WHO-TEQ Values Research Articles

Polychlorinated biphenyls emission from a medical waste incinerator in China

Detailed polychlorinated biphenyls (PCBs) congener patterns were determined in the flue gas from a medical waste incinerator (MWI) using high-resolution gas chromatograph coupled to high-resolution mass spectrometer (HRGC/HRMS). The total PCBs concentration of all homologues (mono- to deca-chlorinated homologues) in the flue gas ranged from 138.01 to 855.35 ng/Nm 3 and the WHO-TEQ value varied from 0.046 to 0.549 ng/Nm 3 under the different operating conditions. PCB-77 concentration was the highest among dioxin-like PCBs and PCB-126 contributed mostly to the WHO-TEQ. The ratios of dioxin-like PCBs in the total PCB concentrations in the flue gas varied between 11.7% and 26.0% (the average value is 18.7%). Three inhibitors, sulfur, urea, and ammonium sulfate were tested to investigate the capacity for preventing PCBs formation. The decomposition efficiency for total PCBs and PCBs TEQ ranged from 38% to 84% and 69% to 92% respectively. It was shown that urea mixed with ammonium sulfate and more activated carbon was proved to be the most effective inhibitor for PCBs formation. The removal efficiencies (REs) of the total PCBs concentration and PCBs TEQ by the bag filter under two conditions were 69% and 85%, and 86% and 94% respectively.

PCB and PCDD/F in sediments and mussels of the Istanbul strait (Turkey)

Sediment and mussel samples collected along the coasts of the Istanbul strait and an island in Marmara Sea (Turkey) were analyzed for six indicator polychlorinated biphenyl (PCB), 12 dioxin-like PCB (dl-PCB) and 17 polychlorinated dibenzo-p-dioxin/furan (PCDD/F) congeners. Samples contained different concentrations of PCBs and among these, congeners 153, 75, 105 and 118 in sediments and congeners 153, 138 and 118 in mussels were most abundant. The concentration levels of total PCBs and PCDD/Fs in sediments ranged from 17.9 to 539 746 pg g −1 dm and 2.04 to 60.5 pg g −1 dm, respectively. The total WHO-TEQ values ranged between 0.01 and 17.8 pg g −1 dm in sediments, and 0.98 and 1.01 pg g −1 ww in mussels. None of the sediment and mussel samples analyzed exceeded the limits suggested in the sediment quality guideline and safe values set by the European Community for seafood intended for human consumption, respectively.

Distribution of polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDDs/Fs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs) in the soil in a typical area of eastern China

The distribution and concentrations of polychlorinated dibenzo- p-dioxins (PCDDs) and dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dioxin-like PCBs, also called co-PCBs) in a typical area of eastern China were evaluated by analysis of 21 soil and 6 sediment samples. The range of WHO-TEQ values for the PCDD/Fs and dioxin-like PCBs in 17 soil samples representing the background investigation in the study area was 0.017–5.04 pg g −1 (dry weight, dw), with a mean value 0.967(±1.361) pg g −1 and medium value 0.348 pg g −1, which indicates that the levels of PCDD/Fs and dioxin-like PCBs over the major part of this district were low. However, the WHO-TEQ values (6.52–16.7 pg g −1 dw) for PCDD/Fs and dioxin-like PCBs in soil samples to the leeward of a known contaminated disassembly industrial park were much higher than that of the background investigation, and the levels of sediment samples downstream of this area were in the range 2.25–34.6 pg g −1 (dw). The levels of WHO-TEQ in soil and sediment samples decreased with an increase in distance from the researched pollution source. The principal component analysis demonstrated that the PCDD/Fs and dioxin-like PCBs in major part of contaminated sediment and soil samples derived from the correlative matrix. Yet the different distribution patterns of them in part of sediment samples strongly indicate that other potential sources may be exist, further researches should be done to get more information about the sources and the distributions of the PCDD/Fs and PCBs.

