### Open Literature Review Summary

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

ECOTOX Record Number and Citation: deNoyelles, F., S.L. Dewey, D.G. Huggins, and W.D. Kettle. 1994. Aquatic mesocosms in ecological effects testing: detecting direct and indirecteffects ofpesticides. In: Graney RL, Kennedy J.H., Rodgers J.H. Jr. 

### (Eds.). Aquatic mescocosm studies in ecological risk assessment. Lewis Publishers, BocaRaton, FL. Pp. 577-603 (MRID 47543609).

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: November24, 2009

Purpose ofStudy: This study examines the potential effects ofatrazine to aquatic plants and animals in experimental ponds (mesocosms).

Summary ofStudy Findings:

Methods: The study's methods are described in far more detail in otherpapers by deNoyelles and colleagues. In particular, this study often references deNoyelles 

### etal., 1989, reviewedpreviously.

The study's data are from the 80S-day study (see deNoyelles 

### etal., 1989 review), which usedten 0.045-ha earthen pond mesocosms. Two replicates each at nominal atrazine concentration level of0 (control), 20, 100, 200, and 500**~g/L** 

### were used. Atrazine application occurred in a single addition at the beginning ofeach summerto the treatment ponds, over 3 successive years (1981-1983) for the 20, 100, and 200**~g/L** 

### treatment ponds and over2 successive years (1982-1983) for the 500**~g/L** 

### treatmentponds. (The first application for the 20-200**~g/L** 

### ponds was June 21, 1981, andthe first treatmentfor the 500**~g/L** 

### ponds was May 30, 1982.) Actual concentrations were measured


# '1.1•••111 2087827

### immediately after addition (differed by <10% ofnominal) andperiodically during the experiment, with declines to 70% and 25% oforiginal measuredconcentrations after 6 and 12 months, respectively. Four species offish were stocked to represent different food web niches: 

### Ctenopharyngodon idella (grass carp, amacrophyte grazer), 

### Dorsoma cepedianum (gizzard shad, afilter-feeding omnivore), 

### Ictaluruspunctatus (channel catfish, abenthic-feeding omnivore), and

### Lepomis macrochirus (bluegill sunfish, a visual predator).

Forfurther details, including statistical analyses ofresults, the authors reference deNoyelles 

### etaf., 1989. Other studies are referenced for further descriptions ofparticular methods, including Carney, 1983 (previously reviewed), Dewey, 1986 (review forthcoming), Huggins, 1990 (aUniversity ofKansas Ph.D. thesis, notpresently included inthe literature review), and Huggins, Johnson, and deNoyelles, 1994 (a structural equation modeling study from the same volume as this study, Ch. 33, notpresently included in the literature review).

Beforethese study results are presented, the authors summarize a large numberof mesocosm studies thatmeasured direct and indirect effects ofvarious pesticides and were conducted priorto the issuance ofthe 1988 EPA mesocosm technical guidance document forpesticide registration studies (EPA-600/4-85/013, "Methods for measuring the acute toxicity ofeffluents to freshwater and marine ecosystems"). The summary for atrazine will be presented in this review, before the study results (see below).



### Results: Summary

## 0/ atrazinemesocosmstudy resultspriorto 1988 Effects are tabulated for differenttypes ofmesocosm studied, with direct or indirect increases or decreases noted for phytoplankton, periphyton, macrophytes, rotifer and crustacean zooplankton, macroinvertebrates, insects, and fish, with alteration ofphysical or chemical parameters also noted. Foratrazine, phytoplankton were generally indirectly increased, periphyton andmacrophytes were directly decreased, and fish were indirectly decreased, with lack ofobservations and/orno consistenteffects reported for zooplankton, macroinvertebrates, and insects. Most studies also noted indirect alteration to physical and/or chemical parameters. See Table I.



