amphibian skin is permeable, toxins can be absorbed directly into the > bloodstream," says Storfer. "Their eggs are also permeable to environmental > toxins, which makes them indicators of environmental contamination," adds > Forson. > > "This is one of the few, rare examples of a toxin causing an indirect, > increased susceptibility to infection," says Andrew Blaustein, an ecologist > at Oregon State University in Corvallis. However, the specific mechanism by > which immunosuppression occurs still needs to be established, says Tyrone > Hayes, a biologist at the University of California, Berkeley. This is > especially important because atrazine has been associated with breast and > prostate cancer in humans, he says. > > Related site > > # Environmental Protection Agency report on atrazine and amphibians " />
Search OCA:
Get Local!

Find Local News, Events & Green Businesses on OCA's State Pages:

OCA News Sections

Organic Consumers Association

Corn Herbicide Atrazine Damages Human & Animal Immune System

Pesticides have wreaked havoc on global amphibian populations, and now new
> evidence suggests that the problem may be even worse than thought. One of
> the most common herbicides—atrazine—appears to have an added deadly effect:
> It makes tiger salamanders more vulnerable to certain infections. Because
> atrazine also has deleterious effects on humans and other mammals,
> researchers fear this new effect on amphibians may be a harbinger of a
> larger problem for other species.
>
> Atrazine is the second most popular agricultural pesticide in the United
> States, used primarily to control weeds on corn, sugar cane, and
> residential lawns. The compound mimics the hormone estrogen, and over the
> past 10 years, scientists have noticed that frogs and other amphibians
> exposed to the herbicide develop deformed genitalia and smaller voice
> boxes, making mating calls softer and reproduction impossible. Atrazine was
> introduced in 1958, and scientists started noticing upticks in fungal and
> viral diseases in exposed animals in the late 1990s. Studies confirmed that
> atrazine suppresses the immune system, but whether this led to increased
> infection rates remained a mystery.
>
> To solve the conundrum, biologists Diane Denise Forson and Andrew Storfer
> of Washington State University in Pullman took a closer look at the tiger
> salamander, a small amphibian commonly found in marshes and ponds around
> the globe. Tiger salamanders tend to live in areas exposed to atrazine, and
> over the past few years biologists have noted a rise in their
> susceptibility to the Ambystoma tigrinum virus (ATV), which causes internal
> hemorrhaging and death. In the lab, the researchers exposed 384 tiger
> salamander larvae to levels of atrazine similar to those found in nature,
> and then introduced ATV for 3 days at the 12-week larval stage. (Atrazine
> is commonly sprayed in the spring, during this stage of development.)
>
> Tiger salamanders exposed to atrazine were twice as likely to become
> infected with ATV than were those not exposed to the herbicide, the team
> reports in this month's issue of Ecological Applications. In addition, when
> combined with sodium nitrate, a type of fertilizer, atrazine lowered the
> levels of white blood cells that fight disease by nearly 20%. "Because
> amphibian skin is permeable, toxins can be absorbed directly into the
> bloodstream," says Storfer. "Their eggs are also permeable to environmental
> toxins, which makes them indicators of environmental contamination," adds
> Forson.
>
> "This is one of the few, rare examples of a toxin causing an indirect,
> increased susceptibility to infection," says Andrew Blaustein, an ecologist
> at Oregon State University in Corvallis. However, the specific mechanism by
> which immunosuppression occurs still needs to be established, says Tyrone
> Hayes, a biologist at the University of California, Berkeley. This is
> especially important because atrazine has been associated with breast and
> prostate cancer in humans, he says.
>
> Related site
>
> # Environmental Protection Agency report on atrazine and amphibians

For more information on this topic or related issues you can search the thousands of archived articles on the OCA website using keywords: