Polychlorinated Biphenyl Concentrations and Estimated Intakes in Fish Oil Supplements on the Japanese Market.

Polychlorinated biphenyls (PCBs) are synthetic organic contaminants that are widespread in the environment. There are 209 PCB congeners. Fish oil produced from marine fish is widely used as a health supplement. PCB contamination of fish oil is of concern. We determined the concentrations of all 209 PCB congeners in commercially available fish oil supplements from Japan and estimated PCB intakes for humans consuming the supplements. We determined the concentrations of non-dioxin-like PCBs separately. The total PCB concentrations in 37 fish oil supplements purchased in Japan were 0.024-19 ng/g whole weight, and the non-dioxin-like PCB concentration range was also 0.024-19 ng/g whole weight. The total PCB intakes calculated for a 50 kg human consuming the supplements were 0.039-51 ng/day (0.00078-1.0 ng/(kg body weight per day)) and the non-dioxin-like PCB intake range was also 0.039-51 ng/day (0.00078-1.0 ng/(kg body weight per day)). The total PCB intakes were much lower than the tolerable daily intake of 20 ng/(kg body weight per day) recommended by the WHO. The results indicated that PCBs in the fish oil supplements pose acceptable risks to humans consuming the fish oil supplements daily.

Determination of N,N-dimethyldodecylamine and N,N-dimethyloctadecylamine in river and sea water using liquid chromatography tandem mass spectrometry.

We developed a selective method for determining N,N-dimethyldodecylamine (DMDA) and N,N-dimethyloctadecylamine (DMOA) concentrations in river and sea water samples using liquid chromatography/tandem mass spectrometry (LC/MS/MS). DMDA and DMOA are suspected to be toxic, and DMDA is categorized as a "Class I Designated Chemical Substance" under the "Act on Confirmation, etc. of Release Amounts of Specific Chemical Substances in the Environment and Promotion of Improvements to the Management Thereof" in Japan. The analytes are extracted from a water sample using solid phase extraction and the extract is evaporated and dissolved in 1 mL methanol for LC/MS/MS analysis. We analyzed DMDA and DMOA in real water samples and found that the analyte peaks were resolved effectively. The method detection limits for DMDA and DMOA were 4.7 and 0.80 ng/L, respectively.

[Inter-laboratory crosscheck study of dioxins and PCBs in human blood samples].

We developed an analytical method for accurately determining the concentrations of dioxin and polychlorinated biphenyls(PCBs) in a blood volume of 5 g. Inter-laboratory crosscheck is available for maintaining the quality of dioxin and PCB analysis. We carried out the crosschecks of dioxin and PCB analysis in the blood with domestic analysis organizations. Two crosschecks each of dioxin and PCB analysis were carried out from 2007 through 2011. As a result, the findings of our analysis accorded well with the analyses of the other organizations. We believe that our analytical method is sufficiently reliable.

Improvement of measurement method for hydroxylated polychlorinated biphenyls (OH-PCBs) in blood samples using LC/MS/MS.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are well known as metabolites of PCBs in the human body. We improved a measurement method for OH-PCBs in blood samples using LC/MS/MS. A new 2 microm particle column was used, and the analytical conditions for the LC/MS/MS measurements were optimized. The improved method is more sensitive than the conventional method for 5g blood samples. And, this method is effective at determining the concentrations of OH-PCBs, PCBs and dioxins from the same sample without special treatment of the sample such as derivatization.

Concentration of hydroxylated polychlorinated biphenyls (OH-PCBs) in the blood of Yusho patients in 2010.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are formed as major metabolites of PCBs by cytochrome P450 enzyme-mediated oxidation. It has been reported that their total concentration in serum samples of Yusho patients ranged from 390 to 1300 pg/g. We measured the concentration of OH-PCBs in blood collected from 183 Yusho patients living in Japan in 2010. The major OH-PCB metabolites were 4-OH-CB187 (ND-1300 pg/g-wet), 4-OH-CB146 + 3-OH-CB153 (8.4-1200 pg/g-wet), 4-OH-CB109 (ND-530 pg/g-wet) and 4'-OH-CB172 (ND-380 pg/g-wet). The total OH-PCBs ranged from 36 to 3800 pg/g-wet. A positive relationship between the concentrations of OH-PCBs and PCBs was observed, but no significant relationship between the concentrations of OH-PCBs and PCDD/DFs was observed.