Occurrence and bioaccumulation study of PCDD and PCDF from mineral feed additives

Extraction of polychlorinated dibenzo- p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) was evaluated in sepiolite matrices. Soxhlet extraction using different extracting strategies and acid treatment were tested. Acid treatment or Soxhlet extraction using a mixture of toluene:ethanol as solvent allowed to reach the minimum requirements for recovery rates. However, Soxhlet extraction using a mixture cyclohexane:toluene as extracting solvent did not allow to comply with these minimum requirements. Significant differences were obtained in TEQ units when acid treatment was applied in comparison to Soxhlet extraction. This fact can be explained because the use of drastic acid conditions allows removing strongly adsorbed analytes which can be uniquely extracted after a total destruction of the crystalline. On the contrary, Soxhlet extraction was not able to destroy the structure of sepiolite and as a consequence the PCDDs/Fs remain adsorbed in the internal structure of the mineral. A bioaccumulation study was also conducted to evaluate the transference of PCDDs/Fs from the sepiolite into the animal when fed with feed containing sepiolite. Four groups of chickens were exposed through diet to a control feed, feed with 3% w/w sepiolite, spiked feed contaminated with PCDDs/Fs and feed containing contaminated kaolinitic clay. Livers of animals were analyzed throughout the exposure period. Results of this trial showed that the performance of broilers was not affected by the presence of dioxins at levels tested, and chickens did not show any abnormal behaviour. Dioxins intentionally added to the diet were significantly absorbed and accumulated in liver, whereas the PCDDs/Fs from sepiolite were not available for chickens since livers from broilers fed 3% sepiolite presented similar WHO-TEQ values than those from broilers fed control diet.

Significant decreasing trend in human dietary exposure to PCDD/PCDFs and PCBs in Catalonia, Spain

The concentrations of polychlorinated dibenzo- p-dioxins and dibenzofurans (PCDD/PCDFs), and 18 polychlorinated biphenyls (PCBs) were determined in samples of foodstuffs widely consumed by the population of Catalonia, Spain. The dietary intake of PCDD/PCDFs and dioxin-like (DL)-PCBs was subsequently estimated for the population of this Spanish region. These results were compared with those of a previous survey performed during 2000. For PCDD/PCDFs, the highest WHO-TEQ values corresponded to oils and fats (0.223 ng/kg), followed by fish and seafood (0.131 ng/kg) and dairy products (0.057 ng/kg), while the lowest levels were found in fruits (0.003 ng/kg), as well as in vegetables and milk (0.009 ng/kg). For DL-PCBs the highest WHO-TEQ values corresponded to the groups of fish and seafood (0.761 ng/kg) followed by oils and fats (0.169 ng/kg), and dairy products (0.039 ng/kg), while the lowest values were observed in fruits (0.004 ng/kg), and vegetables (0.005 ng/kg) and tubers (0.006 ng/kg). The current dietary intakes of PCDD/PCDFs, DL-PCBs, and PCDD/PCDFs plus DL-PCBs were estimated to be 25.7, 52.4, and 78.1 pg WHO-TEQ/day vs. 95.4, 150.1, and 245.5 pg WHO-TEQ/day found in our previous survey. It means reductions of 73%, 65%, and 68%, for PCDD/PCDFs, DL-PCBs, and PCDD/PCDFs plus DL-PCBs, respectively. The current estimated intake for an adult male, 1.12 pg WHO-TEQ/kg body weight per day, is lower than most intakes recently reported in a number of countries over the world.

PCDD/F and dioxin-like PCB in Hong Kong air in relation to their regional transport in the Pearl River Delta region

PCDD/F and dioxin-like PCB were measured in 142 air samples of Hong Kong. The annual average PCDD/F and dioxin-like PCB concentrations obtained for Hong Kong air at Tap Mun (PCDD/F: 1724 ± 1984; dioxin-like PCB: 1572 ± 1170 fg m −3), Yuen Long (PCDD/F: 2927 ± 2695; dioxin-like PCB: 4331 ± 1962 fg m −3) and Tsuen Wan (PCDD/F: 1875 ± 1502; dioxin-like PCB: 2972 ± 1510 fg m −3) from January 2004 to March 2005 were comparable to other urban centers around the world and were within the Japanese and USA ambient air quality guidelines. A clear seasonal pattern was observed for PCDD/F, generally with a 50–60 times higher air concentration in winter when background northerly wind was weaker and land–sea breeze prevailed, resulting in regional transport; and a lower concentration in summer, due to the inflow of clean oceanic southeasterly wind from the South China Sea. A higher WHO-TEQ value of dioxin-like PCB (mainly attributed to the relatively higher WHO-TEQ value of PCB 126) in Yuen Long during winter, compared with other months, could also be related to the regional transport by the winter monsoon wind and the low mixing height in winter. Spatially, air concentrations of PCDD/F and dioxin-like PCB demonstrated a west-to-east gradient (with Yuen Long > Tsuen Wan > Tap Mun). It is suggested that PCDD/F and dioxin-like PCB were transported into the western airshed of Hong Kong from the Pearl River Delta by land–sea breeze circulation and confined to the northwestern part, due to the blocking effect of the northwestern airshed in Hong Kong.