### Results/rom the 80S-day, 1981-1983 

### study In the 80S-day study, declines in phytoplankton occurred within the first few days ofthe first exposureto atrazine, butreturnedto (or exceeded) control pond levels within one month. However, after subsequenttreatments no short-term declines occurred. Species composition remained altered, andthe phytoplankton community as awhole was demonstrated to develop tolerance orresistance to atrazine. See Figure 1 for the study's depiction ofthe data (graphs 

### a and b 

### showproduction in mg C/m3

### /h for 1982 and 1983,

2and c and 

### dshow biomass in chI 

### a Ilg/L for 1982 and 1983, respectively). DeNoyelles 

### et aI., 1989 is cited for methods.

Grazing rotifer and crustacean zooplankton, the planktonic insect 

### Chaoborus, and the filter-feeding gizzard shad all were unaffected by atrazine treatment eitherdirectly or indirectly. These animals all depend on phytoplankton for their food base, and were apparently unaltered by changes in the species composition ofthe phytoplankton community. Channel catfish, benthic omnivores, were also unaffected by atrazine treatment. See Figure 2, graphs 

### a, b, and h (gizzard shad, channel catfish). DeNoyelles 

### etaI., 1989 is cited for methods.

Macrophytes were strongly affectedby atrazine treatment: the submergentmacrophyte community in general, "particular species" (the authors referthe readerto deNoyelles 

### et aI., 1989 and Carney, 1983), and the emergent community (primarily cattails, 

### Typha latifola and 

### T angustifolia) all were reduced, especially at concentration at or above 100 Ilg/L, and did notrecover. Atthe 20 and 100 Ilg/L treatment levels, there was arelative increase of

### Chara, butno otherindications ofcommunity tolerance orresistance were noted. See Figure 1, graphs 

### e andjfor some ofthe data (submersed macrophyte coverage ofthe pond bottom). DeNoyelles et aI., 1989, Carney, 1983, and Huggins et aI. from Ch. 33 ofthe same volume as this study are cited for methods.

Grass carp, a macrophyte grazer, declined in both individual biomass and total biomass perpond atatrazine concentrations at or above 100 Ilg/L, where macrophyte densities
were low. Although macrophyte densities were also lower in the 20 Ilg/L pond, grass carp did not decline there as much, which the authors attribute to highermacrophyte growth rates atthe low treatment level (thereby maintaining an adequate food supply). See Figure 2, graph h. Grass carp grazing, in turn, affected the response ofboth submergent and emergentmacrophytes. With grass carp present, the added grazing pressure reduced macrophyte densities compared to areas ofthe same ponds fenced off from the grass carp. Although atrazine alone was enough to maximally reduce submergent macrophytes at concentrations of200 Ilg/L orabove, at 100 Ilg/L, onlythe
areas with grass carp achieved similarreductions. At the low 20 Ilg/L concentrations, grass carp-affected areas had similarmacrophyte coverto the control ponds' grass carpaffected areas. In one ofthe control ponds (24C), grass carp were lost in September 1982, "probably due to transient vertebrate predation (snapping turtle)" in the authors' words. This pond had more macrophyte coverthan the othercontrol pond in 1983. (However, in the 500 Ilg/L pond 26C, grass carp were also lost in September 1982, but macrophyte reduction in 1983 was still near-total.)

Some insects that did not feed on macrophytes butused them for theirhabitat or for epiphytic algal food declined with atrazine treatment. Such insects included Chironomidae (mostly herbivores and detritivores in the epiphytic microhabitat), in particular

### Endochironomus (an herbivore on epiphytic algae) and

### Ablabesmyia (predator

3

### on microcrustacea and Chironomidae including Endochironomus). 

### See Figure 1, graphs g and h 

### (note: total emerging insects were dominated by Chironomidae) and Figure 2, graphsjandg. DeNoyelles eta!', 

### 1989, Dewey, 1986, and Huggins, 1990 (Ph.D. thesis) are cited for methods.

Frogpopulations naturally colonizedthe ponds, and declines in tadpole biomass (primarily Rana catesbeiana) 

### occurred at all atrazine concentrations. The authors attribute the effectto declines in macrophytes and shoreline vegetation affecting egg deposition and survival as well as to declines in periphyton feeding sites. See Figure 2, graph h

### (tadpoles).
Bluegill sunfish declined in total biomass in all ponds at or above 100 )Jg/L atrazine concentration. The authors attributethis effectto decline inthe emerging insect populationthatprovide amajorfeeding base for adultbluegill. See Figure 2, graph h 

