Polychlorinated dibenzo-p-dioxins and related compounds: the blood levels of young Japanese women

Detectable Dioxins in Human Saliva and Their Effects on Gingival Epithelial Cells

Dioxin, a powerful hormone-disrupting chemical, exhibits serious health effects when it reaches body fat. Here we analyzed coplanar polychlorinated biphenyls (PCBs) and polychlorinated-dibenzo- p-dioxins (PCDDs) in human saliva as compared with blood specimens, and examined their effects on human gingival epithelial cells (HGEC). High levels of tri- and tetrachlorinated PCBs were found in saliva, whereas we detected predominantly hexa- and heptachlorinated PCBs in blood. Among PCDDs, the saliva and blood specimens contained mainly 1,2,3,4,6,7,8,9-octachlorodibenzo- p-dioxin (OCDD). Among the toxic dioxins proposed by the World Health Organization (WHO) in 1998, 2,3′,4,4′,5-pentachlorobiphenyl (PCB 118) and OCDD, which were mainly found in saliva, significantly induced IL-8 production in HGEC. Furthermore, these two dioxins markedly augmented IL-8 production stimulated with fimbriae from Porphyromonas gingivalis, which is well-known as a pathogenic factor in periodontal diseases. These results suggest that dioxins in saliva may be a risk factor for periodontal diseases.

Application of pharmacokinetic modelling for 2,3,7,8-tetrachlorodibenzo-p-dioxin exposure assessment

Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and mono- and non-ortho polychlorinated biphenyls (dioxin-like PCBs) are identified as a family or group of organic compounds known as 'dioxins' or dioxin-like chemicals (DLCs). The most toxic member of this group is 2,3,7,8-tetrachlorodibenzo-(p)-dioxin (TCDD). Historically, DLCs have caused a variety of negative human health effects, but a disfiguring skin condition known as chloracne is the only health effect reported consistently. As part of translational research to make computerized models accessible to health risk assessors, the Concentration- and Age-Dependent Model (CADM) for TCDD was recoded in the Berkeley Madonna simulation language. The US Agency for Toxic Substances and Disease Registry's computational toxicology laboratory used the recoded model to predict TCDD tissue concentrations at different exposure levels. The model simulations successfully reproduced the National Health and Nutrition Examination Survey (NHANES) 2001-2002 TCDD data in age groups from 6 to 60 years and older, as well as in other human datasets. The model also enabled the estimation of lipid-normalized serum TCDD concentrations in breastfed infants. The model performed best for low background exposures over time compared with a high acute poisoning case that could due to the large dose and associated liver toxicity. Hence, this model may be useful for interpreting human biomonitoring data as a part of an overall DLC risk assessment.

Blood levels of dioxins, furans, dioxin-like PCBs, and TEQs in general populations: a review, 1989-2010

A comprehensive worldwide literature review of blood levels of dioxins and dioxin-like compounds in non-exposed adult general populations was performed. The studies published in 1989-2010 reporting information on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho-PCBs (nPCBs), mono-ortho-PCBs (mPCBs) levels and Toxic Equivalencies (TEQs, a summary weighted measure of their combined toxicity) were reviewed. TEQs were calculated using as standard the most recent WHO 2005 reevaluation of Toxic Equivalency Factors (TEFs). Weighted multiple regression analyses adjusted for year, subject's age, type of sample analyzed, method used for values below detection limit, and central tendency measure used were performed for each congener and standardized TEQs (log-transformed). We identified 187 studies regarding 29,687 subjects of 26 countries. Year of blood collection ranged from 1985 to 2008. The studies reporting congener levels 161. In adjusted analyses, European countries showed higher levels of most dioxin-like congeners and TEQs. A strong positive association of subjects' age with most congeners and with TEQ values was found, confirming previous findings. Significant decreases over time (1985-2008) were documented for PCCDs, PCDFs, and TEQs including their contributions. No significant decrease was found for non-ortho-PCBs, notably PCB 126. Only some mono-ortho-PCBs showed clear significant declines. Accordingly, TEQs including only PCB contribution did not decrease over time. In interpreting these findings, it should be considered that for dioxin-like PCBs the analysis period was shorter (17 years), since these compounds were first measured in 1992.

