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 of the ecotoxicological impact of the triazines lrgarol 1051 and atrazine on

microalgal cultures and natural microalgal communities in Lake Geneva. Chemosphere. 53:

935-944. (MRID 48261102)

Purpose of Review:

Determine potential effects of atrazine on an aquatic community. Endpoints from this study

contribute to the weight-of-evidence regarding effects of atrazine on aquatic plant communities

and associated determination of a Level ofConcern (LOC).

Date ofReview: October 7,2009

Purpose of Study:

The purpose ofthis study was to investigate the effects ofIrgarol1 051 on phytoplankton and

periphyton and compare observed effects to those of atrazine. Three experiments were

performed with Irgarol 1051 (algal monocultures, natural lake communities, and indoor

nanocosm communities) and for comparison two experiments were performed with atrazine

(algal monocultures and natural lake communities).

Summary of Study 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, clear polystyrene microplates

under continuous light conditions (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 growth phase

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-solvent concentration 0.05%) was added to

- 1 - 11••••••,1 20R7Rn'3
Isix 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~occuselongatus which were

,measured at 144 hours due to slower grovvth. TheoretIcal SIgmoId curves were fitted to the data

iusing the least-squares method (Streibig et al., 1998 and Seguin et al., 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 of algal monocultures (from Table 1 ofstudy).

I Atrazine EC50

Taxal Endpoint (llg/L)

i Bacillariophyceae

Asterionella formsa 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 for P. 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 of 2000 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 exposed to Irgaroll OS 1, while Buchillon was considered a less

. exposed location. Atrazine concentrations in Ouchy, Thonon, and Buchillon on June 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 relevant to the

current analysis of atrazine.

Reviewer Comments:

No tabular or plotted results were presented to support the reported ECx values.

This study primarily investigated the effects of Irgarol 1051 on phytoplankton and periphyton,

with atrazine used as a comparative pesticide.

Description of Use 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 on phytoplankton and periphyton sampled in Lake Geneva. No information was

provided on methodology (number of doses, 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 cannot be determined for purposes of developing an LOC.

Limitations of Study:

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 on phytoplankton and periphyton sampled in Lake Geneva. No information was

provided on methodology (number of doses, concentrations, number ofreplicates, etc.) used for

the short-term atrazine toxicity testing. No results were presented to support the reported EC50

values. There was potential contamination with Irgarol 1051 and other pesticides.

Primary Reviewer: Lynne Binari, M.S., Subcontractor to Cambridge Environmental Inc.

Secondary Reviewer: Michael Lowit, Ph.D., Ecologist, EPA ~I/t;w/~
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