What's New Archives - March 24, 2022

National Exposure Report Transitions to an Online Interface

CDC's National Report on Human Exposure to Environmental Chemicals (referred to as the Report) is now available in an online interface that allows users to search for chemicals in multiple ways, compare data tables quickly, and access the information without having to download or manage several large PDF files.

All information previously associated with the Report remains available but is now housed in one online location: https://www.cdc.gov/environmental-exposure-report/. Data tables can be accessed by following the "Click Here for Biomonitoring Data" link at the top of the webpage.

Data tables are now viewed using an HTML-based interface. Basic instructions are embedded within the interface; a more detailed User Guide is available via hyperlink at the top of the page. Users can search for chemicals using a drop-down menu that retains the familiar organization of prior versions of the Report, or via a keyword search. Up to six tables can be populated by selecting different "table viewer" tabs.

Data tables are presented in HTML format and are in compliance with Section 508 Accessibility requirements to assist users with visual impairments. Users interested in downloading PDF versions of a data table can do so by clicking a link near the top of the table; each data table also includes a link to a PDF document containing tables for the entire chemical group to which the selected chemical belongs.

Due to the sheer volume of data, prior editions of the Report organized data for chemicals measured in individual samples from the general U.S. population in two PDF volumes, one for NHANES 1999-2010 and another for NHANES 2011-2018. The online interface has allowed us to facilitate access to all these tables by aggregating them into one section:

• Analysis of Whole Blood, Serum, and Urine Samples, NHANES 1999-2018 presents data tables for individual samples from the general U.S. population.

Other types of data, such as measurements in pooled samples or from special subsets of the NHANES population, remain available in two separate sections:

• Analysis of Pooled Serum Samples for Select Chemicals, NHANES 2005-2016 presents data tables for persistent organic pollutants and pesticides that were measured in pooled samples. Data tables for these chemicals that are based on individual samples can be found in "Analysis of Whole Blood, Serum, and Urine Samples, NHANES 1999-2018."
• Analysis of Chemicals Found in Cigarette Smoke in a Special Sample of U.S. Adults, NHANES 2011-2016 presents data for a sample of adult cigarette smokers and nonsmokers from NHANES 2011-2012 through 2015-2016.

Archival Information

As a means of retaining important information, the following three sections from the March 2021 Report are republished here.

Stratification by Cigarette Smoking Status

Summary statistics for chemicals within the following sections are stratified by cigarette smoking status, which is defined as a serum cotinine concentration more than 10 ng/mL in adult participants from NHANES, excluding those who reported using other tobacco products.

• Tobacco alkaloids and metabolites
• TSNAs
• Aromatic amines

Change in the Population Sampled for Urinary Chemicals: NHANES 2015–2016

Beginning with the NHANES 2015–2016 survey period, the age for urine collection was lowered from age 6 years to age 3 years. This change was made to obtain data for younger children, a vulnerable population with limited urinary data. The urinary environmental chemicals are measured in a full sample (i.e., all children able to provide a urine specimen) of children 3 to 5 years old. For ages 6 years and older, the urinary environmental chemicals are measured in a representative one-third sample of participants.

The addition of ages 3 to 5 years to the survey population will mean that descriptive statistics (geometric mean, selected percentiles) for the total population and non-age-related demographic groups beginning in NHANES 2015–2016 will not be directly comparable to descriptive statistics in earlier NHANES survey periods. This is because the populations sampled are not equivalent.

PFOS and PFOA Results for NHANES 2013–2014 and 2015–2016

Starting in 2013, we began measuring linear and branched isomers of both PFOS and PFOA and no longer measured total PFOS and total PFOA. Collectively, the isomers of each chemical represent more than 95% of what was previously reported as PFOS and PFOA. Data tables for each of the four isomers are also presented.

PFOS and PFOA are calculated by summing the linear and branched isomers for each participant before applying the appropriate sample weight. Because the 2013–2014 and 2015–2016 values are a calculated sum, there is no limit of detection (LOD) for PFOS and PFOA. For more details, see the "Calculation of PFOS and PFOA as the Sum of Isomers" link available at https://www.cdc.gov/environmental-exposure-report/. The calculated PFOS and PFOA results can be used to compare with previous measurements and to examine trends in the general U.S. population.