Health effects of chronic exposure to polychlorinated dibenzo-P-dioxins (PCDD), dibenzofurans (PCDF) and coplanar PCB (Co-PCB) of municipal waste incinerator workers

A national survey of polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF) in emission gases from the municipal waste incinerators in 1997 revealed that the Nose Bika Center was heavily contaminated by PCDF. Ninety-four workers underwent a physical examination, and blood biochemistry, lymphocyte marker, and NK activity studies were carried out, along with blood dioxin measurements. Information on working history, life-style, and dietary habits was obtained by questionnaire and interview. The blood dioxin levels were as follows. The median TEQ of dioxins was 39.7 pg I-TEQ/g lipid, and the range was 13.3 to 805.8. The median 2,3,7,8-TCDD concentration was 3.9 pg TEQ/g lipid, and the range was <1 pg TEQ/g lipid (one case) to 13.4 pg TEQ/g lipid. The median TEQ of coplanar PCB was 10.8 pg I-TEQ/g lipid, and the range was 3.1 to 54.2 pg TEQ/g lipid. The congener-specific distribution was quite similar to that in soil around incinerator and waste in the factory. The relationship between dioxin concentrations and work history in the factory showed that the fluidized incinerator and fly ash treatment areas were high-risk work areas. Correlation analyses between body burden, PCDD/PCDF TEQ, Co-PCB TEQ and various laboratory data showed significant positive correlations between dioxin levels and GGT, total protein, uric acid and calcium, and a negative correlation with Fe. However, these correlations disappeared as a result of multivariate analysis adjusted for age, smoking status, and alcohol drinking. Increased NK activity and lower response to PHA stimulation remained significant even after adjusting for age. History of hyperlipidemia and allergy had significantly increased odds ratios. A study on the risk to other workers in the same type of incinerators is under way. Health effects of chronic exposure mainly to PCDF will be clarified by follow-up.     

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in serum samples of workers at an infectious waste incineration plant in Japan

In 1998-2000, concentrations of summed polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in the exhaust gas of an infectious waste incineration plant were 17-510 ng toxic equivalents (TEQ)/m(3), which reached levels above the Japanese legal limit value of 80 ng TEQ/m(3). The incinerator ceased operation in November 2000. This study was aimed at determining whether the incinerator workers were exposed to high levels of PCDDs and PCDFs. Blood samples of five workers were collected at 1 month and 16 months after the end of the occupational dioxin exposure. For comparison, blood samples were also collected from control subjects. Ash remaining in the incinerator and dust deposited around the conveyer and incinerator areas were collected; TEQ values were 44 and 10 ng TEQ/g, respectively. A month after the end of occupational dioxin exposure, mean TEQ for the workers was 49.1 pg TEQ/g lipid, which was 2.7 times as high as that for the controls. At 16 months, the mean TEQ for the workers decreased to 29.4 pg TEQ/g lipid, which was 1.6 times that for the controls. Ratios of serum level of each congener of PCDDs and PCDFs between 1 and 16 months after exposure were 0.44 to 0.69. This study showed that the serum dioxin levels for the infectious waste incinerator workers were higher than the controls, and the serum dioxin level decreased after the end of the occupational dioxin exposure.     

An evaluation of the occupational health risks to workers in a hazardous waste incinerator

A study was conducted to evaluate the health impact of airborne pollutants on incinerator workers at IZAYDAS Incinerator, Turkey. Ambient air samples were taken from two sampling points in the incinerator area and analyzed for particulate matter, heavy metals, volatile and semi-volatile organic compounds (VOCs and SVOCs) and dioxins. The places where the maximum exposure was expected to occur were selected in determining the sampling points. The first point was placed in the front area of the rotary kiln, between the areas of barrel feeding, aqueous and liquid waste storage and solid waste feeding, and the second one was near the fly ash transfer line from the ash silo. Results were evaluated based on the regulations related to occupational health. Benzene, dibromochloropropane (DBCP) and hexachlorobutadiene (HCBD) concentrations in the ambient air of the plant were measured at levels higher than the occupational exposure limits. Dioxin concentrations were measured as 0.050 and 0.075 pg TEQ.m(-3), corresponding to a daily intake between 0.007 and 0.01 pg TEQ. kg body weight(-1).day (-1). An assessment of dioxin congener and homologue profiles suggested that gaseous fractions of dioxin congeners are higher in front of the rotary kiln, while most of them are in particle-bound phases near the ash conveyor. Finally, the necessity of further studies including occupational health and medical surveillance assessments on the health effects of the pollutants for the workers and the general population in such an industrialized area was emphasized.     

