Saturday, August 14, 2004
Private File Attachment:
The major determinants of human polychlorinated biphenyl (PCB) body burden include the source and route of exposure and the toxicokinetic processes occurring after uptake. Heretofore this was not possible until the discovery of electronic capture detection. The DeCaprio et al study explains the methodology of using the machine to record the PCB body burden by ” multivariate exploratory data analysis techniques which were applied to the congener-specific serum PCB data. A self-training receptor model, polytopic vector analysis (PVA), was employed to determine the number, composition, and relative proportions of independent congener patterns that contributed to the overall serum PCB profile for each Mohawk subject. PVA identified five such patterns, each of which was characterized by a unique mix of congeners.” (DeCaprio 2005). The Mohawk Nation at Akwesasne is a Native American community of about 10,000 people located at the juncture of New York State and the Canadian provinces of Ontario and Quebec on the St. Lawrence River andwere the focus of this study. First blood samples of over 700 men and women were taken. Then the blood samples were scanned by using a an ultratrace analytical method using dual-column gas chromatography with electron-capture detection using the quality control procedures as released in DeCaprio et al (2000). Table 1 contains all of the datas for the congeners. Descriptive statistics are used and in addition, the maximum likelihood estimation (MLE) method of Helsel and Cohn (1988) was used to calculate these summary statistics for congeners that were detected in at least 20% of the samples. The median PCB level was shown to be higher in males vs. females, and as Mohawks aged they had more PCB in their congeners.