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.     

Effects of contamination level of dioxins and related chemicals on thyroid hormone and immune response systems in patients with "Yusho"

Effects of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) on thyroid hormone and immune response systems were examined in 16 Yusho patients at about 30 years after the outbreak of the Yusho accident. Their toxic equivalent (TEQ) levels in the blood were 27.8-1048.5 pg/g fat with the median level of 222.4 pg/g fat, which was about seven times higher than that of healthy Japanese people. Even at such high blood TEQ concentrations, they seemed not to affect the serum levels of thyroid hormones, thyroid stimulating hormone (TSH), immunoglobulins (A, G and M), autoantibodies (antinuclear antibody, rheumatoid and lupus erythematosus (LE) factors), and lymphocyte subsets in the blood. However, positive rates of rheumatoid factor were considered to increase in higher blood TEQ groups. This investigation was done using rather small number of Yusho patients, so further large-scale investigations are needed to get more conclusive findings concerning their effects on thyroid hormone and immune response systems.     

Comparative toxicities of the polychlorinated dibenzofuran (PCDF) and biphenyl (PCB) mixtures which persist in Yusho victims

The toxic Yusho oil contained a mixture of polychlorinated biphenyls (PCBs) which were contaminated by other halogenated aromatics including the highly toxic polychlorinated dibenzofurans (PCDFs). It has been reported that the PCBs and PCDFs which persist in the liver of victims still suffering from Yusho poisoning include the following compounds; 2,3′,4,4′,5-penta-,2,2′,4,4′,5,5′-,2,2′,3′,4,4′,5- and 2,3,3′,4,4′,5-hexa, 2,2′,3,4,4′,5,5′- and 2,2′,3,3′,4,4′,5-heptachlorobiphenyls and the 2,3,7,8-tetra-, 1,2,4,7,8-, 1,2,3,7,8- and 2,3,4,7,8-penta- and 1,2,3,4,7,8-hexachlorodibenzofurans. All of these PCBs and PCDFs have been synthesized and reconstituted to approximate their composition in human liver. A comparison of the dose-response effects of the reconstituted PCB and PCDF mixtures in causing weight loss, thymic atrophy and the induction of cytochrome P-448-dependent monooxygenases indicated that the PCDF mixture was at least 700 times more active than the PCBs. Since the ratio of PCBs/PCDFs persisting in Yusho patients' blood and liver was less than 600:1 and 5:1 respectively, the results suggest that the PCDFs are the major etiologic agent in Yusho poisoning.     

Comparison between "Yusho" patients and healthy Japanese in contamination level of dioxins and related chemicals and frequency of sister chromatid exchanges

Highly toxic organochlorine chemicals such as polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (CoPCBs) were determined in the peripheral blood and sebum from the face of 16 "Yusho" patients of about 27 yr after the outbreak of Yusho accident, and 39 healthy Japanese people. The mean total toxic equivalent (TEQ) levels of PCDDs, PCDFs and CoPCBs in the blood were still about seven times higher in Yusho patients than in healthy Japanese at the age of 45 yr and more. The sebum excretion of these chemicals seemed proportional to their blood levels in Yusho patients. These toxic chemicals, however, did not enhance frequencies of sister chromatid exchanges (SCEs) in the control and 7,8-benzoflavone (ANF) treated cultures in Yusho patients. Hence, no significant difference was observed in the mean SCE rates between the Yusho patients and general Japanese people of more than 45 yr of age. In this study, the number of Yusho patients examined is limited, so further large-scale investigations are needed to get more conclusive results concerning the genotoxic potency such as SCE induction.     

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.     

Comparison of the concentrations of polychlorinated biphenyls and dioxins in mothers affected by the Yusho incident and their children

Accumulated maternal dioxins are passed onto the fetus and neonate via the placenta and maternal milk. In Japan in 1968, an accidental human exposure to rice oil contaminated with polychlorinated biphenyls (PCBs) and other dioxin-related compounds, such as polychlorinated dibenzofurans (PCDFs), led to development of Yusho oil disease. We investigated differences in blood dioxin concentrations in mother-children pairs affected by the Yusho incident. From 2002 to 2008, blood samples were collected from 26 pairs of Yusho mothers and their children (19 mothers, 26 children). Specific congeners of seven polychlorinated dibenzo-p-dioxins (PCDDs), ten PCDFs, and four non-ortho PCBs were analyzed. The children had significantly lower TEQ concentrations of PCDDs, PCDFs, and coplanar PCBs compared to their mothers. The mother-child difference in blood concentrations varied with the congeners; the largest for 2,3,4,7,8-pentaCDF and the smallest for 1,2,3,4,6,7,8-heptaCDD. The level for 2,3,4,7,8-pentaCDF, which characterizes Yusho oil disease, was approximately 17-30 times higher in the mothers than in the general population, whereas there were no significant differences between children in the formula-fed group and the general population. In contrast, the mean level for 2,3,4,7,8-pentaCDF in the breast-fed group was approximately 1.5 times, (range 0.5-6.5 times) higher than that in the general population. Over 30 years after the Yusho incident, the mean blood dioxin levels in the offspring were only a fraction of the levels in their mothers. This is more consistent with exposure via breast milk than via transplacental transfer in the Yusho incident.     

Congener profiles of PCBs and PCDD/Fs in Yucheng victims fifteen years after exposure to toxic rice-bran oils and their implications for epidemiologic studies

In 1978-1979, a mass poisoning occurred in central Taiwan from rice-bran oil contaminated by heat-degraded PCBs was later called the Yucheng (oil disease in Chinese). Only a few studies have so far investigated the levels of specific polychlorinated biphenyl (PCB) or polychlorinated dibenzodioxin/furan (PCDD/F) congeners in the Yucheng victims. This study aimed to investigate the serum residual levels of thirty-three PCBs and seventeen 2,3,7,8-substituted PCDD/F congeners in the Yucheng victims 15 years after the exposure. Forty-one blood samples were collected from individual Yucheng victims in 1994-1995. The mean levels of total 33 PCBs and 17 PCDD/Fs were 2468 ng/g lipid (13.3 ng/g sample) and 6550 pg/g lipid (30.9 pg/g sample) respectively. The higher levels were found in PCBs #99, #138, #153, #156, #170, #179, and #180 among 33 PCB congeners, while 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, and OCDD had the higher concentrations among 17 PCDD/F congeners. The total TEQ was contributed in decreasing order by 10 PCDFs (44%), three non-ortho-PCBs (24%), six mono-ortho-PCBs (20%), and seven PCDDs (12%). The mean total PCB levels and TEQ value of the 17 PCDD/Fs in the Yucheng victims 15 years after the toxic exposure were still 9 and 46 times higher than those in the general population in Taiwan. Principle component analysis (PCA) indicated that seven PCB congeners, PCBs #99, #138, #153, #156, #170, #179, and #180, accounted for 73% of the total variances in PCBs. On the other hand, six PCDD/F congeners, 2,3,4,7,8-PeCDF, 1,2,3,4,7,8-HxCDF, 1,2,3,6,7,8-HxCDF, 1,2,3,6,7,8-HxCDD, 1,2,3,4,6,7,8-HpCDF, and OCDD, accounted for 97% of the total variances in PCDD/Fs. In addition, PCA revealed that at least three characteristic patterns of congener profiles for PCBs were observed among the Yucheng victims. Similar trend was also observed for PCDD/Fs. These patterns may reflect distinctive exposure scenarios and/or different metabolizing capabilities among the Yucheng victims. We suggest that these patterns, in contrast to total PCB and PCDD/F levels, may be valuable for the future epidemiologic studies when linking exposure with specific health effect.     