Determination of 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers in sediment samples from the sea using liquid chromatography-tandem mass spectrometry.

A selective method has been developed for determining the concentration of 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers in sediment samples from the sea, using liquid chromatography/tandem mass spectrometry (LC/MS/MS). 4,4'-diaminodiphenylether is a suspected toxic compound, and categorized as "Class I Designated Chemical Substance" in Japan. We have investigated the levels of 4,4'-diaminodiphenylether in sediments to evaluate long-term water pollution. The methods detection limits for the 4,4'-, 3,4'-, and 2,2'-diaminodiphenylethers were 2.0, 1.7, and 4.8 ng/g-dry, respectively.

Measurement method for hydroxylated polychlorinated biphenyls in the blood of Yusho patients by liquid chromatography-electrospray tandem mass spectrometry.

Hydroxylated polychlorinated biphenyls (OH-PCBs) are formed as major metabolites of PCBs by cytochrome P450 enzyme-mediated oxidation. It has been reported that their total concentration in serum samples of Yusho patients ranged from 390 to 1300 pg/g. We developed a measurement method for OH-PCBs in blood samples by LC/MS/MS. This method is effective at determining the concentrations of PCDDs, PCDFs, Co-PCBs and OH-PCBs from the same sample without special treatment of the sample. The concentration of OH-PCBs in the blood of Yusho patients was examined using this method. The major OH-PCB metabolites were 4-OH-CB187 (54-906 pg/g-wet), 4-OH-CB146 + 3-OH-CB153 (32-527 pg/g-wet), 4-OH-CB109 (ND-229 pg/g-wet) and 4'-OH-CB172 (ND-143 pg/g-wet). The total OH-PCBs ranged from 95 to 1740 pg/g-wet.

Relationship between the concentrations of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in maternal blood and those in breast milk.

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 89 primiparous mothers in Sapporo City, Japan, and studied the relationships of these compounds between blood and breast milk for these women plus 30 primiparous mothers in whom these data had been previously reported. The present study is one of the few studies in which the concentration distributions of PCDDs, PCDFs, dioxin-like PCBs, and non-dioxin-like PCBs have been investigated in blood and breast milk collected from the same mothers. The arithmetic mean TEQ concentrations of PCDDs, PCDFs, non-ortho PCBs, and mono-ortho PCBs in blood and breast milk of these 119 subjects were 8.2, 2.9, 5.1, and 0.4 pg TEQ g(-1)lipid, respectively, and 4.8, 2.0, 4.0, and 0.4 pg TEQ g(-1)lipid, respectively, with the total TEQ concentrations of these dioxin-like compounds being 7.0-36 (mean: 17, median: 14) and 5.7-41 (mean: 11, median: 10) 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 43-445 (mean: 120, median: 106) and 34-366 (mean: 90, median: 81) ng g(-1)lipid, respectively, indicating that the total TEQ concentration and the total concentration of 56 non-dioxin-like PCB congeners in the maternal blood were notably higher than those in the breast milk. Statistically significant correlations were observed between maternal age and the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs or the total concentration of 56 non-dioxin-like PCB congeners in maternal blood, and significant correlations were also observed between maternal age and the total TEQ concentration of these dioxin-like compounds or the total concentration of 56 PCB congeners in breast milk. The total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs in maternal blood showed a close correlation to that in subjects' breast milk, and there was also good correlation between the total concentration of 56 non-dioxin-like PCB congeners in maternal blood and that in subjects' breast milk. Pearson and Spearman correlation analyses showed a relationship between the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs and the total concentration of 56 non-dioxin-like PCB congeners in maternal blood, and also showed an association between the total TEQ concentration of these dioxin-like compounds and the total concentration of 56 PCB congeners in breast milk. The concentration of hexaCB-153 in maternal blood showed significant correlations to the total TEQ concentration of PCDDs, PCDFs, and dioxin-like PCBs or the total concentration of 56 non-dioxin-like PCBs in that sample. Moreover, the concentration of hexaCB-153 in breast milk also showed significant correlations to the total TEQ concentration of these dioxin-like compounds or the total concentration of 56 PCB congeners in that sample. These findings suggested that hexaCB-153 may be an indicator of total TEQ concentrations of PCDDs, PCDFs, and dioxin-like PCBs and total concentrations of 56 non-dioxin-like PCB congeners in blood and breast milk of primiparous mothers.

