How does atrazine affect frogs

In addition, microscopic examination of the internal organs of the frogs is required to detect the hidden effects from low-dose exposure. To date, atrazine's effects on mammals and amphibians have been tested only at large doses, not at doses commonly found in the environment.

In their journal article, Hayes and his colleagues write, "The effective doses in the current study Hayes doubts that atrazine has such severe effects on humans, because the herbicide does not accumulate in tissue and humans don't spend their lives in water like frogs do. Nevertheless, the effects of atrazine on frogs could be a sign that the herbicide is subtly affecting human sex hormones, too, interfering with androgens, such as testosterone, that control male sex characteristics.

Some studies in cell culture point to a possible biochemical explanation for the observed effects on amphibian sex organs. John P. Giesy, a professor of zoology at Michigan State University in East Lansing, and his colleagues found last year that, at large doses, atrazine ups production of the enzyme aromatase, which converts androgen hormones to estrogen hormones.

Extrapolating these results from mammalian cells to amphibians, Hayes argues that atrazine could feminize male frogs by promoting the conversion of male hormones to female hormones. The lowered androgens would interfere with voice box development, while increased estrogens would promote ovaries within the testes. More than 60 million pounds of the herbicide were applied last year in the United States alone.

Manufacturer Syngenta estimates that farmers use the herbicide to control weeds on about two-thirds of all U. On average, it improves corn yield by slightly more than four percent. The compound is generally considered safe, however, because it quickly decomposes in the environment and, being water soluble, is quickly excreted from the body. Aquatic life, however, swim and breed in atrazine-contaminated field runoff. Though previous studies showed deformities and abnormalities in adult amphibians only at very high doses, no one had looked in detail at hormone levels in frogs or at effects on tadpoles, the larval stage of frogs.

Prodded by the EPA, Syngenta approached Hayes, an expert on amphibian hormones, to find out if atrazine disrupts sex hormones in amphibians. He has developed several very sensitive assays to detect chemicals that affect hormones, including a test for estrogen-like chemicals that might induce human breast cancer. Though Hayes initially received funds from Syngenta for the studies, all the current published studies were conducted independent of Syngenta. Source: Phys. This entry was posted on Thursday, October 19th, at am and is filed under Uncategorized.

You can follow any responses to this entry through the RSS 2. You can skip to the end and leave a response. Pinging is currently not allowed. Name required. Mail will not be published required. Pest Management Providers: Register Today! Biosolids 1 Sewage Sludge 1. United Nations 1. Water Regulation Herbicides like atrazine are now found in 57 percent of U.

Geological Survey. The EPA, for its part, announced yet another review of the herbicide last October because of human health concerns, after declaring the chemical treatment safe in Ultimately, atrazine may be silencing the amphibian calls of the wild: "It leads to them not croaking," Hayes says, noting that atrazine may be contributing to the global decline in amphibians, along with chytrid fungus.

So this is not just a frog problem. David Biello is a contributing editor at Scientific American. Follow David Biello on Twitter. Already a subscriber? Sign in. Thanks for reading Scientific American. Create your free account or Sign in to continue. See Subscription Options. Go Paperless with Digital.