University of California, Davis, scientists are helping rice farmers in Uruguay stop polluting their waterways -- including drinking-water sources and a globally valuable nature reserve.
With funding from the U.S. National Institutes of Health's Fogarty International Center, the UC Davis researchers helped Uruguayan university colleagues devise a simple water test that tells whether it is safe to drain flooded rice fields.
The test checks for the herbicide clomazone, which is used on 78 percent of Uruguay's rice fields.
Clomazone in high doses can cause liver disease in experimental animals. It also is known to disrupt fish hormones, affecting their ability to reproduce, which becomes a problem for all the plants and animals in the region.
However, clomazone usually degrades to safe levels during the rice-growing season. Holding water on the fields for just the right amount of time can make the water safe for streams and rivers, without damaging the farmer's harvest.
The new test technology gives scientists a way to determine whether the degradation process is complete; eventually, it should be available to farmers in a simple "dipstick" field test. The farmer would take a few ounces of water from the rice paddy, dip in the test stick, and wait a few minutes for results. If the stick color turns one color, the water is safe to release. If it turns a different color, the farmer should wait a few days and test again.
Developing best rice-farming practices to avoid release of toxic chemicals to the environment is especially urgent in Uruguay, because water drained from the country's main area of rice cultivation flows into the marshlands of the Eastern Biosphere Reserve (Reserva de Biosfera Humedales del Este). This reserve is managed as part of the United Nations' UNESCO Man and Biosphere Reserve Program, which promotes environmentally sustainable human development.
This reserve is also the he
|Contact: Jerold Last|
University of California - Davis