Table of Contents

Component Description

Volatile Organic Compounds (Human Blood):

Exposure to volatile organic compounds (VOCs) is ubiquitous. Chronic exposure to extremely high levels of some VOCs can lead to cancer and neurocognitive dysfunction (1,2).
Nearly 200 air toxics have been associated with adverse health effects in occupational studies or laboratory studies, but have not been monitored in general population groups. Information on levels of exposure to these compounds as measured by their levels in blood is essential to determine the need for regulatory mechanisms to reduce the levels of hazardous air pollutants to which the general population is exposed.

Volatile Organic Compounds (Home Tap Water):

In addition to assessing levels of VOCs in blood, VOC levels will be measured in home tap water specimens provided by NHANES participants. Specifically, trihalomethanes (THMs) and the fuel additive methyl tertiary-butyl ether (MTBE) are measured in these samples.

Eligible Sample

Participants aged 20 to 59 years on a one-third sample were tested.

Description of Laboratory Methodology

Measurements of Trihalomethanes (THMs) and MTBE in Tap Water:

The prevalence of water disinfection by-products in drinking water supplies has raised concerns about possible health effects from chronic exposure to these compounds. The objective is to support studies exploring the relationship between exposure to THMs and health effects.

This automated analytical method uses headspace solid-phase microextraction (SPME) coupled with capillary gas chromatography and mass spectrometry (3). This method quantities trace levels of THMs (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) and MTBE in tap water.

Detection limits of less than 100 pg/mL for all analytes and linear ranges of three orders of magnitude are adequate for measuring the THMs in tap water samples tested from across the United States. THMs are stable for extended periods in tap water samples after quenching of residual chlorine and buffering to pH 6.5, thus enabling larger epidemiologic field studies with simplified sample collection protocols.

Measurements of THMs and MTBE in Whole Blood:

The prevalence of water disinfection by-products (e.g. THMs) in tap water has raised concerns about possible health effects from chronic exposure to these compounds. Exposure to the fuel oxygenate MTBE has also raised concerns. People can be exposed to THMs and MTBE through a variety of sources, including use of household tap water that contains these chemicals. The objective of this study is to support studies exploring the relationship between health effects and exposure to THMs and MTBE. THMs and MTBE were quantified in human blood using capillary gas chromatography (GC) and high-resolution mass spectrometry (MS) with selected ion mass detection and isotope-dilution techniques (4). This method quantified trace levels of THMs (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) and MTBE in human blood. Analyte responses were adequate for measuring background levels after extraction of these volatile organic compounds with either purge-and-trap extraction or headspace SPME. Detection limits ranged from 0.3–2.4 pg/mL, with linear ranges of three orders of magnitude. This method provided adequate sensitivity for measuring the THMs and MTBE in most blood samples tested from diverse U.S. reference population.

Measurements of other VOCs in Whole Blood:

An additional 11 VOCs were measured in human blood using SPME in conjunction with gas chromatography and bench top quadrupole mass spectrometer (5). A combination of SPME and multiple single-ion monitoring minimizes the interferences and chemical noise associated with whole-blood samples. Detection limits are below 50 ppt (pg/mL) for a majority of the VOCs tested.

Data Processing and Editing

Specimens were processed, stored and shipped to Division of Laboratory Sciences, National Center for Environmental Health, National Centers for Disease Control and Prevention, Atlanta, Georgia. Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed data processing and editing protocols. The analytical methods are described in the Description of the Laboratory Methodology section.

Laboratory Quality Assurance and Monitoring

The NHANES quality control and quality assurance protocols (QA/QC) meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed quality control and quality assurance instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Read the LABDOC file for detailed QA/QC protocols.

Analytic Notes

Measures of volatile organic compounds in blood and water were assessed in participants aged 20 to 59 on a one-third sample. Use the special weights included in this data file when analyzing data. Read section 10.3 below before beginning analysis.

The analysis of NHANES 2001-2002 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2001-2002 Household Questionnaire Data Files contain demographic data, health indicators, and other related information collected during household interviews. They also contain all survey design variables and sample weights for these age groups. The phlebotomy file includes auxiliary information such as the conditions precluding venipuncture. The household questionnaire and phlebotomy files may be linked to the laboratory data file using the unique survey participant identifier SEQN.

Detection limits: The detection limit was variable for many of the analytes in the data set. In addition two variables are provided for each of these analytes. The variable named LBD___LC indicates whether the result was below the limit of detection. There are three values: “0”, “1”, and “2”. “0” means that the result was at or above the limit of detection. “1” indicates that the result was below the lower limit of detection. “2” means the result was above the upper limit of detection of the assay.
The other variable named LBX___ provides the analytic result for that analyte. In cases, where the result was below the limit of detection, the value for that variable is the detection limit divided by the square root of two.