A longitudinal study of trends in blood dioxins and dioxin-like compounds levels in residents from two locations in Japan during 2002-2006

To investigate the recent changes in background exposure to dioxin-related compounds, the concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (dl-PCBs) in the blood of individual residents in Japan were repeatedly examined. Twenty-six subjects (mean age, 52.7 +/- 1.8) from District A and 23 subjects (mean age, 56.1 +/- 1.2) from District B were longitudinally analyzed from 2002 to 2006. District A is a rural area in Osaka prefecture, and District B is an urban area in Saitama prefecture. For the longitudinal analysis of these concentrations, we used the generalized estimating equation (GEE). The PCDD + PCDF concentrations decreased significantly between 2002 and 2006 (p < 0.0001), but the concentrations of dl-PCBs declined to a smaller degree over the 5-year period. A time x body mass index (BMI) interaction suggests that the reduction rate of blood PCDDs + PCDFs and dl-PCB concentrations in subjects with a BMI greater than the 75th percentile is lower than that of subjects with a BMI less than the 75th percentile from 2002 to 2004 over the 5-year period. From other reports on the dietary intake of PCDDs, PCDFs, and dl-PCBs in Japan, the total amount of daily dioxin intake decreased, but the percentage of dl-PCBs increased yearly in the first half of the 2000s. The reason for the difference in the 5-year change in blood concentrations between PCDDs +PCDFs and dl-PCBs may be explained by the yearly change in the dietary dioxin intake.

PCDDs/PCDFs and dioxin-like PCBs: recent body burden levels and their determinants among general inhabitants in Japan

OBJECTIVE

The objective was to grasp the recent body burden levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (DL-PCBs) and to investigate their determinants among general inhabitants in Japan.

METHODS

This study was performed on 1374 participants aged 15-73 years, who were not occupational exposure to PCDDs/PCDFs and DL-PCBs, living widely in 75 different residential areas of 25 prefectures in Japan. Seven PCDDs, ten PCDFs, twelve DL-PCBs, which are assigned a toxicity equivalent factor, and biochemical factors were determined in fasting blood. A questionnaire survey on life-style was also performed.

RESULTS

The median of total toxicity equivalent (TEQ) was 20pgTEQ/g lipid. The TEQs of PCDDs/PCDFs, DL-PCBs and total TEQ increased with age. The intake frequency of fish-and-shellfish was positively associated with the TEQ of DL-PCBs in both sexes. Current smoking was negatively related to the TEQ of DL-PCBs in male subjects but not in female subjects. Feeding status was significantly related to the TEQs of PCDDs/PCDFs, DL-PCBs and total TEQ, being lowest in breast feeding and highest in never and bottle feeding. According to the results of subgroup analysis, parity was not associated with the TEQs.

CONCLUSIONS

The fish-and-shellfish consumption may contribute to the accumulation of DL-PCBs, and smoking may induce some biological action for the elimination of DL-PCBs from the human body. Breast feeding is considered to be one of the major excretory pathways of PCDDs/PCDFs and DL-PCBs in women, while parity may not largely contribute to the elimination of these pollutants.

Concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and dioxin-like polychlorinated biphenyls in blood and breast milk collected from 60 mothers in Sapporo City, Japan

