Pesticides in breast milk

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Pesticides in breast milk
Sanie Hernandez, PhD Student School of Public
Health, UC Berkeley
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Purpose

• We propose to develop and validate sensitive
  methods to test non- persistent and persistent
  pesticides and other environmental chemicals in
  breast milk.
• These methods will be applied to samples
  collected from CHAMACOS participants, who are
  recent mothers living in an agriculture area with
  demonstrated exposures.
• Help determine the dietary route of exposure to
  infants

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Components of Breast Milk
Colostrum the first milk that is thick and
yellowish in color which provides the newborn
with complete food, adequate protection against
infections and also helps in bonding
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Persistent pesticides

• Organochlorines are lipophilic
• Tend to bioaccumulate in fatty tissues
• Can be released when fat stores are mobilized
• Examples DDT/DDE

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Non-persistent pesticides

• Less stable and persistent than organochlorines
• Not expected to be present in breast milk
• Kow coefficients suggest that some may partition
  into fats
• Given that 85 of breast milk is water, some OPs
  may reach breast milk by diffusion

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Previous Studies
Lederman, S.A. Environmental Contaminants in
Breast Milk from the Central Asian Republics.
Reproductive Toxicology.1996 10 (2)93-104.

• Only article to report levels of OPs in breast
  milk among other chemicals
• 1.9 mg/L Metaphos (Methyl parathion) in women
  from Kazakhstan
• Methods section of paper was vague and provided
  no information on recruitment, origin of samples
  or analytical methods.

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Specific Aims
 1.      We will collect a pool of breast milk
samples from women not living in an agricultural
area. 2.      We will establish acquisition
criteria and limits of detection with GC/MS
instruments. 3.      We will determine recovery
and validation data for target analytes. 4.     
We will apply the validated method to a subset of
CHAMACOS samples. 5.      We will publish an
article on the validated method and the
analytical results of CHAMACOS samples.
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Activities
Sample collection Committee for the Protection
of Human Subjects review of protocol and consent
forms for sample collection Subject recruitment
and sample collection Epidemiology Establish
target analyte list using questionnaire data,
pesticide use reporting data, environmental
sample results Lab activities test standards for
retention times Establish acquisition settings
for instruments Experiment with multi-residue
methods
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Breast MilkPesticide Analyte List
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Challenges

• Recruiting participants to contribute breast milk
• Panic that breast milk may be toxic
• Low volume of CHAMACOS samples
• Wide range of target analytes from different
  chemical classes
• Fats in breast milk may complicate analysis

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Method Development Timeline
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Stir Bar Sorptive Extraction
The GERSTEL-Twister looks like a conventional
magnetic stirring rod, and works the same -
except for one small difference While it is
stirring, it adsorbs and concentrates the organic
contents onto its coating of polydimethylsiloxane
(PDMS).
After stirring, it can be directly transferred to
the GERSTEL-TDS 2 for thermo-desorption. This
means that the thermo-desorption, chromatography
and subsequent detection of the organic compounds
adsorbed on the PDMS coating are performed
directly on Twister.
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Final Target Analyte List

• 19 of the original 40 compounds were detected
  and found to have a linear response (7 of these
  remaining compounds are OPs)

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Continuing work

• Sample Collection
• gt 2 L of breast milk has been collected. We
  will continue to recruit participants until we
  have a total of 3 L collected.
• Lab work
• establish the limit of detection/ limit of
  quantification
• Method validation
• Epidemiology
• determine if this is the best method for
  CHAMACOS needs

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A study of exposures and health of migrant
children living in an agricultural
communityhttp//www.chamacos.org