Nationally representative data on urinary levels of bisphenol A (BPA) and its metabolites in the United States from the 2005–2006 National Health and Nutrition Examination Survey (NHANES) were used to estimate daily BPA intakes. In addition, NHANES data on potential sources of BPA exposure and personal characteristics were explored for their association with urinary BPA levels. On the basis of 2005–2006 NHANES urinary BPA data and assumptions described in this paper, median daily intake for the overall population is approximately 34 ng/kg-day. Median daily BPA intakes for men are statistically significantly higher than for women; there is a significant decrease in daily BPA intake with increasing age. Gender- and age-specific median intakes differ from the overall population by less than a factor of 2. Although estimates of daily BPA intake have decreased compared with those from the 2003–2004 NHANES, it is premature to draw conclusions regarding trends at this time, as there is no indication that BPA use declined from 2003 to 2006. On the basis of an assessment of urinary BPA and questionnaire data from the 2005–2006 NHANES, consumption of soda, school lunches, and meals prepared outside the home — but not bottled water or canned tuna — was statistically significantly associated with higher urinary BPA.
16 April 2008 in Journal of Exposure Science & Environmental Epidemiology
The reductive dissolution of goethite (α-FeOOH) and hematite (α-Fe 2 O 3 ) by phenolic reductants has been examined in order to improve the understanding of iron transformations in soils, sediments and aquifers. Rates of goethite reductive dissolution by hydroquinone increased as the pH was increased from pH 1.8 to 4.65, arid the following reaction stoichiometry was obeyed: 2 α - FeOOH + QH 2 = 2 Fe 2+ + Q + 4 OH − . As the pH was increased from pH 4.5 to 6.0, the reductive dissolution rate decreased to below the detection limit. At pH 3.4, the reductive dissolution of hematite was two orders of magnitude slower than goethite. The relationship between structure and reactivity was examined for a series of mono-, di-, and tri-hydroxybenzene reductants. Rates of reductive dissolution decreased in the following order: catechol ∼- hydroquinone > 3,4-dihydroxybenzoic acid > resorcinol-phenol-4-hydroxybenzoic acid.