Table of Contents

Component Description

Sulfonylurea herbicides are a group of non-selective herbicides that act by disrupting plant protein synthesis. They have been introduced relatively recently and are widely used, but application rates are relatively low. Potential sources for human exposure include foods grown in treated soil or contaminated water. Urinary measurement of sulfonylurea herbicides can be used to assess human exposure. 

Bensulfuron methyl (URXBSM), Chlorsulfuron (URXCHS), Ethametsulfuron methyl (URXEMM), Foramsulfuron (URXFRM), Halosulfuron (URXHLS), Mesosulfuron methyl (URXMSM), Metsulfuron methyl (URXMTM), Nicosulfuron (URXNOS), Oxasulfuron (URXOXS), Primisulfuron methyl (URXPIM), Prosulfuron (URXPRO), Rimsulfuron (URXRIM), Sulfometuron methyl (URXSMM), Sulfosulfuron (URXSSF), Thifensulfuron methyl (URXTHF), Triasulfuron (URXTRA), Tribenuron methyl (URXTRN)

Because of their increasing use in agricultural applications, a method to measure both occupational and incidental human exposures to Sulfonylurea herbicides was developed.

Eligible Sample

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

Description of Laboratory Methodology

Bensulfuron methyl (URXBSM), Chlorsulfuron (URXCHS), Ethametsulfuron methyl (URXEMM), Foramsulfuron (URXFRM), Halosulfuron (URXHLS), Mesosulfuron methyl (URXMSM), Metsulfuron methyl (URXMTM), Nicosulfuron (URXNOS), Oxasulfuron (URXOXS), Primisulfuron methyl (URXPIM), Prosulfuron (URXPRO), Rimsulfuron (URXRIM), Sulfometuron methyl (URXSMM), Sulfosulfuron (URXSSF), Thifensulfuron methyl (URXTHF), Triasulfuron (URXTRA), Tribenuron methyl (URXTRN)

A method for measuring 17 sulfonylurea (SU) herbicides in human urine was developed. Urine samples were extracted using solid phase extraction (SPE), pre-concentrated, and analyzed by high-performance liquid chromatography–tandem mass spectrometry using turbo-ionspray atmospheric pressure ionization. Carbon 13-labeled ethametsulfuron methyl was used as an internal standard. Chromatographic retention times were under 7 minutes. Total throughput was estimated as >100 samples per day. The limits of detection (LOD) ranged from 0.05 µg/L to 0.10 µg/L with an average LOD of 0.06 µg/L. Average total relative standard deviations were 17%, 12% and 8% at 0.1 µg/L, 3.0 µg/L and 10 µg/L, respectively. Average extraction efficiencies of the SPE cartridges were 87% and 86% at 2.5 µg/L and 25 µg/L, respectively. Chemical degradation in acetonitrile and urine was monitored over 250 days. Estimated days for 10% and 50% degradation in urine and acetonitrile ranged from 0.7 days to >318 days.

Laboratory Quality Assurance and Monitoring

Urine specimens are processed, stored, and shipped to the Division of 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 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.

NCEH developed and distributed a quality control protocol for all the laboratories which outlined the Westgard rules used when running NHANES specimens. Any problems encountered during shipping or receipt of specimens, instrument calibration, reagents, and any special considerations are submitted to NCHS and Westat. Summary statistics for each control pool, QC graphs, are reviewed by NCHS 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 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 current use pesticide metabolites 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 2003-2004 data files using the unique survey participant identifier SEQN.

Detection Limits

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 detection limit divided by the square root of 2 is the value that is provided for results that are below the limit of detection.

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 - Environmental C 2 year weights

Variable Name:
WTSC2YR
SAS Label:
Environmental C 2 year weights
English Text:
Environmental C 2 year weights
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 520135.04901 Range of Values 2694 2694
. Missing 0 2694

URXBSM - Bensulfuron methyl (ug/L)

Variable Name:
URXBSM
SAS Label:
Bensulfuron methyl (ug/L)
English Text:
Bensulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.0354 Range of Values 2494 2494
. Missing 200 2694

URDBSMLC - Bensulfuron methyl comment code

Variable Name:
URDBSMLC
SAS Label:
Bensulfuron methyl comment code
English Text:
Bensulfuron methyl 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 0 0
1 Below lower detection limit 2494 2494
. Missing 200 2694

