Dechlorination of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans on fly ash

Dechlorination of commercial mixtures of polychlorinated biphenyls (PCB) as well as polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) on extracted and non-extracted fly ash obtained from municipal waste incinerator (MWI) was studied in closed systems under nitrogen atmosphere at temperatures of 260°C and 340°C. Decomposition results (given as the difference between PCB or PCDD/F molar amounts before and after the experiment (in %) due predominantly to dechlorination reactions) and detoxification data (expressed similarly but related to toxic PCB and PCDD/F congeners only and given in I-TEQ units) are reported. Detoxification of Delor 105/80T at 260°C and 340°C at a loading of 0.65 wt% was 99.48% and 100%, respectively. The decomposition of Delor 103 at 340°C and for the loading of 0.75 wt% corresponded to 99.99%. The detoxification capability of PCDD/Fs on extracted and non-extracted fly ash for loading of 130 and 264 ng/0.4 g of fly ash at 340°C made 96 and 98%, respectively.     

Absorption of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans by breast-fed infants

The absorption of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans was studied in four breast-fed infants. The absorption was measured by comparing the estimated total intake and the excretion in faeces, during 48 hours, at three different time points; 1, 2 and 3 months post parta. The levels of the analysed compounds in the human milk are typical for Sweden, i.e 20 ppt toxic equivalents for the dibenzo-p-dioxins and dibenzofurans and for the polychlorinated biphenyls 16 ppt toxic equivalents. For most of the congeners the absorption is found to be over 95%. Higher excretion is noticed for heptachlorinated and octachlorinated dioxins.     

Detailed study on the levels of polychlorinated dibenzo-p-dioxins,polychlorinated dibenzofurans and polychlorinated biphenyls in Yusho rice oil

One bottle of Yusho rice oil was obtained from a Yusho family in 1998. The levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) in the causal oil were investigated with two different approaches and the individual concentrations of all the 17 2,3,7,8-substituted PCDD/F and 14 coplanar PCB (Co-PCB) congeners were elucidated for the first time. The concentrations of PCDDs and PCDFs were found to be 0.60 and 8.8 ppm, respectively. For PCBs, more than 130 PCB peaks were observed and a total concentration of 850 ppm including 170 ppm of Co-PCBs was obtained. The toxic equivalents (TEQs) of PCDDs, PCDFs, and Co-PCBs were calculated to be 17, 470, and 120 ppb, respectively. The relative contribution of these classes to the total TEQ in Yusho oil is 3%, 77%, and 20%, respectively, indicating that PCDFs play a major role in the toxicity of Yusho oil. Furthermore, it was confirmed that 2,3,4,7,8-penta-CDF contributes 58% to the total TEQ, supporting the view that this compound is the principal causal agent in Yusho poisoning. It is noteworthy that the most toxic 2,3,7,8-tetra-CDD was newly discovered, although it contributes only 0.1% to the total TEQ. Based on our data, the smallest TEQ intake during the latent period was estimated to be 0.067 mg for Yusho patients. This value is about 60% of that previously reported, suggesting a lower minimum threshold level for the development of the toxic symptoms of Yusho.     

Trend studies of polychlorinated biphenyls, dibenzo-p-dioxins and dibenzofurans in human milk

Human milk has been used in studies of long-term changes in the concentrations of organochlorine contaminants in mothers from the Stockholm region. The previously observed decline (1972 to 1985) in the levels of polychlorinated biphenyls (PCBs), dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) seems to have ceased for certain compounds since the levels were about the same in samples collected in 1985 and 1989. Calculating with the proposed toxicity equivalency factors for the different congeners of PCDDs, PCDFs and PCBs it is seen that the congeners of PCBs contribute more to the possible toxicity than those of PCDDs and PCDFs. The mono-ortho substituted congener 2,3′,4,4′,5-pentachlorobiphenyl (IUPAC No. 118) contributes with the largest part.     

