Open Literature Review Summary

Chemical Name: Atrazine CAS No: 1912-24-9

ECOTOX Record Number and Citation: Berard, A., U. Dorigo, 1. MerCier, K. Becker-van Slooten, D. Grandjean and C. Leboulanger. 2003. Comparison ofthe ecotoxicological impact ofthe triazines lrgarol 1051 and atrazine on microalgal cultures and natural microalgal communities in Lake Geneva. Chemosphere. 53: 935-944. (MRID 48261102)
Purpose ofReview: Determine potential effects ofatrazine on an aquatic community. Endpoints from this study contribute to the weight-of-evidence regarding effects ofatrazine on aquatic plant communities and associated determination ofa Level ofConcern (LOC).

Date ofReview: October 7,2009
Purpose ofStudy: Thepurpose ofthis study was to investigate the effects ofIrgarol1 051 on phytoplankton and periphyton and compare observed effects to those ofatrazine. Three experiments were performed with Irgarol 1051 (algal monocultures, natural lake communities, and indoor nanocosm communities) and for comparisontwo experiments were performed with atrazine (algal monocultures and natural lake communities).
Summary ofStudy Findings: This review summarizes effects from atrazine exposure. No methods were reported for the short-term toxicity testing on natural lake communities exposed to atrazine.

Methods: Nine algal species (Table 1) were separately cultivated in 96-well, clearpolystyrene microplates under continuous lightconditions 

### (ca. 100-150 llE/m2/s at the microplate lid). Growth was monitored daily via optical density measurements at 650 nrn (OD650) using a Dynex MRX CE97 spectrophotometer. Inocula were prepared from batch flask cultures in exponential growthphase which were diluted to yield an initial OD650 of**~0.120.** Nine atrazine concentrations ranging from 0.216-2160 llg/L were tested (seven ofthe tested concentrations were not reported). Atrazine (purity 98%) dissolved in acetone (final co-solventconcentration 0.05%) was added to



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# ,1 20R7Rn'3Isix microplate wells for each treatment concentration. Six untreated acetone (0.05%) controls !Were also included. Final OD650 measurements (endpoints) were taken at 96 hours, except for 

### ;Chlamydomonas intermedia, Staurastrum sebaldii, an?**Syn.echo~occus** 

### elongatus which were ,measured at 144 hours due to slower grovvth. TheoretIcal SIgmoId curves were fitted to the data iusing the least-squares method (Streibig 

### etal., 1998 and Seguin 

### etal., 2002).

I [Results: iEC50 results for the different algal monocultures are presented in Table 1.
I iTable 1. Estimated EC50 values for atrazine based on growth ofalgal monocultures (from Table 1 ofstudy). I Atrazine EC50

Taxal Endpoint (llg/L)

i Bacillariophyceae Asterionellaformsa 96 >2,160 Navicula accomoda 96 164 Nitzschia 96 412 Chlorophyceae Chlamydomonas intermedia 144 34 Chlorella vulgaris 96 4.3 Pseudokirchneriella subcapitata 96 115 Scenedesmus acutus 96 56 Cyanobacteria 144 NOE2 Zygnematophyceae

. Staurastrum sebaldii 144 282 [ 1 All strains were isolated from Lake Geneva, except forP. subcapitata, which was obtained from the USEPA i (Corvallis, Oregon) to be used as a laboratory reference species. i 2 No observed effect. I
i Phytoplankton and periphyton were collected from three locations in Lake Geneva (Ouchy, i Buchillon, and Thonon) in June and August of2000 and treated with atrazine (concentrations not i reported) to investigate short-term effects on chlorophyll 

### a fluorescence. Ouchy and Thonon
i were selected as sites potentially exposedto IrgarollOS 1, while Buchillon was considered a less

. exposed location. Atrazine concentrations in Ouchy, Thonon, and Buchillon onJune 29,2000 i were reported as 25.6, 26.3 and 30.7 ng/L, respectively. On the same date, measured ; concentrations ofIrgarol1051 were 140.3 (Ouchy), 32.2 (Thonon), and 1.6 ng/L (Buchillon).

Reported EC150 values (theoretical toxic concentration that increased fluorescence by 50%) i were 28.0-42.8 IJ,g/L and 206.2-605.9 IJ,g/L for phytoplankton from the Buchillon and Ouchy 

### I sites, respectively. For periphyton, reported EC50 values were 366.7 IJ,g/L (Buchillon) and [ 1,790.3 IJ,g/L (Thonon). I

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-Data Summary Table: No data table is presented because there were no reported endpoints that are relevantto the current analysis ofatrazine.
Reviewer Comments: No tabular or plotted results were presented to supportthe reported ECx values.

This study primarily investigated the effects ofIrgarol 1051 on phytoplankton and periphyton, with atrazine used as a comparative pesticide.
Description ofUse in Document: Invalid

Rationale for Use: For atrazine, there were no nanocosm community-level effects examined in this study. The only results presented for atrazine were for monoculture experiments and short-term toxicity experiments onphytoplankton and periphyton sampled in Lake Geneva. No information was provided on methodology (number ofdoses, concentrations, number ofreplicates, etc.) used for the short-term atrazine toxicity testing. Although ECx values were reported, individual atrazine concentrations tested and toxicity test results at each concentration were not provided, thus an exposure profile cannotbe determined for purposes ofdeveloping an LOC.

Limitations ofStudy: For atrazine, there were no nanocosm community-level effects examined inthis study. The only results presented for atrazine were for monoculture experiments and short-term toxicity experiments on phytoplankton and periphyton sampled in Lake Geneva. No information was provided on methodology (number ofdoses, concentrations, number ofreplicates, etc.) used for the short-termatrazine toxicity testing. No results were presentedto support the reported EC50 values. There was potential contamination with Irgarol 1051 and other pesticides.
Primary Reviewer: Lynne Binari, M.S., Subcontractorto Cambridge Environmental Inc. Secondary Reviewer: Michael Lowit, Ph.D., Ecologist, EPA

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