Simple and sensitive determination of 2,4-xylenol in surface water samples from river and sea by gas chromatography-mass spectrometry.

A simple and selective method was developed for determination of the concentration of 2,4-xylenol in river and sea water samples using gas chromatography/mass spectrometry (GC/MS). Trace amounts of 2,4-xylenol were collected in a Oasis HLB Plus cartridge, eluted with acetonitrile. The method detection limit of 2,4-xylenol was 1.4 ng/L. The trace peaks of 2,4-xylenol were found in water samples from the river and the sea, and the concentrations were all less than 1.4 ng/L. The nine peaks of the 2,3-, 2,4-, 2,5-, 2,6-, 3,4-, 3,5-xylenol, and o-, m-, p-ethyl phenol that gave the same m/z ratio were separated efficiently.

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.

Determination of brominated flame retardants and brominated dioxins in fish collected from three regions of Japan.

The concentrations of brominated dioxins which are polybrominated dibenzo-p-dioxins/polybrominated dibenzofurans (PBDD/DFs) and mono-bromo polychlorinated dibenzo-p-dioxins/dibenzofurans, polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) were investigated in a total of 45 fish samples collected from three regions in Japan. In the brominated dioxins, 1,2,3,4,6,7,8-heptabromodibenzofuran (HpBDF) was the most abundant congener, and it was found in seven fish samples at 0.10-25.6 pg/g wet weight (ww). The highest concentration of 1,2,3,4,6,7,8-HpBDF was found in the pike eel. Regarding other congeners, 2,3,7,8-tetrabromodibenzo-p-dioxin was detected in the sea bream at 0.02 pg/g ww, and 2,3,7,8-tetrabromodibenzofuran was detected in the conger eel at 0.03 pg/g ww. 3-Bromo-2,7,8-trichlorodibenzofuran was detected in the Sardinella zunasi and the conger eel at 0.01 pg/g ww and 0.02 pg/g ww, respectively. Using toxic equivalency factors of chlorinated dioxins, we calculated the PBDD/DFs concentrations of these fish samples at 0.001-0.256 pg TEQ/g ww. PBDEs were detected in all of the fish samples. The concentrations of total PBDEs were 0.01-2.88 ng/g ww. The seerfish and the yellowtail containd PBDEs in high concentrations. The most dominant congener in most of the fish was 2,2',4,4'-tetrabromo diphenyl ether. TBBPA was detected in 29 fish samples at 0.01-0.11 ng/g ww. The mean level of TBBPA was about one-tenth or less of the total level of PBDEs. A good correlation was obtained between total PBDEs and fat content. On the other hand, no correlation was obtained between TBBPA and fat content. The daily intakes from fish were estimated to be 0.58 ng/kg body weight (bw)/day for total PBDEs, 0.03 ng/kg bw/day for TBBPA, and 0.01 pg TEQ/kg bw/day for brominated dioxins in the case assuming that the average bw of a Japanese adult person is 50 kg and that the average fish consumption is 82 g/day. For PBDEs, the provisionally calculated value was much less than the lowest observed adverse effect level value (1 mg/kg bw/day). For brominated dioxins, the daily intake was at a very low level compared with the Japanese daily intake of polychlorinated dioxins from fish. Even if the value of PBDD/DFs is added to the amount of chlorinated dioxin exposure, it was estimated that it is less than the tolerable daily intake (4 pg TEQ/kg bw/day) in Japan.

