EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 1Some of the studies and manufacturer data reporting aquatic toxicity for cationic polymers generally and chitosan in particular.ChitosanBullock et al (2000)Toxicity of acidified chitosan for cultured rainbow trout12/15 fish died within24 h exposed to 0.75 ppm; 6/15 died within 24 h, exposed to 0.075 ppmMortality at 6 days with exposure to 0.038 ppm:Lowest observed effect – 38 ppbNo mortality at 14 days with exposure to 0.019 ppm:No observed effect – 19 ppbMay be toxicant alters glycoprotein; affecting negative chargeon gills; favoring adhesion or ionic imbalance interfering withoxygen uptakeAuthors suggest further research necessary to determine exact toxic mechanism of solubilized chitosanRomoren et al (2002)Immersion delivery of plasmid DNA...rainbow troutMortality depended on chitosan concentration, molecular weightand deacetylationAll fish in one study died when exposed to 15 μg/ml (ppm) of chitosan.At 10 μg/ml (10 ppm), fish exposed to higher molecular weight chitosan died; at 5 μg/ml (ppm) no lethality observedNational Site Solutions, LLC, chitosan manufacturer (2004) – Powerpoint presentationAcute toxicity: 1.7 mg/l (ppm) at 96 hoursfor rainbow trout (chitosan acetate)Acute toxicity: 6.4 mg/l (ppm) at 96 hoursfor rainbow trout (chitosan lactate)Cationic Polyelectrolyte (including polyacrylamide)Beisinger & Stokes (1986) –Effect of synthetic polymers...10 anionic (one was toxic to daphnids only) & 15 cationic polymers4 species: daphnids, fathead minnows, midges and gammaridsDaphnids (LC50at 48-hr): 0.09 mg/L (ppm) to >100 mg/l (ppm);(8 cationic polymers were≤1.2 mg/L (ppm))Fathead minnows (LC50at 96-hr): 0.88 mg/L (ppm) to >100 mg/L (ppm); (3 cationic polymers were≤1.05 mg/L (ppm))Many of the cationic polyelectrolytes are very toxic with largedifferences in toxicity of various formulations; addition of anionic prior to discharge may detoxify cationicMuir et al (1997)Localization, depuration, bioaccumulation and impairment of ion regulation...rainbow troutSublethal doses: 3 cationic polymers(EDP 7200μg/l (ppb), CYT 307 μg/l (ppb), STK 342 μg/l (ppb))After 3-hour polymer exposure, saw decreased swimming and mucous-like substance stream from gillsBlood pH decreased from 7.1 to 6.6; sodiumand chloride concentrations decreasedTotal ammonia and potassium increasedGills appear to be gas exchange and ion regulation site, suggests toxicity when ion regulation is impaired by the binding of cationic polymersWeston et al (2009)Toxicity of Anionic Polyacrylamide Formulations when used for Erosion ControlOil-based PAM toxic to 4 of 5 species tested at less than10 mg/L (ppm) (normal erosion control concentration)Other PAMs showed minimal toxicity even at 10x normal concentration ; may be due to oil or otheringredients in the formulationEPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 2Author(s)TitleResultsCitationChitosanGraham Bullock,Vicki Blazer,Scott TsukudaSteve SummerfeltToxicity of acidifiedchitosan for culturedrainbowtrout _OncorhynchusmykissChitosan dissolved in acetic acidadded to a culture system at 1.0 ppm to remove organic solids,acute toxicity to rainbow trout _Oncorhynchus mykisscontrolled experimentsto determine toxicitytrout average weight of 120.5 g for all tests7-day exposure:chitosan acutely toxic at 0.75 and 0.075 ppm12 of 15 died within 24 h at 0.75ppm; six died within 24 h at 0.075 ppm; one on day 7 at 0.038 ppm;none died at 0.019 ppm14 day exposure:At 0.038 ppm trout began dying on day 6 inone tank and on day 8 in two other tanksNo trout died in three tanks exposed at 0.019 ppmHistological examination of gills, skin, muscle, and internal organs indicated significant and consistentpathological changes only ingills. Lesions similar to mercury exposure.Lifting of lamellar epithelial cells occurredin trout exposed to 0.019 and 0.038 ppm.In trout exposed to 0.75 or 0.075 ppmchitosan, large areas of lamellar fusion and severe gill lesions wereobserved.These results show that soluble acidified chitosan is highly toxic to rainbow trout even at low concentrationsAquaculture (2000). 