Recent trend of polychlorinated dibenzo-p-dioxins and their related compounds in the blood and sebum of Yusho and Yu Cheng patients

We investigated the levels of polychlorinated dibenzo-p-dioxins (PCDDs) and their related compounds in blood and sebum from Yusho and Yu-Cheng patients and findings compared with those of normal subjects. Concentrations of these compounds in blood and sebum still were obviously reflected the chemical concentration in the causal rice oil ingested 17 or 26 years since the outbreak. In addition, sebum form the body surface was the most useful sample for monitoring the amount of chemicals contaminating the human body.     

PCDFs and related compounds in humans from Yusho and Yu-Cheng incidents

Mass food poisoning incidents, called Yusho and Yu-Cheng, were caused by the ingestion of rice oils which had been contaminated with polychlorinated biphenyls (PCBs), polychlorinated dibenzofurans (PCDFs) and polychlorinated quaterphenyls (PCQs). This paper reviews the formation of toxic PCDFs in the rice oil from PCBs, intakes of PCBs, PCDFs and PCQs by the patients and the behavior of PCBs, PCDFs and PCQs in the human body.     

The Binghamton state office building PCB, dioxin and dibenzofuran electrical transformer incident: 1981–1986

The Binghamton State Office Building (BSOB) polychlorinated biphenyl (PCB) and chlorinated benzene containing electrical transformer arcing and fire incident of February 5, 1981, was the first recognized incident of its kind. A surge of excess electricity led to an electrical panel malfunction at 5:30 AM. For about 30 minutes intense heat was generated as electrical arcing occurred. Dense smoke containing polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs) as well as biphenylenes billowed up through air shafts and contaminated all areas of the building later tested for these chemicals. This incident was the first outside a laboratory setting to demonstrate the conversion of PCBs, in the presence of oxygen and heat, to PCDFs, and of the chlorinated benzenes to PCDDs. It demonstrated a hitherto unsuspected potential health hazard of PCB and chlorinated benzene containing electrical transformers, and by implication, capacitors, when not properly separated from areas of buildings used by workers and public. The building has been shut since then and an estimated $40,000,000 may be spent on direct cleanup and rehabilitative costs prior to reopening of the building, if it is to be reopened. Elevated levels of serum PCBs were detected in workers, eg., firefighters initially involved in the fire, which stabilized at lower levels later in the year. Elevated penta- and hexa- chlorinated furan isomers corresponding to isomers found in the soot (and identical to some Yusho isomers) were found in some cleanup workers. Electron microscopy of percutaneous liver biopsies of three patients chemically exposed from the incident showed lesions similar to those seen in guinea pigs fed the soot, which was biologically quite active. This incident, and others occurring afterward, has led the US Environmental Protection Agency to ban PCB containing transformers from similar buildings.     

Blood levels of PCDDs,PCDFs, and coplanar PCBs in Yusho mothers and their descendants: Association with fetal Yusho disease

Maternal exposure to polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) may result in adverse health effects in their children. In Japan in 1968, an accidental human exposure to rice oil contaminated with PCDDs, PCDFs, and PCBs, led to the development of Yusho disease. Yusho mothers delivered descendants with low birth weights and hyperpigmented skin and mucosa, which are characteristic of fetal Yusho disease (FYD). The Yusho cohort was used to evaluate the effect of maternal exposure to PCDDs, PCDFs, and PCBs on the development of FYD. Blood samples, obtained from 64 Yusho mothers (117 descendants: 10 with FYD and 107 without FYD), were analyzed for congeners of seven PCDDs, 10 PCDFs, and four coplanar PCBs. We investigated the association between the maternal estimated blood levels of dioxins at delivery and the risk of fetal Yusho disease. We also studied the differences in dioxin blood levels in 24 mother–descendant pairs (5 with FYD and 19 without FYD). The estimated levels of total PCDD TEQ, total PCDF TEQ, total coplanar PCB TEQ, and total TEQ in the maternal blood at delivery were associated with significantly increased risk of FYD. The odds ratios, which present the risk of FYD for a 10-fold increase in blood dioxin, were largest for 1,2,3,6,7,8-HexaCDD (odds ratio = 28.6, 95% confidence interval = 1.67–489.9, p = 0.02). The levels of 1,2,3,6,7,8-HexaCDD in both the Yusho mothers and their descendants with FYD were higher than the levels in those without FYD. These findings suggest that 1,2,3,6,7,8-HexaCDD is the most important causative congener for the development of FYD.     