Determination of hexaconazole in surface water samples from river and the sea by liquid chromatography-electrospray tandem mass spectrometry.

A simple and selective method was developed for determining the concentration of hexaconazole in river and sea water samples by using liquid chromatography/tandem mass spectrometry with an electrospray ionization interface in the positive ion mode and selective reaction monitoring mode. Trace amounts of hexaconazole were collected in a Sep-Pak Plus tC18 cartridge that was eluted with methanol. The detection limit for hexaconazole was 6 ng/l. The recovery of a standard aqueous solution containing 1 microg/l was 96%. The recovery of hexaconazole in the river and sea water samples was 95% and 90%, respectively. Hexaconazole was not detected in the sea water samples. Trace peaks of hexaconazole were found in the river water samples, the concentration being less than 6 ng/l in all cases. The biological degradation of hexaconazole was tested by using river water. No degradation of hexaconazole was apparent in river water incubated at 20 degrees C for 3 weeks.

Dioxin concentration in the blood of patients collected during medical check-up for Yusho in 2004-2005.

We measured the concentrations of polychlorinated dizenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-ortho coplanar polychlorinated biphenyls (non-ortho PCBs) in blood collected from 242 Yusho patients and 74 Yusho-suspected persons in 2004 and 237 Yusho patients and 114 Yusho-suspected persons in 2005. The sums of toxic equivalents (TEQ) concentrations of PCDDs, PCDFs, and non-ortho PCBs in the blood of Yusho patients in 2004 and 2005 were 126.1 and 124.2 pg TEQ/g lipid, respectively, and the concentrations were 3.4 and 3.3 times higher than those of normal controls that had been previously reported, respectively. Those of the Yusho-suspected persons were about 0.8 and 1.0 times higher than those of normal controls, respectively. Although the TEQ concentrations of PCDDs and non-ortho PCBs among Yusho patients, Yusho-suspected persons, and normal controls were nearly the same, the PCDFs levels of Yusho patients were about 9.8 and 9.5 times higher than those of normal controls in 2004 and 2005, respectively. The concentration of 2,3,4,7,8-pentachlorodibenzofuran (2,3,4,7,8-PeCDF), which was the highest among PCDFs congeners for Yusho patients, was about 10. 6 and 10.2 times higher than that of the normal controls in 2004 and 2005, respectively. In the case of Yusho-suspected persons, the concentrations were 0.9 and 1.4 times higher than those of normal controls, respectively. However, some of the Yusho-suspected persons showed a high concentration of 2,3,4,7,8-PeCDF that was approximately 15 times greater than concentrations in normal controls. Of 74 Yusho-suspected persons measured in 2004, 7 persons were officially registered as Yusho patients based on the "New Diagnostic Criteria" that officially became the diagnostic criteria for Yusho exposure on September 29, 2004, which included a concentration of 2,3,4,7,8-PeCDF in the blood, and in 2005, 14 persons of 114 Yusho-suspected persons were officially registered as Yusho patients.

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.

Concentration and distribution of dioxins and related compounds in human tissues.

Polychlorinated dibenzo-p-dioxin, polychlorinated dibenzofuran and dioxin-like polychlorinated biphenyl concentrations in human blood, lung, liver, bile, pancreas, spleen, kidney and mesentery fat were determined to assess the concentrations and distribution of these chemicals in human tissues from 20 donors. The mean TEQ concentrations in blood, lung, liver, bile, spleen, pancreas, kidney and mesentery fat were 119, 178, 228, 50, 113, 163, 138 and 139 pg TEQ/g lipid, respectively. Parallel levels were seen in the blood, spleen, kidney and mesentery fat; in the lungs and pancreas, the levels were somewhat higher. Among the organ tissues samples, the highest concentration was observed in the liver and the lowest in the bile. Mean total-TEQ concentration of the liver was about 4.5 times higher than that of bile. Positive correlations were observed among the concentrations of dioxins in various tissues. However, the concentrations in bile were not correlated with any tissues. It is suggested that the distribution behavior of dioxin-like congeners in human tissues varies among tissues and the kinds of congeners ingested. To evaluate the relationship between the accumulation levels of dioxins and their pathophysiological significance or risk, data must be accumulated from a more extensive group of human samples.

