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With rising populations and limited availability, coupled with the impacts of a changing climate, water must be safely and sustainably managed. Atrazine concentrations in surface water have declined dramatically over the last two decades and pose no threat to humans. The herbicide is also critical in helping enable no-till farming, which reduces soil erosion.

Drinking Water

Woman pouring a glass of water

Atrazine is one of the most studied molecules in history. More than 7,000 studies attest to its safety, which is why the EPA has repeatedly reapproved its use after extensive, successive reviews as part of the ongoing re-registration process. In 2011, after reviewing the latest safety data, the World Health Organization raised its recommended atrazine limit in drinking water from 2 to 100 parts per billion. In the U.S., the limit remains much lower — at 3 parts per billion, though the Office of Pesticide Programs has calculated it could safely be set 193 times higher at 580 parts per billion. Australian regulators decided in 2008 to maintain their standard at 40 ppb. The fact is, a 150-pound adult could drink hundreds of gallons of water containing the EPA limit of 3 ppb atrazine every day for 70 years and would still not reach a level of exposure shown to have any effect in laboratory studies.

The Syngenta/EPA Atrazine Monitoring Program (AMP) monitored at-risk community water systems on a weekly basis. This program continually proved that the state-run quarterly Safe Drinking Water Act monitoring program protected human health through quarterly sampling. When the weekly monitoring data was averaged over a year, no human health thresholds were ever exceeded. From 2004-2019, the program demonstrated the safety of drinking water in the most vulnerable drinking water systems and also determined that the Safe Drinking Water Act was protective for the 3ppb Maximum Containment Level (MCL). For this reason, the U.S. EPA allowed the discontinuation of the AMP. Drinking water is still protected and monitored by the state-run quarterly Safe Drinking Water Act monitoring program. Additionally, all community water systems (CWS) are monitored for atrazine levels under the Safe Drinking Water Act. Results of that program are annually reported to EPA and the CWS also report local results to consumers of the drinking water.

The Atrazine ecological exposure monitoring program was started in 2004 to monitor atrazine levels in watersheds across the United States. It is the most robust monitoring program for atrazine ever carried out. It includes daily sampling data throughout the atrazine use season. On October 22, 2019, EPA issued an Atrazine Regulatory Update (October 2019) that re-evaluated and raised the concentration equivalent level of concern (CE-LOC) used to assess atrazine’s potential effects on aquatic plant communities from 10 µg/L to 15 µg/L. EPA reconfirmed the CE-LOC of 15 µg/L in its Atrazine Proposed Interim Registration Decision (December 2019) and Atrazine Interim Registration Decision (September 2020).

Soil Runoff

The Earth’s surface may be about 70% water, but less than 1% of that is available as freshwater to humans. Today, more than 68 countries suffer from water shortages, and some 2.1 billion people lack access to safe water. Experts believe that with a rising world population, food production must double. It is clear that agriculture, which consumes 70% of the world’s usable water, must be a leader in managing water resources. That’s why atrazine is such a crucial tool in the farmer’s toolkit. The herbicide enables conservation tillage and related practices, which have helped decrease soil erosion in U.S. farmland by 34% between 2005 and 2016. It is leading to the complete elimination of pesticide runoff into streams and rivers in certain areas.

Soil runoff is an enemy of aquatic creatures. It buries fish and crustacean habitats and reduces sunlight, starving plants and algae, and undermines food chains. Sediment also carries ammonium nitrogen, which is toxic to fish, as well as nitrate and phosphate, which deplete oxygen in water. Atrazine-enabled no-till and conservation tillage agriculture help reduce the sedimentation and toxicity caused by soil runoff, providing aquatic wildlife a safer and cleaner habitat.

Cracked Soil

Read the Science

Learn more about the science behind atrazine.