If air and water can pass through an amphibian’s delicate permeable skin, so can airborne and waterborne chemicals.
Runoff washes a slew of pollutants—pesticides, herbicides, fertilizers, leaked or spilled petroleum products and road salt—into amphibian habitats. Groundwater can carry chemicals leached from landfills. And even treated wastewater isn’t flushed of pharmaceuticals.
What isn’t immediately lethal can have sinister long-term effects on amphibians and their habitats.
Pesticides can compromise an amphibian’s immune system, leaving it vulnerable to infection. Some pesticides can impair an animal’s neurological functions so that it has difficulty swimming, feeding, or defending itself.
Atrazine, a herbicide used widely in agriculture and lawn care, interferes with how frogs’ (and other animals’) endocrine, or hormone, systems work. Even low levels shrink male frogs’ voice boxes, weakening their mating calls and making them less likely to attract a female. But it gets worse. A researcher studying male frogs exposed to atrazine during embryonic development found that about a third had malformed reproductive organs, while many others had both male and female sex organs, sometimes in multiples.
The active ingredient in birth-control pills also has been identified as the cause of “intersex” amphibians and fishes. Because pharmaceuticals, and even vitamins and supplements, are nearly impossible to remove from wastewater, this potent synthetic estrogen is polluting aquatic habitats.
Amphibians are our canaries in the coal mine. Levels of the endocrine-disrupting herbicide that scrambled test frogs’ reproductive systems were slightly below what’s allowed in our drinking water. Amphibians can absorb pesticides used on crops grown 100 miles away—evidence of their exquisite sensitivity, but also of the pervasiveness of toxins in our shared environment. Scientists with the U.S. Geological Survey identified 10 chemicals in frog tissues, including residues of DDT, an insecticide that was banned in the United States more than 40 years ago.
When we help amphibians, we are also helping ourselves.
Make a change to help
Do everything you can to keep toxic chemicals out of our environment. Practice pesticide-free lawn care and gardening. If you live in Chicago, many police stations have receptacles in which you can safely recycle your pharmaceuticals.