Atmospheric deposition of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in the Kanto Region, Japan

The atmospheric bulk (dry and wet) deposition of dioxins was investigated at four locations (Tokyo, Yokohama, Tsukuba, and Tanzawa) in the Kanto region (in Japan) over one year using a stainless-steel pot. Annual average polychlorinated dibenzo-p-dioxins/polychlorinated dibenzofurans (PCDD/PCDF) deposition fluxes were estimated to be from 450 to 1300 ng/m2/yr, and the annual average TEQ fluxes from 5.7 to 17 ng-TEQ/m2/yr at the four locations. The PCDD/PCDF deposition flux was higher in winter than in summer. The deposition flux could be related to ambient temperature, particularly for less chlorinated PCDDs/PCDFs, while the deposition flux is not necessarily related to the amount of precipitation. The PCDD/PCDF deposition flux increased as the particle deposition flux increased, for the winter samples. Based on the ratio of the PCDD/PCDF deposition fluxes to the particle deposition fluxes, the contribution of the reentrainment of soil particles to the TEQ of PCDD/PCDF deposition was considered to be negligible in this region. Based on the air concentrations monitored near our deposition sampling points by the municipalities, the ratio of the annual deposition flux to the annual average air concentration was roughly estimated to be 0.082 cm/s. The range of deposition flux in the Kanto region was estimated to be from 1.5 to 31 (median: 9.8) ng-TEQ/m2/yr based on the range of air concentration data measured by the municipalities. The total annual deposition flux in the entire Kanto region was estimated to range from 50 to 900 g-TEQ/yr (median 320 g-TEQ/yr). This estimated flux was of the same order as the sum of estimated emissions from municipal solid waste incinerators and industrial waste incinerators in the Kanto region. The contributions of dioxin-like PCBs in Yokohama, Tsukuba, and Tanzawa depositions were less than 10% of the total TEQ; however, in Tokyo it was almost equal to or more than 50%.     

Distribution of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and non-ortho coplanar polychlorinated biphenyls in river and offshore sediments

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and non-ortho chlorine substituted coplanar polychlorinated biphenyl (Co-PCBs, non-ortho Cl CBs) in river and offshore sediment samples were analyzed isomer-specifically using (13)C-labeled their respective internal standards and a selected ion monitoring method of high resolution gas chromatograph-mass spectrometry (GC-MS). These compounds were found in all samples analyzed. The average concentrations of the total PCDDs, PCDFs and Co-PCBs in the 23 sediment samples taken from rivers were 11 000, 1300 and 160 pgg(-1) of dry wt, respectively, those in six offshore sediments were 7600, 980 and 52 pgg(-1), respectively. The concentrations of Co-PCBs were much lower than those of PCDDs and PCDFs in all sediment samples. The magnitude of these concentrations was in the order of lower reach of river > offshore area > upper reach of river. The concentrations of PCDDs and PCDFs in the rural river were higher than those in the urban river, whereas the Co-PCB concentration in an urban river was six times higher than that in a rural river. The Co-PCB concentrations in the urban area and industrial area were higher than that in any other area. These findings suggest that the pollution by PCDDs and PCDFs was derived from some kinds of incinerations and herbicides applied in the past and that Co-PCB pollution was caused by PCB preparation used in the past in urban and industrial areas and by municipal waste incineration in urban areas.     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and non-ortho and mono-ortho polychlorinated biphenyls in blood of Yusho patients

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho polychlorinated biphenyls (non-ortho PCBs) and mono-ortho polychlorinated biphenyls (mono-ortho PCBs) in blood collected from 279 Yusho patients living in Japan, 92 Yusho-suspected persons living in Japan and 127 normal controls living in Fukuoka Prefecture, and compared among the groups in terms the concentrations of these compounds. The total toxic equivalents (TEQ) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in the bloods of Yusho patients and Yusho-suspected persons were 161.4 and 51.2 pg TEQ/g lipid, respectively and were about 3.5 and 1.1 times higher than those of normal controls, respectively. Although the TEQ concentrations of PCDDs, non-ortho PCBs, and mono-ortho PCBs among Yusho patients, Yusho-suspected persons and normal controls were nearly the same, the PCDFs levels of Yusho patients were significantly higher than those of Yusho-suspected persons and about 10.3 times higher than those of normal controls. In Yusho patients, PCDFs contributed about 65% to the total TEQ concentration. Among the PCDFs congeners for Yusho patients, the concentration of 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) was about 11.3 times higher than that of normal controls. These findings indicated that Yusho patients even now, more than 34 years after the outbreak of Yusho, have much higher blood levels of 2,3,4,7,8-PeCDF in general than do unaffected persons.     