Special sample weights are required to analyze these data properly. Use the special weights included in this data file when analyzing data. Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues.

The assay method was expanded during this the two-year cycle to measure additional analytes. However, because of confidentiality reasons the results can't be released.

References

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 20 YEARS - 59 YEARS

WTSVOC2Y - VOC subsample 2 yr MEC Weight

Variable Name:
WTSVOC2Y
SAS Label:
VOC subsample 2 yr MEC Weight
English Text:
VOC subsample 2 yr MEC Weight
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 576402.46313 Range of Values 1449 1449
. Missing 0 1449

WTSVOC4Y - VOC subsample 4 yr MEC Weight

Variable Name:
WTSVOC4Y
SAS Label:
VOC subsample 4 yr MEC Weight
English Text:
VOC subsample 4 yr MEC Weight
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 345630.72173 Range of Values 1449 1449
. Missing 0 1449

LBXWBF - Water Bromoform (ng/mL)

Variable Name:
LBXWBF
SAS Label:
Water Bromoform (ng/mL)
English Text:
Water Bromoform Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0337 to 30 Range of Values 1038 1038
. Missing 411 1449

LBDWBFLC - Water Bromoform Comment Code

Variable Name:
LBDWBFLC
SAS Label:
Water Bromoform Comment Code
English Text:
Water Bromoform Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 626 626
1 below detectable limit 411 1037
2 detectable result and exceeds the calibrated range of assay 1 1038
. Missing 411 1449

LBXWCF - Water Chloroform (ng/mL)

Variable Name:
LBXWCF
SAS Label:
Water Chloroform (ng/mL)
English Text:
Water Chloroform Result
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0849 to 147 Range of Values 1038 1038
. Missing 411 1449

LBDWCFLC - Water Chloroform Comment Code

Variable Name:
LBDWCFLC
SAS Label:
Water Chloroform Comment Code
English Text:
Water Chloroform Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 914 914
1 below detectable limit 124 1038
2 detectable result and exceeds the calibrated range of assay 0 1038
. Missing 411 1449

LBXWBM - Water Bromodichloromethane (ng/mL)

Variable Name:
LBXWBM
SAS Label:
Water Bromodichloromethane (ng/mL)
English Text:
Water Bromodichloromethane Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 32 Range of Values 1024 1024
. Missing 425 1449

LBDWBMLC - Water Bromodichloromethane Comment Code

Variable Name:
LBDWBMLC
SAS Label:
Water Bromodichloromethane Comment Code
English Text:
Water Bromodichloromethane Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 926 926
1 below detectable limit 98 1024
2 detectable result and exceeds the calibrated range of assay 0 1024
. Missing 425 1449

LBXWCM - Water Dibromochloromethane (ng/mL)

Variable Name:
LBXWCM
SAS Label:
Water Dibromochloromethane (ng/mL)
English Text:
Water Dibromochloromethane Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 34.8 Range of Values 1047 1047
. Missing 402 1449

LBDWCMLC - Water Dibromochloromethane Comment Code

Variable Name:
LBDWCMLC
SAS Label:
Water Dibromochloromethane Comment Code
English Text:
Water Dibromochloromethane Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 911 911
1 below detectable limit 136 1047
2 detectable result and exceeds the calibrated range of assay 0 1047
. Missing 402 1449

LBXWME - Water MTBE (ng/mL)

Variable Name:
LBXWME
SAS Label:
Water MTBE (ng/mL)
English Text:
Water Methyl tert. butyl ether (MTBE) Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 1.9 Range of Values 1023 1023
. Missing 426 1449

LBDWMELC - Water MTBE Comment Code

Variable Name:
LBDWMELC
SAS Label:
Water MTBE Comment Code
English Text:
Water Methyl tert. butyl ether (MTBE) Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 254 254
1 below detectable limit 769 1023
2 detectable result and exceeds the calibrated range of assay 0 1023
. Missing 426 1449

LBXV4C - Blood Tetrachloroethene (ng/mL)

Variable Name:
LBXV4C
SAS Label:
Blood Tetrachloroethene (ng/mL)
English Text:
Blood Tetrachloroethene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0187 to 14.6 Range of Values 978 978
. Missing 471 1449