Polychlorinated biphenyls and dibenzofurans retained in the tissues of a deceased patient with Yucheng in Taiwan

Various tissues from a deceased Yucheng (oil disease) patient were analyzed for individual polychlorinated biphenyl (PCB) and dibenzofuran (PCDF) congeners. With a few exceptions, PCBs with 5 or less chlorine atoms were almost completely excreted from the patient's tissues about two years after the ingestion of the toxic oil. In contrast, most PCB congeners with 6 or more chlorine atoms were retained in the tissues. The intestinal fat contains the highest level of PCBs while the liver contains the highest concentration of PCDFs. The major PCDF congeners retained in the tissues were 1,2,3,4,7,8-hexaCDF, 2,3,4,7,8-pentaCDF, and 1,2,4,7,8-pentaCDF. The former two congeners, especially 2,3,4,7,8-pentaCDF, are very toxic PCDFs; they may play important roles in the etiology of Yucheng.     

Evaluation of cumulative PCB exposure estimated by a job exposure matrix versus PCB serum concentrations

Although polychlorinated biphenyls (PCBs) have been banned in many countries for more than three decades, exposures to PCBs continue to be of concern due to their long half-lives and carcinogenic effects. In National Institute for Occupational Safety and Health studies, we are using semiquantitative plant-specific job exposure matrices (JEMs) to estimate historical PCB exposures for workers (n?=?24,865) exposed to PCBs from 1938 to 1978 at three capacitor manufacturing plants. A subcohort of these workers (n?=?410) employed in two of these plants had serum PCB concentrations measured at up to four times between 1976 and 1989. Our objectives were to evaluate the strength of association between an individual worker’s measured serum PCB levels and the same worker’s cumulative exposure estimated through 1977 with the (1) JEM and (2) duration of employment, and to calculate the explained variance the JEM provides for serum PCB levels using (3) simple linear regression. Consistent strong and statistically significant associations were observed between the cumulative exposures estimated with the JEM and serum PCB concentrations for all years. The strength of association between duration of employment and serum PCBs was good for highly chlorinated (Aroclor 1254/HPCB) but not less chlorinated (Aroclor 1242/LPCB) PCBs. In the simple regression models, cumulative occupational exposure estimated using the JEMs explained 14–24 % of the variance of the Aroclor 1242/LPCB and 22–39 % for Aroclor 1254/HPCB serum concentrations. We regard the cumulative exposure estimated with the JEM as a better estimate of PCB body burdens than serum concentrations quantified as Aroclor 1242/LPCB and Aroclor 1254/HPCB.     

Accumulation properties of polychlorinated biphenyl congeners in Yusho patients and prediction of their cytochrome P450-dependent metabolism by in silico analysis

In what has become known as the Yusho incident, thousands of people in western Japan were poisoned by the accidental ingestion of rice bran oil contaminated with polychlorinated biphenyls (PCBs) and various dioxins and dioxin-like compounds. In this study, we investigated the accumulation patterns of 69 PCB congeners in the blood of Yusho patients in comparison with those of non-exposed controls. The blood samples were collected at medical check-ups in 2004 and 2005. To compare the patterns of PCB congeners, we calculated the concentration ratio of each congener relative to the 2,2′,4,4′,5,5′-hexaCB (CB153) concentration. The concentration ratios of tetra- and penta-chlorinated congeners in the blood of Yusho patients were significantly lower than those of controls. To examine the cytochrome P450 (CYP)-dependent metabolic potential of the 2,3′,4,4′5-pentaCB (CB118), CB153, and 2,3,3′,4,4′5-hexaCB (CB156) congeners, we conducted PCB-CYP (CYP1A1, CYP1A2, CYP2A6, and CYP2B6) docking simulation by in silico analysis. The docking models showed that human CYP1A1, CYP2A6, and CYP2B6 isozymes have the potential to metabolize CB118 and CB153. On the other hand, it was inferred that CB156 is difficult to be metabolized by these four CYP isozymes. These results indicate that CYP1 and CYP2 isozymes may be involved in the characteristic accumulation patterns of PCB congeners in the blood of Yusho patients.     

