Mikiya Kitagawa

Time-trend (1973–2000) of polybrominated diphenyl ethers in Japanese mother’s milk

The time-trend and recent concentrations of polybrominated diphenyl ethers (PBDEs) in Japanese mothers milk were investigated. The time-trend of 16 PBDEs (BDE-28, 37, 47, 66, 71, 75, 77, 85, 99, 100, 119, 153, 154, 138, 183, and 190) in pooled milk samples from mothers living in Osaka between 1973 and 2000 was analyzed. Additionally, PBDE concentrations in individual milk samples collected from 13 mothers living in Kanagawa and Okayama in 1999 were measured. The total concentration of all PBDE congeners (SigmaPBDEs) measured in the pooled samples increased during the period between 1973 (<0.01 ng/g lipid) and 1988 (1.64 ng/g lipid), and remained low afterwards while showing remarkable changes in PBDE congener profiles. The SigmaPBDEs in the 1999 individual milk samples were also low (0.56-3.97 ng/g lipid), except for a single sample (291 ng/g lipid). The source of this exposure could not be identified.

GC/MS analysis of polybrominated diphenyl ethers in fish collected from the Inland Sea of Seto, Japan

Development of an analytical method for polybrominated diphenyl ethers (PBDEs) in fish and their concentration in Japanese marine fish were investigated. Fish homogenate was extracted with diethyl ether/hexane (1 + 3). The extract was cleaned up by automated gel permeation chromatography (GPC) and then by mini-column chromatography, which consisted of three layers of silica gel and sulfuric acid-impregnated silica gel. The PBDE fraction was concentrated and injected into a GC/MS with negative chemical ionization (NCl). Recoveries of the 15 individual PBDEs (BDE-15, 28, 37, 47, 66, 71, 75, 77, 85, 99, 100, 119, 153, 154, and 209) each at a fortification level of 4 ng/g lipid were in the range of 88-128% and the relative standard deviations (RSD) were 0.43-7.6% (n = 4). Seven species of marine fish (conger eel, flounder, gray mullet, horse mackerel, red sea bream, sea bass, and yellowtail) were collected from the Inland Sea of Seto, and were analyzed with the developed method. Seven PBDEs (BDE-28, 47, 66, 99, 100, 153, and 154) were detected in all the samples. The most abundant PBDE congener was BDE-47 found in all the samples. Relatively high levels of PBDEs were found in the gray mullets and yellowtails.

Rapid analysis of 56 pesticide residues in natural medicines by GC/MS with negative chemical ionization

Many methods for determining pesticide residues in food have been reported. Although natural medicines should be confirmed to be as safe as food, few methods for determining pesticide residues in natural medicines have been reported. In this study, 56 pesticides were detected in natural medicines with a simple, rapid sample preparation method. This study indicates that the proposed method is useful for analyzing pesticides in natural medicines.

Surveillance of Polychlorinated Biphenyl Congeneric Patterns in Human Breast Milk from 1973 to 2000 in Osaka, Japan

ObjectiveBecause the analysis of polychlorinated biphenyls (PCBs) in 1970’s was performed using a packed column gas chromatograph, with an electron capture detector to determine total-PCB concentration, analytical data obtained by this analysis do not meet the requirement for the risk assessment of PCB congeners. In this context, the present study was carried out to reevaluate the congeneric analysis data by analyzing breast milk fat specimens that have been kept frozen.MethodsPCB congeners in human breast milk were analyzed by high-resolution gas chromatography/high-resolution mass spectrometry (HRGC/HRMS) using a capillary column for the selected ion monitoring (SIM) of PCBs.ResultsTwelve major PCB congeners were detected in breast milk. The concentrations of all congeners of PCBs in breast milk were found to decrease annually, and their changes over time differed greatly for each congener. Between 1973 and 2000, almost no changes in the proportions of the 12 congeners of heptachlorinated biphenyls (HpCBs) and hexachlorinated biphenyls (HxCBs) were found whereas a marked and a slight decrease in the proportion of pentachlorinated biphenyls (PeCBs) and tetrachlorinated biphenyls (TeCBs), respectively, were observed.ConclusionsThe PCB contamination of the Japanese population is estimated to be largely caused by seafood intake, but the proportions of PCB congeners in fish commodities were different from those in breast milk. The absorption, metabolism and therefore the accumulation of PCBs in the human body differ greatly depending on the congener.