### (note thatbluegill >7cm are all adults; not all bluegill <7 cm are adults).

The amphipodHyallela azteca 

### increased in abundance with atrazine treatment. Other insects, like Caenis 

### spp., Dicrotendipes simpsoni, Parachironomus 

### spp., and Glyptotendipes 

### spp. were more abundant at levels of20, 100, and 200 )Jg/L, but only when comparedto the high macrophyte control pond (24C, the one where grass carp were lost). At 500 )Jg/L treatment, these species were less abundantbut still greaterthan the low macrophyte control (pond 26C). The Ceratopogonidae had a similardistribution overthe treatment levels, but didnot differbetween the two control ponds. The authors propose several possible indirectmechanisms potentially responsible forthese effects. See Figure 2, graphs c, d, 

### and e. 

### Huggins, 1990 (Ph.D. thesis) and Huggins eta!., 1994 

### (same volume as this study) are cited for methods.

4Table 1. Direct and indirecteffects ofatrazine detected from mesocosm studies conducted prior to the original mesocosm guidance document (Touart, 1988) for pesticide registration studies. From study table 1.

Mesocosm Phyto- Periphyton Macrophytes Rotifer Crustacean Macro- Insects Fish Physical/ References plankton zooplankton zooplankton invertebrates Chemical farm ornatural direct ponds, indirect direct direct not indirect direct decrease, indirect indirect constructed increase decrease decrease monitored increase decrease indirect decrease alteration I ponds, stocked decrease with fish experimental direct earthenponds, decrease, direct direct not indirect not not indirect indirect 2 stocked with indirect decrease decrease monitored decrease monitored monitored decrease alteration fish increase experimental direct earthenponds, decrease, not direct not indirect no effects no effects no effects no effects 3,4

stocked with indirect monitored decrease monitored decrease fish mcrease experimental direct indirect earthenponds, decrease, direct direct no effects no effects no effects increase & indirect indirect 5,6

stockedwith indirect decrease decrease decrease alteration fish increase decrease direct direct limnocorrals decrease, decrease, not not not not not not indirect 7, 8 indirect indirect monitored monitored monitored monitored monitored monitored alteration increase increase I Walker, C.R. 1961. Weeds 12:134-139 2 deNoyelles, F., Jr., W.D. Kettle andD.E. Sinn. 1982. Ecology 63: 1285-1293 3 Gunkel, G. 1983. Arch. Hydrobio!. Supp!. 65:235-267 4 Gunkel, G. 1984. Arch. Hydrobio!. Supp!. 69:130-168 5 deNoyelles, F., Jr., W.D. Kettle, C.H. Fromm, M.F. Moffet and S.L. Dewey. 1989. Misc. Pub. No. 75, Entom. Soc. ofAmerica, 41-56. 6 Dewey, S.L. 1986. Ecology 67:148-162 7 Hemlan, D., N.K. Kaushik, K.R. Solomon. 1986. Can. J. Fish. Aquat. Sci. 43: 1917-1925 8 Hamilton, P.B. 1987. Environ. Pollut. 46:83-103



### 5

# Ji 8

Figure 1. Distribution ofaquatic organisms in 0.045-ha pond mesocosms treated with atrazine at 20 /-lg/L (22L, 23L), 100 /-lg/L (11M, 15M), 200 /-lg/L (14MH, 16MH), and 500 /-lg/L (21H, 25H) plus controls (24C, 26C). Graphs a, c, e, g are from 1982, and b, d,j, h are from 1983.

6lOOOO :lOtiO

- 0

Figure 2. Distribution ofaquatic organisms in pond mesocosms as described in Figure 1. Results are all from 1983.

7

### Data Summary Table: Effect Magnitude of Nominal Day of Time Weighted Did Comments Effect Atrazine Study Average Recovery relative to Concentration tYrect Atrazine**Occur~** 