Isomer pattern and elimination of dioxins in workers exposed at a municipal waste incineration plant

The aim of this study was to clarify patterns of serum concentrations of dioxins in the employees of a waste incineration plant and to estimate elimination rates and half-lives of serum dioxin isomers, and the maximum serum concentrations of dioxin isomers at the time of plant shutdown. Sixteen subjects participating 3 times or more in annual health examinations during an 8-yr period from 2000 to 2007 were recruited for this study. Serum concentrations of dioxins expressed as TEQ/g lipid decreased gradually after plant shutdown with the highest decrease observed in polychlorinated dibenzofurans (PCDFs) followed by polychlorinated deibenzo-p-dioxins (PCDDs) and then coplanar PCBs. The serum toxic equivalency (TEQ) concentrations of PCDF and PCDD congeners in the employees were higher than those in the general population survey by the Ministry of the Environment, Japan, whereas the serum concentrations of coplanar PCBs were similar to those in the general population. The estimated half-lives and elimination rates of PCDDs and PCDFs in the highly exposed workers increased compared with the moderately exposed workers. The estimated geometric mean serum concentrations of PCDDs, PCDFs and total dioxins at the time of plant shutdown were 35, 53 and 107 pg TEQ/g lipid, respectively.     

Polychlorinated dibenzo-p-dioxin and dibenzofuran concentrations in serum samples of workers at intermittently burning municipal waste incinerators in Japan

Objectives: To find whether or not incinerator workers employed at intermittently burning municipal incineration plants are exposed to high concentrations of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs).

Methods: 20 Workers employed at three municipal waste incineration plants (incinerator workers) and 20 controls were studied. The previous job, dietary, smoking, and body weight and height were obtained from a questionnaire survey. Concentrations of PCDDs and PCDFs were measured in serum samples of the workers and the deposited dust of the plants. The influence of occupational exposure on concentrations of PCDDs and PCDFs in serum samples was examined by multiple regression analysis.

Results: Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin (HpCDD) among the PCDDs, and 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among the PCDFs. The toxicity equivalents (TEQs) of summed PCDDs and PCDFs in the deposited dust were 0.91, 33, and 11 ng TEQ/g, respectively, for plants I, II, and III. The means of TEQ in serum samples of summed PCDDs and PCDFs in the incinerator workers and controls were 22.8 and 16.4 pg TEQ/g lipid for area I, 29.4 and 19.3 pg TEQ/g lipid for area II, and 22.8 and 24.9 pg TEQ/g lipid for area III, which were almost the same as for the general population of Japan. No significant differences in the TEQ of PCDDs and TEQ of PCDDs and PCDDs were found between the incinerator workers and the controls. However, the TEQ of PCDFs was significantly higher among the incinerator workers in areas I and II, and the 1,2,3,4,6,7,8-HpCDF concentration was also significantly higher for all three areas. When the occupational exposure index for each constituent of PCDDs and PCDFs was defined as the product of the duration of employment at the incineration plant and the concentration of the constituent in the deposited dust, multiple regression analysis showed that the concentrations of HxCDF, HpCDF, and TEQ of PCDFs in serum samples increased with the occupational exposure index. The multiple regression analysis also suggested that significant factors affecting the concentrations in serum samples were area for HxCDD, age for TCDD, PeCDD, PeCDF, TEQ of PCDDs, TEQ of PCDFs, and TEQ of summed PCDDs and PCDFs, and BMI for HxCDD, HpCDD, and OCDD.

