) is significantly higher than that sampled with cylindrical vessels (1.11 ± 0.69-5.64 ± 5.2 pg I-TEQ/m(2)/day, n = 23). Based on the Mann-Whitney statistical analysis, the p value (0.037) of PCDD/F deposition flux between those two samplers measurement is lower than 0.05. The difference is attributed to the fact that part of the PCDD/F depositions collected by traditional cylindrical vessels is photodegraded and revolatilized. In addition, the wet deposition flux of PCDD/Fs (3.66 to 470 pg I-TEQ/m(2)/rainy day, n = 23) observed in Taiwan is significantly higher than the dry deposition flux (0.38 to 4.55 pg I-TEQ/m(2)/sunny day, n = 23). The results demonstrate that the wet deposition is the major PCDD/F removal mechanism in the atmosphere. Furthermore, the overall PCDD/Fs deposition velocity and scavenging (rainout) coefficient in Taiwan are calculated as 0.20 ± 0.07 cm/s and 6.5 ± 0.2 × 10(4), respectively.     

Dioxins and polychlorinated biphenyls (PCBs) in fish oil dietary supplements: Occurrence and human exposure in the UK

Commercially available fish oil supplements sourced from retail outlets in the UK, as well as by mail order, were surveyed in 2000-02 for dioxin (PCDD/Fs) and polychlorinated biphenyl (PCB) content. Sampled products were representative of market share. The WHO-TEQ values for these products ranged from 0.18 to 8.4 ng kg^-1 for ΣPCDD/F and from 1.1 to 41 ng kg^-1 for Σ dioxin-like PCBs. The results suggest a downward trend in the levels of dioxins in fish oil supplements over the last decade, since levels for similar products ranged from 0.3 to 10 ng kg^-1 for ΣPCDD/F WHO-TEQ in 1996. Levels of ICES (International Council for the Exploration of the Seas) 7 PCBs in the current study ranged from 8.3 to 267 µg kg^-1. Subsequent to this survey, European Union legislation has been introduced that includes a maximum limit of 2 ng kg^-1 WHO-TEQ for dioxins in fish oil products for human consumption. Twelve of the 33 products reported here would have exceeded this limit. Negotiations are in progress to incorporate dioxin-like PCBs into the European Union regulations. When manufacturer-recommended doses were applied to the observed levels, the estimated upper bound human exposure to dioxins and dioxin-like PCBs from dietary intake of these products ranged from 0.02 to 7.1 pg WHO-TEQ kg^-1 body weight day^-1 for adults and from 0.02 to 10 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren. This level rises to 1.8-8.9 pg WHO-TEQ kg^-1 body weight day^-1 for adults and 1.4-14 pg WHO-TEQ kg^-1 body weight day^-1 for schoolchildren when combined with the average exposure from the whole diet in 1997. Again, subsequent to this survey, the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) revised the UK tolerable daily intake (TDI) for mixtures of dioxins and dioxin-like PCBs from 10 to 2 pg WHO-TEQ kg^-1 body weight day^-1. This is in line with the tolerable weekly intake (TWI) of 14 pg WHO-TEQ kg^-1 body weight set by the Scientific Committee on Food (SCF).     

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in green leafy vegetable 'Komatsuna'.

The effects of ordinary household cooking processes on concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) were investigated in 'komatsuna', a green leafy vegetable popular in Japan. The concentrations of dioxins were compared using isomer-specific analyses of both uncooked and cooked edible parts of the plant. The mean total 2,3,7,8-chlorine substituted PCDD and PCDF concentrations were reduced from 46.53 pg/g and 0.714 pg/g to 8.301 pg/g and 0.210 pg/g by washing with tap water, and further reduced to 6.054 pg/g and 0.148 pg/g by subsequent boiling, respectively. The cooking processes markedly decreased the concentrations of PCDD/Fs, while having little effect on those of dioxin-like PCBs. The mean total concentration as 2,3,7,8-tetraCDD equivalents (TEQ) was reduced from 0.058 pgTEQ/g to 0.026 pgTEQ/g by washing with tap water and further reduced to 0.019 pgTEQ/g by subsequent boiling. These results suggest that ordinary cooking processes provide a means of reducing the level of dioxins in green leafy vegetables.