Persistent organic pollutants in Detroit River suspended sediments: polychlorinated dibenzo-p-dioxins and dibenzofurans,dioxin-like polychlorinated biphenyls and polychlorinated naphthalenes

Suspended sediments from the Detroit River were collected in 1999 and 2000 using sediment traps at sites ranging from western Lake Erie to southern Lake St. Clair and analyzed to determine the spatial distributions of contaminants including polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/PCDFs), dioxin-like PCBs (DLPCBs) and polychlorinated naphthalenes (PCNs). Concentrations of all three contaminant classes were clearly elevated at sites in the lower reaches of the river in the Trenton Channel. The potential influence of the Trenton Channel as a source of contamination to western Lake Erie was further evidenced by PCDD/PCDF homologue profiles, which indicated a contribution from chemical manufacturing in addition to the normal background combustion profile. Toxic equivalents (TEQs) for PCDDs/PCDFs generally exceeded those for DLPCBs; combined total TEQs in July 2000 for these two compound classes ranged from 2.30 pg/g in southern Lake St. Clair to 306 pg/g at a station just downstream of the outflow of Monguagon Creek in the Trenton Channel. The spatial distribution of PCN contamination was similar to that of PCDDs/PCDFs and DLPCBs, with the highest level of total PCNs (8200 ng/g) detected at a site in the Trenton Channel near Elizabeth Park; TEQs for PCNs in the Trenton Channel ranged from 73 to 3300 pg/g. The data indicate that PCNs represent a significant contribution to dioxin-like biological activity in Detroit River suspended sediments.     

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 Besos 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%.     

Polychlorinated dibenzo-p-dioxins,dibenzofurans and polychlorinated biphenyls in polar bear,penguin and south polar skua

Concentrations of 2378-substituted polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (DFs) and non- and mono-ortho-substituted polychlorinated biphenyls (dioxin-like PCBs) were measured in livers of polar bears from the Alaskan Arctic and in eggs of Adelie penguin and south polar skua and weddell seal liver, fish and krill from Antarctica. This is one of the first reports to document the concentrations of PCDDs/DFs in polar bear livers from Alaska, and in penguin and skua eggs from Antarctica. Concentrations of total PCDD/DFs in livers of polar bears ranged from 8 to 66 (mean: 26) pg/g, on a lipid weight basis. Concentrations of total PCDD/DFs in Antarctic samples were in the increasing order on a lipid weight basis; weddell seal liver (8.9 pg/g) < fish (11-17 pg/g) < krill (27 pg/g) > penguin eggs (30 ng/g) > seal liver (57 ng/g) > fishes (6.2 ng/g) > krill (0.9 ng/g). Concentrations of 2378-tetrachlorodibenzo-p-dioxin equivalents (TEQs) calculated based on the WHO TEFs were higher in the eggs of polar skua (mean: 344: range: 220-650 pg/g, lipid wt.) from Antarctica than in polar bear livers from Alaska (mean: 120; range: 69-192 pg/g). In general, concentrations of PCDFs were greater than those of PCDDs in polar organisms. 23478-PeCDF is one of the dominant congener found in several samples. Concentrations of TEQs in polar bear livers and skua eggs were close to those that may cause adverse health effects. Dioxin-like PCBs, particularly, non-ortho coplanar PCBs were the major contributors to TEQ concentrations in penguin and skua eggs whereas mono-ortho PCBs accounted for a major portion of TEQs in polar bear livers.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in rice plants: possible contaminated pathways