Conclusion: This study showed that incinerator workers employed at intermittently burning incineration plants were not necessarily exposed to high concentrations of PCDDs and PCDFs. However, the increases in the concentrations in serum of HxCDF, HpCDF and TEQ of PCDFs with the occupational exposure index suggest that the incinerator workers had inhaled dust containing PCDDs and PCDFs during their work.

     

Diet as a source of human exposure to polychlorinated dibenzo-P-dioxins (PCDD)

Dioxins are highly toxic by-products of many industrial processes e.g. chemical and municipal waste incineration or production of chlorophenols. These compounds penetrate the environment via air, water and soil and are then incorporated in food chains. The major source of human exposure (90% of total exposition) is consumption of a wide variety of common foods (meat, fish and dairy products) containing small amounts of dioxins. The average daily intake of PCDD via food was estimated in the range of 1-3 pg/kg bw. Common characteristics of all congeners detected in foodstuffs were 2,3,7,8-chlorine substitution. Commercial milk samples could be contaminated by PCDD/DFs present in the pulp used for the production of the milk cartoon. Also higher levels of these xenobiotics were found in samples from cows grazing in the vicinity of incinerators as compared to samples from rural farms. Human exposure to dioxin begins early in life since breast-feeding is the best way to nourish an infant. The nursing baby in developed countries get a particularly high dose of dioxins (about 85 pg TEQ/kg bw/day). Food contamination with dioxins leads to enhanced accumulation of these compounds in human tissues to the extent of exceeding acceptable level.     

垃圾焚烧发电地区儿童二噁英暴露水平及特征研究

目的分析垃圾焚烧发电厂周边儿童体内二噁英负荷水平、分布特征和人群二噁英外暴露水平。方法设距垃圾焚烧发电厂1km S镇为污染点,200km外的L镇为对照点,采集S镇90名及L镇60名10～11岁儿童外周静脉血,另采集两地土壤、鲫鱼和鸡蛋各3份,检测样本中二噁英浓度及计算毒性当量(TEQ)并分析对比。结果污染点儿童血中二噁英浓度与TEQ均显著高于对照组(P<0.05);鸡蛋和鲫鱼中二噁英浓度与TEQ、土壤中二噁英浓度均显著高于对照组(P<0.05)。两地样本的二噁英单体分布类似,其中单体浓度最高的为八氯代二苯并二噁英(OCDD),TEQ贡献最高的为2,3,4,7,8-五氯代二苯并呋喃(2,3,4,7,8-PeCDF)。结论垃圾焚烧发电厂周边土壤中二噁英浓度增高,当地儿童噁恶英外暴露和内负荷水平均显著增高。     

Association between dioxins/furans exposures and incinerator workers' hepatic function and blood lipids

This study examined the effects of dioxins/furans on blood lipids and hepatic function and assessed potential interaction between hepatitis B virus (HBV) infection and dioxins on hepatic function for 133 male workers of municipal waste incinerators. We found that total cholesterol levels in workers with blood dioxins/furans levels of 15.4-59.0 pg TEQ/g lipid (high-exposure workers) averaged 13.5 mg/dL higher than workers with 5.5-15.3 pg TEQ/g lipid (low-exposure workers). The adjusted odds ratio for total cholesterol abnormality (>220 mg/dL) was 2.8 (95% confidence interval = 1.0-7.9) between high and low-exposure workers. High-exposure workers showed consistently, although not statistically significantly, higher abnormality in gamma-glutamyltransferase (>52 U/L), alanine aminotransferase (>41 U/L), and aspartate aminotransferase (>37 U/L) than did low-exposure workers. However, there was no statistically significant interaction between dioxins/furans and HBV on these hepatic enzymes among incinerator workers.     

