Kazuhiro Tobiishi

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.

Follow-up Survey of Dioxins Concentrations in the Blood of Yusho Patients in 2002-2003

We measured the concentrations of polychlorinated dizenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and non-ortho-coplanar polychlorinated biphenyls (Co-PCBs) in blood collected from 279 Yusho patients and 92 Yusho-suspected persons living in Japan in 2002, 269 Yusho patients and 74 Yusho-suspected persons living in Japan in 2003 and 128 normal controls living in Fukuoka Prefecture, and compared with the concentrations of these compounds among the groups. The total TEQ concentrations of PCDDs, PCDFs, and Co-PCBs in the blood of Yusho patients were 3.6 times and 3.3 times higher than those in the normal controls in 2002 and 2003, respectively. In the case of Yusho-suspected persons, the concentrations were 1.1 times and 1.0 times higher in 2002 and 2003, respectively. Among the TEQ concentrations of PCDDs, PCDFs, and Co-PCBs, the concentrations of PCDFs in the blood of Yusho patients were 10.3 times and 9.4 times higher than those of the normal controls in 2002 and 2003, respectively, whereas the concentrations of PCDDs and Co-PCBs in blood were identical in Yusho patients, Yusho-suspected persons and normal controls. Yusho patients indicated the highest concentrations ratio of PCDFs to the total TEQ concentrations. Moreover, of the PCDFs congeners for Yusho patients, the concentrations of 2,3,4,7,8-PeCDF were about 11.0 times and 10.1 times higher in 2002 and 2003 than those in normal controls. These results indicated that Yusho patients have a much higher concentration of 2,3,4,7,8-PeCDF in their blood than do unaffected persons even though over 34 years have passed since the outbreak of Yusho.

A Rapid Method, Combining Microwave-Assisted Extraction and Gas Chromatography-Mass Spectrometry with a Database, for Determining Organochlorine Pesticides and Polycyclic Aromatic Hydrocarbons in Soils and Sediments

ABSTRACT A rapid method for determining organochlorine pesticides and polycyclic aromatic hydrocarbons in soils and sediments was developed to allow pollution surveys to be performed in emergencies. The method involves microwave-assisted extraction and uses an automated identification/quantification system with a gas chromatography mass spectrometry database. A sample (3 g) is extracted with a 3:2 v/v hexane:water mixture (10 mL) for 30 min using a microwave-assisted extraction system at 120°C. The hexane extract is then cleaned using silica gel, then analyzed by gas chromatography mass spectrometry. The total analysis time is approximately 4 h. The precision of the quantitative results and accuracy of the analyte identification were determined. The total analyte concentrations were generally comparable to (61%–110% of) the concentrations determined using a Soxhlet extraction method, but the concentrations of individual high-molecular-weight polycyclic aromatic hydrocarbons were unacceptably low compared with the concentrations determined using the Soxhlet method. However, these compounds (e.g., benzo(ghi)perylene and indeno(1,2,3-cd)pyrene) were subsequently efficiently extracted using a hexane:water:ethanol mixture. The accuracy of identification was evaluated using accurate masses determined by gas chromatography time-of-flight mass spectrometry, and the mass error was 2 ppm for 21 of the 22 compounds identified using the new method.

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.