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Biomarkers of exposure to pesticides in humans

Ekman, Eva LU (2017)
Abstract (Swedish)
Idag används årligen över 2 miljoner ton bekämpningsmedel (BM) i världen. Av
dessa står Sverige för drygt 9000 ton, eller knappt en halv procent. Den här
avhandlingen handlar om att ta fram metoder för att bestämma rester av vissa
bekämpningsmedel i kroppsvätskor (urin) hos människor och sedan använda
metoderna för att mäta exponering för bekämpningsmedlen i en befolkningsgrupp. Arbetet är en del av forskningen inom detta område på Avdelningen för Arbets- och miljömedicin vid Lunds universitet.
I avhandlingen behandlas svampmedlena mankozeb, tiabendazol och pyrimetanil,
insektsmedlen klorpyrifos och gruppen pyretroider samt ogräsmedlet 2,4-
diklorfenoxi-ättiksyra. Alla används som växtskyddsmedel, pyretroiderna... (More)
Idag används årligen över 2 miljoner ton bekämpningsmedel (BM) i världen. Av
dessa står Sverige för drygt 9000 ton, eller knappt en halv procent. Den här
avhandlingen handlar om att ta fram metoder för att bestämma rester av vissa
bekämpningsmedel i kroppsvätskor (urin) hos människor och sedan använda
metoderna för att mäta exponering för bekämpningsmedlen i en befolkningsgrupp. Arbetet är en del av forskningen inom detta område på Avdelningen för Arbets- och miljömedicin vid Lunds universitet.
I avhandlingen behandlas svampmedlena mankozeb, tiabendazol och pyrimetanil,
insektsmedlen klorpyrifos och gruppen pyretroider samt ogräsmedlet 2,4-
diklorfenoxi-ättiksyra. Alla används som växtskyddsmedel, pyretroiderna också
som biocider för att skydda människor och byggnader mot t.ex. mygg eller löss.
Även om BM är framtagna för att verka mer eller mindre specifikt mot
skadegörare är de oftast också giftiga (toxiska) för människor. Exponering för BM
kan leda till akuta besvär och olika kroniska sjukdomar. Hanteringen av BM är
därför reglerad med bland annat olika typer av gränsvärden. Ett exempel på
gränsvärde är ADI (acceptable daily intake) ”den mängd en person kan få i sig
varje dag under en hel livstid utan att hälsan påverkas”.
För att kunna koppla en exponering för BM till en hälsoeffekt måste
exponeringsdata vara tillförlitliga. I avhandlingen har metoder för bestämning av
exponeringsbiomarkörer tagits fram. Dessa exponeringsbiomarkörer är metaboliter dvs. biologiska nedbrytningsprodukter av bekämpningsmedlen. För att mäta koncentrationen av en specifik biomarkör i urinen användes analystekniken vätskekromatografi med masspektrometrisk detektion (LC-MS/MS). Eftersom bra analysmetoder saknades har tre nya LC-MS/MS metoder utvecklats eller förfinats för att mäta exponering för mankozeb, tiabendazol och pyrimetanil. Metoderna validerades – dvs. kontrollerades med tester så att analysresultaten är pålitliga och genom att testa respektive exponeringsbiomarkörs pålitlighet. Genom att två försökspersoner fick en låg dos (25-100% av ADI-värdet) av bekämpningsmedelet på huden eller oralt kunde det fastställas att biomarkören i urinprovet verkligen härstammade från bekämpningsmedlet.
Resultaten visade att BM togs upp både genom huden och magtarmkanalen för att
sedan utsöndras bl a i urinen. Resultaten visade också att utsöndringen till urinen
tog olika lång tid för de tre nämnda ämnena (timmar till dag/ar/). Det är intressant eftersom kort utsöndringstid kräver upprepade mätningar för att en god uppfattning om exponeringen ska erhållas. 5-OH-TBZ och OH-PYR kunde också påvisas i hälften av hundratals urinprov från den sydsvenska allmänbefolkningen.
Sättet att använda BM på påverkar hur det sprids i miljön och därmed hur vi
människor exponeras. Vissa, exempelvis jordbruksarbetare, kan exponeras i
arbetsmiljön. Allmänheten exponeras i sin hemmiljö via maten men också genom
egen användning av ogräs- och insektsmedel. Människor som lever i områden där
BM används, kan exponeras indirekt, t ex genom drift av BM med luften.
Exponeringsförhållandena motiverar undersökning av halter av BM-rester i olika
befolkningsgrupper, särskilt i känsliga grupper som gravida kvinnor och deras
foster. Avhandlingen syftar till att bidra till ökad kunskap inom området.
Inom avhandlingen mättes också totalt 8 exponeringsbiomarkörer av BM i 900
urinprov från 445 gravida kvinnor boende nära bananplantager i Costa Rica. I
proverna detekterades ETU i 100%, 5-OH-TBZ i 64% och OH-PYR i 87%.
Övriga exponeringsbiomarkörer hittades i stort sett i alla prov och värdena var i
nivå med vad som hittats hos gravida kvinnor i varierande miljöer världen över.