Attic dust and human blood samples collected near a former wood treatment facility

A wood treatment facility operating in southern Alabama released dioxins and other hazardous substances into the surrounding community over a period of approximately 35 years. The facility used a variety of chemical insecticides including pentachlorophenol (PCP), chromated copper arsenate (CCA), and creosote (which contains polycyclic aromatic hydrocarbons (PAHs)) to treat wood. The health risks associated with the released contaminants are numerous and significant. To evaluate the historic exposure to the contaminants from the facility, blood samples and health surveys were collected from 21 current and past residents of the adjacent, isolated community and analyzed for concentrations of polychlorinated dibenzo-p-dioxins (dioxins) and polychlorinated dibenzofurans (furans). In addition, attic dust sampling was performed in 11 buildings located within a 1-mile radius of the former wood treatment facility. The average total dioxin toxic equivalent (TEQ) concentration in the residents' blood samples was 36.6 pg/g lipids. In the attic dust, the average total dioxin TEQ concentration, benzo[a]pyrene (PAH) TEQ concentration, and arsenic concentration were 145 ng/kg, 0.98 and 29.8 mg/kg, respectively. The concentrations of dioxins measured in the blood samples exceed the 90th percentile total dioxin levels found in the general US adult population. Concentrations of dioxin, arsenic, and PAHs found in the attic samples exceeded the US Environmental Protection Agency (USEPA) Region 4 soil exposure cancer risk preliminary remediation goal (PRG) values. These findings indicate a very significant potential for related health effects in these communities.     

Relationships between dioxin concentrations in deposited dust and those in serum of workers at municipal waste incineration plants]

Relationships between concentrations of polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) in deposited dust and those in the serum of incinerator workers were examined at 13 municipal incineration plants. The following results were found. 1) Dust analysis showed that dominant constituents were octachlorodibenzo-p-dioxin (OCDD) and 1, 2, 3, 4, 6, 7, 8-heptachlorodibenzo-p-dioxin (HpCDD) among PCDDs, and 1, 2, 3, 4, 6, 7, 8-heptachlorodibenzofuran (HpCDF) and octachlorodibenzofuran (OCDF) among PCDFs. The toxicity equivalents (TEQs) of total PCDDs and PCDFs in the deposited dust were 0.54 to 33 ngTEQ/g, which were about 1,000 to 10,000 times as high as those in general soil. 2) The mean of serum TEQ of PCDDs, that of PCDFs and that of total PCDDs and PCDFs in the incinerator workers were 16, 12 and 28 pg TEQ/g lipid, respectively, for all the incinerator workers. Concentrations of hexachlorodibenzofurans (HxCDFs) and HpCDFs in the serum were significantly higher in the incinerator workers than the general population, which suggests that these workers had inhaled these chemicals during their work. 3) The concentration of 1, 2, 3, 4, 6, 7, 8-HpCDF and the TEQ value of PCDFs and in the serum were positively correlated with those in dust except for three plants where large-scale remodeling of the equipment was conducted within the past seven years. Consequently, deposited dust analysis may be useful for judging whether health examination containing blood dioxin measurement is necessary or not.     

Fish intake,plasma ω-3 polyunsaturated fatty acids,and polychlorinated dibenzo-<Emphasis Type="Italic">p</Emphasis>-dioxins/polychlorinated dibenzo-furans and co-planar polychlorinated biphenyls in the blood of the Japanese population

OBJECTIVES: To evaluate background exposure levels and determinants of the individual variations in the exposure to dioxins in Japan. METHODS: A cross-sectional study was performed on 131 men and 122 women (aged 20-76 years), who resided in five prefectures of Japan and had no occupational exposure to dioxins. Seven polychlorinated dibenzo-p-dioxins (PCDDs), ten polychlorinated dibenzo-furans (PCDFs) and 12 polychlorinated biphenyls (PCBs), which are assigned a toxicity equivalent factor, were determined in fasting blood. Biochemical analysis of plasma and a questionnaire survey on life-style, including dietary habit, were also performed. Factors associated with the levels of dioxin-related compounds in blood were evaluated by multiple linear regression. RESULTS: The median of total toxicity equivalents (TEQs) in men and women was 17 and 16 pg TEQ/g lipid, respectively, with no gender difference. After adjustment for age and other covariates, plasma concentrations of eicosapentaenoic acid, a biomarker of fish intake, were found to be positively associated with blood levels of total dioxin, PCDDs, PCDFs and PCBs, all of which were expressed on a TEQ basis (P<0.01). The frequency of intake of coastal fish, such as horse mackerel, mackerel and sardine, was also associated with TEQ-based concentrations of PCDFs (P=0.03) and PCBs (P=0.08). The intake of raw fish was positively related to total dioxins (P=0.06) and PCBs (P=0.03). CONCLUSIONS: The level of intake of marine fish, especially raw fish and coastal varieties, may be associated with increased blood levels of dioxin-related compounds among the population. Despite high fish consumption in Japan, the body burden of dioxins in the population was not found to be higher than that in western countries.     

