Urine Chemical Content May Be a False Measure of Environmental Exposure

Abstract

Dr Trasande and his group in the article on phthalates conclude that urine phthalate concentrations (represented by urine di-2-ethylhexylphthalate [DEHP] concentrations) were associated with increased insulin resistance in this cross-sectional study of adolescents. Dr Trasande refers to this as an association and indicated that this study cannot rule out the possibility that insulin-resistant children ingest food with higher phthalate content or that insulin-resistant children excrete more DEHP. Without knowing the tissue or serum concentration of DEHP or referring to primate studies, the authors' hypotheses are appropriate.The second article by Eng et al deals with bisphenol A (BPA). It is most important for authors to be familiar with the literature concerning the chemical that they are evaluating. Unfortunately, the BPA article fails to cite important publications dealing with the metabolism of BPA. For example, Daniel Doerge, a well-known authority on the metabolism of BPA, has co-written 5 publications that Eng et al have not cited. [3][4][5][6][7][8] In 2011, in a report entitled, "Twenty-Four Hour Human Urine and Serum Profiles of Bisphenol A during High-Dietary Exposure" 3 these investigators found that urinary BPA is not a surrogate of a serum or tissue exposure to BPA, but reflects the intake of BPA in the diet of the individual whose urine has been collected. This study, published in Toxicological Sciences, studied 20 adult volunteers who ingested 100% of 1 of 3 specified meals comprising of standard grocery store items for breakfast, lunch, and dinner. They studied the serum concentration of BPA, which was only measurable in the serum of the patients with exposure of 1.3 to 3.9 times higher than the 95th percentile of aggregate US exposure. "BPA serum concentrations were primarily less than or equal to the limit of detection…and were on average, 42 times lower than urine concentrations. During these high dietary exposures, BPA concentrations in serum were undetectable in 83% of the 320 samples collected and BPA concentrations were determined to be less than or equal to LOD [limit of detection] in all samples."Because there is little BPA in the serum even with large intakes of BPA and the metabolism of BPA in the serum destroys its endocrine receptor affinity, there is little justification to assume that BPA has toxic exposure in the human, even with very high exposure in the diet.Most BPA articles in humans use the urine content of BPA as a surrogate of exposure, when in reality it is a measure of the intake of BPA

Bisphenol A Exposure Enhances Atherosclerosis in WHHL Rabbits

“…BPA is rapidly catabolized in WHHL rabbits within 24 hr, and serum levels of residual BPA were not significantly increased, suggesting that serum levels of BPA cannot predict the actual levels and toxic effects of BPA exposure [56] . Nevertheless, BPA exposure led to increased atherosclerosis in aortic and coronary atherosclerosis.…”

Bisphenol A, obesity, and type 2 diabetes mellitus: genuine concern or unnecessary preoccupation?

“…To date, urinary BPA concentrations have not been followed longitudinally and linked prospectively to the development of either obesity and/or diabetes. Finally, there is tremendous controversy as to whether urinary BPA is able to even accurately assess level of exposure (35). A number of studies have shown that urinary BPA is reflective of recent dietary intake of BPA, but does not accurately reflect exposure at the tissue or serum level (36, 37).…”

Εφαρμογή Νέων Μεθόδων Ελέγχου Για Την Εκτίμηση Της Ασφαλούς Χρήσης Ανακυκλωμένων Υλικών Συσκευασίας Για Άμεση Ή Έμμεση Επαφή Με Τρόφιμα

“…Η παραπάνω διαδικασία εφαρμόστηκε εις τριπλούν για την διεξαγωγή ασφαλών συμπερασμάτων.Ο ποσοτικός προσδιορισμός των ανακτημένων ουσιών από τα χαρτόνια έγινε σύμφωνα με τις καμπύλες αναφοράς που κατασκευάστηκαν με τις συγκεντρώσεις των πρότυπων ουσιών από τα επιμολυσμένα V1 χαρτόνια τα οποία περνούσαν την ανωτέρω διαδικασία για την κάθε επιθυμητή συγκέντρωση.Με το πρώτο θερμοκρασιακό πρόγραμμα διάρκειας 43 λεπτών που εφαρμόστηκε στον αέριο χρωματογράφο GC προκειμένου να προσδιορισθούν οι ουσίες 1 -35, ανιχνεύθηκαν πολλές ενώσεις της ομάδας των επιμολυντών 26 -35 τα πρώτα 14 λεπτά, ενώ από τα 14 λεπτά και μετά ανιχνεύθηκαν οι υπόλοιπες ουσίες. Η ομάδα των φθαλικών εστέρων64,65,66,67 ανιχνεύθηκε από τα 17-33 λεπτά περίπου. Χρωματογράφημα όλων των υπό μελέτη ενώσεων με το θερμοκρασιακό πρόγραμμα i Με το θερμοκρασιακό αυτό πρόγραμμα επετεύχθη ο ποιοτικός προσδιορισμός σχεδόν όλων των επιμολυντών στην ίδια συγκέντρωση, δεν ήταν όμως δυνατό να γίνει ποσοτικός προσδιορισμός για τις ουσίες 26-35.…”