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Health Indicator Report of Community Water: Atrazine Concentration

Atrazine is a man-made white, crystalline solid organic compound, which is not highly volatile, chemically reactive, or flammable. It dissolves in water; it does not bind tightly to soil and can leach into ground and surface waters ( ). Atrazine is a widely used herbicide for control of broadleaf and grassy weeds ( ). It's one of the chloro-S-triazine herbicides, which act by inhibiting plant photosynthesis. Human health effects of exposure to environmental levels of atrazine are largely unknown. Atrazine does not bioaccumulate or build-up in the human body. Some metabolites of atrazine (particularly diaminochloroatrazine), may mediate some of its toxic effects ( ). It is unknown whether or not atrazine can cross the placenta from a pregnant mother to a developing fetus or be secreted in breast milk. Some human studies (epidemiologic and ecologic) of birth defects (e.g., gastroschisis, hypospadias, increases in upper limb reductions and obstructive genitourinary defects), developmental and reproductive toxicity, and carcinogenicity, have shown both positive and no associations with exposure to atrazine. However, there are many limitations of these studies, mainly related to methods used to assess exposure, including the fact that the effects cannot be attributed to atrazine alone; this is primarily due to multiple chemicals or multiple pesticides exposures of the studied populations or ecologic and/or retrospective nature (;;; Davis JA; Birth Defects Res A Clin Mol Teratol 73 (11): 926 (2005); Rocheleau et al., J Pediatr Urol 5: 17 (2009)). The most recent prospective population-based cohort study showed associations between urinary biomarkers of prenatal exposure to atrazine and adverse effects on fetal growth (specifically, birth weight, birth length and small head circumference (Chevrier et al., Environ Health Perspect 119: 1034 (2011)). Reproductive and developmental toxicity (including decreased body weight, myocardial muscle degeneration, liver toxicity, developmental ossification defects, impaired fertility, altered estrus cycles, increased pituitary weight, delayed onset of puberty, and reduced levels of luteinizing hormone, prolactin, and testosterone) are primary effects resulting from chronic, high levels exposure to atrazine in laboratory animals (; Nevertheless, some of these effects are unlikely to occur in humans due to biological differences between humans and the studied animals. Atrazine product formulations can act as mild skin sensitizers and irritants. At acute, high level exposure, triazinic herbicides (such as atrazine) may induce fatigue, dizziness, nausea, irritation of the skin, eyes and respiratory tract, or allergic eczema, but these effects are unlikely to occur from drinking water environmental exposure. Atrazine is not mutagenic and it is not genotoxic. The International Agency for Research on Cancer (IARC) has determined that atrazine is not classifiable as to its carcinogenicity to humans (Group 3) ( and the US Environmental Protection Agency (EPA) classified atrazine as unlikely to be carcinogenic to humans (


Data Source: New Mexico Environment Department's Drinking Water Bureau, New Mexico Safe Drinking Water Information System (SDWIS). Measured atrazine concentrations in finished drinking water can be used to understand the distribution of potential atrazine exposure level for populations served by community water supplies. Due to potential errors in estimating service population, the measures may overestimate or underestimate the number of potentially affected people. These measures allow for comparison of potential atrazine exposure between the populations served by different water systems over time.

Data Source

New Mexico Environment Department, Drinking Water Bureau

Data Interpretation Issues

To measure atrazine concentration in CWS, drinking water samples are usually taken at entry points to the distribution system or representative sampling points after water treatment has occurred. Measures do not account for the variability in sampling, number or sampling repeats, etc. Furthermore, concentrations in drinking water cannot be directly converted to exposure because water consumption varies by climate, level of physical activity, and between persons. Due to potential errors in estimating service population, the measures may overestimate or underestimate the number of potentially affected people. In addition, the older data (i.e., 1999 through 2004) may be of poor quality that could results in over- or underestimated atrazine concentration in CWS drinking water during 1999-2004.