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 paired samples of blood and breast milk collected from 60 mothers in Sapporo City, Hokkaido Prefecture, Japan. The present study is one of the few studies in which PCDDs, PCDFs, and dioxin-like PCBs have been measured in blood and breast milk collected from 60 same mothers. Of these 60 mothers, 30 were primipara (mean: 30.1 years, median: 28.0 years) and 30 were multipara (mean: 32.2 years, median: 32.5 years). The arithmetic mean TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of the primiparous mothers were 9.0, 3.3, 5.7, and 0.4 pg TEQ g(-1) lipid, respectively, and 5.2, 2.2, 4.5, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations of these dioxin-like compounds being 9.3-42.9 (mean: 18.4, median: 17.3) and 7.0-41.1 (mean: 12.3, median: 11.4) pg TEQ g(-1) lipid, respectively. In the case of multiparous mothers, the arithmetic mean TEQ concentrations of these dioxin-like compounds in blood and breast milk were 7.1, 2.7, 5.3, and 0.4 pg TEQ g(-1) lipid, respectively, and 3.9, 1.7, 3.8, and 0.4 pg TEQ g(-1) lipid, respectively, with the total TEQ concentrations being 3.4-28.1 (mean: 15.5, median: 13.9) and 2.7-20.0 (mean: 9.8, median: 9.2)pg TEQ g(-1) lipid, respectively. The total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of primiparous mothers in Sapporo City appeared to be generally lower than those recently surveyed throughout the greater area of Japan. Significant correlations were observed between age and the total TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in the blood of primiparae and multiparae, and significant correlations were also observed between age and the total TEQ concentrations of these dioxin-like compounds in the breast milk of primiparae and multiparae. The total TEQ concentrations of PCDDs, PCDFs, and dioxin-like PCBs in the blood of primiparous mothers showed a close correlation to those in their breast milk and also showed good correlations between the total TEQ concentrations of these dioxin-like compounds in the blood of multiparous mothers and those in their breast milk. The result of a comparison of the arithmetic mean concentrations of each congener of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk indicated that the transfer of octachlorodibenzo-p-dioxin (OCDD) from the blood to the breast milk was lower than those of other congeners. In contrast, among mono-ortho PCBs congeners, the arithmetic mean concentrations of 2,3',4,4',5-pentachlorobiphenyl (PentaCB) (#118) and 2,3,3',4,4'-PentaCB (#105) in the breast milk were slightly higher than those in the blood, which suggested that breast-fed infants may be at higher risk from mono-ortho PCBs.

Evaluation of age, gender and regional concentration differences for dioxin-like chemicals in the Australian population

The results of this study provide a measure of the levels of dioxin-like compounds (polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls) in pooled blood serum collected throughout Australia in 2003. De-identified samples selected from surplus pathology samples were stratified on the basis of gender, region and age. In total 9090 samples were collected and analysed as 96 pools. Dioxin-like chemicals were detected in all strata. The mean and median levels expressed as TEQ values for all pooled samples were 10.9+/-1.0 pg TEQ g(-1) lipid and 8.3 pg TEQ g(-1) lipid. For males and females the mean levels were 10.4+/-0.6 pg TEQ g(-1) lipid and 11.5+/-1.5 pg TEQ g(-1) lipid, respectively. A direct relationship of increasing dioxin-like chemical levels with increasing age was observed and could be described by the following equation: Levels in blood expressed as pg TEQ g(-1) lipid = 3.3 exp(0.0251 age) (r2 = 0.87). No significant differences were observed in the levels of dioxin-like chemicals in samples collected from males and females. In addition, the levels of dioxin-like chemicals across the five regions were similar within each age range. In summary, the levels of dioxin-like chemicals in the Australian population are low compared to international levels and are similar across all regions of Australia within each designated age range. The levels of these chemicals increase with age and can be estimated if the age of an individual is known.

Predictors of serum dioxin levels among adolescent boys in Chapaevsk, Russia: a cross-sectional pilot study

BACKGROUND

Toxicological studies and limited human studies have demonstrated associations between exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) and adverse developmental and reproductive health effects. Given that children may be particularly susceptible to reproductive and developmental effects of organochlorines, and the paucity of information available regarding childhood exposures to dioxins in particular, we undertook a pilot study to describe the distribution of, and identify potential predictors of exposure to, dioxin-like compounds and dioxins among adolescent boys in Chapaevsk, Russia. The pilot study was also designed to guide the development of a large prospective cohort study on the relationship of exposure to PCDDs, PCDFs, and PCBs with growth and pubertal development in peri-pubertal Chapaevsk boys.

METHODS

221 boys age 14 to 17 participated in the pilot study. Each of the boys, with his mother, was asked to complete a nurse-administered detailed questionnaire on medical history, diet, and lifestyle. The diet questions were used to measure the current and lifetime consumption of locally grown or raised foods. Blood samples from 30 of these boys were sent to the Centers for Disease Control and Prevention (CDC) for analysis of dioxins, furans and PCBs.

