Health questions raised about herbicide
A new study shows that frogs exposed to a common herbicide changed from male to female in about 10 percent of the cases, raising questions about the safety of atrazine for humans.
Atrazine, is one of the most commonly applied pesticides in the world, according to the study in the Proceedings of the National Academy of Sciences released Monday. And it's the most commonly detected pesticide contaminant of ground, surface and drinking water -- it's found in the waterways that feed the Chesapeake Bay.
The study calls it a "potent endocrine disruptor that is active at low, ecologically relevant concentrations."
The frogs in the study were chemically castrated and feminized by atrazine. Ten percent developed into females that produced viable eggs. The offspring were all male with decreased fertility, and "exemplify the role that atrzaine and other endocrine-disrupting pesticides likely plan in global amphibian declines," the study says.
It's one study, but what could this mean for humans?
The Washington Post reports today that the EPA, which reapproved atrazine's use in 2006, is taking another look at the public health implications.
Baltimore Sun file photo of Sandy Point State Park on the Chesapeake Bay
Comments
The story would be improved by covering additional key aspects of this chemical. Atrazine is a pesticide, but more accurately it is a herbicide used to control unwanted plants. Atrazine is used in conservation tillage, such as "no-till" farming where whole fields are sprayed, unwanted plants all die and turn brown so that planted crops do not have to share sunlight, soil nutrients and water with other plants. That step used to be done by mechanical cultivation, starting with the hoe at the dawn of agriculture then on to plows and huge tractor driven devices of more modern times. But such soil disturbances resulted in severe erosion which damaged our waterways and led to valuable soil and productivity losses. Now, "No-till" farming practices have significantly helped prevent soil erosion and sedimentation in our streams, rivers and the Chesapeake Bay, they have improved soils and crop yields, reduced energy use and saved time and money.
While this side of the story should also be told, such major benefits must be balanced with observed harm. Atrazine's negative effects on our environment should be more closely studied, it is currently banned in the European Union and is a top suspect in the intersex fish concerns happening nationwide. However, there is already sufficient evidence to immediately merit substantial action on parallel tracks; we need to reduce atrazine application and runoff rates as well as further investigate alternatives. The sooner the better. Greater care must be taken with application methods, such as 1) aerial over-spraying, 2) proximity to water-pathways such as intermittent streams and swales, 3) timing, for instance, better guidelines/restrictions on applying before impending rain events, predicted or observed, and 4) tailoring towards specific plant species/groups of concern, 5) improving product adherence to plant surfaces, and 6) reducing both atrazine and its breakdown constituents toxicity and life.
No-till farming has greatly decreased erosion from farms, largely due to atrazine, let us maintain this progress and improve our methods, thereby helping to keep our waters naturally clean and healthy, our economy sustainable, and the sound of frogs part of Spring.
Come on Spring!
Posted by: Jim Cummins | March 3, 2010 1:00 PM