Uptake of dioxins was confirmed in rice plants. We determined (i) dioxin concentrations and isomer profiles in leaf+stem samples of rice plants grown in three soils with different dioxin concentrations and isomer profiles and (ii) temporal changes in dioxin concentrations and isomer profiles in rice grown in a paddy field on which agricultural chemicals containing dioxin impurities had been used in previous years. Principal-component and chemical mass-balance analyses of the data showed that dioxin concentrations and isomer profiles in the rice grown in the different soils were similar, even though the dioxin concentrations and isomer profiles of the soils were different. However, the dioxin concentrations in the rice were influenced by dioxin levels in the atmospheric gas phase. Changes in dioxin levels during the growing period of the rice were also strongly influenced by adhesion of the soil to plant components during the early stage of growth, but gradually the influence of the atmospheric gas phase became predominant. Calculated dietary uptake estimates indicated that, even in rice grown in Japan on soil contaminated with high concentrations of dioxins, the amount of dioxins ingested by humans from rice is extremely small, and the amount of dioxins ingested by livestock from forage rice is similar to that for other forage crops.     

Maternal transfer of organochlorine pesticides, polychlorinated dibenzo-p-dioxins, dibenzofurans, and coplanar polychlorinated biphenyls in frogs to their eggs

Previous study confirmed that there were sexual differences in concentrations of organochlorine pesticides and dioxins in frogs during the breeding season. The present study utilized the egg masses from the previous study to determine the cause(s) of the sexual differences. When concentrations of the detected chemicals were compared between the female frogs and their eggs, it was found that the concentrations in the eggs were several times those in their mothers. The results indicated that maternal transfer reduced tissue concentrations in females. Since the weight of each egg mass was half that of the mother, two-thirds of the chemicals in a female frog were transferred to its eggs. In addition, the degree of maternal transfer differed among compounds. Maternal transfer of PCDDs and PCDFs with four or five chlorine atoms and coplanar PCBs followed the fugacity model. However, maternal transfer decreased for PCDDs/DFs with six or more chlorines as the octanol-water partition coefficient increased. From these results, maternal transfer was confirmed as the cause of sexual differences in concentrations of organochlorine pesticides and dioxins in adult frogs during the breeding season.     

Congener-distribution patterns and risk assessment of polychlorinated biphenyls,dibenzo-p-dioxins and dibenzofurans in Korean human milk

Polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and biphenyls (PCBs) were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry in human milk samples from an urban and an industrial area in Korea. All PCB congeners were analyzed to characterize the congener distribution as well as to evaluate the toxic equivalent quotient (TEQ) values and the total concentration. In homologue distributions of PCBs, two distinct patterns were found. The mean concentrations of PCDD/Fs and PCBs were 15.13 and 5.64 TEQ pg/g fat (based on WHO TEF, 1997), respectively. The contamination in Korean human milk is comparable to that found in other countries. From these results a daily intake of 60 TEQ pg/kg/day for an infant was estimated. The assumptions were that the infant breast feeds for 1 year, has an average body weight of 10 kg during this period, and ingests 800 g/day of human milk containing a mean concentration of 20.84 TEQ (PCDD/Fs) pg/g fat (based on primipara mothers).     

Health risk assessment for polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated naphthalenes in seafood from Guangzhou and Zhoushan, China

This study determined the concentrations of organochlorine contaminants in common seafood in two Chinese coastal cities (Guangzhou and Zhoushan), and assessed the health risk due to the daily consumption of contaminated seafood. Twenty-six pooled samples, belonging to five food categories (fish, bivalves, shrimp, crab, and cephalopods), were purchased from local markets in Guangzhou and Zhoushan in 2003 and 2004. These samples were analyzed for total polychlorinated biphenyls (PCBs), non- and mono-ortho-PCBs (coplanar PCBs), polychlorinated naphthalenes (PCNs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs/DFs). The concentrations of total PCBs and coplanar PCBs in fish samples were higher in Guangzhou than in Zhoushan, while the levels of PCNs and PCDDs/DFs were comparable between the two cities. The total daily intake values of dioxin-like compounds were 1.05 and 0.86pg WHO-TEQ/kg body weight in Guangzhou and Zhoushan, respectively. Hazard ratios of non-cancer risk in the two cities were all less than unity.     

