Recent research conducted by the University of Pittsburgh suggests that glyphosate—the most commonly used pesticide in the world—is causing "morphological changes" to some exposed animals, namely tadpoles.
Marketed by Monsanto as Roundup, the popular weed killer and companion to genetically modified crops may be interfering with the hormones of tadpoles, says the research team, even despite the fact that weed-killing herbicides like glyphosate are inherently intended to not adversely affect animals, only plants.
Tadpoles can naturally grow larger tails to help them escape predators sensed in their immediate environment, and similar body shape changes were noted after exposure to both environmentally relevant and sub-lethal doses of glyphosate. According to lead researcher Professor Rick Relyea, "This discovery highlights the fact that pesticides, which are important for crop production and human health, can have unintended consequences for species that are not the pesticide's target." Involuntary changes to the tadpole's hormonal system, as observed in the study as a result of glyphosate exposure, could create a major survival disadvantage for the animals. According to the study, "Roundup completely eliminated two species of tadpoles and nearly exterminated a third species, resulting in a 70% decline in the species richness of tadpoles."
Frogs and tadpoles are considered indicator species because they're especially sensitive to changes in their immediate environment, often before other life forms begin to show signs of stress. And, says Relyea, "Roundup is not only lethal to tadpoles. A new study has discovered that Roundup can be highly lethal to terrestrial frogs and toads as well," creating more concern about the use of the controversial herbicide.
According to the most current data from the EPA, in 2007 180 to 185 million pounds of glyphosate were used for agricultural purposes, and home and garden use was between 5 to 8 million pounds.
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Image: Velo Steve