Table of Contents

Locator Record

Title: Environmental Phenols (L24EPH_C )
Contact Number: 1-866-441-NCHS
Years of Content: 2003 - 2004
First Published: June, 2007
Revised: March, 2013
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Environmental Phenols
Record Source: NHANES 2003 - 2004
Survey Methodology: NHANES 2003 - 2004 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

Biomonitoring of urinary environmental phenols is used to determine their prevalence in humans and the relevance of human exposure in public health. The sources of human exposure to these phenolic compounds include industrial pollution, pesticide use, food and bottled water, and personal care products. Specifically, bisphenol A (BPA) is used in the manufacture of polycarbonate plastics and epoxy resins, which have been used in baby bottles, as protective coatings on food containers, and as composites and sealants in dentistry.

Alkylphenols such as 4-tert-octylphenol, are used in the manufacture of nonionic surfactants used in detergents. Phenols are also used as sunscreen agents for skin protection, and as UV filters in cosmetic products and plastics to improve stability (e.g., benzophenone-3 [BP-3]), or used as bactericides (e.g., triclosan) in soap and other personal care products. Measurement of environmental phenols is useful to assess recent human exposure.

Eligible Sample

Participants aged 6 years and older who met the subsample requirements.

Description of Laboratory Methodology

Bisphenol A (BPA) and Alkylphenols (APs) have been previously measured in biological matrixes by using gas chromatography (GC) or high performance liquid chromatography (HPLC) coupled with different detection techniques. To achieve enhanced sensitivity and selectivity, the phenols have been derivatized to alkyl or acyl derivatives before GC-mass spectrometry (GC/MS) analysis.6-14 We have developed a sensitive method for measuring BPA, 4-tert-octylphenol (tOP), benzophenone-3 (BP-3), and one chlorophenols triclosan. The method uses solid phase extraction (SPE) coupled on-line to HPLC and tandem mass spectrometry (MS/MS). With the use of isotopically labeled internal standards, the detection limits in 100 μL of urine are 0.1-2 nanograms per milliliter (ng/mL), sufficient for measuring urinary levels of phenols in non-occupationally exposed subjects.

Laboratory Quality Assurance and Monitoring

Urine specimens are processed, stored, and shipped to the Division of Environmental Health Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention for analysis.

Detailed specimen collection and processing instructions are discussed in the NHANES Laboratory/Medical Technologists Procedures Manual (LPM). Vials are stored under appropriate frozen (–20°C) conditions until they are shipped to National Center for Environmental Health for testing.

Mobile Examination Centers (MECs)

Laboratory team performance is monitored using several techniques. NCHS and contract consultants use a structured quality assurance evaluation during unscheduled visits to evaluate both the quality of the laboratory work and the quality-control procedures. Each laboratory staff person is observed for equipment operation, specimen collection and preparation; testing procedures and constructive feedback are given to each staff. Formal retraining sessions are conducted annually to ensure that required skill levels were maintained.

The NHANES QA/QC protocols meet the 1988 Clinical Laboratory Improvement Act mandates. Detailed QA/QC instructions are discussed in the NHANES LPM.

Analytical Laboratories

NHANES uses several methods to monitor the quality of the analyses performed by the contract laboratories. In the MEC, these methods include performing blind split samples collected on “dry run” sessions. In addition, contract laboratories randomly perform repeat testing on 2.0% of all specimens.

NCHS developed and distributed a quality control protocol for all the contract laboratories which outlined the Westgard rules used when running NHANES specimens. Progress reports containing any problems encountered during shipping or receipt of specimens, summary statistics for each control pool, QC graphs, instrument calibration, reagents, and any special considerations are submitted to NCHS and Westat quarterly. The reports are reviewed for trends or shifts in the data. The laboratories are required to explain any identified areas of concern.

All QC procedures recommended by the manufacturers were followed. Reported results for all assays meet the the Division of Environmental Health Laboratory Sciences’s quality control and quality assurance performance criteria for accuracy and precision (similar to specifications outlined by Westgard (1981).