Trends of PCDD/F and PCB concentrations and depositions in ambient air in Northwestern Germany

Time series of polychlorinated dioxins and furans (PCDD/F) and polychlorinated biphenyls (PCB) in ambient air of a large conurbation in North-Western Germany are presented and analyzed. The trend of PCDD/F concentrations, starting from as early as 1988, shows a pronounced decrease by at least one order of magnitude, demonstrating that the emission reductions were effective. The PCDD/F depositions also have decreased by a factor of 5 since 1992. However, both trends have leveled out since 2005. Time series of PCB concentrations and depositions starting in 1994 show only slight decreases for the concentrations and almost no decrease for the depositions. From the decay rates following first order kinetics, half-lives in the order of 5-15 years for the PCDD/F and 15-31 years for the sum of the six indicator PCB could be calculated, which are much longer than the half-lives estimated from their reactivity towards the OH radical. Apparently, small fresh emissions (PCDD/F), considerable secondary emissions and evaporation from contaminated soils slow down their decay in the atmosphere of big conurbations. Analyzing the decay rates of individual PCB congeners shows that the lower chlorinated and more volatile ones are removed faster than the higher chlorinated congeners, probably via gas phase reactions with the OH radical. It can be concluded from the present study that the input of PCDD/F and PCB into the food chain via the air path will continue for another one or two decades in big conurbations.     

Current state of yusho and prospects for therapeutic strategies

The mass food poisoning incident yusho occurred in Japan in 1968. It was caused by the ingestion of rice bran oil contaminated with polychlorinated biphenyls and various dioxins and dioxin-like compounds including polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDFs). Notably, PCDFs were found to contribute to approximately 65% of the total toxicity equivalent in the blood of yusho patients. Lipophilic dioxins are retained in the body for a longer period than previously estimated. Victims suffered from characteristic skin manifestations associated with non-specific systemic symptoms, neurological symptoms, and respiratory symptoms. The severe symptoms seen in the initial phase subsequently faded, but recently, improvements have scarcely been observed. The Yusho Group has been researching treatments for this condition. Several clinical trials with chelating agents or dietary fibers aimed at accelerating the excretion of compounds. While some treatments increased dioxin excretion, none provided satisfactory symptom relief. Concurrently, various phytochemicals and herbal extracts have been found to possess biological activities that suppress dioxin-induced toxicity via aryl hydrocarbon receptor or activate the antioxidant nuclear factor-erythroid 2-related factor-2 (NRF2) signal pathway, making them promising therapeutic candidates. Here, we summarize the current status of yusho and findings of clinical trials for yusho patients and discuss the treatment prospects.

     

Congener-specific approach to human PCB concentrations by serum analysis

The objective of this study was to evaluate all congeners of polychlorinated biphenyls (PCBs) in human serum samples. Concentrations of all PCB congeners in the serum of 87 volunteers were determined by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS). The participants consisted of 47 males and 40 females, including 25 men working at municipal solid waste incinerators (MSWIs). The mean concentrations of total PCBs and dioxin-like PCBs were 242.77ng/g lipid (median: 180.17ng/g lipid) and 18.57ng/g lipid (median: 15.34ng/g lipid), respectively. Penta-, hexa-, and heptachlorinated biphenyls contributed more than 80% of the total PCBs detected in human serum. Congener-specific analysis indicated that PCB153, PCB138, PCB180, PCB187, and PCB118 contributed 57.3% of the total PCBs detected in human serum samples. A statistical analysis was performed to determine whether there were significant correlations between PCB concentrations and specific variables such as age, gender, smoking habits, occupation, and body mass index (BMI). However, serum PCB concentrations correlated only with age. In addition, we found that total PCBs and dioxin-like PCBs highly correlated with PCB153 (correlation coefficient r=0.93, p<0.01) and PCB118 (correlation coefficient r=0.98, p<0.01), respectively. Thus these two congeners could be satisfactory indicators for total PCBs and dioxin-like PCBs in human serum.     