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 prenatal exposure to polychlorinated biphenyls and dioxins on mental and motor development in Japanese children at 6 months of age.

Several studies have shown that prenatal and/or postnatal background-level exposure to environmental chemicals, such as polychlorinated biphenyls (PCBs) and dioxins, induces adverse effects on the neurodevelopment of children. However, other studies have not detected any harmful influences on neurodevelopment. Furthermore, except in western countries, no developmental tests have been carried out in relation to detailed assessment of exposure to PCBs and dioxins. In this study (the Hokkaido Study on Environment and Children's Health), the effect of prenatal exposure to background levels of PCBs and dioxins on infant neurodevelopment in Japan/Sapporo was elucidated. The associations between the total or individual isomer level of PCBs and dioxins in 134 Japanese pregnant women's peripheral blood and the mental or motor development of their 6-month-old infants were evaluated using the second edition of the Bayley Scales of Infant Development. The mean level of total toxicity equivalency quantity (TEQ) was 18.8 (4.0-51.2) pg/g lipid in blood of 134 mothers. After adjustment for potential confounding variables, the total TEQ value was shown not to be significantly associated with mental developmental index (MDI) or psychomotor developmental index (PDI). However, the levels of one polychlorinated dibenzo-p-dioxin (PCDD) isomer, total PCDDs, and total PCDDs/polychlorinated dibenzofurans (PCDFs) were significantly negatively associated with MDI, and the levels of two PCDD isomers and three PCDF isomers were significantly negatively associated with the PDI. In conclusion, the background-level exposure of several isomers of dioxins during the prenatal period probably affects the motor development of 6-month-old infants more than it does their mental development.

Effects of cooking on concentrations of polychlorinated dibenzo-p-dioxins and related compounds in fish and meat.

We investigated the cooking-induced changes in concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) (dioxins) using mackerel and beef. The concentrations of dioxins (29 congeners) were determined by isomer specific analyses and were compared between uncooked and cooked samples. The cooking procedures examined in this study included grilling as a fillet, boiling as a fillet, and boiling as tsumire (small, hand-rolled balls) for mackerel and boiling as a slice, broiling as a slice, and broiling as a hamburger for beef. Three trials were carried out for each cooking method. Generally, concentrations of dioxins were reduced in every cooking trial. When nondetected congener concentrations were assumed to be half the limit of detection for mackerel, the maximum percentage reductions of total concentrations given as 2,3,7,8-tetraCDD equivalents (TEQ) were 31% in grilling as a slice, 14% in boiling as a slice, and 21% in boiling as tsumire under the conditions of this study. In contrast, for beef, the reductions were 42% in boiling as a slice, 42% in broiling as a slice, and 44% in broiling as a hamburger. These results suggest that ordinary cooking processes with heating undoubtedly reduce the dioxin content in animal products, and the reductions estimated should be considered when dioxin intake is evaluated using contamination data for individual food items.

Contamination levels of PCDDs, PCDFs and Co-PCBs in commercial baby foods in Japan.

To examine dioxin contamination in commercial baby foods in Japan, congener analyses of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and coplanar polychlorinated biphenyls (Co-PCBs) were performed on 102 varieties of baby foods obtained from supermarkets in 2001-2002. The toxic equivalent quantity (TEQ) levels for dioxins in samples ranged from < 0.001 to 0.135 pg-TEQ/g wet weight when undetected or trace levels of congeners were taken as zero. Among 102 samples tested, 26 samples exceeded 0.010 pg-TEQ/g. The highest TEQ value was for "sardine, vegetables" (0.135 pg-TEQ/g), followed by "Japanese radish (daikon), sardine" (0.080 pg-TEQ/g). Thus, dioxins were detected at low levels in baby foods containing animal products such as fishes and/or dairy products.