### if controls (f.1g/ L) Occurred Concentration so, when from Day 0to (see

When Effect comment)? Occurred' Phytoplankton biomass and d . J pro uctlOn Change in phytoplankton species composition J Submerged macrophyte coverI Total 85% 20 Ilg/L 464 13.1 Ilg/L Effects and 90% 100 JJg/L 464 65.4 JJg/L dates emergmg no estimated insects 70% 500 ).1g/L 121' 404.6 ).1g/L from Figure I >100% 20 ).1g/L 807 12.6 ).1g/L (increase) Effects and Hyallela (# >100% 100 ).1g/L 764 62.2 ).1g/L not dates per sampler) (increase) applicable estimated >100% 500 ).1g/L 464' 326.8 ).1g/L from Figure 2 (increase) >100% 20 ).1g/L 842 12.7).1g/L (increase) Effects and Ceratopo- >100% not dates gonidae (# per (increase) 100 ).1g/L 842 63.4 ).1g/L applicable estimated sampler) >100% from Figure 2 (increase) 500 ).1g/L 499' 328.5 ).1g/L 300% 20 ).1g/L 842 12.7).1g/L not Effects and Parachiro- (increase) applicable dates nomus (# per 50% 100 ).1g/L 842 63.4 flg/L no estimated sampler) 100% 500 ).1g/L 499' 328.5 flg/L no from Figure 2 Endochiro- 80% 20 JJg/L 785 12.5 Ilg/L Effects and 90% 100 flg/L 785 62.7 flg/L dates nomus (# per no estimated sampler) 100% 500 flg/L 442' 324.5 flg/L from Figure 2 Ablabesmyia 100% 20 Ilg/L 701 12 flg/L Effects and 100% 100 Ilg/L 701 60.1 Ilg/L dates (# per no estimated sampler) 100% 500 flg/L 358' 303.8 flg/L from Figure 2**~30%** 20 Ilg/L 842 12.7 flg/L Effects and Tadpoles**~60%** 100)J.g/L 842 63.4 Ilg/L dates (biomass per**~90%** 200 flg/L 842 126.7 flg/L no estimated pond)**~60%** 500 )J.g/L 499' 328.5 )J.,g/L from Figure 2

8Note: 

### *Days are calculated SInce InItial atrazIne addItIOn (5/30/1982 for the 500 f!g/L treatmentponds)

I See DataSummary Table in review ofdeNoyelles et a!., 1989. Effect Magnitude of Nominal Day of Time Weighted Did Comments Effect Atrazine Study Average Recovery relative to Concentration Effect Atrazine Occur- if controls (Jlg/L) Occurred Concentration so, when from Day 0 to (see

When Effect comment)? Occurret 0% (similar) 201lg/L 842 12.7Ilg/ L Effects and Grass carp**~75%** 1001lg/L 842 63.4 Ilg/L dates (biomass per**~60%** 200 Ilg/L 842 126.7 IlgiL no estimated pond)**~75%** 500 Ilg/L 499* 328.5Ilg/L from Figure 2 Bluegill 0% (similar) 201lg/L 842 12.7Ilg/L Effects and sunfish**~75%** 1001lg/L 842 63.4 Ilg/L dates (biomass per >90% 2OOllg/L 842 126.7 Ilg/L no estimated pond)**~75%** 5001lg/L 499* 328.5Ilg/L from Figure 2

. .. ..



### Time weighted average concentrations could notbe calculated with confidence. The effect days are rough estimates, and the study does notprovide data on atrazine concentrations oradditions apart from stating that atrazine was added to bring concentrations up to within 10% ofnominal occurred atthe beginning ofeach summer, and atrazine had reduced to 70% ofthe original concentration after 6 months and 25% after 12 months. Fromthese statements, and briefexamination ofFigure 1 in the deNoyelles etal. 1989 review, the following assumptions were made to allow calculation oftime-weighted averages: 1. Effect days are accurate (even though concentrations are available from Day 842 of "80S-day study") 2. Application every 350 days (based on deNoyelles etal. 1989 review, Figure 1) 3. Since mostrecent application, lineardecline in first 180 days to 70% oforiginal 4. Original 

### =90% ofnominal 5. 

### In prior application intervals, piecewise linear decline (70% after 180 days, 25% after 350 days) See below forthe calculated time-weighted average concentrations, and the linked Excel spreadsheet for more details.2

2An importantnote: in this paper, the authors state the following: "The exposure was a single addition of atrazine atthe beginning ofeach summerto the same ponds with 20-, 100-, and 200-f!gll treatments for 3 successive years (1981 to 1983), and the 500-f!g/1 treatment for 2 successive years (1982, 1983)." No further details are provided, orcomplications to this simple method mentioned. However, Dewey, 1986, Carney, 1983, and deNoyelles etaI., 1989 all describe a more complex treatmentmethod: the two 500 f!g/L ponds were created out of20 f!glL ponds previously treated with commercial atrazine, and one ofthe 200 Ilg/Lponds was not created until 1982, and then outofa 100 Ilg/L commercial treatmentpond. The TWAs calculated for this study reflectthe informationprovided in this 1994 study, notthe information in these other studies.