Levels of PCDD/F and dioxin-like PCB in Baltic fish of different age and gender

Concentrations of polychlorinated dibenzo-p-dioxins (PCDD), polychlorinated dibenzofurans (PCDF) and polychlorinated biphenyls (PCB) in Baltic Sea fish like herring (Clupea harengus membras), sprat (Sprattus sprattus balticus), perch (Perca fluviatilis), pikeperch (Sander lucioperca) and flounder (Platichthys flesus trachurus) collected from four areas of the Estonian coastal waters are reported. All samples are studied for their relationship between the length (cm) and wet weight (g); length (cm) and age (years); lipid content and dry matter. The level of PCDD/F and PCB concentrations in younger 1-5 years old Baltic herring and sprat collected in 2002-2005 from the eastern and central parts of the Gulf of Finland, Gulf of Riga and Open Baltic Sea (Central Baltic) is related to the fish age and compared with those found in the 1990s. In addition, PCDD/F and PCB concentrations of different age groups herring, sprat, perch, pikeperch and flounder collected in 2003-2004 from the Lake Peipsi, Gulf of Finland, Gulf of Riga and Open Baltic Sea are related also to their age. Consequently, it was manifested that in older Baltic fish the concentrations of PCDD/F and PCB were higher than in the younger age groups. By the help of principle component analysis (PCA) the effect of gender on the concentrations of PCDD/F for the juvenile Baltic herring and sprat collected in 2004-2005 is investigated for the first time. It was summarized that the biological factor age plays a large role for the contamination of the fish with important toxic organohalogenated compounds such as PCDD/F.     

销毁含多氯联苯废弃物焚烧炉的二噁、类二噁和多氯联苯排放

我国正在研制专用于销毁高浓度多氯联苯（ＰＣＢｓ）的焚烧炉,主要处理废旧的含（ＰＣＢｓ）的电力电容器和变压器,应用可靠准确的监测方法测定了试验性焚烧炉渣、烟灰排气和废水中的二口恶口英（ｄｉｏｘｉｎｓ）,类二口恶口英多氯联苯（ｄｉｏｘｉｎｌｉｋｅＰＣＢｓ）和ＰＣＢｓ含量,结果表明该炉试烧高浓度ＰＣＢｓ时,焚毁率可以达到９９．９９９９％,炉渣中的２,３,７,８ＴＣＤＤ毒性当量为８７．８６ｐｇＴＥＱ／ｇ,烟灰中残留二口恶口英和类二口恶口英的总２,３,７,８ＴＣＤＤ毒性当量为４７．２３ｎｇＴＥＱ／ｇ．     

PCB levels and congener patterns from Korean municipal waste incinerator stack emissions

Congener specific polychlorinated biphenyl (PCB) data from the stack gas of nine Korean municipal waste incinerators was used to determine characteristic congener patterns of emitted PCBs. Principal component analysis revealed three classes of incinerators according to their pattern of PCB congener emissions: those resembling the background sampling material; those producing large quantities of a few tetra-chlorinated congeners; those producing large proportions of mono (MO-) and non-ortho (NO-) congeners relative to di-ortho (DO-) levels. Also, correlations between individual PCB congeners and polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) were discovered for several NO-PCBs and tetra and penta chlorinated PCDFs. Full PCB congener data is presented along with operating conditions for each incinerator.