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 ( μ g/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 μ g/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 (inclu ding total score) were significantly different among the six Midwest sites and the three sites wi th 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 an d when differences were reported for the three periphyton metrics there was no consistent patt ern 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 evalu ated 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 at razine is the likely cause of the differences reported.

- The interpretation of these spatially and temporally limi ted periphyton and aquatic macrophyte data from six Midwest stream sites sampled in 2012 with varying degrees of atrazine exposure does not suggest that atrazin e has adversely impacted these resident plant communities.

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

Rationale for Use: The study contributes to the unders tanding of aquatic plant community composition within streams exposed to atrazi ne 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 conc entrations 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'