人体胎盘组织二噁英和多溴联苯醚化合物负荷水平初步研究

目的 建立人体胎盘组织样品氯化二苯并二噁英(PCDD)和呋喃(PCDFs)、多氯联苯(PCBs)、多溴联苯醚(PBDEs)化合物同时准确定量检测分析方法,揭示上述持久性有机污染物人体负荷水平,并初步进行危险性评估.方法 采用国际权威标准方法--核素(同位素)稀释的高分辨气相色谱/高分辨双聚焦磁式质谱联用(HRGC/HRMS)技术,以多离子检测方法对人体胎盘组织样品中17个PCDD/Fs和12个共平面PCBs以及7个PBDEs化合物分别进行定性和定量分析,用WHO-TEF值计算所有样品的毒性当量浓度∑TEQ(PCDD+PCDFs+PCBs)和PBDEs浓度,进一步对人体二嗯英和PBDEs化合物负荷水平进行危险性评估.结果 6个胎盘组织样品中PCDD/Fs和PCBs化合物毒性当量总浓度∑TEQ(PCDD+PCDFs+PCBs)中位数是18.15 WHO-TEQ pg/g脂肪.范围分布在5.14～67.01 WHO-TEQ pg/g脂肪之间.2,3,4,7,8-PeCDFs、1,2,3,7,8-PeCDDs、PCB126是毒性当量的主要贡献者,合计占65%.以7个化合物计算PBDEs总浓度,6个样品的中位数值为2.73 ng/g脂肪,均数为7.17 ng/g脂肪,范围是0.95～25.99 ng/g脂肪.BDE47是最主要的污染同系物,占到35%.浓度最高的一个受试样品其毒性当量总浓度∑TEQ(PCDD+PCDFs+PCBs)已经达到世界上已知高暴露区人体二噁英污染负荷水平.结论 我们在本研究中建立了人体组织样品中持久性有机化合物二噁英和PBDEs化合物同时准确定量检测方法,高二噁英负荷水平的样品提供者可能对胎儿存在健康危害的高暴露风险,对于健康的远期影响还需要深入进行医学追踪研究.     

Dioxins in the environment and in the blood and breast milk of residents of the town of Chapayevsk]

Chapayevsk has a 30-year history of producing organochlorines, leading to environmental dioxin pollution. As much as 3 kg of these substances are annually formed at the plant. The concentrations of dioxins in the ambient air were found to be 0.001 to 1.13 pg/m3, in 1-TEF dioxin equivalent or 0.00001-1.76 pg/m3, as calculated by using WHO-TEF for dioxin-like compounds, those in the urban drinking water were 0.1 to 20.83 pg/liter, in the soil near the plant, 141 ng TEQ/kg, by decreasing to 37 ng/kg in the downtown (2-7 km from the plant) and 4 ng/kg at a distance of 7-10 km from the plant, their levels in the vegetables and fruits were 0.002 to 10.6 pg/kg. The direct indicator of dioxin exposure is its detection in human breast milk and blood. Examination of the content of dioxins in the breast milk of Chapayevsk women versus those living in other towns and cities of Russia has shown considerably higher levels of dioxins, such as 2,3,7,8-TCDD, 1,2,3,7,8-PCDD, 1,2,3,4,7,8-GCDD, and octa-dioxins. The mean content of dioxins in the breast milk (7 pooled samples from 40 individual trials) was 43.3 pgTEQ/fat. It is significantly higher than that detected in the populations of other Russian territories and other countries. The mean blood concentrations of dioxins in peoples living near the plant was 75.2 pgTEQ/fat, those were lower (24.5 pgTEQ/fat) in those living at 5-7 km of the plant.     