Air concentrations of PCDD/Fs, PCBs and PCNs using active and passive air samplers

The concentrations of polychlorinated dibenzo -p-dioxins and furans (PCDD/Fs), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs) were determined in air samples collected at four sampling sites located in two zones of Barcelona (Spain): near a municipal solid waste incinerator (MSWI) and a combined cycle power plant (3 sites), and at a background/control site. Samples were collected using high-volume active samplers. Moreover, 4 PUF passive samplers were deployed at the same sampling points during three months. For PCDD/Fs, total WHO-TEQ values were 27.3 and 10.9 fg WHO-TEQ m −3 at the urban/industrial and the background sites, respectively. The sum of 7 PCB congeners and the ∑PCN levels were also higher at the industrial site than at the background site. In order to compare active and passive sampling, the accumulated amounts of PCDD/Fs, PCBs and PCNs in the four passive air samplers, as well as the total toxic equivalents in each sampling site were also determined. To assess the use of PUF passive samplers as a complementary tool for PCDD/F, PCB and PCN monitoring, sampling rates were calculated in accordance with the theory of passive air samplers. PUF disks allowed establishing differences among zones for the POP levels, showing that they can be a suitable method to determine POP concentrations in air in areas with various potential emission sources. Although both particle and gas phase were sorbed by the PUFs, data of gas phase congeners are more reproducible.

Some Clinico and Histopathological Changes in Female Goats Experimentally Exposed to Dioxin

Female Baladi goats were used for investigating the toxicological effects of dioxin. Each animal in the treated group was given an oral dose of 4 mL of stock standard solution of dioxin (labelled and native congeners) diluted in 5 mL distilled water (1/3 of LD50) for three times with 2 days interval and slaughtered 16 days post treatment. Blood and tissue samples were taken and subjected for haemogram, biochemical and pathological studies as well as for determination of dioxin residues. Results revealed that exposure of female goats to dioxin induced anemia, leucocytopenia, neutropenia and eosinophilia with non significant increases in activities of serum ALT and AST as compared with untreated group. Meanwhile, activity of ALP and BUN concentration were significantly increased. Histopathological examination showed degenerative and necrotic changes associated with inflammatory reaction in liver and kidney, in addition to cystic glandular hyperplasia and adenomyosis in uterus. In ovarian tissue, marked decrease ofpreantral follicles together with cystic atretic follicle were noticed. The average percentage residues ofpg WHO-TEQ values for dioxins (PCDDs and PCDFs) in liver, kidney, mammary gland, uterus and milk after oral dose were 0.013, 0.0012, 0.0012, 0.009 and 0.0012%, respectively. It was concluded that oral exposure to dioxin in female goats induced adverse effects on liver and kidney. Dioxins had estrogenic like effect as indicated by uterine and ovarian histopathological changes.

