What is biomonitoring?
Biomonitoring measures if an individual or population is over-exposed to toxic chemicals. Human exposure to environmental chemicals can occur from many sources, such as food and consumer products, air, water, and soil. Biomonitoring is the assessment of both individual and population exposures to environmental contaminants by measuring the concentration of chemical and/or resultant metabolites in human specimens, such as saliva, blood, urine, or hair. Unusually high levels of chemicals in a human body may indicate that a person’s workplace, home, or community is contaminated with those substances. Biomonitoring identifies and quantifies harmful chemicals in the human body to provide scientific evidence of the degree of exposure to a particular product or chemical. Biomonitoring data has been used to confirm exposures and validate public health policies. This information, when paired trend analysis, improves understanding of the relationship between exposure to environmental chemicals and their impact on health.
U.S.-based biomonitoring projects:
Agricultural Health Study
The Agricultural Health Study (AHS) is a multifaceted scientific project spearheaded by four federal partners including the National Cancer Institute (NCI), the National Institute of Environmental Health Sciences (NIEHS), the Environmental Protection Agency (EPA), and the National Institute for Occupational Safety and Health (NIOSH). The collaborative effort began in 1993 with the goal of answering important questions about how agricultural, genetic factors, and lifestyle affect the health of farming populations. The Agricultural Health Study is a prospective study of cancer and other health outcomes in a cohort of licensed Iowa and North Carolina pesticide applicators and their respective spouses. Between 1993 and 1997, 52,394 licensed private pesticide applicators (mostly farmers) enrolled, as did 32,345 of their spouses. In its first two phases, the study also included 4,916 Iowan commercial pesticide applicators. The average ages at enrollment were 47 years, 38 years, and 47 years for private applicators, commercial applicators and spouses. Their participation has provided, and continues to provide, data that researchers need to help the current and future generations of farmers and their families live healthier lives.
California Environmental Biomonitoring Program
The California Environmental Biomonitoring Program (also known as Biomonitoring California) is a collection of smaller studies, targeting specific populations (e.g., fire fighters, breast cancer patients and controls, etc.). The California Department of Public Health (CDPH), Office of Environmental Health Hazard Assessment (OEHHA), and Department of Toxic Substances Control (DTSC) have collectively developed and implemented the initiative. Biomonitoring California was established by Senate Bill 1379, authored by Senator Don Perata and Senator Deborah Ortiz, which was passed by the California Legislature and signed into law by Governor Schwarzenegger in 2006. The Biomonitoring California program has received funding from CDC over the last ten years to assess environmental contaminants across the state and has been generating human biomonitoring data and releasing it publicly. Two state laboratories, the CDPH Environmental Health Laboratory (EHL) and the DTSC Environmental Chemistry Laboratory (ECL), provide analytical expertise and capacity for measuring environmental chemicals; these include pesticides, parabens, metals, perchlorate, bisphenol A (BPA), per- and polyfluorinated substances (PFAS), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organophosphate flame-retardants (OPFRs). Biomonitoring California involves interested members of the public throughout the state in the process of developing and carrying out the program.
Center for the Health Assessment of Mothers and Children of Salinas
The Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) Study is the longest running longitudinal birth cohort study of pesticides and environmental exposures and the health of pregnant women and their children living in the agricultural region of Salinas Valley, Monterey County, California. Between October 1999 and November 2000, 601 pregnant women were enrolled in the CHAMACOS birth cohort study, resulting in 538 live births. Eligible women were older than 18 years of age, less than 20 weeks gestation, eligible for Medi-Cal, receiving perinatal care at local community clinics, Spanish-or English-speaking, and planning to deliver at the county hospital in Salinas, California. Urine samples were collected from 253 participating children at 42-months of age. Written informed consent was obtained from all participants and the study was approved by the Committee for the Protection of Human Subjects at the University of California Berkeley. The study followed these families for 19 years, measuring exposures to pesticides and other chemicals and assessing children’s health, growth, and development every 1-2 years. In 2010-2011, CHAMACOS expanded the study by enrolling additional 9-year-old children. More than 600 children continue to participate and will be followed until adulthood.
National Health and Nutrition Examination Survey
The Center for Disease Control (CDC) via its U.S. National Health and Nutrition Examination Survey (NHANES) has conducted annual general population health evaluations for nearly two decades and has detected traces of 2,4-D in urine in some populations. The NHANES program began in the early 1960s and, in 1999, became a continuous program with a changing focus on varieties of health and nutrition measurements to meet emerging needs. The survey examines a nationally representative sample of about 5000 persons each year and involves the collection of blood and urine samples and the subsequent analysis of about 60 parameters, including heavy metals, volatile organic compounds, pesticides, phthalates, hormones, and viruses. In the NHANES survey, the trace amount of 2,4-D detected in urine is less than 1 part per billion (equal to less than one drop of water in an Olympic-sized swimming pool) and thousands of times lower than the amount scientists and regulators around the world have determined to be safe for humans. To facilitate, NHANES contacts select households and asks a short set of questions (gender, age, and race) about all persons in that household. A computer process then randomly selects some, all, or none of the household members to correlate the evaluations, and monitor trends in selected environmental exposures, diseases, and behaviors, while deciphering emerging public health needs.
Biomonitoring is a scientific way to observe levels of pesticide exposure in human populations and is a crucial component of evaluating existing pesticide regulations and restrictions. Currently used pesticides generally have short biological half-lives and are rapidly excreted in urine. Measurement of urinary biomarkers is an established method to understand chemical exposures and determine means to protect potentially vulnerable populations and communities.