Exposure assessment of workers to airborne PCDD/Fs, PCBs and PAHs at an electric arc furnace steelmaking plant in the UK

Occupational exposure studies were undertaken at a UK electric arc furnace (EAF) steelmaking plant to investigate the exposure of workers via inhalation to dioxins, polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene (B[a]P). Surveys were undertaken in areas including the melting shop, the casting department and a furnace control cabin. The highest concentrations of dioxins and PCBs were found inside the melting shop nearby EAFs, whereas dioxin and PCB concentrations in the casting department and inside the control cabin were significantly lower. Risk characterization was carried out by comparing the daily intake of dioxins and PCBs through inhalation with the recommended tolerable daily intake (TDI). Health risk assessments were also carried out by combining exposure data with inhalation cancer potency factors to quantify the cancer risk. For the most exposed category of workers (melting shop workers), the estimated daily intake via inhalation was 0.35 pg WHO-TEQ kg(-1) body weight (bw) in the worst case scenario. Considering that the average UK adult exposure to dioxins from the diet is 1.8 pg WHO-TEQ kg(-1) bw day(-1), the results indicated that the estimated daily intake of dioxins via inhalation at the EAF would not result in the recommended range of the TDI (1-4 pg WHO-TEQ kg(-1) bw day(-1)) being exceeded. Cancer risks for a 40-year occupational exposure period were determined by multiplying the inhalation dose by the inhalation cancer potency factor for 2,3,7,8-tetrachlorodibenzo-p-dioxin. For melting shop workers, cancer risks from exposure to dioxins and PCBs ranged from 2.05 x 10(-5) to 7.54 x 10(-5). Under most regulatory programmes, excess cancer risks between 1.0 x 10(-4) and 1.0 x 10(-6) indicate an acceptable range of excess cancer risk, suggesting a limited risk from dioxin exposure for workers in the EAF plant. For the calculation of excess cancer risks, no account has been taken of the protection provided by protective respiratory equipment worn by EAF workers. If personal protective equipments were taken into consideration, it is likely that the excess cancer risks for EAF workers would have been lower and considered as negligible. The highest concentrations of PAHs were found in the melting shop and the casting areas of the plant. In the melting shop area, B[a]P concentrations ranged from 1.4 to 24.5 ng m(-3), with a mean value of 7 ng m(-3). No workplace exposure limits have been published by the Health and Safety Executive in the UK for PAHs; however, the B[a]P concentrations found were below the limit value of 150 ng m(-3) (8-h time-weighted average) specified for workplace exposure in France. Exposure assessment of workers to PAHs via inhalation was carried out by calculating a potential cancer risk considering a 40-year occupational exposure period and B[a]Peq concentrations. Estimated cancer risks for the most exposed category of workers (i.e. melting shop workers) ranged from 3.66 x 10(-6) to 1.64 x 10(-5). The cancer risks determined in this study were well within an acceptable range of excess cancer risk of 1.0 x 10(-4) to 1.0 x 10(-6), specified by the US Environmental Protection Agency.     

Dietary exposure to polychlorinated biphenyls and dioxins from infancy until adulthood: A comparison between breast-feeding, toddler, and long-term exposure.

