Atrazine and Atrazine Metabolites
Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) is a chlorotriazine herbicide used extensively for control of pre- and early post-emergent broadleaf and grassy weeds. It is used mainly in agricultural applications to promote growth of maize (corn), sorghum, sugarcane, and some other minor crops. It has also been linked to golf course and personal lawn maintenance, as well as past uses in highway and railroad applications.
Atrazine is broken down relatively quickly in soil and sediment by soil microorganisms. Chemical hydrolysis of atrazine in water of acidic or basic nature can be relatively rapid as well, but the compound is fairly stable in neutral waters such as most groundwater.1
In 2004, the European Union banned use of atrazine due to persistent contamination of groundwater at levels above regulatory allowances. This ban, however, followed restrictions established by both Germany and Italy 13 years earlier. Germany and Italy, both producers of maize, were quick to follow the European Union’s Drinking Water Directive, which established low tolerances for pesticides in drinking water.
In 2006, after rigorous review of current data, the US EPA determined atrazine to be within the parameters of safe use for human health.2 However, the US EPA is currently reevaluating atrazine due to the large amount of evidence of drinking water contamination, as well as indications of endocrine disruption and potential carcinogenicity. Results from testing of nearly 100 community water systems around the US are due to be released in 2011.
Of primary concern is the persistent detection of atrazine and its metabolites in water bodies, and in particular in drinking water sources. In 2010, the World Health Organization (WHO) released a background document titled “Atrazine and Its Metabolites in Drinking-water” to be used as part of its Guideline for Drinking Water Quality (GDWQ).3 Within this document the WHO outlines environmental levels and human exposure, kinetics and metabolism, and a toxicological summary of atrazine and its primary metabolites.
With maximum allowable levels in the low- to sub-ppb range, it is imperative to have an accurate analytical method for determination of atrazine and its metabolites. In addition, while many laboratories are utilizing liquid chromatographic (LC) methods for the analysis of these compounds in water, the occurrence of matrix effects can greatly impact the accuracy of quantification. For analysts looking to not only detect trace levels of atrazine and its metabolites, but to also accurately quantify at low levels, the use of stable-isotope-labeled standards in an isotope dilution method is vital. CIL has recognized the need for these standards and has answered the call with high-quality standard solutions.
References
1. Wikipedia – Atrazine: Biodegradation
2. US EPA Pesticides Registration – Atrazine updates March 2011
3. WHO/HSE/WSH/10.01/11 – Atrazine and Its Metabolites in Drinking Water (WHO 2010)