URXCHS - Chlorsulfuron (ug/L)

Variable Name:
URXCHS
SAS Label:
Chlorsulfuron (ug/L)
English Text:
Chlorsulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 4.17 Range of Values 2566 2566
. Missing 128 2694

URDCHSLC - Chlorsulfuron comment code

Variable Name:
URDCHSLC
SAS Label:
Chlorsulfuron comment code
English Text:
Chlorsulfuron 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 1 1
1 Below lower detection limit 2565 2566
. Missing 128 2694

URXEMM - Ethametsulfuron methyl (ug/L)

Variable Name:
URXEMM
SAS Label:
Ethametsulfuron methyl (ug/L)
English Text:
Ethametsulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 0.0707 Range of Values 2458 2458
. Missing 236 2694

URDEMMLC - Ethametsulfuron methyl comment code

Variable Name:
URDEMMLC
SAS Label:
Ethametsulfuron methyl comment code
English Text:
Ethametsulfuron methyl 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 0 0
1 Below lower detection limit 2458 2458
. Missing 236 2694

URXFRM - Foramsulfuron (ug/L)

Variable Name:
URXFRM
SAS Label:
Foramsulfuron (ug/L)
English Text:
Foramsulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0424 to 0.0424 Range of Values 2423 2423
. Missing 271 2694

URDFRMLC - Foramsulfuron comment code

Variable Name:
URDFRMLC
SAS Label:
Foramsulfuron comment code
English Text:
Foramsulfuron 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 0 0
1 Below lower detection limit 2423 2423
. Missing 271 2694

URXHLS - Halosulfuron (ug/L)

Variable Name:
URXHLS
SAS Label:
Halosulfuron (ug/L)
English Text:
Halosulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0495 to 0.0495 Range of Values 2530 2530
. Missing 164 2694

URDHLSLC - Halosulfuron comment code

Variable Name:
URDHLSLC
SAS Label:
Halosulfuron comment code
English Text:
Halosulfuron 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 0 0
1 Below lower detection limit 2530 2530
. Missing 164 2694

URXMSM - Mesosulfuron methyl (ug/L)

Variable Name:
URXMSM
SAS Label:
Mesosulfuron methyl (ug/L)
English Text:
Mesosulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.0354 Range of Values 2494 2494
. Missing 200 2694

URDMSMLC - Mesosulfuron methyl comment code

Variable Name:
URDMSMLC
SAS Label:
Mesosulfuron methyl comment code
English Text:
Mesosulfuron methyl 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 0 0
1 Below lower detection limit 2494 2494
. Missing 200 2694

URXMTM - Metsulfuron methyl (ug/L)

Variable Name:
URXMTM
SAS Label:
Metsulfuron methyl (ug/L)
English Text:
Metsulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.05 Range of Values 2494 2494
. Missing 200 2694

URDMTMLC - Metsulfuron methyl comment code

Variable Name:
URDMTMLC
SAS Label:
Metsulfuron methyl comment code
English Text:
Metsulfuron methyl 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 1 1
1 Below lower detection limit 2493 2494
. Missing 200 2694

URXNOS - Nicosulfuron (ug/L)

Variable Name:
URXNOS
SAS Label:
Nicosulfuron (ug/L)
English Text:
Nicosulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0707 to 1.64 Range of Values 2422 2422
. Missing 272 2694

URDNOSLC - Nicosulfuron comment code

Variable Name:
URDNOSLC
SAS Label:
Nicosulfuron comment code
English Text:
Nicosulfuron 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 6 6
1 Below lower detection limit 2416 2422
. Missing 272 2694

URXOXS - Oxasulfuron (ug/L)

Variable Name:
URXOXS
SAS Label:
Oxasulfuron (ug/L)
English Text:
Oxasulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0424 to 0.0424 Range of Values 2540 2540
. Missing 154 2694

URDOXSLC - Oxasulfuron comment code

Variable Name:
URDOXSLC
SAS Label:
Oxasulfuron comment code
English Text:
Oxasulfuron 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 0 0
1 Below lower detection limit 2540 2540
. Missing 154 2694

URXPIM - Primisulfuron methyl (ug/L)