ETU-halterna var nära halterna hos italienska jordbruksarbetare. 5-OH-TBZ och
OH-PYR har inte tidigare uppmätts i en befolkningsgrupp. Några gravida kvinnor
i studien arbetade på bananplantagerna med att packa bananer; de hade signifikant högre halter av biomarkören för tiabendazol jämfört med de som inte arbetade. De hade också högre halter av exponeringsbiomarkörerna för mankozeb och klorpyrifos. BM-exponeringen för de gravida kvinnorna är oroande och understryker vikten av att utföra tillförlitliga exponeringsmätningar – som också ska leda till lämpliga åtgärder att minska exponeringen. (Less)
Abstract
Almost every human is exposed to pesticides, in work environments, by domestic use and via diet, drinking water and personal products. Current research expresses concern that low dose exposure over time can lead to adverse health effects. It is therefore important to biomonitor exposure to pesticides in different groups, especially vulnerable groups such as pregnant women. However, there is a general lack of validated bioanalytical methods in order to generate reliable biomonitoring data for the quantification of exposure biomarkers to pesticides. The present thesis describes efforts directed at addressing this shortage.
Three new high throughput LC-MS/MS (liquid chromatography coupled with tandem mass spectrometry) methods were... (More)
Almost every human is exposed to pesticides, in work environments, by domestic use and via diet, drinking water and personal products. Current research expresses concern that low dose exposure over time can lead to adverse health effects. It is therefore important to biomonitor exposure to pesticides in different groups, especially vulnerable groups such as pregnant women. However, there is a general lack of validated bioanalytical methods in order to generate reliable biomonitoring data for the quantification of exposure biomarkers to pesticides. The present thesis describes efforts directed at addressing this shortage.
Three new high throughput LC-MS/MS (liquid chromatography coupled with tandem mass spectrometry) methods were developed and validated for the quantification of the exposure biomarkers for ethylenebisdithiocarbamates (EBDCs): ethylenethiourea (ETU); thiabendazole (TBZ): 5-hydroxythiabendazole (5-OH-TBZ) and pyrimethanil (PYR): 4-hydroxypyrimethanil (OH-PYR). Human experimental studies, where two volunteers were orally and dermally exposed,
were conducted to confirm that these three biomarkers are metabolites of their parent compounds. For ETU, however, only dermal exposure was studied. In these studies, also basic pharmacokinetics were determined. In an epidemiological cohort study of 445 pregnant women living close to banana plantations in Costa Rica, the LC-MS/MS method for ETU and a modified version of the combined methods for 5-OH-TBZ and OH-PYR were applied to assess exposure to EBDCs, TBZ, PYR and chlorpyrifos, pesticides used on the plantations. Commonly used pyrethroids and 2,4-dichlorophenoxyacetic acid were also assessed. Exposure to TBZ and PYR had not been studied earlier in pregnant women or other human populations. The LC-MS/MS methods were selective and had excellent sensitivity; the limit of detection was ≤0.2 ng/mL. The precision and accuracy were also excellent; the coefficient of variation was ≤15%. In all the experimental studies, the exposure biomarkers ETU, 5-OH-TBZ and OH-PYR were excreted in urine as conjugates. In the dermal exposure experiments, the urinary elimination half-life (t½) was a few days for ETU and hours for 5-OH-TBZ and OH-PYR. In the oral exposure experiments, the t½ was a few hours both for 5-OH-TBZ and OH-PYR. The exposure biomarkers of TBZ and PYR were determined in hundreds of samples from a general Swedish population; half of them had levels of 5-OH-TBZ and of OH-PYR above the limit of detection. In 909 urine samples repeatedly collected from the 445 pregnant women, ETU was detected in 100%, 5-OH-TBZ in 65% and OH-PYR in 87% of the samples. The concentrations of ETU seem comparable to levels in Italian agricultural workers. Further, the other pesticide exposure biomarkers were detected in almost all the samples. The pregnant women working at the banana plantations were significantly more exposed to TBZ and EBDCs than the nonworking pregnant women in the cohort and, in addition, the exposure to chlorpyrifos was slightly higher among the working women.
In conclusion, the developed LC-MS/MS methods can be used in biomonitoring of EBDCs, TBZ and PYR in large exposure studies of general populations. The metabolites ETU, 5-OH-TBZ and OH-PYR were confirmed to be reliable urinary
exposure biomarkers after dermal and oral exposure. Hydrolysis to release the analyte from the conjugate in urine is essential in the LC-MS/MS methods. Some new pharmacokinetic information on ETU, TBZ and PYR were obtained from exposure experiments in two volunteers. Because of the short t½ of the biomarkers, repeated sampling is recommended in exposure assessments. The exposure to pesticides in pregnant women in Costa Rica is of great concern. (Less)
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author
supervisor
opponent
  • senior forskare Småstuen Haug, Line, Oslo
organization
alternative title
Bekämpningsmedelsexponeringsbiomarkörer i människor
publishing date
type
Thesis
publication status
published
subject
keywords
Biomarker, Mass Spectrometry, Pharmacokinetics, Exposure assessment, Peticides, Pregnant Women, Biomonitoring, Urine, LC-MS/MS, Biomarker, Mass Spectrometry, Pharmacokinetics, Exposure assessment, Peticides, Pregnant Women, Biomonitoring, Urine, LC-MS/MS
pages
71 pages
publisher
Lund University, Faculty of Medicine
defense location
Lundmarkssalen, Astronomihuset, Sölvegatan, Lund.