Atrazine concentrations (in micrograms of atrazine per liter of water or mcg/L) in community drinking water systems (CWS) are combined with information about each CWS (such as service population) to generate the following measures shown in this report: 1) statewide atrazine concentration distribution in CWSs by mean and maximum over time, 2) annual distribution of mean and maximum atrazine concentration for persons served by CWS and 3) annual distribution of mean and maximum atrazine concentration by CWS. EPHT data queries -- -- provide detailed results by year for 1) mean atrazine concentration by CWS for a select year, 2) maximum atrazine concentration by CWS for a select year, 3) mean atrazine concentration and the number of CWS by year, 4) maximum atrazine concentration and the number of CWS by year, 5) mean atrazine concentration and the number of persons served by year, 6) maximum atrazine concentration and the number of persons served by year, 7) quarterly distribution of number of CWS by mean atrazine concentration or 8) quarterly distribution by number of people served by mean atrazine concentration. Additionally, users may query the number of persons served and the number of CWS in the state for a select year. A CWS is a public water system (PWS) that serves year-round residents of a community, subdivision, or mobile home park that has at least 15 service connections or an average of at least 25 residents. These CWSs are a subset of all New Mexico PWSs. To measure atrazine concentration in CWS, drinking water samples are usually taken at entry points to the distribution system or representative sampling points after water treatment has occurred.


Concentration of atrazine.


Not applicable

How Are We Doing?

Atrazine was first registered as an herbicide in 1958, however, its uses have been greatly restricted since 1993. It is designated as a Restricted Use Pesticide, meaning that it can only be purchased and used by certified pesticide applicators; the general population is not permitted to buy or use atrazine. Liquid formulations of atrazine are likely to contain a hydrocarbon solvent. Atrazine is used mainly on farms, on crops including sugarcane, corn, pineapple, sorghum, and macadamia nuts, and on evergreen tree farms, as well as to control weeds growing on the highways and railroad tracks ( ). It can be applied (sprayed) pre- and post-emergence to agricultural fields or crops to kill weeds. In addition, atrazine is used in residential turf applications and on golf courses and sod farms to control weeds.

What Is Being Done?

Atrazine can enter drinking water mainly as run-off into surface water sources or through leaching into ground water from herbicide-contaminated soils in areas of its applications. Through its extensive use on soils and as an herbicide, atrazine may enter the environment. It may leach out of soil and be washed away in surface runoff to reach streams, rivers, lakes, and enter ground water. When applied to soils, it may remain there for several months, but sometimes can remain even a few years ( ). However, atrazine is not expected to bioaccumulate in the environment. It can be taken up by all plants. It can remain for a long time in bodies of water due to its slow degradation process in rivers and lakes. It can also persist in ground water for a long time. In surface water, the half-life of atrazine is more than 200 days. When released into the air, its half-time ranges from 14 to 109 days. It can attach onto particulates in the air and travel long distances away from its application sites. For the general public, ingestion of contaminated drinking water and inhalation of contaminated outdoor air near the sites of its application are the primary pathways of potential exposure to atrazine ( Animal data indicate that about 80% of atrazine administered directly into rats stomach (by gavage) was absorbed (no human data are available following oral exposure). In humans, atrazine was slowly and poorly absorbed through the skin (only from 0.3 to 5.1% was absorbed dermally in 20 hours). Once absorbed by humans, atrazine is rapidly distributed through the blood stream to organs and tissues (such as fat tissue), metabolized, and primarily excreted through the kidneys in the urine over 24-48 hours. Atrazine levels in drinking water from most (about 99% in 2014) community water systems (CWS) in New Mexico were below the Environmental Protection Agency (EPA)-established drinking water standard or Maximum Contaminant Level (MCL) for atrazine of 3 micrograms per liter (3 mcg/L) or 3 parts per billion (3 ppb) (Safe Drinking Water Act (SDWA)). This MCL is the highest level of atrazine which is allowed in drinking water and it is the enforceable standard. Community systems' drinking water is routinely monitored and tested for atrazine to comply with the 3 mcg/L EPA standard for atrazine. Every year, each CWS sends their customers a consumer confidence report (also called a water quality report) that lists any levels of atrazine measured. EPA also requires all CWS to give their customers public notice when their water supply violates the atrazine standard. This would include information about what is being done to correct the situation. However, people who use their private wells water for drinking are solely responsible for testing the water for atrazine (for information about laboratories certified to test drinking water and certified home treatment units visit Some people who drink water containing atrazine in excess of EPA's standard and over many years may experience reproductive difficulties, although there is no conclusive scientific evidence that these effects occur in humans.

Page Content Updated On 04/17/2019, Published on 04/17/2019
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Content updated: Wed, 17 Apr 2019 15:35:59 MDT