RESULTS

The median (25th, 75th percentile) concentrations for total PCDDs, PCDFs and coplanar PCBs were 95.8 pg/g lipids (40.9, 144), 33.9 pg/g lipids (20.4, 61.8), and 120 pg/g lipids (77.6, 157), respectively. For WHO-TEQs, the median (25th, 75th percentile) for total PCDDs, PCDFs, and coplanar PCBs were 0.29 (0.1, 9.14), 7.98 (5.27, 12.3), and 7.39 (4.51, 11.9), respectively. Although TCDD was largely non-detectable, two boys had high TCDD levels (17.9 and 21.7 pg/g lipid). Higher serum levels of sum of dioxin-like compounds and sum of dioxin TEQs were positively associated with increased age, consumption of fish, local meats other than chicken, PCB 118, and inversely with weeks of gestation.

CONCLUSION

The total TEQs among Chapaevsk adolescents were higher than most values previously reported in non-occupationally exposed populations of comparable or even older ages. Dietary consumption of local foods, as well as age and weeks of gestation, predicted dioxin exposure in this population.

Concentrations of dioxins and related compounds in the blood of Fukuoka residents

Blood samples of 152 residents (male 75 and female 77) aged 20-60 years in Fukuoka, Japan, were analyzed for dioxin toxic compounds of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho polychlorinated biphenyls (non-ortho PCBs) and mono-ortho polychlorinated biphenyls (mono-ortho PCBs) as well as 35 PCB congeners and 12 chlorinated pesticides by high-resolution gas chromatography/high-resolution mass spectrometry. Average concentrations of dioxin toxic equivalents (TEQ) from PCDDs, PCDFs, non-ortho PCBs, mono-ortho PCBs and their total in the blood of 152 residents were 10.28, 5.56, 7.75, 4.57 and 28.15 ppt in lipid, respectively. These total TEQ levels were comparable to the blood TEQ levels of normal Japanese (n=735). Lipid basis total TEQ levels progressively increased in the males from 17.1 ppt at age 20s to 47.5 ppt at age 50s and in the females from 19.5 ppt at age 20s to 54.5 ppt at age 50s. Dioxin toxic contribution of PCBs to total TEQ was increased from 31% at age 20s to 55% at age 50s. Average concentrations of total 35 PCBs and total 12 pesticides in the blood of 151 residents were 386 and 1079 ppb in lipid, respectively. Average concentrations (ppb in lipid) of total PCBs and total pesticides also progressively increased in the males from 213 and 444 at age 20s to 868 and 2140 at age 50s, respectively, and in the females from 199 and 588 at age 20s to 550 and 1977 at age 50s, respectively. The levels of TEQ, PCBs, hexachlorobenzene, beta-hexachlorocyclohexane, dieldrin, p,p'-dichlorodiphenyldichloroethylene, p,p'-dichlorodiphenyltrichloroethane, trans-nonachlor and cis-nonachlor were positively correlated with each other in most of the combinations, and the highest correlations (r>0.8) were observed between total TEQ and PCBs in both sexes.

Background exposure to PCDDs/PCDFs/PCBs and its potential health effects: a review of epidemiologic studies

Here we review epidemiologic studies dealing with the dietary intake and the body burden of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzo-furans (PCDFs)/ polychlorinated biphenyls (PCBs) in the general population, and potential adverse health effects of these substances, especially on the risk of diabetes mellitus and endometriosis, and on thyroid function and the neurodevelopment of infants. The mean or median intake of dioxin-related compounds among the general populations of various countries is lower than the maximum tolerable daily intake (TDI) set by the WHO in 1998 (4pg TEQ/kg/day). However, there have been few reports on the distribution of intake and the proportion of subjects whose exposure levels exceed the maximum TDL. At present, it remains unclear whether background exposure to dioxin-related compounds is associated with increased risk of diabetes (because of lack of longitudinal studies), endometriosis (because of lack of studies with sufficient statistical power), or altered thyroid function (because of inconsistent results on humans). Consistent results have been reported for the association between exposure to background levels of PCBs/dioxins, especially trans-placental PCBs, and defective neurodevelopment of infants in the U.S. and Europe. Thus, efforts should be made to further decrease the body burden among women of reproductive age by reducing the release of PCDDs/PCDFs/PCBs into the environment.