defense date
2017-01-12 09:15
ISBN
978-91-7619-382-2
language
English
LU publication?
yes
id
6ccb43cf-210b-4b2f-88b1-79dfff44630e
date added to LUP
2016-12-20 12:55:46
date last changed
2016-12-21 12:29:07
@phdthesis{6ccb43cf-210b-4b2f-88b1-79dfff44630e,
  abstract     = {Almost every human is exposed to pesticides, in work environments, by domestic use and via diet, drinking water and personal products. Current research expresses concern that low dose exposure over time can lead to adverse health effects. It is therefore important to biomonitor exposure to pesticides in different groups, especially vulnerable groups such as pregnant women. However, there is a general lack of validated bioanalytical methods in order to generate reliable biomonitoring data for the quantification of exposure biomarkers to pesticides. The present thesis describes efforts directed at addressing this shortage.<br/>Three new high throughput LC-MS/MS (liquid chromatography coupled with tandem mass spectrometry) methods were developed and validated for the quantification of the exposure biomarkers for ethylenebisdithiocarbamates (EBDCs): ethylenethiourea (ETU); thiabendazole (TBZ): 5-hydroxythiabendazole (5-OH-TBZ) and pyrimethanil (PYR): 4-hydroxypyrimethanil (OH-PYR). Human experimental studies, where two volunteers were orally and dermally exposed,<br/>were conducted to confirm that these three biomarkers are metabolites of their parent compounds. For ETU, however, only dermal exposure was studied. In these studies, also basic pharmacokinetics were determined. In an epidemiological cohort study of 445 pregnant women living close to banana plantations in Costa Rica, the LC-MS/MS method for ETU and a modified version of the combined methods for 5-OH-TBZ and OH-PYR were applied to assess exposure to EBDCs, TBZ, PYR and chlorpyrifos, pesticides used on the plantations. Commonly used pyrethroids and 2,4-dichlorophenoxyacetic acid were also assessed. Exposure to TBZ and PYR had not been studied earlier in pregnant women or other human populations. The LC-MS/MS methods were selective and had excellent sensitivity; the limit of detection was ≤0.2 ng/mL. The precision and accuracy were also excellent; the coefficient of variation was ≤15%. In all the experimental studies, the exposure biomarkers ETU, 5-OH-TBZ and OH-PYR were excreted in urine as conjugates. In the dermal exposure experiments, the urinary elimination half-life (t½) was a few days for ETU and hours for 5-OH-TBZ and OH-PYR. In the oral exposure experiments, the t½ was a few hours both for 5-OH-TBZ and OH-PYR. The exposure biomarkers of TBZ and PYR were determined in hundreds of samples from a general Swedish population; half of them had levels of 5-OH-TBZ and of OH-PYR above the limit of detection. In 909 urine samples repeatedly collected from the 445 pregnant women, ETU was detected in 100%, 5-OH-TBZ in 65% and OH-PYR in 87% of the samples. The concentrations of ETU seem comparable to levels in Italian agricultural workers. Further, the other pesticide exposure biomarkers were detected in almost all the samples. The pregnant women working at the banana plantations were significantly more exposed to TBZ and EBDCs than the nonworking pregnant women in the cohort and, in addition, the exposure to chlorpyrifos was slightly higher among the working women.<br/>In conclusion, the developed LC-MS/MS methods can be used in biomonitoring of EBDCs, TBZ and PYR in large exposure studies of general populations. The metabolites ETU, 5-OH-TBZ and OH-PYR were confirmed to be reliable urinary<br/>exposure biomarkers after dermal and oral exposure. Hydrolysis to release the analyte from the conjugate in urine is essential in the LC-MS/MS methods. Some new pharmacokinetic information on ETU, TBZ and PYR were obtained from exposure experiments in two volunteers. Because of the short t½ of the biomarkers, repeated sampling is recommended in exposure assessments. The exposure to pesticides in pregnant women in Costa Rica is of great concern.},
  author       = {Ekman, Eva},
  isbn         = {978-91-7619-382-2},
  keyword      = {Biomarker,Mass Spectrometry,Pharmacokinetics,Exposure assessment,Peticides,Pregnant Women,Biomonitoring,Urine,LC-MS/MS,Biomarker,Mass Spectrometry,Pharmacokinetics,Exposure assessment,Peticides,Pregnant Women,Biomonitoring,Urine,LC-MS/MS},
  language     = {eng},
  pages        = {71},
  publisher    = {Lund University, Faculty of Medicine},
  school       = {Lund University},
  title        = {Biomarkers of exposure to pesticides in humans},
  year         = {2017},
}