Dietary exposure to polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls of the French population: Results of the second French Total Diet Study

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) bioaccumulate through the food chain and are therefore of public health concern. Exposure to these compounds was assessed in the second French Total Diet Study (TDS). Food samples (n=583) were collected to be representative of the whole diet of the population, prepared as consumed, and analyzed. Contamination data were combined with national individual food consumption data. Mean exposure (95th percentile) to PCDD/F+DL-PCBs was assessed to be 0.57 (1.29) pg TEQ(WHO-98) (kg bw)(-1) d(-1) in the adult population and 0.89 (2.02) pg TEQ(WHO-98) (kg bw)(-1) d(-1) in the child and teenager population. Less than 4% of the population exceeded the health-based guidance value for PCDD/F+DL-PCBs. Mean exposure (95th percentile) to the six indicator PCBs (PCB 28, 52, 101, 138, 153, 180) was estimated at 2.71 (7.90) ng (kg bw)(-1) d(-1) in the adult population and 3.77 (11.7) ng (kg bw)(-1) d(-1) in the child and teenager population. Only 2.6% of the adults [CI(95%): 1.9; 3.3] and 6.5% of the children and teenagers [5.2; 7.8] exceeded the health-based guidance value for total PCBs. These results show that the contamination levels in food and therefore the exposure of the general French population to PCDD/Fs and PCBs have declined (by a factor of 3.2 for PCDD/F+DL-PCBs and about three for total PCBs) since the last evaluation, which was conducted using another methodology in 2005 and 2007, and show the efficiency of the European risk management measures which came into force after these evaluations.     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in blood collected from 195 pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho coplanar polychlorinated biphenyls (non-ortho PCBs), and mono-ortho coplanar polychlorinated biphenyls (mono-ortho PCBs) in blood collected between 2002 and 2004 from 195 pregnant women living in Sapporo City of Hokkaido Prefecture, Japan. The present study is one of the few studies in which PCDDs, PCDFs, and dioxin-like PCBs have been measured in the blood of pregnant women. Of the 195 pregnant women, 101 were primipara (mean: 28.8 years) and 94 were multipara (mean: 32.4 years). The arithmetic mean total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs of primiparous and multiparous mothers in Sapporo City were 17.4 (median: 15.7) and 14.0 (median: 13.9)pgTEQ/glipid, respectively, and the concentrations were in the range of 6.6-43.4 and 3.4-28.2pgTEQ/glipid, respectively. In regard to the relationship between the total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in maternal blood and the number of deliveries or age of primiparous and multiparius mothers, the levels of these dioxin-like compounds tended to decrease with increases in the number of deliveries and significantly increased with increasing maternal age in both groups. Furthermore, significant correlations were observed between the total TEQ concentrations of these dioxin-like compounds and the age of primiparae and multiparae. The total TEQ concentration of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs measured in 195 pregnant women has decreased compared to past levels in Japan for the last several decades. The results of the present study have indicated that dioxin contamination in the blood of young women in Japan is continuing to decrease.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans and polychlorinated biphenyls levels in human breast milk from different regions of Turkey

