At a glance
- The Updated Tables, February 2012, include results from the NHANES survey periods 2003-2004, 2005-2006, and 2007-2008.
- Newly reported chemicals include thiocyanate and nitrate anions, sulfonyl urea herbicides, and various pesticides.
- Subsample weights for the 2007-2008 survey period have been revised, resulting in slight differences in data compared to previous Updated Tables.
- Adjustments have been made to urinary perchlorate measurements and phthalate metabolite values due to volume bias and insufficient purity of analytical standards.
Updated Tables, February 2012
The Updated Tables in this release include several chemicals that have not previously been reported and have results available from one or more of the three survey periods of 2003-2004, 2005-2006, and 2007-2008. Newly reported chemicals include the anions thiocyanate and nitrate, the sulfonyl urea herbicides (17 chemicals), and the following pesticides: acephate, methamidophos, dimethoate, omethoate, ethylene thiourea, and propylene thiourea.
For the 2007-2008 survey period, NHANES has recently revised the subsample weights to correct for misspecification of domains used for calculating the subsample weights. Consequently, some data are slightly different relative to those data that appeared in previous Updated Tables. Datasets that were revised include the following chemicals or chemical groups: the pesticides 2,4- and 2,5-dichlorophenol, ortho-phenylphenol, 2,4,5-and 2,4,6-trichlorophenol; the environmental phenols bisphenol A, triclosan, 4-tertoctylphenol, benzophenone-3, and four parabens; perfluorochemicals (12 chemicals); phthalate metabolites (15 chemicals); and urinary metals, including mercury, and total and speciated arsenic (21 chemicals).
Urinary perchlorate results were recently found to have a slight bias (-3.2%) in the sample volume accuracy of the aliquotting technique used for NHANES 2005-2006. Additional work by CDC indicated that perchlorate measurements from NHANES 2001-2004 were biased by -4.7%, and therefore, a factor of 1.049 was applied to adjust perchlorate measurements for this slight volume bias. Consequently, those perchlorate data that were previously reported (2001-2004) are slightly different in this Updated Tables because of these slight adjustments.
CDC learned that analytical standards of five phthalate metabolites used for all CDC projects since 1999 were of insufficient purity. As a result of further investigation, CDC determined that a correction factor should be applied to each value (including the limit of detection) for these five metabolites as follows: Mono-ethyl phthalate, 0.66; Mono-benzyl phthalate, 0.72; Mono-n-octylphthalate, 1.68; Mono-isononyl phthalate, 1.54; and Mono-cyclohexyl phthalate, 2.01. These correction factors have been applied to the five analytes for NHANES survey periods 1999-2000, 2001-2002, 2003-2004, 2005-2006, and 2007-2008. Consequently, the data tables in the Updated Tables for these phthalate metabolites show results that are slightly different from the data tables presented in the Fourth Report on Human Exposure to Environmental Chemicals and in all of the previous Reports.
2,4,5-Trichlorophenol, 2,4,6-trichlorophenol, 2,4-dichlorophenol, 2,5-dichlorophenol, ortho-phenylphenol, and pentachlorophenol were reported in the Fourth Report on Human Exposure to Environmental Chemicals for NHANES 1999-2000 and 2001-2002 survey periods. Due to improvements in analytical methods, the data for these six analytes in the NHANES 1999-2000 and 2001-2002 survey periods have been removed from the NHANES website and are not reported in the Updated Tables. Data for these analytes are included in these Updated Tables beginning with the NHANES 2003-2004 survey periods.