Analytic Notes

Subsample weights

Measures of urinary environmentals were measured in a one third subsample of persons 6 years and over. Special sample weights are required to analyze these data properly. Specific sample weights for this subsample are included in this data file and should be used when analyzing these data.

Variance estimation

The analysis of NHANES 2003-2004 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 2003-2004 Demographic Data File contains demographic and sample design variables. The recommended procedure for variance estimation requires use of stratum and PSU variables (SDMVSTRA and SDMVPSU, respectively) in the demographic data file.

Links to NHANES Data Files

This laboratory data file can be linked to the other NHANES 2003-2004 data files using the unique survey participant identifier SEQN.

Detection Limits

The detection limits were constant for all of the analytes in the data set. Two variables are provided for each of these analytes. The variable named URD___LC indicates whether the result was below the limit of detection. There are two values: “0” and “1”. “0” means that the result was at or above the limit of detection. “1” indicates that the result was below the limit of detection.

The other variable named URX___ provides the analytic result for that analyte.

The lower limit of detection for the environmental phenols (bisphenol A (BPA) and alkylphenols (APs)) is:

Lower Limit of Detection for the Environmental Phenols (bisphenol A (BPA) and Alkylphenols (APs))
Analyte Item ID  LLOD 
Urinary Bisphenol A URXBPH 0.36
Urinary 2,4,4’-Trichloro-2’-hydroxyphenyl ether (Triclosan) URXTRS 2.27
Urinary 2-Hydroxy-4-metoxybenzophenone (Benzophenone-3) URXBP3 0.34

Please refer to the Analytic Guidelines for further details on the use of sample weights and other analytic issues.

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 6 YEARS - 150 YEARS

WTSC2YR - Two-year MEC weights of subsample C

Variable Name:
WTSC2YR
SAS Label:
Two-year MEC weights of subsample C
English Text:
Two-year MEC weights of subsample C
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 456851.11941 Range of Values 2612 2612
. Missing 0 2612

URXUCR - Creatinine, urine (mg/dL)

Variable Name:
URXUCR
SAS Label:
Creatinine, urine (mg/dL)
English Text:
Urinary creatinine
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
7 to 648 Range of Values 2530 2530
. Missing 82 2612

URXBPH - Urinary Bisphenol A (ng/mL)

Variable Name:
URXBPH
SAS Label:
Urinary Bisphenol A (ng/mL)
English Text:
Urinary Bisphenol A
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.3 to 149 Range of Values 2517 2517
. Missing 95 2612

URDBPHLC - Urinary Bisphenol A comment

Variable Name:
URDBPHLC
SAS Label:
Urinary Bisphenol A comment
English Text:
Urinary Bisphenol A comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2353 2353
1 Below lower detection limit 164 2517
. Missing 95 2612

URXBP3 - Urinary Benzophenone-3 (ng/mL)

Variable Name:
URXBP3
SAS Label:
Urinary Benzophenone-3 (ng/mL)
English Text:
Urinary 2-Hydroxy-4-metoxybenzophenone (Benzophenone-3)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.2 to 21700 Range of Values 2517 2517
. Missing 95 2612

URDBP3LC - Urinary Benzophenone-3 comment

Variable Name:
URDBP3LC
SAS Label:
Urinary Benzophenone-3 comment
English Text:
Urinary 2-Hydroxy-4-metoxybenzophenone (Benzophenone-3) comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 2444 2444
1 Below lower detection limit 73 2517
. Missing 95 2612

URDTRS - Urinary Triclosan (ng/mL)

Variable Name:
URDTRS
SAS Label:
Urinary Triclosan (ng/mL)
English Text:
Urinary 2,4,4'-Trichloro-2'-hydroxyphenyl ether (Triclosan)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.6 to 3790 Range of Values 2517 2517
. Missing 95 2612

URDTRSLC - Urinary Triclosan comment

Variable Name:
URDTRSLC
SAS Label:
Urinary Triclosan comment
English Text:
Urinary 2,4,4'-Trichloro-2'-hydroxyphenyl ether (Triclosan) comment code
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 At or above the detection limit 1864 1864
1 Below lower detection limit 653 2517
. Missing 95 2612