Polychlorinated biphenyls in preserved human umbilical cords

Development of Artificial Urine Certified Reference Material for Quantification of Neonicotinoid Insecticides

BACKGROUND

Neonicotinoid insecticides (neonicotinoids) are widely used, however, they can negatively affect human health. Thus, neonicotinoids and their metabolites in human urine are analyzed globally to assess exposure levels and health risks. To properly assess the exposure levels and health risks, accurate analytical results are a necessity.

OBJECTIVE

This study aims to develop urine certified reference material (CRM), NMIJ CRM 7408-a, for the quantification of neonicotinoids.

METHOD

To develop NMIJ CRM 7408-a, commercially available artificial urine was used as the raw material to which the target neonicotinoids were added. Analyses of neonicotinoids in NMIJ CRM 7408-a were carried out by isotope dilution mass spectrometry (IDMS).

RESULTS

Sample homogeneity was assessed, with the results showing that acetamiprid, clothianidin, thiacloprid, and thiamethoxam exhibited sufficiently homogeneous distributions in the material. The relative uncertainties due to inhomogeneity were 1.2-7.0%. The results obtained from long-term stability assessment indicated that the target neonicotinoids were stable. The relative uncertainties due to instability were 9.4-17.2% (for an expiry date of 21 months). The characterization for providing concentration values was carried out using one (clothianidin and thiacloprid) or two (acetamiprid and thiamethoxam) analytical methods. The certified values of the target neonicotinoids (acetamiprid, clothianidin, thiacloprid, and thiamethoxam) were 0.19-1.38 µg/kg.

CONCLUSIONS

This is the first frozen artificial urine CRM in which neonicotinoids were quantified by IDMS and will be useful for evaluating the accuracy of analysis and validation of analytical methods for the determination of neonicotinoids in urine.

HIGHLIGHTS

NMIJ CRM 7408-a, which has been certified for four neonicotinoids, was developed by NMIJ.

Retrospectivein utero exposure assessment of PCBs using preserved umbilical cords and its application to case-control comparison

OBJECTIVES

The aim of this study is to assess preserved umbilical cords as chemical exposure media to investigatein utero chemical exposure. Furthermore, we aim to apply preserved umbilical cords to retrospective studies of the relationship betweenin utero chemical exposure and neurodevelopment disorders.

METHODS

Two sets of preserved umbilical cord samples were analyzed for exposure to polychlorinated biphenyls (PCBs): one composed of samples from 20 healthy Japanese subjects and the other set included samples from 17 autistic patients and 7 healthy sibling of theirs.

RESULTS

The possibility of external PCBs contamination during storage of preserved umbilical cord samples was found, and due to this problem, the study design should be limited to the comparison between PCBs concentration in preserved cord samples from autistic patients and that in those from their sibling. Total PCBs concentrations in preserved cords from autistic patients and their control siblings were compared and we found no statistically significant difference between them (Wilcoxon signed rank test, p>0.05).

CONCLUSIONS

The association between autism andin utero PCBs exposure was not clarified in this study; however, retrospective studies such as a case-control study of siblings using preserved umbilical cords can be a method of choice for examining the possible relationship betweenin utero chemical exposure and child hood disorders.

PCB contamination assessment of yusho patients by using preserved human umbilical cord

PCB concentrations in umbilical cord preserved from the time when Yusho patients and healthy subjects gave birth were examined. The total concentration of the 12 DL-PCB isomers ranged from 130 to 12,000 pg/g in the umbilical samples, was about 700 pg/g around 1950 but began to increase in the mid 1960s, reached about 12,000 pg/g between 1968 and 1970 immediately after the Yusho incident. However, the DL-PCB concentration was high between 1968 and 1970 in not only the designated Yusho patients but also healthy subjects, and the maximum DL-PCB concentration was close between the two groups.

Congener-specific analysis of non-dioxin-like polychlorinated biphenyls in blood collected from 195 pregnant women in Sapporo City, Japan

We conducted a congener-specific analysis of non-dioxin-like polychlorinated biphenyls (non-dioxin-like PCBs) in blood collected between July 2002 and July 2004 from 195 pregnant women living in Sapporo City of Hokkaido Prefecture, Japan. The present study is one of the few studies in which full congener concentrations of non-dioxin-like PCBs have been measured in the blood of pregnant women. Of the 195 pregnant women, 101 were primipara (mean: 28.8 years, median: 28.0 years) and 94 were multipara (mean: 32.3 years, median: 33.0 years). Among the 197 non-dioxin-like PCB congeners, 58 congeners were identified in the blood of pregnant women. The arithmetic mean total concentrations of 58 non-dioxin-like PCB congeners in the blood of primiparous and multiparous mothers in Sapporo City were 42.2-329.3 (mean: 114.5, median: 98.6) and 31.5-258.0 (mean: 100.3, median: 91.4)ngg(-1)lipid, respectively. The results show that the contamination of non-dioxin-like PCBs in the blood of women has decreased compared to past levels in other domestic areas, in which the subject age was similar to that in this study. The results of the present study indicate that current levels of non-dioxin-like PCBs in the blood of Japanese women and can be used as baseline data for future temporal trends. The sums of the ratios of the concentrations of hexaCBs and heptaCBs to the total concentrations of 58 non-dioxin-like PCB congeners in the blood of primiparous and multiparous mothers were 78.5% and 77.7%, respectively. The hexaCBs ratios in the blood of primiparous and multiparous mothers were 45.4% and 44.7%, respectively. HexaCB-153 among hexaCBs congeners, the most abundant congener in the blood of primiparous and multiparous mothers, contributed approximately 22.0% and 21.8% to the total concentrations of 58 non-dioxin-like PCBs congeners that were measured in the blood, respectively. Among the non-dioxin-like PCB congeners measured in the present study, hexaCB-138, heptaCB-170, heptaCB-180, and heptaCB-182/heptaCB-187 also showed high ratios to total concentrations of 58 non-dioxin-like PCB congeners detected in the blood of primiparous and multiparous mothers. With regard to the relationship between the total concentrations of 58 non-dioxin-like PCB congeners in maternal blood and the number of deliveries or the age of primiparous and multifarious mothers, the total levels of these PCB congeners tended to decreases 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 concentrations of these PCB congeners in blood and the age of primiparae and multiparae. The concentrations of hexaCB-153 in the blood of primiparous and multiparous mothers showed a close correlation to the total concentrations of these PCBs, suggesting that hexaCB-153 could be an indicator of total concentrations of non-dioxin-like PCB congeners in the blood of pregnant women.