185: 273–280Link:http://www.sciencedirect.com/science/article/pii/S0044848699003592/KristineRomøren, Beate J.Thu, ØysteinEvensenI mmersion deliveryof plasmid DNA II.A study of thepotentials of achitosan baseddelivery system inrainbow trout(Oncorhynchusmykiss) fryToxicity depended mainly on chitosanconcentration, but also molecularweight and degree of deacetylationToxicity reduced due tocharge reduction when chitosan complexed with DNAIn vitro experiments support in vivo observationsChitosan (1 mg/ml) dissolved in 25 mM Na-acetate bufferRainbow trout fry had average weight of about 1 g.In freshwater tanks, acclimated for 1 weekJournal of Controlled Release85 (2002) 215–225Link:http://www.sciencedirect.com/science/article/pii/S016836590200278XEPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 3Author(s)TitleResultsCitationComparing chitosan with similar molecular weight butdifferent acetylation, highly deacetylated appearedmore toxic than less deacetylatd types. Most toxic had high deacetylation and high molecular weight. All fishdied at chitosan concentration of 15 μg/mlSecond set of experiments using polyplexes of chitosan and chitosan with DNA that had reduced charge andfixed chitosan concentrations at 15 μg/mlMortality depended on molecular weight of chitosan with shorter survival for higher molecular weightMortality likely caused by positively charged chitosan and negatively charged groups on gillsRizzo, L., DiDennaro, A.,Gallo, M. and V.BelgiornoCoagulation/chlorination of surface water:A comparisonbetween chitosan andmetal saltsCoagulation and subsequent chlorination are typical for treating surface water to produce drinking waterToxicity tests compared chitosan and two metal salts, aluminum sulfate and ferric chlorideChitosan: 1.0 mg/L and 0.5 mg/LAluminum sulfate and ferricchloride: 40 mg/L and 60 mg/LToxicity tests performed before and after chlorination of raw and coagulate/settled water samplesOrganisms: 24-h newbornDaphnia magna(ISO 66431 method)Chlorine effect stopped by adding sodiumthiosulphate in chlorinated samplesFivedaphnidsin each test beaker with 50 mL effective volume.Samples were adjusted to pH 6 to make performance of chitosan for comparing chitosan with metal saltsWater samples were spiked with humic acid to evaluate effect on acute toxicity in finished waterExperiment conducted in quadruplicate; samples were diluted when immobilization was 100%All coagulants reduced water sample toxicity from 100% to 0% immobilization ofdaphnidsSpiking coagulated samples with 10mg humic acids/L increased toxicityto 100%; humic acids may improvemetal uptake causing toxicity indaphnidsCoagulated samples that were chlorinated increased toxicity for all unspiked coagulated samples except forone with 60 mg/L of alum. Chitosan was the most toxic,followed by ferric chlorideand aluminum sulphateCoagulated/chlorinated samples that were spiked with humic acids showed lower toxic effectToxic effects may depend on several factors: type of dissolved metals, initial humic acid concentration,coagulant type and dose, residual humic acid content post-coagulation, formation of humate-metalcomplexes, chlorine dose and formation of chlorination by-productsToxicity of chitosan in drinkingwater treatment may increase, depending on surface water characteristicsSeparation and PurificationTechnology (2008). 62: 79-85Macpherson, J.Natural SiteSolutions2004StormKlearTM(Chitosan) Toxicityand ApplicationsPresentation: October21, 2004Sacramento, CAPowerful cationic biopolymerRemoved in the treatment processResidual chitosan detected to 100 μlin treated water using field test kitLiqui-Floc (chitosan acetate) Aquatic Toxicity ResultsToxicity to fish EC50 or IC50 - Oncorhynchus mykiss (rainbow trout) – 1.7 mg/l - 96 hAcute oral, LD50 (mice) >16g/kgGel-Floc (chitosan lactate)Aquatic Toxicity ResultsAcute oral, LD50 (mice) >10g/kgToxicity to fish EC50 or IC50 - Oncorhynchus mykiss (rainbow trout) – 6.4 mg/l - 96 hMacpherson, J. StormKlearTM(Chitosan) Toxicity andApplications. (2004, October).Presentation in Sacramento,CA.Link:https://webdisk.ucalgary.ca/~walkerd/public_html/PAM%20erosion%20control%20info/chitosan_Gel-Floc_sedconRFS.pdfSanta CruzBiotechnology,Inc.Material Safety DataSheetChitosan2009Refer to data for ingredients, which follows:CHITOSAN:■Toxic to aquatic organisms.