Atrazine control a must for drinking water 

By MINDY POEHL | Central Texas Edition

Monty Dozier, water quality Extension specialist, explains how atrazine contaminates water and how to properly control problems with water. � Photo by Mindy Poehl

Dec. 8, 2005 -  At the 17th Annual Texas Plant Protection Conference, held in College Station Nov. 30- Dec. 1, all things agriculture was the main topic. After hearing discussions on crops, fertilizers, and pesticides, Monty Dozier, water quality Extension specialist, spoke about the successful management strategy used to get rid of the high atrazine levels in Aquilla Lake.

�"Atrazine is the most widely used herbicide in Texas corn and grain sorghum production," Dozier said. " Atrazine is also used on sugarcane and on fallow wheat fields, in pine plantations and is found in some products available for use on home lawns, commercial turf grass and golf courses."

�In Aquilla, Texas, the local drinking water is supplied by a small reservoir. Between 1997 and 1998, atrazine was repeatedly detected in the tap water provided through the Aquilla system. The levels of atrazine exceeded the federal drinking water standard.�

�"The safe drinking water standard is set by the U.S. Environmental Protection Agency and is known as an MCL (maximum contaminant level), explained Dozier. "The MCL for atrazine is 3 parts per billion. In 1998, the MCL exceeded 3 parts per billion and this led to the development of a Total Maximum Daily Load (TMDL) for atrazine in the Aquilla Reservoir watershed, because the lake was listed on the Texas 303(d) list for infected water."

�After the development of the TMDL, an implementation plan was prepared. Working with area farmers, state and federal agency personnel, effectively dealt with levels of atrazine in the Aquilla Reservoir.

�"A major component of the implementation plan was the placement of best management practices (BMPs) designed to reduce off-target losses of atrazine in surface runoff," Dozier said. "The BMPs included preplant incorporation of atrazine, use of grass filter strips, vegetated waterways, sediment control structures and others."

�Texas Cooperative Extension and Texas Agricultural Experiment Station established a network of automatic and passive samplers in several locations of the watershed to collect runoff water generated by storms. They also collected routine stream water samples and lake sediment samples to be analyzed.

�"The monitoring effort and sampling was used to validate the effectiveness of BM and educational efforts in reducing atrazine concentrations," explained Dozier. "Now, the atrazine concentrations have been reduced by over 60 percent compared to the 1997-1998 levels, and the Aquilla Reservoir was removed from the Texas 303 (d) list for atrazine."

�Implementation of TMDL's can help preserve toxic waters back to efficiently controlled waters.