The Silent Spring Household Exposures Study

Focus Household exposures to chemicals, specifically 89 endocrine disrupting compounds (EDCs) and mammary carcinogens, in 120 homes on Cape Cod, Massachusetts.
Participants Women who lived in the same home for at least ten years in the target areas on Cape Cod.
Data Collected Indoor air, household dust, and urine samples. Questionnaires on products used or stored in homes. GIS (geographic information system) data incorporated targeted historic pesticide use into the study.
Unique Perspective For thirty of the chemicals, this was the first measurement done in an indoor environment.
Conducted By Silent Spring Institute.

What Chemicals Showed up in Samples from Homes?

Many of the chemicals found were both typical in household exposure studies and expected. These include polybrominated diphenyl ethers or PBDEs (common source: flame retardents), phthalates (common source: solvents and plasticizers), parabens (common source: preservatives in food and pharmaceuticals), and pesticides (common source: insecticides, herbicides, fungicides).

Some of the findings were more surprising. For example, 4-Nonylphenol (common source: laundry detergents, disinfecting cleaners, and hair care products) was detected in air samples. EPA and industry documents seemed to indicate this chemical would not volatilize (off-gas). Finding it in the air samples means more research is necessary to find out what levels are being inhaled.

Also 4-4' DDT was one of the most common pesticides detected in the household dust samples. DDT has been banned for three decades, so finding it indoors was unexpected. This finding indicates that DDT is not breaking down indoors and leads to the need for further research.

Concentrations of PBDEs in household dust were much higher in the homes in this study than in similar studies of homes in the European Union where some types of PBDEs are banned.

What Products Were Identified on the Questionnaires?

The study questionnaires asked about products women might use or store in their homes. The final list of products was generated from an original list of chemicals or ingredients that have been suspected of being endocrine disrupting compounds or mammary (breast) carcinogens. That list of chemicals was refined through several methods including identifying chemicals in commercial use and those that could be analyzed in samples in a laboratory using the methods the study had chosen. The list was not a complete inventory but included many products that might be important for analysis including chemicals found in nail polish, hair spray, some cleaners, and some detergents.

Where Can I Read More?

The study has been written about in several articles and papers. These are available on the Silent Spring web site on the Household Exposure Study page.

What's Happening Now?

Researchers are continuining to work with the data collected in this study. Ruthann Rudel, a senior scientist at Silent Spring Institute, explained that one current research direction is to explore the relationships between the findings in air, dust, and urine samples as well as some of the questionnaire answers.

Future Plans

One way researchers at Silent Spring would like to extend the work done in the Household Exposure Study is to identify a list of products or practices from the first study, and identify a list of alternatives.