■Do NOT allow product to come in contact with surface waters or to intertidalareas below the mean high water mark.Link:http://datasheets.scbt.com/sc221421.pdfEPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 4Author(s)TitleResultsCitationDo not contaminate water when cleaning equipment or disposing of equipment wash-waters.Wastes resulting from use of the product must be disposed of on site or at approved waste sites.■Cationic substances, and their polymers and those polymers that are reasonably anticipated to become cationic in thenatural aquatic environment (pH range4-9) may be environmental hazards.Exempt from this concern are those polymers to be used onlyin solid phase, such as ion-exchange resins, and wherethe FGEW (Functional Group Equivalent Weight)of cationic groupsis not 5000 and above.Cationic groups such as alkylsulfoniums, alkylphosphoniums and quaternary ammonium polymers are highly toxic tofish and other aquatic organisms. Similarly potentially cationic groups such as amines and isocyanates are of concern.Some cationics, however, may fall into the category of PLCs (polymers of low concern) provided they possess lowcharge density, and/or are not water-soluble or are not self-dispersing polycarboxylates or poly- (aromatic or aliphatic)sulfonate polymers.EcotoxicityIngredient Persistence: LOWWater/Soil Persistence: LOWAir BioaccumulationMobility HIGHSIGMAALDRICHMaterial Safety DataSheetChitosanVersion 3.0Revision Date04/10/2008Print Date06/26/2008Sigma-AldrichCatalog:Version 5.3Revision Date06/03/2011Print Date10/17/201112. ECOLOGICAL INFORMATIONToxicityToxicity to fish LC50 - Oncorhynchus mykiss (rainbow trout) - 0.038 mg/l - 48 hPersistence and degradabilityno data availableBioaccumulative potentialno data availableMobility in soilno data availablePBT and vPvB assessmentno data availableOther adverse effectsno data availablehttp://web.mst.edu/~../deptweb/msds/test/pdfs/41/94/419419-a.pdfC. Dautremepuits,S. Paris-Palacios,S. Betoule and G.VernetModulation inhepatic and headkidney parameters ofcarp (CyprinuscarpioL.) induced bycopper and chitosanCopper used as fungicide inChampagne region in FranceChitosan has antifungal and heavy metal ion chelating propertiesConsidered chitosan as biopesticide alternative to copper in vineyardsInvestigated potential toxicity of chitosan on aquatic animal health and compared its toxicity to copperWater soluble chitosan (Chitogel, AberTech, France) added to spring waterSeven treatments: 37.5, 75, 150, 225, 300 and 375 mg/l and a control with no chitosanMortality recorded every 12 h for 96 hMedian lethal concentration at 96h using StatPhar 2.4 softwareLC50determined as 30018 mg/lSublethal effects observed when antioxidant enzymes were measured in the liver and head kidney after 4days exposureDefense against oxidative stress seemed to be dose-dependent at concentrations below the LC50at 96 hoursof 300 mg/lComparative Biochemistry andPhysiology, Part C 137 (2004)325–333http://www.sciencedirect.com/science/article/pii/S1532045604000559EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 5Author(s)TitleResultsCitationY.Y. Mosleh, S.Paris-Palacios, M.T. Ahmed, F.M.Mahmoud,M.A. Osman, andS. BiagiantiRisbourgEffects of chitosan onoxidative stress andmetallothioneins inaquatic wormTubifex tubifex(Oligochaeta,Tubificidae)T. tubifexworms collected from sediment in vineyard retention basin; held 6 months before experimentWorms were about 1.5 gSpecies is very resistant to pollution, usually last macroinvertebrate to disappear from a contaminated siteTwenty worms were placed in crystallizing dishes with spring water. Chitosan (chitogel 2.5% San-QuentinFallavier, Fr) was added for final concentrations of 25,62 and 125 mg/l and incubated in growth chamber for2, 4 and 4 days. Three dishes for each concentration and for each duration.Minimum of 3 independent experiments in triplicate. Data are presented as the mean ± standard deviation.Chemosphere 67 (2007) 167–175http://www.sciencedirect.com/science/article/pii/S0045653506012069M. Sekine, A.Takeshita, N.Oda, M. Ukita, T.Imai and T.HiguchiOn-site treatment ofturbid river waterusing chitosan, anatural