Heavy metals, polycyclic aromatic hydrocarbons and polychlorinated biphenyls in surface sediments of the Naples harbour (southern Italy)

The Naples's harbour is one of the largest and most important commercial and tourist port of the Mediterranean basin. It is located on the southeast coast of Italy and receives industrial and municipal wastewaters from the city of Naples. Due to its social and economic impact, a comprehensive assessment of levels and sources of contamination of bottom sediments in this area of the Mediterranean basin is essential to identify potential danger due to mobilization of contaminants produced by managing of the same sediments. In this study, superficial sediments collected from 189 sampling sites were analyzed for grain size, heavy metals (Cr, Cu, Ni, Pb, V, Zn, Co, Sn, Cd, Hg, As, Al and Fe), 16 priority polycyclic aromatic hydrocarbons (PAHs) and perylene and 38 individual polychlorinated biphenyl (PCB) congeners. Compared to the estimated local background, Cu, Zn, Pb, Cd, Sn and Hg show enrichment factors >3 and only Hg evidences a median value higher than the NOAA (effects range - median) guidelines. Principal component analysis allowed us to clearly discriminate two areas mainly affected by heavy metals contamination and influenced by different sources related to industrial, commercial and/or urban activities. Priority PAHs are predominantly represented by three-five-ring compounds with concentrations ranging between 9 and 31774 ng g(-1) and frequently higher than the NOAA ER-M index. A prevalent pyrolitic origin of PAH was assessed on the basis of the relative abundance of the different congeners and selected isomer ratios. The concentrations of PCBs, as sum of the 38 congeners, ranged from 1 to 899 ng g(-1), with a predominance of highly chlorinated (tetra- and penta-chlorobiphenyls) congeners. WHO-TEQ values, calculated for the PCDD-like PCB congeners, suggest a relatively high level of toxicity. Generally, the concentration of PAHs and PCBs were higher near the sites of intense industrial, shipping and/or commercial activities suggesting a direct influence of these sources on the pollutant distribution patterns.

DRE-CALUX bioassay in comparison with HRGC/MS for measurement of toxic equivalence in environmental samples

CALUX, Chemically Activated LUciferase gene eXpression bioassay, has proven valuable for screening for and assessing toxic equivalents of dioxin-like compounds, because it detects all AhR (arylhydrocarbon receptor) ligands in a variety of sample matrices. In this study, we tried to validate DRE (dioxin-response elements)-CALUX bioassay, which has been developed by cloning mouse cyp1a1 gene in front of luciferase reporter gene. We compared DRE-CALUX bioassay with high resolution gas chromatography/mass spectrometry (HRGC/MS) for assessing environmental samples from Korea. 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) dose response study showed high correlation (r2=0.89) between DRE-CALUX bioassay and EROD (ethoxyresorufin O-deethylase) bioassay, a commonly used bioassay method. The mean TEQ value of water samples was 0.57 pg-TEQ(HRGC/MS)/L and 4.97 pg-TEQ(CALUX)/L. For soil samples, HRGC/MS-TEQ values ranged from 0 to 47.18 pg-TEQ/g (dry) and correlated well (r2=0.98) with values obtained by CALUX-TEQ which ranged from 0.92 to 649.97 pg-TEQ/g (dry). The difference between the absolute TEQ values might be due to the presence of dioxin-like compounds without WHO-TEQ values rather than the difference between CALUX-REP and WHO-TEQ. Based on this study, we suggest that DRE-CALUX bioassay can serve as an alternative bioassay method for high-throughput analysis of large number of environmental samples.

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).

Bioassay monitoring of waste PCB samples during chemical destruction treatments

Capacitor oil samples (PCBs > 90%wt) were treated in a bench scale experiment to investigate the destruction of PCBs during chemical destruction processes (a catalytic hydrodechlorination treatment with palladium carbon and additional treatment with potassium tert-butyloxide). Using those results, this study confirmed the decrease of PCBs and other undesirable dioxin-like compounds such as PCDD/Fs in treated samples during the treatment. Dioxin-responsive chemical-activated luciferase expression (DR CALUX) AhR reporter gene bioassay was used to evaluate dioxin-like activity in the samples. During the treatment, the efficiency for PCB capacitor oil was around 99.99% or more in WHO-TEQ and CALUX-TEQ, whereas the sum of PCBs was reduced at a resulting efficiency of >99.9999%. In this study, a new cleanup procedure for separating PCBs from the mineral oil matrix was also developed for DR CALUX. The procedure consists of dimethylsulphoxide partitioning followed by silica gel-44% sulphuric acid reflux treatment and activated carbon chromatography. With the cleanup, CALUX-TEQ values were in good agreement with WHO-TEQ values and were as much as 3.3 times higher than WHO-TEQs for untreated/treated PCB-containing insulating oil samples. The DR CALUX results of mineral oil samples containing various PCB concentrations of 0.5-50 mg/kg (corresponding WHO-TEQs: 0.012-1.2 microg-TEQ/g) also correlated well with WHO-TEQs (CALUX-TEQ/WHO-TEQ ratio = 1.0-3.0), which was consistent with the theoretical quantification limit of the CALUX. These results supported the validity of the proposed clean-up method.

