Health studies and advisories
||Background and cancer study
Public Health believes the amount of arsenic and lead contamination in King County soils is not likely to pose a health emergency to residents, but it is a health concern. This is because no amount of arsenic or lead is safe to ingest or inhale. Arsenic and lead in large amounts can cause acute health problems, and smaller amounts over many years can cause long-term health problems. Whether or not a person could get sick from the arsenic and lead in the soil depends on:
- how much of these heavy metals are in the soil that a person inhaled or ingested;
- over how many years a person inhaled or ingested the contaminants; and
- a person's individual susceptibility.
More information about lead, arsenic, and your health.
Public Health and state agencies conducted a study on cancer rates on Vashon-Maury Island to see if there were more cases of the kinds of cancers caused by arsenic. Researchers found no statistically different rates of cancer on Vashon-Maury Island compared to elsewhere.
||Dirt Alert -- Guidelines for reducing your exposure to contaminated soils
The amount of arsenic and lead found in contaminated soil does not likely present an immediate health risk. As a precaution, however, people should avoid eating or breathing in contaminated dirt or dust. Children who crawl on the floor, play in dirt, and put hands and toys in their mouths are the most vulnerable. It's okay to get the dirt on your skin because arsenic and lead are not absorbed through the skin. To keep from breathing in contaminated dust or accidentally eating contaminated dirt or dust, Public Health recommends that all King County residents follow these guidelines to reduce exposure to contaminated soils:
- Wash hands and face thoroughly after working or playing in the soil, especially before eating. It's best to avoid eating, drinking, or smoking in areas with bare soil, because it's easy for dirt on your hands to get into your mouth.
- Frequently wash toys, pacifiers and other items that go into children's mouths.
- Take off shoes before entering the house.
- Wash garden vegetables and fruits carefully to remove all soil particles. Take care to get dirt out of the crevices of vegetables such as broccoli. Additional gardening tips.
- Damp-mop floors and wipe down counters, tables and window ledges regularly. Avoid using a vacuum as a method to keep contaminated dust under control. Most vacuum cleaners tend to stir dust up into your breathing zone. If you prefer to use a vacuum cleaner, use one with a HEPA (high efficiency particulate air) filter.
Additional soil safety steps:
- Wash soil-laden clothes separately from other clothes.
- Prevent pets from tracking contaminated soils into your home. Keep them out of areas with exposed dirt.
- Consider wearing a mask if you spend time in dusty environments.
- Cover bare soils with grass or other material.
- Keep children from playing in contaminated dirt. The most likely way to become exposed to arsenic and lead in the soil is from ingesting (eating) dirt. Toddlers and young children tend to play in dirt and then put their fingers/toys/other items in their mouths.
- Post a colorful poster in your house to remind you of some of these key safety steps
- Post a sign at your door asking people to remove shoes before coming inside.
Public Health - Seattle & King County and the state Department of Ecology soil studies have confirmed widespread arsenic and lead contamination in King County soils. Much of the arsenic and some of the lead are potentially linked to the Asarco copper smelter smokestack emissions. The smelter was located on Commencement Bay in Tacoma, and operated from the late 1900s to the 1980s. Public Health's Tacoma Smelter Plume Project homepage has links to reports on the studies, fact sheets on arsenic, lead and pica behavior.
The studies found arsenic and lead contamination at various levels throughout the sample areas. The areas studied extended from Vashon-Maury Island and Federal Way north to Shoreline and east to Duvall and Issaquah. Soil contamination varies widely. In general:
- The closer to the smelter the more significant the contamination, with south coastal King County and Vashon-Maury Island tending to have the highest levels of arsenic and lead.
- Older properties where the soil has not been disturbed or dug up tend to be more contaminated.
- New properties where the soil has been disturbed tend to not have arsenic or lead contamination.
The levels of soil contamination do not present a public health emergency; however, Public Health recommends that all families take precautions to reduce exposure to potentially contaminated soil. The Soil Safety Guidelines focus on reducing ingestion and inhalation, and include:
- Washing hands before eating
- Keeping dust under control with frequent damp mopping
- Removing shoes before entering the home
- Keeping children off of bare patches of soil
We will mail copies of the guidelines to your office for distribution if you wish. For information and resources on arsenic and lead, call the Public Health Environmental Health Services office at 206-263-9566 or email us using our online Contact form.
Public Health recommends that families with concerns about exposure to arsenic or lead consult their health care provider about appropriate testing options. Dr. Jim White, toxicologist at the Washington State Department of Health, is also available to answer questions about arsenic at 360-236-3192. Children exposed to lead in the soil may be appropriate candidates for blood lead testing, particularly if they live in older homes with peeling paint, other children in the household have tested high for lead in the blood, or have other exposures to lead in the environment. For more information about blood lead testing refer to the lead screening guidelines for children developed by the Centers for Disease Control and Prevention in their publication titled "Screening Young Children for Lead Poisoning." It may be found in the publications section of the CDC lead poisoning prevention site.
Other useful links:
||Pica -- eating non-food items
Pica is a medical condition typically defined as the persistent eating of non-food items for a period of at least one month. People with pica crave and eat materials such as dirt, clay, chalk, lead chips, laundry starch, dishwashing soap, chalk, burnt matches, and many other non-food substances. Some of these substances are poisonous. Read more.