LBDV4CLC - Blood Tetrachloroethene Comment Code

Variable Name:
LBDV4CLC
SAS Label:
Blood Tetrachloroethene Comment Code
English Text:
Blood Tetrachloroethene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 319 319
1 below detectable limit 658 977
2 detectable result and exceeds the calibrated range of assay 1 978
. Missing 471 1449

LBXVBF - Blood Bromoform (pg/mL)

Variable Name:
LBXVBF
SAS Label:
Blood Bromoform (pg/mL)
English Text:
Blood Bromoform Result (pg/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.3451 to 132 Range of Values 774 774
. Missing 675 1449

LBDVBFLC - Blood Bromoform Comment Code

Variable Name:
LBDVBFLC
SAS Label:
Blood Bromoform Comment Code
English Text:
Blood Bromoform Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 649 649
1 below detectable limit 125 774
2 detectable result and exceeds the calibrated range of assay 0 774
. Missing 675 1449

LBXVBM - Blood Bromodichloromethane (pg/mL)

Variable Name:
LBXVBM
SAS Label:
Blood Bromodichloromethane (pg/mL)
English Text:
Blood Bromodichloromethane Result (pg/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.1499 to 85.9 Range of Values 785 785
. Missing 664 1449

LBDVBMLC - Blood Bromodichloromethane Comment Code

Variable Name:
LBDVBMLC
SAS Label:
Blood Bromodichloromethane Comment Code
English Text:
Blood Bromodichloromethane Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 774 774
1 below detectable limit 11 785
2 detectable result and exceeds the calibrated range of assay 0 785
. Missing 664 1449

LBXVBZ - Blood Benzene (ng/mL)

Variable Name:
LBXVBZ
SAS Label:
Blood Benzene (ng/mL)
English Text:
Blood Benzene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.017 to 1.3 Range of Values 837 837
. Missing 612 1449

LBDVBZLC - Blood Benzene Comment Code

Variable Name:
LBDVBZLC
SAS Label:
Blood Benzene Comment Code
English Text:
Blood Benzene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 443 443
1 below detectable limit 394 837
2 detectable result and exceeds the calibrated range of assay 0 837
. Missing 612 1449

LBXVCF - Blood Chloroform (pg/mL)

Variable Name:
LBXVCF
SAS Label:
Blood Chloroform (pg/mL)
English Text:
Blood Chloroform Result (pg/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
1.5415 to 22000 Range of Values 744 744
. Missing 705 1449

LBDVCFLC - Blood Chloroform Comment Code

Variable Name:
LBDVCFLC
SAS Label:
Blood Chloroform Comment Code
English Text:
Blood Chloroform Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 714 714
1 below detectable limit 27 741
2 detectable result and exceeds the calibrated range of assay 3 744
. Missing 705 1449

LBXVCM - Blood Dibromochloromethane (pg/mL)

Variable Name:
LBXVCM
SAS Label:
Blood Dibromochloromethane (pg/mL)
English Text:
Blood Dibromochloromethane Result (pg/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.1407 to 81.1 Range of Values 781 781
. Missing 668 1449

LBDVCMLC - Blood Dibromochloromethane Comment Code

Variable Name:
LBDVCMLC
SAS Label:
Blood Dibromochloromethane Comment Code
English Text:
Blood Dibromochloromethane Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 627 627
1 below detectable limit 154 781
2 detectable result and exceeds the calibrated range of assay 0 781
. Missing 668 1449

LBXVCT - Blood Carbon Tetrachloride (ng/mL)

Variable Name:
LBXVCT
SAS Label:
Blood Carbon Tetrachloride (ng/mL)
English Text:
Blood Carbon Tetrachloride Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0035 to 0.747 Range of Values 742 742
. Missing 707 1449

LBDVCTLC - Blood Carbon Tetrachloride Comment Code

Variable Name:
LBDVCTLC
SAS Label:
Blood Carbon Tetrachloride Comment Code
English Text:
Blood Carbon Tetrachloride Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 68 68
1 below detectable limit 674 742
2 detectable result and exceeds the calibrated range of assay 0 742
. Missing 707 1449

LBXVDB - Blood 1,4-Dichlorobenzene (ng/mL)

Variable Name:
LBXVDB
SAS Label:
Blood 1,4-Dichlorobenzene (ng/mL)
English Text:
Blood 1,4-Dichlorobenzene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0368 to 86 Range of Values 807 807
. Missing 642 1449

LBDVDBLC - Blood 1,4-Dichlorobenzene Comment Code

Variable Name:
LBDVDBLC
SAS Label:
Blood 1,4-Dichlorobenzene Comment Code
English Text:
Blood 1,4-Dichlorobenzene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 413 413
1 below detectable limit 389 802
2 detectable result and exceeds the calibrated range of assay 5 807
. Missing 642 1449