organicpolymer coagulantField study in Imou River, Yamaguchi Prefecture, Japan at river construction siteFLONAC #250 (1:1 mix of chitosan flake and acetic acid)Jar test: optimum concentration – 1.5 mg/L; continuously injected for two hours“Strange” fish surfacing behavior observed in highturbidity area of stream about 50 m downstream ofstation where injected. Fish didn’t take breath at surface but stayed calm and quiet below surface with headsslightly up.No dead fish, no quickly moving fish observedNo other behavior determined strange at other stream sectionsToxicity test conducted based on observationAcute toxicity teston larva of tenOryzias latipes(Japanese rice fish) in petri dish with 25 mL test water,cultivated 48 h at 25oCDead and abnormal larvae counted at 1, 2, 3, 6, 12, 24 and 48 hoursControl test conducted with water treated with activated carbonChitosan shows low but constant abnormal behaviorFins of larva seem to cling to bodyToxicity test inconclusivefor chitosan toxicityWater Science & Technology(2006). Vol 53 No 2 pp 155–161Cationic & Anionic PolymersBeisinger, K.E.and G. N. StokesEffects of syntheticpolyelectrolytes onselected aquaticorganismsAcute Bioassay:fathead minnows and daphnidspolyelectrolyte concentration of 100mg/L (10 anionic and 15 cationic)if toxic, then used less sensitive gammarids and midgesused 5-8 concentrations of polyelectrolytes, along with controlsJournal of the Water PollutionsControl Federation (1986). Vol.58, No. 3: 207-213EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 6Tests for gill damage in fish (30-day-old) in 1 L of waterWater and polyelectrolytesolutions renewed dailyLC50Daphnids (48-hr): 0.09 mg/L to >100 mg/l; 8 polymers were≤1.2 mg/LFathead minnows (96-hr): 0.88 mg/L to >100 mg/L; (3 polymers were≤1.05 mg/L)Hypothesize suffocation of fishDifferent sensitivies betweenspecies suggest different modes of action; may also becaused by oligomers asimpuritiesAnionic polyelectrolytes could be added before discharging to a wastewater to detoxify cationicpolyelectrolytesMuir, M.M.,Kosteretz, K.G.,and J.J. LechLocalization,depuration,bioaccumulation andimpairment of ionregulation associatedwith cationic polymerexposure in rainbowtrout (Oncorhynchusmykiss)ExperimentStatic exposure to three commercial14C-labelled cationic polmers:EDP, epichlorhydrin-deimethylamine; CYT, polyacrylamide ester; and STK, polyacrylamide amide14C concentrated in gill tissueTrout hatched and then raised in-house, in flowing, dechlorinated water20 liter glass aquariaN=9 fish and tissue samples pooled in groups of three fishConcentrations high enough to cause morbidity but not mortality;Blood pH, and blood ions (Na+, total NH3and Cl-) were measuredResultsSequential exposure did not resultin any cumulative levels of14C concentrated in gill tissueAt end of each 3 hour polymer exposure, fish exhibited decreased swimming and mucous-like substancestreaming from gill areaDuring first CYT exposure one fish died.Four fish died after the first SYT exposureBlood pH decreased from 7.1 to 6.6Total ammonia increased two exposures, but a 2-fold increase was only statisticallysignificant in one of theexposuresSodium and chloride concentrationsdecreased in both exposures but was significant in only one of theexposuresPotassium concentrations increasedData from tissue distribution studies showed three cationic polymers are limited to the gillsIn addition to gas exchange gills appear to be ion regulation siteFreshwater fish such as rainbow trout are hypertonic to water and get sodium and chloride from waterDecrease in blood sodium and chloride as well as increased total ammonia are consistent with interrupted ionregulationStudies indicate humicacid additions to water reduce cationic polymer toxicity14C concentrations were significantly reduced in gill tissue by proponed exposure to polymer-free water andpolymer-free water with HA.Presence of HA in polymer-free depuration water didn’tmarkedly increase rate of 14C disappearance fromgills after exposure to two polymer butdid decrease for one polymer (EDP).ConclusionsGills appear to be the only cationic polymer binding site in fishBinding of polymers appears to be reversible in polymer-free