Open Literature Review Summary 

Chemical Name: Atrazine

CAS No: 1912-24-9

PC Code: 080803

ECOTOX Record Number and Citation: 

Hall, Jr., L.; Killen, W.; Brain, R.; et al. (2014) Atrazine: Assessment of Periphyton, Aquatic 

Macrophytes, Benthic Communities, and Physical Habitat in Midwestern United States Streams 

Coinciding with Varying Historical Concentrations of Atrazine. Journal of Environmental Science 

and Health Part A 49(2014):1091-1099. MRID 49535804. 

Date of Review: March 1, 2016

- This research article describes the condition of natural streams with varying degrees 

of atrazine contamination. 

- The study sites were selected from a few of the AEEMP monitoring program and that 

have been the subject of study in other studies (Andrus et al. 2013; Andrus et al. 

2015). 

Table 1: Peak and 60-day maximum running average concentrations (μg/L) of measured 

atrazine concentrations reported in the AEEMP monitoring program (EPA calculated averages). 

Shaded cells indicate exceedances of the CELOC (60-day maximum average = 3.4 μg/L) 

Year IA-03 IL-10 IL-17 MO-05 MO-07N OH-05 

Peak 60-

day 

Avg 

Peak 60-

day 

Avg 

Peak 60-

day 

Avg 

Peak 60-

day 

Avg 

Peak 60-

day 

Avg 

Peak 60-

day 

Avg 

2010 50.6 10.5 5.0 0.4 36.7 5.7 84.2 12.9 92.5 20.2 11.0 2.0 

2011 39.8 4.9 11.5 1.4 228.2 17.2 70.5 6.2 90.9 14.6 30.6 1.4 

2012 17.8 2.0 5.4 0.7 39.4 6.3 14.0 4.0 41.1 11.9 14.8 1.9 

The study authors concluded: 

- Water quality conditions such as temperature, pH and salinity were similar at all sites but 

dissolved oxygen, conductivity and turbidity were different. 
- Five of the eight physical habitat metrics (including total score) were significantly different 

among the six Midwest sites and the three sites with the highest total physical habitat scores 

had both low-range and high-range previous exposure to atrazine. 

- There were no significant differences in the structure of periphyton communities with 

various degrees of previous atrazine exposure as 9 of the 12 periphyton metrics evaluated at 

each site were not significantly different and when differences were reported for the three 

periphyton metrics there was no consistent pattern with previous levels of atrazine exposure. 

- Aquatic macrophyte spatial coverage was not significantly different among the six Midwest 

sites with varying levels of previous atrazine exposure. 

- All ten of the benthic community metrics evaluated at each of the sites showed significant 

differences among sites; however, it is highly likely that physical habitat characteristics and 

not previous exposure to various levels of atrazine is the likely cause of the differences 

reported. 

- The interpretation of these spatially and temporally limited periphyton and aquatic 

macrophyte data from six Midwest stream sites sampled in 2012 with varying degrees of 

atrazine exposure does not suggest that atrazine has adversely impacted these resident plant 

communities.

Description of Use in Document (QUAL, QUAN, INV): QUAL 

Rationale for Use: The study contributes to the understanding of aquatic plant community 

composition within streams exposed to atrazine and other agricultural and anthropogenic 

stressors. 

Limitations: The primary limitation in this study is the lack of a set of reference streams which 

have had limited or no atrazine exposure. The authors have discussed a rank of exposure from 

low to moderate to high, however for 2012 all of the exposures were similar and below the 60-

day CELOC threshold established in 2009, with the exception of MO-07 which exceeded the 

10ppb CELOC. The streams have peak values that reach toxic levels for individual species based 

on laboratory testing, and 60-day average concentrations for IA-03, IL-17, MO-05, and MO-07 

exceed the 2015 CELOC of 3 ug/L. However, these exceedances of the CELOC represent a 50% 

chance of an effect on the communities, so not seeing a strong and direct atrazine influence in 

the study results is not unanticipated, especially given the prior exposure history to atrazine, 

the predominance of pollution tolerant diatoms, and the similarity of agricultural histories 

expected in these streams. 

Primary Reviewer: Frank T. Farruggia Ph.D., EPA/OCSPP/OPP/EFED/ERB3 

Digitally signed by FRANK 

FARRUGGIA 

DN: c=US, o=U.S. Government, 

ou=USEPA, ou=Staff, cn=FRANK 

FARRUGGIA, 

dnQualifier=0000048865 

Date: 2016.03.24 09:01:42 -04'00'