LBXVEB - Blood Ethylbenzene (ng/mL)

Variable Name:
LBXVEB
SAS Label:
Blood Ethylbenzene (ng/mL)
English Text:
Blood Ethylbenzene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0117 to 1.2 Range of Values 879 879
. Missing 570 1449

LBDVEBLC - Blood Ethylbenzene Comment Code

Variable Name:
LBDVEBLC
SAS Label:
Blood Ethylbenzene Comment Code
English Text:
Blood Ethylbenzene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 536 536
1 below detectable limit 343 879
2 detectable result and exceeds the calibrated range of assay 0 879
. Missing 570 1449

LBXVME - Blood MTBE (pg/mL)

Variable Name:
LBXVME
SAS Label:
Blood MTBE (pg/mL)
English Text:
Blood Methyl t-Butyl Ether (MTBE) Result (pg/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.1344 to 2290 Range of Values 672 672
. Missing 777 1449

LBDVMELC - Blood MTBE Comment Code

Variable Name:
LBDVMELC
SAS Label:
Blood MTBE Comment Code
English Text:
Blood MTBE Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 617 617
1 below detectable limit 41 658
2 detectable result and exceeds the calibrated range of assay 14 672
. Missing 777 1449

LBXVOX - Blood o-Xylene (ng/mL)

Variable Name:
LBXVOX
SAS Label:
Blood o-Xylene (ng/mL)
English Text:
Blood o-Xylene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0233 to 1.2 Range of Values 981 981
. Missing 468 1449

LBDVOXLC - Blood o-Xylene Comment Code

Variable Name:
LBDVOXLC
SAS Label:
Blood o-Xylene Comment Code
English Text:
Blood o-Xylene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 393 393
1 below detectable limit 588 981
2 detectable result and exceeds the calibrated range of assay 0 981
. Missing 468 1449

LBXVST - Blood Styrene (ng/mL)

Variable Name:
LBXVST
SAS Label:
Blood Styrene (ng/mL)
English Text:
Blood Styrene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0106 to 100 Range of Values 950 950
. Missing 499 1449

LBDVSTLC - Blood Styrene Comment Code

Variable Name:
LBDVSTLC
SAS Label:
Blood Styrene Comment Code
English Text:
Blood Styrene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 516 516
1 below detectable limit 432 948
2 detectable result and exceeds the calibrated range of assay 2 950
. Missing 499 1449

LBXVTC - Blood Trichloroethene (ng/mL)

Variable Name:
LBXVTC
SAS Label:
Blood Trichloroethene (ng/mL)
English Text:
Blood Trichloroethene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0066 to 3.86 Range of Values 922 922
. Missing 527 1449

LBDVTCLC - Blood Trichloroethene Comment Code

Variable Name:
LBDVTCLC
SAS Label:
Blood Trichloroethene Comment Code
English Text:
Blood Trichloroethene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 29 29
1 below detectable limit 893 922
2 detectable result and exceeds the calibrated range of assay 0 922
. Missing 527 1449

LBXVTO - Blood Toluene (ng/mL)

Variable Name:
LBXVTO
SAS Label:
Blood Toluene (ng/mL)
English Text:
Blood Toluene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.0177 to 16.8 Range of Values 954 954
. Missing 495 1449

LBDVTOLC - Blood Toluene Comment Code

Variable Name:
LBDVTOLC
SAS Label:
Blood Toluene Comment Code
English Text:
Blood Toluene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 909 909
1 below detectable limit 44 953
2 detectable result and exceeds the calibrated range of assay 1 954
. Missing 495 1449

LBXVXY - Blood m-/p-Xylene (ng/mL)

Variable Name:
LBXVXY
SAS Label:
Blood m-/p-Xylene (ng/mL)
English Text:
Blood m-/p-Xylene Result (ng/mL)
Target:
Both males and females 20 YEARS - 59 YEARS
Hard Edits:
0 to 99999.9999
Code or Value Value Description Count Cumulative Skip to Item
0.024 to 3.6 Range of Values 962 962
. Missing 487 1449

LBDVXYLC - Blood m-/p-Xylene Comment Code

Variable Name:
LBDVXYLC
SAS Label:
Blood m-/p-Xylene Comment Code
English Text:
Blood m-/p-Xylene Comment Code
Target:
Both males and females 20 YEARS - 59 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 detectable result 928 928
1 below detectable limit 34 962
2 detectable result and exceeds the calibrated range of assay 0 962
. Missing 487 1449