water with or without negatively-chargedorganic matterToxic effects data suggest that the gills are an ion regulation site and that gill epithelial cellular membranemechanisms responsible forion regulation are impaired by binding cationic polymersXenobiotica (1997). Vol 27,No. 10: 1005-1014http://informahealthcare.com/doi/pdf/10.1080/004982597239985EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 7Rowland, C.D.,Burton, G.A., andS.M. Morrison.Implication ofPolymer Toxicity in aMunicipalWastewater EffluentMontgomery, OH Wastewater Treatment facilityFinal effluent 24-h composited samples collected in borosilicate glass jars; just prior to entering streamAcute (near-field) and chronic (far-field) mixing zones andupstream receiving water grab samples collectedin plastic and stored on iceUpstream samples used for dilutionwater and field reference controlLaboratory culture water control test accompanied WET testsCeriodaphnia dubiatoxicity tests with toxicant elimination steps included extensive effluent characterizationand manipulationC-380 dry cationic polyacrylamide polymerHyperfloc, a water-in-oil emulsion cationic acrylamide copolymerBoth products were proprietary and no toxicity data was availableToxicity Test ResultsC18 extraction column effluent samplesfrom plastic containers exhibited 100%C. dubiasurvival after 48hours of exposureSame effluent from glass jars hada markedly reduced survival rate of 44% (±0.53) within the first 24 hoursand none survived after 48 hoursEffluent manipulation ruled outsurfactants as a toxicantIn all effluent samples collected, reduced toxicity was observed for plastic containers.Appears to be potential for sorption of cationic polymers to plastic containers, reducing toxicityGlass containers are suggested forstorage of effluent samples where polymer toxicity is suspectedEnvironmental Toxicology andChemistry. (2000). Vol. 19,No. 8: 2136-2139Weston, D.P.,Lentz, R.D.,Cahn, M.D.,Ogle, R.S.,Rothert, A.K., andM.J. Lydy.Toxicity of AnionicPolyacrylamideFormulations whenUsed for ErosionControl inAgricultureToxicity Test ResultsFreshwater amphipod, midge, daphnia,fathead minnow, freshwater algaeResults indicate toxicity depends on product formulationFrom standpoint of aquatic toxicity itappears that solid and water basedproducts are preferable to oil-basedformsGranular form: four of five species no toxicity; daphnia reproductive IC50 5mg/L and LC50 of 29 mg/LTablet form: no toxicity in onespecies tested: LC50 > 100 mg/LWater –based form: no toxicity in mostspecies. At 100 mg/Ltoxic to algae.Oil-based form: toxic to amphipod,midge and daphnia; fathead minnowhad statistically significantmortality at 1.5 mg/L and LC50 of 16.6 mg/L; algae seemed unaffectedJournal of EnvironmenalQuality. (2009). Vol 38: 238-247.http://ddr.nal.usda.gov/bitstream/10113/23619/1/IND44161449.pdfSojka, R.E.,Bjorneberg, D.L,Entry, J.A., Lentz,R.D., and W.J.OrtsPolyacrylamide inAgriculture andEnvironmental LandManagementPAM refers to a broad class of compounds sold since1995 to reduce irrigation-induced erosion and enhanceinfiltration with increasing non-agricultural applicationsNonionic and cationic PAMs risky to aquatic organisms at low concentrations; anionic are notPAM toxicity lower in natural waters due to humicsubstances and other dissolved organic compoundsIncreased germination when PAM mixed with grass seedPAM increases infiltration at optimal application rate; applying toomuch can restrict infiltrationCareful control of PAM concentration is importantResults from field and lab tests showed Chitosannot as effective as PAM for erosion controlAdvances in Agronomy (2007).Vol 92: 75-162http://ddr.nal.usda.gov/bitstream/10113/15474/1/IND43896010.pdfAlbassam,M.,Moore, J., and A.SharmaUltrastructural andClinicopathologicalStudies on theToxicity of CationicAcrylamide-basedFlocculant toRainbow TroutAbstract. Rainbow trout (Sa/rno gairdnerz) of two age groups were exposed to a cationic acrylamide-basedftocculant at various concentrations in static bioassay chambers. Atlethal concentrations the flocculant producedsevere gill alterations in all fish. The principal alterationswere necrosis and separationof the respiratory epithelialcells covering