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Project Details

The CHAMACOS Cohort Study

Photo of Salinas Valley children at a CHAMACOS community event.
Project Summary: 

The CHAMACOS Study is a longitudinal birth cohort study examining chemicals and other factors in the environment and children’s health.

In 1999-2000, we enrolled 601 pregnant women living in the agricultural Salinas Valley. We are following their children through age 12 to measure their exposures to pesticides and other chemicals and to determine if this exposure impacts their growth, health, and development.

In 2010-2011 we enrolled 300 additional 9-year-old children into the cohort and will be following them also until age 12.

The CHAMACOS Study investigates:

  • How children are exposed to pesticides and other environmental chemicals
  • How these exposures are related to children’s growth, neurodevelopment, and health
  • The mechanisms by which these exposures may impact health
  • Ways to reduce exposure to children and families

Our work is faciliated through strong community-based partnerships.

Main Findings: 

Organophosphate (OP) pesticides:

Mothers’ exposure to organophosphate (OP) pesticides during pregnancy is associated with:

  • Shorter duration of pregnancy
  • Poorer neonatal reflexes
  • Lower IQ and poorer cognitive functioning in children
  • Increased risk of attention problems in children

Organochlorine (OC) compounds:

DDT--Higher levels of DDT in mother’s blood during pregnancy were associated with:

  • Poorer mental development in their children at age 2
  • But not with neonatal neurodevelopment
  • But not with fetal growth


  • Prenatal exposure to PCBs (organochlorine compounds) is associated with:
  • Altered thyroid hormone levels in mothers. (Go to publication)
  • For certain PCBs, prenatal exposure was associated with neonatal thyroid hormone levels. (Go to publication)

Flame Retardants:

Higher PBDE exposures during pregnancy were associated with:

  • Decreased female fertility. (Go to publication)
  • Altered maternal thyroid hormone levels during pregnancy. (Go to publication)
  • Lower infant birth weight. (Go to publication)
  • But not with neonatal thyroid hormone. (Go to publication)
Policy, Practice or Research Impacts: 

Our research, evaluations, and findings on exposures' effects on children's health, behavior, and development inform sustainable strategies to reduce environment-related childhood disease.

Contact Person: 
Dr. Kim Harley
Contact Person's Email Address:
Principal Investigators: 
Dr. Brenda Eskenazi
Research Publications and Reports: 

See all publications resulting from CHAMACOS research:

Website for Project or Program: 
Clinica de Salud del Valle de Salinas; Natividad Medical Center; Centers for Disease Control and Prevention; Emory University
National Institutes of Environmental Health Sciences (NIEHS), Environmental Protection Agency (EPA), Thrasher Research Fund
Location - States: