Dr. Martin Fenstersheib, Santa Clara County health officer,
points to a draft public health goal report circulated by The
Office of Environmental Health Hazards Assessment, part of the
California Environmental Protection Agency (EPA). The complete
report is available for download on the water district
’s Web site (www.valleywater.org).
The Times carries a weekly question-and-answer column on the perchlorate issue. If you have a question, lease e-mail it to us at [email protected] or fax to 779-3886. We’ll research it and provide the best answer we can find.
Is perchlorate absorbed through the skin? Is it safe for adults to shower or children to soak in the bathtub using perchlorate-tainted water?
Dr. Martin Fenstersheib, Santa Clara County health officer, points to a draft public health goal report circulated by The Office of Environmental Health Hazards Assessment, part of the California Environmental Protection Agency (EPA). The complete report is available for download on the water district’s Web site (www.valleywater.org).
Fenstersheib said the report cites studies that indicate our skin will not generally absorb perchlorate into our bodies, and that showering is safe. Water droplets in showers are too large to inhale and perchlorate salt does not turn to hazardous vapors in the shower. This report suggests that showering and bathing with low-level perchlorate water is not hazardous. Children should be monitored while bathing to ensure that accidental water intake is kept to a minimum.
Is it safe to eat fruits and vegetables watered with perchlorate-tainted water?
Greg Van Wassenhove, director of the county’s agriculture department, says there are some studies that show perchlorate concentrates in leafy vegetables such as lettuce. Close review of the studies show that some of the study vegetables were grown hydroponically – completely in water-based nutrient solutions – rather than in soil.
“We need a risk assessment. I’ve been telling people that there’s no evidence to believe that they’re not safe,” Van Wassenhove said.
Fenstersheib agreed on the need for more study: “This is an emerging issue and there has not been much research done on the extent to which perchlorate may be retained in irrigated crops. The California Department of Health Services and the U.S. Environmental Protection Agency are studying this issue and there is no conclusive information available as yet.”
Will perchlorate-tainted water hurt my lawn?
Van Wassenhove responds: “You’ve got to have salt level pretty high to burn a lawn. The parts per billion (in San Martin-area wells) aren’t any were near what you’ve got to have to burn a lawn.”
Is it safe to drink goat’s milk and eat cheese made from goat’s milk if those goats ingested perchlorate-tainted water? What about nursing mothers?
Fenstersheib responds: “According to the EPA, sensitive populations, like pregnant or lactating women, children and people who have health problems or compromised thyroid conditions, should follow the advice of their health care provider regarding the amount and type of liquids, including water, that should be consumed.
Available research indicates that perchlorate ingested through contaminated water can be found in breast milk. Lactating mothers should use an alternate source of water.
Theoretically, milk from cows and goats could contain perchlorate, although there is limited research on issues involving livestock.”
Is perchlorate used to treat hyperthyroidism?
According to a 2001 study published in Therapeutic Drug Monitoring, perchlorate has been used to treat hyperthyroidism, or an overactive thyroid gland, in the last 50 years.
Although Llagas Creek has tested clean, what kind of relationship does Llagas Creek have to the perchlorate-infected underground aquifer?
According to experts at the Santa Clara Valley Water District, Llagas Creek introduces clean water to the aquifer, which is expected to dilute the concentration of perchlorate found. The creek has a more direct effect on shallow groundwater quality, while the occurrence of perchlorate also extends to the deeper aquifer, which is less prone to dilution from the creek.
Where to go for information:
• Santa Clara Valley Water District: www.valleywater.org
• Larry Ladd – Rancho Cordova perchlorate project: www.perchlorate.org
• Environmental Working Group: www.ewg.org
• Alexander, Hawes & Audet law firm: www.alexanderlaw.com
• San Martin resident Diane Boyd is forming a study committee: 683-9399
• Santa Clara Valley Water District: 888-HEY-NOAH (888-439-6624)
