11.2 fustinoni

BIOMONITORING SHORT AND LONG TERM TERBUTYLAZINE EXPOSURE

BY HAIR AND URINE SPECIMENS

Rosa Mercadante, Elisa Polledri, PierAlberto Bertazzi, Silvia Fustinoni

Dipartimento di Scienze Cliniche e di Comunità

ISBM, Manchester 8th-11th September 2013

Background - exposure assessment

Assessment of pesticides exposure in agriculture workers and rural residents is a difficult task

ISBM, Manchester 8th-11th September 2013 Dipartimento di Scienze Cliniche e di Comunità

– Multiple exposure routes: dermal, inhalation and ingestion – Discontinuous exposures with applications scheduled based

on weather conditions and crops needs– Several technologies-crops-formulations– Workers with low education and scarce awareness about

health risks and their prevention

Biomonitoring• Biomonitoring is a powerful tool to integrate different

exposure routes taking into account personal characteristics

• Urine is a traditional non-invasive matrix for short-term biomonitoring of pesticides


Requirements

• Identification of biomarker• Best sampling time • Analytical assays

Issue

• Representativeness of single spot samples in a context of high intra-individual variability


Real exposure scenario: multiple chemicals, several applications


Traditional biomonitoring:single substance, single

application


Hair

• Hair is an attractive matrix that may integrate exposure over months and reduce intra-individual variability observed in spot urine

• Currently used to assess exposure to drugs of abuse

• Applied to evaluate body burden of metals

• Few studies to assess exposure to organic pollutants

Dipartimento di Scienze Cliniche e di ComunitàISBM, Manchester 8th-11th September 2013

Biomonitoring and matrices


Urine HairAdvantages: • Integration of different exposure routes• Physiological differences between subjects

properly taken into account

Advantages:• Integrates exposure over months:

medium/long-term biomarkers• Overcomes problem in the identification

of pesticide metabolites• Fewer difficulties in sample collection and

storageNo critical sampling timeStability of sample No sanitary personnel required

Disadvantages: •Few biological indices available•Difficulties in the identification of new biomarkers

•Short-term biomarkers•Critical sampling time•Practical difficulties in sample collection due to remote locations of farms, requirement for sanitary personnel (blood), stability of sample

Disadvantages:• Few studies in the assessment of exposure

to organic compounds• Small amount of chemicals in hair• Not all chemicals are significantly

incorporated in hair


Mechanisms of incorporation of chemicals in hair

From: Pragst F, Balikova MA, 2006 Clinica Chimica Acta

Mechanisms of incorporation of chemicals:

Blood circulationSebum and sweatExternal sources

Wide window of data acquisition, (hair grows 0.8-1.3 cm/month)

Monitoring of the past exposure depending on the length of the collected sample


Aims

• Investigate the use of HAIR for

biomonitoring exposure to pesticides

following use in agriculture

• Compare hair and urine as matrices

for biomonitoring


Terbuthylazine (TBA)

herbicide widely used in the cultivation of corn, an inhibitor of photosynthesisSkin and eye irritantPersistent in the environmentIn mammals is metabolized to desethylterbutylazine (DET)

TBA and DET selected ascandidate biomarkers


LC-MS/MS assay with isotopic dilutionD

ipar

timen

to d

i Scie

nze

Clin

iche

e d

i Com

unità

Assay validation

DET in Urine TBA Hair

Precision CV% <10% CV% <10%

Accuracy 100-105% 91-107%

Sensitivity LOQ 0.25 µg/L LOQ 0.01 ng/mg hair

Linearity 0.25-12.5 µg/L 0.01-20 ng/mg hair

TBA in rat hair

TBA was found in rat hair after oral administration


Study subjects

•small farms•applying TBA in different formulates as herbicide, typically once/twice in a season.

•preparing the application mixture by their selves

• 12 AW= corn farmers living in a village of the province of Cremona (Lombardy, Italy)


Study subjects: rural and urban residents

14 rural residents (RR): subjects living in the same village of the farmers

17 urban residents (UR): subjects living and working in the urban area of Milan



AW urine kinetics study

Best sampling time for urine collection:

END OF EXPOSURE (U1)PRIOR TO THE NEXT SHIFT (U2)



Urine sampling protocol


AW: identification of urinary biomarkers

urine collected prior to the next

shift (U2)

• Urinary DET was found in all post-exposure samples • Urinary TBA was found in a few samples


s

best sampling time

DET µg/LTBA µg/L

P> 0.05


Are urinary biomarkers useful to take into account exposure?


TBA and DET were detect only in AW samples

DET µg/LTBA µg/L



Hair sampling protocol


Biomarker identification

• TBA in hair

• No DET in hair

• TBA urban<rural<farmers

(p<0.01)


H1 samples

DET ng/mg hairTBA ng/mg hair


H0 vs H1

AW H0 < H1

TBA levels increases

with exposure

RR H0= H1

Envinonmental

contamination


TBA ng/mg hair in H0TBA ng/mg hair in H1

P< 0.01

P> 0.05


Summary of results

DET is a human metabolite of TBA and that urine collected prior to the next shift is the best sampling time

TBA can be measured in human hair and its levels increases with exposure

Rural residents are exposed TBA

In farmers:

• No correlation between urine and hair biomarkers • No correlation between the amount of TBA used and hair or urinary

biomarkers • Significant correlation between hair TBA and age


Conclusion

• Urinary DET and hair TBA seem to be promising markers for monitoring exposure to TBA

• The use of TBA herbicide in agriculture impacts the exposure of rural residents

• Hair TBA allowed us to highlight an exposure in rural resident, not elicited by urine biomarkers


BIOMONITORING SHORT AND LONG TERM TERBUTYLAZINE EXPOSURE

BY HAIR AND URINE SPECIMENS


Rosa Mercadante, Elisa Polledri, PierAlberto Bertazzi, Silvia Fustinoni


Thank you

11.2 fustinoni

Health & Medicine

biomonitoring exposure

scienze cliniche e

assessment of exposure

hair hair

past exposure

biomonitoring biomonitoring

use of hair

traditional biomonitoring