9Nominal Cone. 20 IJg/L 20 IJg/L 20 IJg/L 20 IJg/L 20 IJg/L 100 IJg/L 100 IJg/L 100 IJg/L 100 IJg/L 100 IJg/L 200 IJg/L 500 IJg/L 500 IJg/L 500 IJg/L 500 IJg/L 500 IJg/L Original Cone. (lJg/L) 18 18 18 18 18 90 90 90 90 90 180 450 450 450 450 450 No. of Application Days Effect Day TWA Intervals Since Last Cone. Cone. Effect Day Completed Addition (lJg/L) (lJg/L) 464 1 114 14.6 13.1 701 2 1 18.0 12.0 785 2 85 15.5 12.5 807 2 107 14.8 12.6 842 2 142 13.7 12.7 464 1 114 72.9 65.4 701 2 1 89.9 60.1 764 2 64 80.4 62.2 785 2 85 77.3 62.7 842 2 142 68.7 63.4 842 2 142 137.4 126.7 121 0 121 359.3 404.6 358 1 8 444.0 303.8 442 1 92 381.0 324.5 464 1 114 364.5 326.8 499 1 149 338.3 328.5



### Reviewer Comments: One cannotreview this study solely on its own merits, because it summarizes and synthesizes the results ofmany other studies andrefers to these other studies extensively for technical details ofmethods and results. Notall studies so referenced are part ofthis open literaturereview. Forthe ones that are, please seethose reviews for reviewer comments. All reviewer comments forthose reviews are directly applicable to this study, insofar as the methods andresults are used or discussed inthis study.

Reviews applicable to this study: deNoyelles 

### etal., 1989 (everything relating to the 805- day study), Carney, 1983 (macrophytes in experimental ponds), Dewey, 1986.

Studies referencedthatare notpart ofthis literature review: Huggins, 1990 (a University ofKansas Ph.D. thesis), and Huggins, Johnson, and deNoyelles, 1994 (from the same volume as this study, Ch. 33).

In terms ofdatapresentation, the study was rather unclear. No statistics were presented. It

### was difficultto estimatethe magnitude ofthe effects from the figures; therefore, effect magnitudes, day ofeffect, and (as previously described) time weighted average concentrations are all extremely crude estimates despite theirnumeric appearance. Overall, the emphasis was far more qualitative than quantitative.



### Description ofUse in 

### Document (QUAL, QUAN, INV): Qualitative

10

# 0!l3/tt Rationale for Use: The paperprovides a synopsis and comparison ofthe results of atrazine mesocosm data from the following studies: Walker (1961), deNoyelles etat. 

### (1982 and 1989), Gunkel (1983 and 1984), Dewey (1986), Herman etat. 

### (1986), and Hamilton (1987). In general, the reported data show direct effects viareduction in plant production and biomass (i.e., phytoplankton, periphyton, andmacrophytes); however, in many ofthe studies recovery ofphytoplankton communities was observed within one month ofatrazine application with a shifttoward species that are resistant ortolerant to atrazine. No recovery ofmacrophytes was observed. Indirect effects were also observed via reduction in food for grazers followed by reducedprey forpredators, altered habitat structure forparticularplants and animals, and reduced competition for unaffected plants.

Limitations ofStudy: Data summarytable results are crude visual estimates from small three-dimensional graphs and shouldnotbe used quantitatively. The study describes many qualitatively interestingresults and possible mechanisms for ecotoxicity in mesocosms, butthe underlying methodology suffers from poorly controlled experimental design (evidenced by frog colonization and snapping turtles apparently eating fish from some ponds) with too few replicates. Additionally, no statistics ordatatables are presented.
Primary Reviewer: SaraHendrix, M.S., StaffScientist, Cambridge Environmental Inc
Secondary Reviewer: Anita Pease, M.S., SeniorBiologist, Environmental Fate and Effects Division, U.S. Environmental Protection Agency.

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