Human breast milk offers the optimal nutrition for all infants and have been widely used in biomonitoring programs to assess human exposure to lipophylic environmental contaminants such as polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB). There are no previous reports from Turkey on chemically determined levels of PCDDs, PCDFs, and PCBs in human breast milk expressed as World Health Organization (WHO) toxic equivalents (TEQ). To get an overview of the levels of these contaminants in Turkish human milk, samples from 51 Turkish women living in the Ankara, İstanbul, Antalya, Kahramanmaraş, and Afyon provinces were analyzed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS) throughout 2007. The mean concentrations of WHO_PCDD/F-TEQ and WHO_PCB-TEQ of all samples from the five regions were 7.5 and 3.1 pg g⁻¹ on a lipid basis, respectively. PCDD/F concentrations ranged between 0.78 and 29.3 pg WHO-TEQ g⁻¹ fat (1.7 and 36.2 pg WHO-TEQ g⁻¹ fat, respectively, including PCB). Of the five studied locations, the lowest levels of ∑TEQs (PCDD/F + PCB) were found in the Afyon (6.8 pg WHO-TEQ g⁻¹ fat) and the highest in the Antalya (15.6 pg WHO-TEQ g⁻¹ fat) province. The results have been discussed in terms of regions and PCDD/F and PCBs for which analyses had been made. The mean levels of PCDD/Fs and PCBs in Turkish human milk are comparable to that found in other countries.     

Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in rice straw smoke and their origins in Japan

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (DL-PCBs) contained in the smoke generated from rice straw burning in post-harvest paddy fields in Japan were analyzed to determine their congener profiles. Both the apportionment of toxic equivalent (TEQ) by using indicative congeners and the comparison of the homolog profiles showed that the PCDDs/PCDFs/DL-PCBs present in the rice-straw smoke were greatly influenced by those present as impurities in pentachlorophenol (PCP) and chlornitrofen (CNP, 4-nitrophenyl-2,4,6-trichlorophenyl ether) formulations that had been widely used as herbicides in paddy fields in Japan. Further, in order to investigate the effects of paddy-field soil on the PCDDs/PCDFs/DL-PCBs present in rice-straw smoke, PCDD/PCDF/DL-PCB homolog profiles of rice straw, rice-straw smoke and paddy-field soil were compared. Rice-straw smoke was generated by burning rice straw on a stainless-steel tray in a laboratory. The results suggested that the herbicides-originated PCDDs/PCDFs/DL-PCBs and the atmospheric PCDDs/PCDFs/DL-PCBs contributed predominantly to the presence of PCDDs/PCDFs/DL-PCBs in the rice-straw smoke while the contribution of PCDDs/PCDFs/DL-PCBs formed during rice straw burning was relatively minimal. The major sources of the PCDDs/PCDFs/DL-PCBs found in the rice-straw smoke were attributed primarily to the paddy-field soil adhered to the rice straw surface and secondarily to the air taken by the rice straw. The principal component analysis supported these conclusions. It is concluded that rice straw burning at paddy fields acts as a driving force in the transfer of PCDDs/PCDFs/DL-PCBs from paddy-field soil to the atmosphere.     

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in blood and breast milk collected from pregnant women in Sapporo City, Japan

We measured the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (PCBs), and non-dioxin-like PCBs in paired samples of blood and breast milk collected from 67 secundiparas in Sapporo City, Japan, and combined this data with those of the 30 secundiparas previously measured. The arithmetic mean total toxic equivalents (TEQ-WHO) concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the 97 secundiparous subjects were 3.0-23 (mean: 13, median: 14) and 2.7-20 (mean: 8.6, median: 8.5) pg TEQ g⁻¹ lipid, respectively. The sums of the concentrations of 56 non-dioxin-like PCB congeners that were measured in the subjects’ blood and breast milk were 16-326 (mean: 107, median: 100) and 12-252 (mean: 73, median: 67) ng g⁻¹ lipid, respectively. The partitioning ratios of individual congeners of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs from blood to breast milk in secundiparas were almost the same as those of primiparas that have been recently reported, suggesting that the partitioning ratios of these compounds from maternal blood to breast milk in women is little affected by delivery. Furthermore, the partition of PCB congeners with chlorine at the 2-, 3-, 4′-, and 5-positions or the 2-, 4-, 4′-, and 5-positions of the biphenyl ring from the blood to the breast milk tended to occur at a higher level than that of other congeners. In particular, the levels of tetraCB-74 and hexaCB-146 in the breast milk for both primiparous and secundiparous mothers were slightly higher than those in the blood.