Impact of FEBRA (fermented brown rice with Aspergillus oryzae) intake and concentrations of PCDDs, PCDFs and PCBs in blood of humans from Japan

Impact of FEBRA (fermented brown rice with Aspergillus oryzae, a rich dietary fiber) intake on the concentrations of polychlorinated-biphenyls (PCBs), -dioxin-like polychlorinated biphenyls (DLPCBs), -dibenzo-p-dioxins (PCDDs), and -dibenzofurans (PCDFs) in blood of nine married Japanese were studied for 2 years. Concentrations of total PCBs (average+/-standard deviation) were greater 326,000+/-263,000 and 207,000+/-89,000 in FEBRA-intake and non-FEBRA-intake groups, respectively, on pg/g lipid (from now onwards data expressed on pg/g lipid). DLPCBs were second major contaminants 94,000+/-77,000 and 60,000+/-28,000, orderly in FEBRA-intake and non-FEBRA-intake groups. The concentrations of PCDD/DFs were several orders of magnitude lower than those of PCBs, whereas PCDDs were greater (433+/-233 and 512+/-511, in FEBRA-intake and non-FEBRA-intake groups, respectively) than PCDFs (56+/-50 and 43+/-35). Calculated toxic equivalency (TEQ) concentrations were 34+/-24 and 23+/-10 in FEBRA-intake and non-FEBRA-intake groups, respectively. In order to corroborate the impact of FEBRA, the changes of PCDD/DFs and PCB concentrations for 0.5-year, 1-year, 1.5-year, and 2-year samples were estimated from average concentration of 1-day before study commences and 1-week study samples. The results explicit FEBRA-intake group eliminated 7%, 33%, 45%, 36%, and 26% and non-FEBRA-intake group eliminated 8%, 28%, 36%, 31%, and 20% of DLPCBs, PCDDs, PCDFs, PCDD/DF TEQ and total TEQ, respectively. This study is the first of its kind showing the possible elimination of PCDDs, PCDFs and their TEQ in humans from Japan after the consumption of FEBRA.

Levels and tissue-dependent distribution of dioxin in Japanese domestic leafy vegetables--from the 1999 national investigation

In 1999, Japanese domestic leafy vegetables were successively investigated for levels of dioxins, including 17 dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), four non-ortho co-planar PCBs (co-PCBs) and eight mono-ortho co-PCBs, all of which had been assigned toxic equivalency factors (TEFs) by WHO in 1997. The mean levels of dioxins in the edible portions were 0.07 (0.09) pg TEQ/g in spinach, 0.13 (0.14) pgTEQ/g in garland chrysanthemum, 0.01 (0.04) pg TEQ/g in mitsuba (marsh parsley) and 0.01 (0.03) pg TEQ/g in chingentsuai (Brassica Campestris var. chinesis), when non-detects were set to zero (and set to half the limit of detection). In order to understand the dioxin pollution of leafy vegetables in detail, a further investigation of dioxin levels in the tissues of spinach was conducted. As a result, the dioxin levels in the leaves were found to be higher than those in the stem and red collar, but they were much lower than those found in the primary and secondary roots, which are considerably affected by the soil, which is recognized as a sink of airborne dioxins. The dioxin levels in edible portions (leaves, stem and red collar) were obviously lower than those in non-edible portions (primary and secondary roots). In addition, from the finding that several lower-chlorinated PCDD/Fs and co-PCBs, namely 2,3,7,8-TCDD/F, 1,2,3,7,8-PeCDD, 1,2,3,7,8/2,3,4,7,8-PeCDFs, 1,2,3,7,8,9-HxCDD, 1,2,3,4,7,8-/1,2,3,6,7,8-HxCDFs, 3,3',4,4'-TCB, 2,3,3',4,4'-/2,3',4,4',5-PeCBs, and 2,3',4,4',5,5'-HxCB, were more highly represented in the dioxins in the leaves than in those in the secondary roots, it was suggested that in leafy vegetables the deposition of gaseous, presumably moderately volatile dioxins in leaf wax is another pollution pathway in addition to the adhesion of dioxin-contaminated particles including soil.