Food is the major source for polychlorinated biphenyl (PCB) and dioxin accumulation in the human body. Therefore, investigating food habits from early ages until reproductive age (25 years) is important in order to assess exposure risk for the next generation. The objective of this study was to assess the PCB/dioxin exposure and the relative contribution of different foods to total exposure during preschool age. Particularly, the importance of lactational PCB/dioxin exposure vs. dietary exposure until adulthood was investigated. A cohort of 207 children was studied from birth until preschool age. Based on 3 planar PCBs and 17 2,3,7,8-substituted dibenzo-para-dioxins (PCDDs) and dibenzofurans (PCDFs) measured in breast milk, a model was developed to calculate the cumulative toxic equivalent (TEQ) intake during breast-feeding (0-1 year). In 3. 5-year-old children, daily dietary intake of planar PCB-TEQ and dioxin-TEQ was measured with a validated food questionnaire. Cumulative TEQ intake from 1 to 5 years was estimated using the PCB- and dioxin-TEQ intake measured with the food questionnaire. Cumulative TEQ intake from 6 to 25 years was estimated using national food consumption and contamination data of PCB- and dioxin-TEQ intake. In toddlers, dairy products contributed 43% to PCB-TEQ and 50% to dioxin-TEQ intake. Meat and meat products contributed 14% and 19%, respectively, and processed foods 23% and 15%, respectively. Breast-feeding for 6 months contributed to the cumulative PCB/dioxin TEQ intake until 25 years of age, 12% in boys and 14% in girls. The daily TEQ intake per kilogram body weight is 50 times higher in breast-fed infants and three times higher in toddlers than in adults. Long-term dietary exposure to PCBs and dioxins in men and women is partly due to breast-feeding (12 and 14%, respectively). After weaning, dairy products, processed foods, and meat are major contributors of PCB and dioxin accumulation until reproductive age. Instead of discouraging breast-feeding, maternal transfer of PCBs and dioxins to the next generation must be avoided by enforcement of strict regulations for PCB and dioxin discharge and by reducing consumption of animal products and processed foods in all ages.     

The Belgian PCB and dioxin incident of January-June 1999: exposure data and potential impact on health

In January 1999, 500 tons of feed contaminated with approximately 50 kg of polychlorinated biphenyls (PCBs) and 1 g of dioxins were distributed to animal farms in Belgium, and to a lesser extent in the Netherlands, France, and Germany. This study was based on 20,491 samples collected in the database of the Belgian federal ministries from animal feed, cattle, pork, poultry, eggs, milk, and various fat-containing food items analyzed for their PCB and/or dioxin content. Dioxin measurements showed a clear predominance of polychlorinated dibenzofuran over polychlorinated dibenzodioxin congeners, a dioxin/PCB ratio of approximately 1:50,000 and a PCB fingerprint resembling that of an Aroclor mixture, thus confirming contamination by transformer oil rather than by other environmental sources. In this case the PCBs contribute significantly more to toxic equivalents (TEQ) than dioxins. The respective means +/- SDs and the maximum concentrations of dioxin (expressed in TEQ) and PCB observed per gram of fat in contaminated food were 170.3 +/- 487.7 pg, 2613.4 pg, 240.7 +/- 2036.9 ng, and 51059.0 ng in chicken; 1.9 +/- 0.8 pg, 4.3 pg, 34.2 +/- 30.5 ng, and 314.0 ng in milk; and 32.0 +/- 104.4 pg, 713.3 pg, 392.7 +/- 2883.5 ng, and 46000.0 ng in eggs. Assuming that as a consequence of this incident between 10 and 15 kg PCBs and from 200 to 300 mg dioxins were ingested by 10 million Belgians, the mean intake per kilogram of body weight is calculated to maximally 25,000 ng PCBs and 500 pg international TEQ dioxins. Estimates of the total number of cancers resulting from this incident range between 40 and 8,000. Neurotoxic and behavioral effects in neonates are also to be expected but cannot be quantified. Because food items differed widely (more than 50-fold) in the ratio of PCBs to dioxins, other significant sources of contamination and a high background contamination are likely to contribute substantially to the exposure of the Belgian population.     

Meta-analysis of dioxin cancer dose response for three occupational cohorts

This article presents a meta analysis of data from three cohorts occupationally exposed to TCDD and related compounds. A statistically significant (p = 0.02) trend was found in total cancer mortality with increasing dioxin exposure. The trend tests show an increase in total cancer at cumulative TEQ (unit of measurement for TCDD-like compounds that is defined as the amount of TCDD that would produce the same toxicity as a mixture of TCDD-like compounds) serum levels that would result from lifetime intake of 7 pg TEQ/kg body weight/day, with no increase at 6 pg/kg/day. A linear dose response provided a good fit to the combined data and predicted an ED(01) (dioxin exposure resulting in a 0.01 increase in lifetime risk of cancer mortality) of 45 pg/kg/day (95% confidence interval, 21-324). The U.S. Environmental Protection Agency estimates that current lifetime human exposures to dioxin average approximately 1 pg/kg/day (99% percentile: 3 pg/kg/day). Although it appears unlikely that current exposures through foods would reach either 7 pg/kg/day or the ED(01), our analysis argues for careful consideration of the upper ranges of long-term average exposures for dioxins.     

