11.2 Fustinoni

Dipartimento di Scienze Cliniche e di Comunità

BIOMONITORING SHORT AND LONG TERM
TERBUTYLAZINE EXPOSURE
BY HAIR AND URINE SPECIMENS

Rosa Mercadante, Elisa Polledri, PierAlberto Bertazzi, Silvia Fustinoni

ISBM, Manchester 8th-11th September 2013

Background - exposure assessment
Assessment of pesticides exposure in agriculture workers
and rural residents is a difficult task
– 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



Traditional biomonitoring:
single substance, single
application

Real exposure scenario:
multiple chemicals,
several applications


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



Biomonitoring and matrices
Urine

Hair

Advantages:
Advantages:
• Integrates exposure over months:
• Integration of different exposure routes
medium/long-term biomarkers
• Physiological differences between subjects
• Overcomes problem in the identification
properly taken into account
of pesticide metabolites
• Fewer difficulties in sample collection and
storage
No critical sampling time
Stability 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
Mechanisms of incorporation of
chemicals:
Blood circulation
Sebum and sweat
External 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

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



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
photosynthesis
Skin and eye irritant
Persistent in the
environment
In mammals is metabolized
to desethylterbutylazine
(DET)

TBA and DET selected as
candidate biomarkers




LC-MS/MS assay with isotopic dilution

DET in Urine

TBA Hair

CV% <10%

CV% <10%

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

Precision

Assay
Accuracy
validation

TBA in rat hair

TBA was found in rat hair after
oral administration



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

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

•preparing the application
mixture by their selves


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

P> 0.05

urine collected
prior to the next
shift (U2)

s


best sampling
time


Are urinary biomarkers useful to take into
account exposure?
DET µg/L
TBA µg/L

TBA and DET were detect only in AW samples


Hair sampling protocol



Biomarker identification
H1 samples
DET ng/mg hair
TBA ng/mg hair

• TBA in hair
• No DET in hair
• TBA urban<rural<farmers
(p<0.01)



H0 vs H1
TBA ng/mg hair in H0
TBA ng/mg hair in H1

P< 0.01

AW H0 < H1
TBA levels increases
with exposure

P> 0.05

RR H0= H1
Envinonmental
contamination


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

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