Hormonal disruption

Chemicals on ‘Dirty Dozen’ list of concern to North State residents

Julia Murphy, dioxin expert at the Butte Environmental Council, recommends that residents remove their shoes before entering their homes to avoid possible dioxin and pesticide contamination from soil adhering to shoe soles.

Julia Murphy, dioxin expert at the Butte Environmental Council, recommends that residents remove their shoes before entering their homes to avoid possible dioxin and pesticide contamination from soil adhering to shoe soles.


‘Dirty Dozen’:
The Environmental Working Group’s list of 12 hormone-altering chemicals:
• Atrazine
• BPA (Bisphenol A)
• Dioxin
• Fire retardants
• Glycol ethers
• Lead
• Mercury
• Organophosphate pesticides
• Perchlorate
• PFCs (perfluorinated chemicals)
• Phthalates
For more information, visit www.ewg.org and click on the “Research” bar.

Of all the toxins confronting people daily, endocrine disruptors rank among the most insidious. These chemicals can have stealth effects—not only impacting the hormones of those exposed, but also creating a genetic legacy that can continue for generations.

“There is no end to the tricks that endocrine disruptors can play on our bodies,” states a recent report by the Environmental Working Group, a research and advocacy organization. Among those tricks: “increasing production of certain hormones; decreasing production of others; imitating hormones; turning one hormone into another; interfering with hormone signaling; telling cells to die prematurely; competing with essential nutrients; binding to essential hormones; [and] accumulating in organs that produce hormones.”

Recently the EWG cataloged 12 such disruptive compounds (see accompanying chart). They range from the familiar (lead, mercury, fire retardants) to the esoteric (atrazine, glycol ethers and phthalates). And some, dioxins especially, are prevalent in the North State.

“It’s one of those Pandora’s Box situations,” said Chico geologist John Lane, of Chico Environmental Science and Planning. “Once you open it up and start looking, it’s much bigger than you expect—and it’s much more ubiquitous than you would expect, especially as nasty as these substances are. Most of them are measured in parts per trillion, which is a very minute amount, and that this could be an unhealthy or dangerous amount is even more alarming. …

“It’s almost like you don’t even want to look for them!”

Yet we should, he added: “As we learn more about them, they become more known to the public, but the regulatory climate moves so slowly … that [regulators] are 10 to 15 years behind in trying to keep us safe.”

Lane refers to endocrine disruptors as “legacy constituents,” and Julia Murphy, a dioxin expert at the Butte Environmental Council, adds that they are “persistent through generations.” Murphy says these chemicals act as “a system disruptor rather than a body disruptor,” meaning they trigger wide-ranging changes that can be heritable—passed on genetically to children, grandchildren, and on down. In addition, the compounds are relatively stable, so they can remain potent for decades.

“It’s important to keep information of containment sites alive,” Murphy said. “Knowledge is key to making good decisions.”

In that vein, Lane and Murphy reviewed the EWG list and highlighted some endocrine disruptors of particular concern in the North State.


A byproduct of industrial processes, dioxin hit local headlines due to a concentration in Oroville. It’s a chemical of particular concern because, Murphy explained, “if you are exposed, you can apparently suffer no ill effects yourself but you can pass on genetic anomalies and disorders to your children.”

Soil can convey dioxin as well as pesticides, so “it’s a good idea to leave your shoes at the door,” Murphy said. “If we bring soil that’s carrying residues into our house, that exposure can build up over time.”


Bisphenol A is so common, there’s a 9 in 10 chance you have traces of it in your body.

“It’s ubiquitous,” Lane said. “We’re finding it on the polar ice caps—everywhere—and we’re not sure how it’s getting there.”

BPA appears in products as varied as plastics, food-can linings and cash-register receipts. “Drinking bottled water is problematic for many reasons,” Murphy said, including the leeching potential of BPA. She recommends drinking tap water, and “if you don’t have a filter, let the water sit in an empty jar in your fridge with the top off.”

Glycol ethers:

These chemicals, found in car parts and antifreeze, are prevalent in areas with auto-recycling facilities that can’t contain the run-off from rainfall.

“More often they’re affecting the environment than human health,” Lane said, “but it also depends on your proximity to these locations and if people are eating waterfowl and fish from that source of the environment.”


This one might be normally associated with ocean tuna but it can also appear in fatty fish caught locally. Species to note include striped bass, Sacramento pikeminnow, largemouth bass, catfish and salmon.

Flame retardants:

While the disruptive chemicals are “being phased out,” Murphy said, it’s important to read the labels on items that have flame retardants, such as tents. Keep an eye out for the acronym PBDE, which stands for polybrominated diphenyl ethers. PBDE-free materials may cost you more, but they’re worth it.

“It’s funny, “Murphy said, “how you have to pay extra for things not in products and food.”