secondary lamellae. Many necrotic chloridecells were also seen, their apical plasma membranewas destroyed, and mitochondria were swollen with separated cristae. An influx of a large amount of fluid intothe interstitial spaces caused partial or complete separation of subepithelial spaces from the covering epithelialcells and basement membranes ofunderlying blood vessels. Clinicopathological alterations included markedVeterinary Pathology (1987).24:34-43EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 8decreases in blood pH, partial pressure of oxygen, bicarbonate and plasma sodium, and chloride concentrations.Hematocrit, total protein, and blood glucose were increased. Fish exposed tosublethal concentrations had gillalterations characterized by hypercellularity and thickening of the secondary lamellae. These were due toundifferentiated cell proliferation and macrophage and lymphocyte infiltration between the covering epithelialcells and the underlying blood vessels. Macrophages and undifferentiated cells had largephagolysosomes containingcytoplasmic organelles, an indication ofcell injury and increased turnover.Bolto, B., and J.GregoryReviewOrganicpolyelectrolytes inwater treatmentAbstract. The use of polymers in the production of drinking water is reviewed, withemphasis on the nature of theimpurities to be removed, the mechanisms of coagulation and flocculation, and the types of polymers commonlyavailable. There is a focus on polymers for primary coagulation, their use as coagulant aids, in the recycling of filterbackwash waters, and in sludge thickening.Practicalities of polymer use are discussed, with particular attention topolymer toxicity, and the presence of residual polymer inthe final drinking water. The questions of polymerdegradation and the formation of disinfection by-products are also addressed.Water Research (2007). 41:2301 – 2324Liber, K., Weber,L.,and C.Le ́vesqueSublethal toxicity oftwo wastewatertreatment polymersto lake trout fry(Salvelinusnamaycush)Abstract. Lake trout fry (Salvelinus namaycush) were exposed in laboratory experiments to two wastewater treatmentpolymers, one anionic (MagnaFloc 156) and one cationic (MagnaFloc 368; Ciba Speciality Chemical), to determine ifthese chemicals which are used and discharged by miningoperations in Canada’s North pose a significant hazard tojuvenile fishes. The cationic polymer was substantially more toxic to lake trout fry than the anionic polymer, with96-h LC50 estimates of 2.08 and >600mg/l, respectively. Separate 30-d exposure experiments yielded no observedand lowest observed effect concentrations, respectively, of 0.25 and 0.5 mg/l for MagnaFloc 368, and 75 and150 mg/l for MagnaFloc 156. In both cases,behavioural responses, especially startle response,were the most sensitivetest endpoints. Histopathologicalassessment revealed that gill pathology appeared within a few days of exposure toboth polymers, apparently as a result oflocalized hypoxia. Acute (4d) effects included cloudy swelling of epithelialcells, increased gill vascularization, and thickening and shortening of the gill lamella. Chronic (30 d) polymer exposureproduced only slightly greater pathological effects than acute exposure, with comparable responses observed only at>1.0 mg/l MagnaFloc 368 and 150 mg/l MagnaFloc 156, suggesting that the fish displayed some level of bothbehavioural and physiological adaptation to therespiratory stress imposed by the two polymers.Chemosphere (2005). 61:1123–1133EPA ORD: Literature Survey of Chitosan& Synthetic Cationic Polymer ToxicityNovember 15, 2011 -- Page 9Performance Comparisons of Chitosan to PAM in Agriculture and ConstructionSOURCE: Sojka, R.E., Bjorneberg, D.L., Entry, J.A., Lentz, R.D. andW.J.Orts. (2007). Polyacrylamidein Agriculture and Environmental Land Management.Advances inAgronomy(2007). Vol 92: 75-162Note: PAM used (18% anionic, 12-15 Mg/mol); 10 ppmSOURCE:Tobiason, S., Jenkins, D., Molash, E., and Rush, S. (2001). Polymer use and testing for erosion and sediment control on construction sites.Erosion Control8, 90-101.<Accessed 25 Oct, 2011:www.erosioncontrol.com/forms/print-19178.aspx>Note: PAM used was Chemco 9836A granular ionic polyacrylamide