Polychlorinated Dibenzo-p-Dioxins, Polychlorinated Dibenzofurans, and Coplanar Polychlorinated Biphenyls in Human Milk in Osaka City, Japan

Forty-eight human milk samples were collected from primiparous mothers in Osaka City from June 1999 to January 2000 and analyzed for polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like coplanar polychlorinated biphenyls (CoPCBs). Mean toxic equivalents (TEQs) in the milk were 13.86 pg I-TEQ/g fat or 16.50 pg World Health Organization (WHO)-TEQ/g fat for PCDDs and PCDFs; 9.87 pg WHO-TEQ/g fat for CoPCBs; and 23.74 pg TEQ/g fat using I-TEQ values of PCDDs and PCDFs or 26.36 pg TEQ/g fat using WHO-TEQ values of PCDDs and PCDFs for total PCDDs, PCDFs, and CoPCBs. The TEQ levels of these chemicals in human milk in Osaka City were in the range of levels in human milk surveyed in Japan, but the TEQ levels of PCDDs and PCDFs and total PCDDs, PCDFs, and CoPCBs from our study were slightly higher than average TEQ levels in human milk in Japan. When comparing our data with the latest data from the United States and some European countries, the TEQ levels of PCDDs and PCDFs in human milk from Osaka City were relatively high, whereas those of CoPCBs were ranked as being of intermediate level. Only TEQ values of CoPCBs in human milk were found to correlate with the increasing age of mothers and their estimated intake of seafood during the year before pregnancy. Concentrations of PCBs 105 and 118 contributed to TEQ values of CoPCBs associated with seafood intake, whereas those of PCBs 156, 157, 114, 189, 167, and 169 contributed to TEQ values of CoPCBs associated with increasing maternal age.

Occurrence of polybrominated diphenylethers, polychlorinated dibenzo- p-dioxins, dibenzofurans and biphenyls in coastal sediments from Spain

Fifteen sediment samples were analysed in order to determine their content of polybrominated diphenylethers (PBDEs), polychlorinated dibenzo- p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs). Samples were collected from several hot spots on the Spanish coast, such as the harbours of Almeria and Tarragona, and the mouths of the Besós and Llobregat rivers in Barcelona. A generic analytical procedure based on Soxhlet extraction followed by an automated cleanup system and gas chromatography-ion trap-mass spectrometry was employed for determining the toxic congeners of PCDDs and PCDFs, as well as dioxin-like PCBs. As regards PBDE determinations, a rapid method based on the use of selective pressurized liquid extraction followed by gas chromatography-negative ion chemical ionization-mass spectrometry was applied. Total toxicity equivalent (WHO-TEQ) values were calculated using the toxicity equivalent factors proposed by WHO for dioxin-like PCBs, PCDDs and PCDFs. WHO-TEQ values ranged from 0.3 to 75 pg/g dry weight (dw), with PCB contribution on the toxicity of the samples between 1 and 84%. Total PBDE levels ranged from 2.7 to 134 ng/g dw, with BDE-209 contribution on the total PBDE contamination between 50 and 99%.

Residues of PCDD, PCDF, and PCBs in some marine organisms in Lake Temsah, Ismailia, Egypt

