Table of Contents

Locator Record

Title: Environmental Phenols (EPH_E )
Contact Number: 1-866-441-NCHS
Years of Content: 2007 - 2008
First Published: October, 2010
Revised: September, 2011
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Environmental Phenols (bisphenol A (BPA), alkylphenols (APs)), and Parabens
Record Source: NHANES 2007 - 2008
Survey Methodology: NHANES 2007 - 2008 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 and parabens 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.

Parabens are short alkyl chain esters of para-hydroxybenzoic acid (PHBA) that are widely used as preservatives in pharmaceuticals, cosmetics and in such personal care products as shampoos, hair and shaving products, facial and skin cleansers, and lotions. Parabens also occur naturally in some foods, including specific fruit juices and wine. After parabens are absorbed in the body, they are rapidly hydroyzed and then conjugated to glucuronide or sulfate and eliminated in the urine. Measurement of urinary environmental phenols and parabens 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. We have developed a sensitive method for measuring BPA, 4-tert-octylphenol (tOP), benzophenone-3 (BP-3), one chlorophenols triclosan, and four parabens. 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 Division of Environmental Health Laboratory Sciences’ 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 environmental phenols and parabens 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 laboratory data must be conducted with the key survey design and basic demographic variables. The NHANES 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 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: 

Analyte Item ID LLOD
Urinary Bisphenol A URXBPH 0.4
Urinary 4-tert-octyl phenol URX4TO 0.2
Urinary 2,4,4’-Trichloro-2’-hydroxyphenyl ether (Triclosan) URXTRS 2.3
Urinary 2-Hydroxy-4-metoxybenzophenone (Benzophenone-3) URXBP3 0.4
Urinary Propyl paraben URXPPB 0.2
Urinary Butyl paraben URXBUP 0.2
Urinary Ethyl paraben URXEPB 1
Urinary Methyl paraben URXMPB 1

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

WTSB2YR - Two-year B subsample weights

Variable Name:
WTSB2YR
SAS Label:
Two-year B subsample weights
English Text:
Two-year B subsample weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 533131.16757 Range of Values 2718 2718
. Missing 0 2718

URXUCR - Urinary creatinine

Variable Name:
URXUCR
SAS Label:
Urinary creatinine
English Text:
Urinary creatinine
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 490 Range of Values 2623 2623
. Missing 95 2718

URX4TO - Urinary 4-tert-octylphenol (ng/mL)

Variable Name:
URX4TO
SAS Label:
Urinary 4-tert-octylphenol (ng/mL)
English Text:
Urinary 4-tert-Octyl phenol
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.14 to 12.5 Range of Values 2604 2604
. Missing 114 2718

URD4TOLC - Urinary 4-tert-octylphenol comment

Variable Name:
URD4TOLC
SAS Label:
Urinary 4-tert-octylphenol comment
English Text:
Urinary 4-tert-octylphenol 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 277 277
1 Below lower detection limit 2327 2604
. Missing 114 2718

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
0.28 to 92900 Range of Values 2604 2604
. Missing 114 2718

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 2502 2502
1 Below lower detection limit 102 2604
. Missing 114 2718

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
0.28 to 193 Range of Values 2604 2604
. Missing 114 2718

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 2438 2438
1 Below lower detection limit 166 2604
. Missing 114 2718

URXTRS - Urinary Triclosan (ng/mL)

Variable Name:
URXTRS
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 2780 Range of Values 2604 2604
. Missing 114 2718

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 2088 2088
1 Below lower detection limit 516 2604
. Missing 114 2718

URXBUP - Butyl paraben (ng/ml)

Variable Name:
URXBUP
SAS Label:
Butyl paraben (ng/ml)
English Text:
Butyl paraben (ng/ml)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.14 to 1150 Range of Values 2604 2604
. Missing 114 2718

URDBUPLC - Butyl paraben comment

Variable Name:
URDBUPLC
SAS Label:
Butyl paraben comment
English Text:
Butyl paraben 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 1203 1203
1 Below lower detection limit 1401 2604
. Missing 114 2718

URXEPB - Ethyl paraben (ng/ml)

Variable Name:
URXEPB
SAS Label:
Ethyl paraben (ng/ml)
English Text:
Ethyl paraben (ng/ml)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.71 to 3130 Range of Values 2604 2604
. Missing 114 2718

URDEPBLC - Ethyl paraben comment

Variable Name:
URDEPBLC
SAS Label:
Ethyl paraben comment
English Text:
Ethyl paraben comment
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 1207 1207
1 Below lower detection limit 1397 2604
. Missing 114 2718

URXMPB - Methyl paraben (ng/ml)

Variable Name:
URXMPB
SAS Label:
Methyl paraben (ng/ml)
English Text:
Methyl paraben (ng/ml)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.71 to 7550 Range of Values 2604 2604
. Missing 114 2718

URDMPBLC - Methyl paraben comment

Variable Name:
URDMPBLC
SAS Label:
Methyl paraben comment
English Text:
Methyl paraben comment
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 2595 2595
1 Below lower detection limit 9 2604
. Missing 114 2718

URXPPB - Propyl paraben (ng/ml)

Variable Name:
URXPPB
SAS Label:
Propyl paraben (ng/ml)
English Text:
Propyl paraben (ng/ml)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.14 to 3270 Range of Values 2604 2604
. Missing 114 2718

URDPPBLC - Propyl paraben comment

Variable Name:
URDPPBLC
SAS Label:
Propyl paraben comment
English Text:
Propyl paraben 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 2468 2468
1 Below lower detection limit 136 2604
. Missing 114 2718