Daily News Archive
From September 12, 2005                                                                                                           

Pesticide “Inerts” Pose Dangers to Wildlife
(Beyond Pesticides, September 12, 2005) Scientists are increasingly finding that the toxicity of pesticide “inerts” and their synergistic effects are harming the environment, according to this month’s Environmental Science & Technology (EST). While inert ingredients often make up the majority of a pesticide’s formula, potential effects of inerts are largely unrecognized by the public and are of little priority to the Environmental Protection Agency (EPA).

The surfactant POEA (polyethoxylated tallow amine), found in Monsanto’s Roundup, is one of many problematic inerts. A recent study out of the University of Pittsburgh unveiled that the inert, POEA, found in Monsanto’s Roundup harmed and killed the majority of tadpoles at commonly used (and EPA-approved) concentrations (see daily news). POEA, like all inert ingredients, is not listed on the product’s label.

Bruce Pauli, Canadian Wildlife Service toxicologist and one of the authors of the study, told EST, “'We know [POEA is] toxic and hope there’s not enough in the water to cause a problem.” But at a time when amphibian populations are declining dramatically for unknown reasons, he asks: “Is that really protecting the environment?'”

This Roundup study is one of several that shed light on the behavior of inerts in the environment, a topic largely ignored by EPA, say many environmental toxicologists inside and outside the agency. As environmental effects often serve as a canary in the coalmine to warn of the potential effects on humans, lack of this data combined with a lack of human health effects data is doubly alarming. In 1995, EPA changed the listing of POEA from an inert of “unknown toxicity” to one that is of “minimal concern.” According to the agency, “the current use pattern in pesticide products will not adversely affect public health or the environment.” Despite growing scientific evidence of the harm caused by inerts used in product formulations such as Roundup, the assessment will likely hold for years into the future.

"'The inerts evaluation for environmental effects is EPA’s dirty little secret,” one EPA scientist requesting anonymity told EST. "'POEA is likely to be the tip of the iceberg, but we don’t know because we don’t have data. The agency assures us that everything’s okay. On the basis of what? Not data.'”

Inert ingredients are added to the active ingredient to improve the efficacy or handling of the final product, and are not listed on product labels to protect industry trade secrets. For example, POEA improves Roundup’s ability to penetrate waxy plant surfaces. In short, inert ingredients have a synergistic effect with other ingredients and increase the product's toxicity and improve the product's effectiveness to kill the target species. Pesticide applications rarely stay within the target area and frequently harm or kill non-target species.

Even though little data exists for inert ingredients, many are known to state, federal and international agencies to be hazardous to human health. For example, Caroline Cox of Northwest Coalition for Alternatives to Pesticides reviewed the more than 1800 chemicals on EPA’s list of inerts of unknown toxicity. She found that 75 are hazardous under the Clean Air Act, 52 under EPA Superfund criteria, 64 under the Clean Water Act, 43 under the Toxics Release Inventory, and 78 under the Toxic Substances Control Act. In addition, 292 inerts of "unknown toxicity" are registered by EPA as active ingredients in other pesticides.

Source: Environmental Science & Technology (full story)

TAKE ACTION: Beyond Pesticides is working to convince EPA to require that all pesticide ingredients, including inerts, be listed on all pesticide product labels. Visit What’s in a Pesticide? and the Lawns Facts & Figures fact sheet for more information.