Residues of PCDDs/F, non-ortho, mono-ortho PCBs, and other PCBs were monitored in the tissues of mullet fish, bolti fish, bivalves and crab taken from Lake Temsah, at Ismailia, Egypt. Results showed that 2,3,7,8 Tetra CDD and 1,2,3,7,8 Penta CDD were the most frequently detected PCDD congeners. Similarly, 2,3,7,8 Tetra CDF, 1,2,3,7,8 Penta CDF and 2,3,4,7,8 Penta CDF were the most frequently detected PCDF congeners. No relationship was apparent between the concentrations of detected PCDDs congeners and the degree of chlorination, except with crab samples in which an increase in the chlorination coincided with a decrease in the concentrations of the congeners. In PCDF congeners, detected residues have had a reversed relationship with chlorination increase. In PCDD congeners, Octa CDD had the highest detected concentrations in the two fish species, while in the bivalves and crab, 2,3,7,8 Tetra CDD had the highest concentrations. The mullet fish had the highest total PCDDs concentration, at 0.398 pg/g fresh weight, followed by crab at 0.395 pg/g fresh weight, then bivalves and bolti fish at 0.187 and 0.062 pg/g fresh weight, respectively. In all the examined organisms, the total concentrations of PCDFs were much higher than the total concentrations of the PCDD congeners. The WHO–TEQ values were 11.92, 39.12, 25, and 3.6 pg/g fresh weight, for mullet fish, bolti fish, bivlaves and crab, respectively. The concentration of the mono-ortho congeners CB 118 was the highest detected of all non-ortho and mono-ortho PCBs congeners, with values of 0.382, 0.022, 0.231 and 0.357 ng/g fresh weight, in mullet fish, bolti fish, bivalves and crab, respectively. The WHO–TEQ concentrations were 0.799, 0.003 pg/g fw, 0.05 pg/g fresh weight, 0.676 pg/g, and 0.799 pg/g fresh weight, for the same species, respectively. The total concentration of PCBs 28, 52, 95, 99, 101, 105, 110, 118, 138, 146, 149, 151, 153, 170, 177, 180, 187 were 6.86 ng/g fresh weight for mullet fish, 0.2 ng/g fresh weight, for bolti fish, 2.72 ng/g fresh weight for bivalves and 2.8 ng/g fresh weight for crab, respectively.

Usefulness of Reporter Gene Assay for AhR agonists, CALUX Assay

The reporter gene expression method CALUX cell bioassay has proven to be a very valuable screening technique for assessing toxic equivalents of dioxin and dioxin-like compounds, because it detects all AhR ligands in a variety of sample matrices. Used with the two specially elaborated clean-up procedures, CALUX cell bioassay was established for various environmental and biological samples. Consequently, the CALUX-TEQ values are correlated with high correlation coefficiencies to WHO-TEQ values derived from HRGC/HRMS. CALUX assay has been applied to the screening and quarantine of food items with possible dioxin contaminations in the EU. In addition, the method has been applied to biological samples such as serum, breast milk and fat tissues. Several reported studies demonstrated that CALUX cell assay is a useful tool and applicable in human epidemiological studies. We need to establish multi-national comparative studies in the field of dioxin contamination.

Exposure of breast-fed children in the Czech Republic to PCDDs, PCDFs, and dioxin-like PCBs

Human milk samples from 81 mothers living in seven selected localities of the Czech Republic collected in 1999–2000 were analyzed for PCDDs, PCDFs, and dioxin-like PCBs. Significant local differences in total WHO-TEQ values were observed (median ranges: 27.8–64.6 pg/g fat) with the highest level in Uherské Hradiště, but the highest PCDD-TEQ value was in Prague. Seven congeners (2,3,7,8-TCDD, 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF, and PCBs 118, 126, 156, and 157) cover about 90–94% of the total TEQ level. The non- and mono- ortho PCBs account for approximately 50–70% of the total TEQ levels in individual groups. The calculated median daily intake of the total TEQ for breast-fed infants ranged from 271 pg/kg b.w./day in Uherské Hradiště to 117 pg/kg b.w./day in Liberec and exceeded by about two orders of magnitude a tolerable daily intake (TDI) of 1–4 pg/kg b.w. recommended by the WHO. Our results confirmed significant local differences in the levels of dioxins and suggest that hot spot locations might exist within the country.