Assessment of Dioxin Intake from Commercial Baby Food in Infant

Commercial baby food was roughly classified into six food groups, including vegetable, fruit, fish, meat, dairy product, and cookie. Dioxin levels in commercial baby food were determined, and dioxin intake in infants was assessed on the basis of the proposed original model food groups. The total daily dioxin intake was 0.070 pg TEQ/kg body weight/day. The total dioxin intake in this study was considerably lower than the Tolerable daily intake (TDI) of 4 pg TEQ/kg body weight/day set by Japanese regulations. The dioxin intake from commercial baby food is considered not to be a serious problem at the moment. We believe that the proposed classification and calculation is suitable for the evaluation of total dioxin intake from commercial baby food.     

Environmental and human exposure to soil chlorinated and brominated polycyclic aromatic hydrocarbons in an urbanized region

Nine chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/BrPAHs) and five parent polycyclic aromatic hydrocarbons (PAHs) were measured in urban surface soil and fly ash samples collected from Shenzhen, south China in winter 2010. The concentrations of total Cl/BrPAHs and PAHs in soil ranged from below the reporting limit to 142 ng/g and from 4.34 to 158 μg/g, respectively, and in fly ash they ranged from 17.7 to 19.5 ng/g and 26.1 to 28.3 μg/g, respectively. Concentrations of Cl/BrPAHs and parent PAHs were not significantly correlated with each other in soil or in fly ash, suggesting that Cl/BrPAHs were formed mainly by mechanisms other than direct halogenation of parent PAHs. Estimated mass inventories of 2-BrFlu varied from 68.1 kg in commercial land to 669 kg in countryside land, the highest among all Cl/BrPAHs. Loss fluxes via soil erosion accounted for only small proportions of total soil mass inventories of Cl/BrPAHs. Average daily human intake via soil ingestion decreased with increasing age, with 2-BrFlu as the main contributor. Children of 0 to 8 years old were the most sensitive subgroup (13.7 pg/kg body wt/d for total Cl/BrPAHs), and females were more sensitive than males in the same age group. The mean dioxin-like toxic equivalency quotient (TEQ) concentration of total Cl/BrPAHs (0.008 ng-TEQ/g) was lower in soil than in fly ash (0.06 ng-TEQ/g). Conversely, the mean TEQ concentration of total parent PAHs (2.23 ng-TEQ/g) was higher in soil than in fly ash.     

Characterization of dioxin exposure in residents of Chapaevsk,Russia

Since 1967, a chemical plant in the town of Chapaevsk (Samara province, Russia) has produced large amounts of chlorinated compounds and is suspected to be a major source of local environmental dioxin contamination. Dioxins have been detected in the local air, soil, drinking water, vegetables, and cow's milk. Human exposure to dioxins is suspected as a factor in the deteriorating local public health. In an effort to characterize nonoccupational dioxin exposure among local residents, during the summer of 1998, 24 volunteers were recruited to donate blood and to provide information about their residence, employment, demographics, medical history, and dietary habits. Selected polychlorinated dibenzodioxins, dibenzofurans, and coplanar biphenyls were measured in blood serum samples. The mean concentration of total dioxin World Health Organization toxic equivalents (WHO-TEQ(98)) based on polychlorinated dibenzo-para-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and coplanar polychlorinated biphenyls (PCBs) was 61.2 (range 16.4-168.1) pg/g lipid. Subjects living in close proximity to the plant (less than 5 km) had significantly higher dioxin levels (mean WHO-TEQ(98), 75.7 pg/g lipid), as compared to subjects living more than 5 km from the plant (mean WHO-TEQ(98), 44.1 pg/g lipid) (P<0.04). Comparisons of the study results with available published data indicate that average blood dioxin levels were substantially higher in Chapaevsk residents than in nonoccupationally exposed populations of other parts of Russia, Europe, and North America. Chronic exposures of such magnitude may have appreciable adverse effects on public health.