Variable Name:
URXPIM
SAS Label:
Primisulfuron methyl (ug/L)
English Text:
Primisulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0424 to 0.0424 Range of Values 2422 2422
. Missing 272 2694

URDPIMLC - Primisulfuron methyl comment code

Variable Name:
URDPIMLC
SAS Label:
Primisulfuron methyl comment code
English Text:
Primisulfuron methyl 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 0 0
1 Below lower detection limit 2422 2422
. Missing 272 2694

URXPRO - Prosulfuron (ug/L)

Variable Name:
URXPRO
SAS Label:
Prosulfuron (ug/L)
English Text:
Prosulfuron(ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.05 Range of Values 2566 2566
. Missing 128 2694

URDPROLC - Prosulfuron comment code

Variable Name:
URDPROLC
SAS Label:
Prosulfuron comment code
English Text:
Prosulfuron 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 1 1
1 Below lower detection limit 2565 2566
. Missing 128 2694

URXRIM - Rimsulfuron (ug/L)

Variable Name:
URXRIM
SAS Label:
Rimsulfuron (ug/L)
English Text:
Rimsulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0424 to 0.0424 Range of Values 2530 2530
. Missing 164 2694

URDRIMLC - Rimsulfuron comment code

Variable Name:
URDRIMLC
SAS Label:
Rimsulfuron comment code
English Text:
Rimsulfuron 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 0 0
1 Below lower detection limit 2530 2530
. Missing 164 2694

URXSMM - Sulfometuron methyl (ug/L)

Variable Name:
URXSMM
SAS Label:
Sulfometuron methyl (ug/L)
English Text:
Sulfometuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.0354 Range of Values 2458 2458
. Missing 236 2694

URDSMMLC - Sulfometuron methyl comment code

Variable Name:
URDSMMLC
SAS Label:
Sulfometuron methyl comment code
English Text:
Sulfometuron methyl 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 0 0
1 Below lower detection limit 2458 2458
. Missing 236 2694

URXSSF - Sulfosulfuron (ug/L)

Variable Name:
URXSSF
SAS Label:
Sulfosulfuron (ug/L)
English Text:
Sulfosulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 0.0354 2529 2529
0.07 0.07 1 2530
. Missing 164 2694

URDSSFLC - Sulfosulfuron comment code

Variable Name:
URDSSFLC
SAS Label:
Sulfosulfuron comment code
English Text:
Sulfosulfuron 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 1 1
1 Below lower detection limit 2529 2530
. Missing 164 2694

URXTHF - Thifensulfuron methyl (ug/L)

Variable Name:
URXTHF
SAS Label:
Thifensulfuron methyl (ug/L)
English Text:
Thifensulfuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0566 to 0.0566 Range of Values 2495 2495
. Missing 199 2694

URDTHFLC - Thifensulfuron methyl comment code

Variable Name:
URDTHFLC
SAS Label:
Thifensulfuron methyl comment code
English Text:
Thifensulfuron methyl 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 0 0
1 Below lower detection limit 2495 2495
. Missing 199 2694

URXTRA - Triasulfuron (ug/L)

Variable Name:
URXTRA
SAS Label:
Triasulfuron (ug/L)
English Text:
Triasulfuron (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0495 to 0.0495 Range of Values 2530 2530
. Missing 164 2694

URDTRALC - Triasulfuron comment code

Variable Name:
URDTRALC
SAS Label:
Triasulfuron comment code
English Text:
Triasulfuron 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 0 0
1 Below lower detection limit 2530 2530
. Missing 164 2694

URXTRN - Tribenuron methyl (ug/L)

Variable Name:
URXTRN
SAS Label:
Tribenuron methyl (ug/L)
English Text:
Tribenuron methyl (ug/L)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0.0354 to 0.0354 Range of Values 2494 2494
. Missing 200 2694

URDTRNLC - Tribenuron methyl comment code

Variable Name:
URDTRNLC
SAS Label:
Tribenuron methyl comment code
English Text:
Tribenuron methyl 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 0 0
1 Below lower detection limit 2494 2494
. Missing 200 2694

URXUCR - Creatinine, urine (mg/dL)

Variable Name:
URXUCR
SAS Label:
Creatinine, urine (mg/dL)
English Text:
Creatinine, urine (mg/dL)
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
3 to 724 Range of Values 2596 2596
. Missing 98 2694