Evaluation of mixture effects in a crude extract of compost using the CALUX bioassay and HPLC fractionation

Potential synergistic interactions between polycyclic aromatic hydrocarbons in a household sewage sludge compost extract were investigated using the Dioxin-Responsive Chemical-Activated Luciferase gene eXpression (DR-CALUX) assay and reverse-phase high-performance liquid chromatography (RP-HPLC) fractionation. The biological activity of the crude extract was measured in vitro using the CALUX assay. The CALUX activity of the extract was as potent as 360-pg CALUX-TEQ (2,3,7,8-TCDD equivalent value) per g sample, this was 70 times above the WHO-TEQ value which was derived from chemical analyses of dioxins/furans and dioxin-like PCBs of the mixture. The CALUX activity pattern of the crude extract and the retention times of 26 polycyclic aromatic compounds (PACs), as determined by RP-HPLC on an octadecylsilica column, suggested that the dioxin-like compounds with the log K OW ( n-octanol/water partition coefficient) values corresponding to 6.0–7.0 contributed highly to the whole activity. The CALUX activity of the crude extract was three times the sum of the CALUX activities of the RP-HPLC separated fractions. Mixture effects were assessed by co-exposure of each HPLC fraction and 2,3,7,8-TCDD to the cells. The four concentration levels of added 2,3,7,8-TCDD corresponded to the TEQ value in the original compost sample. The experimental CALUX activity was higher than the predicted CALUX activity for some fractions. It was demonstrated that some compounds in the compost sample interacted synergistically with 2,3,7,8-TCDD in terms of dioxin-like activity. This finding points out the necessity for detailed investigation of synergistic effects in environmental samples.

Importance of REP values when comparing the CALUX bioassay results with chemoanalyses results: Example with spiked vegetable oils

Differences between chemical activated luciferase gene expression (CALUX) bioassay and chemoanalyses results are observed. This paper shows that calculations of the TEQ values using REP values instead of WHO TEF values give different results. The REP values do affect the results obtained by the CALUX technique. These differences are more marked for the dioxin like PCB compounds (CALUX TEQ values are lower than WHO TEQ values) than for the dioxin compounds (CALUX TEQ values are higher than WHO TEQ values). The CALUX results were compared with the concentrations of the congeners’ spiked into the oil.

Waste wood recycling as animal bedding and development of bio-monitoring tool using the CALUX assay

Animal bedding made of waste wood samples from seven different plants in Japan were chemically analyzed in terms of persistent organic pollutants (POPs) including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/DFs), coplanar polychlorinated biphenyls (Co-PCBs), drin compounds, chlordane compounds and various inorganic toxic compounds (Cr, Cu, As, B, Cd and Pb) to investigate the chemical characteristics and levels of contamination. Further investigation was conducted to determine the success of applying the Chemically Activated Luciferase Expression (CALUX) bioassay to the waste wood samples in combination with a cleanup procedure for the detection of dioxin-like compounds in order to develop the CALUX bioassay as a rapid and cost-effective screening/monitoring method and a contributive tool to risk management in the waste wood recycling process. For the cleanup procedure, crude extracts from wood samples were prepared by dimethylsulfoxide (DMSO)/n-hexane extraction, and then the extracts were processed by silica gel–44% sulfuric acid reflux treatment at 70 °C for 60 min to yield the bioassay fractions.The presence of POPs and inorganic toxic compounds were confirmed in most of the litter samples. In particular, Co-PCBs in one sample (litter dust) showed a high concentration level (1,200,000 pg/g, 240 pg TEQ/g), suggesting the potential for contamination from demolition waste.The CALUX assay-determined TEQs (CALUX-TEQs) were significantly high in the sample after DMSO/n-hexane extraction, probably due to labile aryl hydrocarbon receptor (AhR) ligands such as PAHs; however, they were remarkably reduced through a single silica gel–44% sulfuric acid reflux treatment. The ratio between CALUX-TEQ values and WHO toxicity equivalent values (WHO-TEQ) obtained by congener-specific chemical analysis ranged from 0.058 to 22 and show comparatively good agreement. Underestimation in some samples, however, was observed where WHO-TEQ values of Co-PCBs contributed greatly to total WHO-TEQ values. Reasons for this gap could be lower CALUX assay-determined relative potencies (REPs) than the WHO-TEFs for these congeners or AhR-antagonistic effects of non dioxin-like PCBs which coexist at higher concentration than Co-PCBs. The CALUX assay is proposed as a promising application in the recycling process of wooden materials.