Interpretive Assistance Document for Assessment of Polymers Sustainable Futures Summary Assessment Updated April 2008 This document was developed to help compile estimation results from U.S. EPA OPPT's P2 Framework Models (http://www.epa.gov/oppt/sf/tools/methods.htm') and is used by OPPT during Sustainable Futures (SF) training described at http://www.epa.gov/oppt/sf/meetinqs/train.htm. Participants in the voluntary SF Pilot Project are asked to submit the information as described in this training document along with their SF PMNs in their choice of format. NOTE: Due to the dynamic nature of the Internet, the URLs listed in this document may have changed. A search using any of the publicly available search engines should locate the new URL. ------- ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 This document provides general guidelines for assessment of polymers that have an average number molecular weight (MWn) of greater than 1,000. This document follows the methods used by EPA's New Chemicals Program. This document was developed as a teaching aid to help conduct assessments of large polymers under the Sustainable Futures Initiative. For technical reasons, many of the screening methods contained in the Sustainable Futures Initiative can not be used to evaluate large polymers. The information set out in this document is not final Agency actions, but are intended solely to provide assistance with review. They are not intended, nor can they be relied upon, to create any rights enforceable by any party in litigation with the United States. EPA officials may decide to follow the guidance provided in this document, or to act at variance with the guidance, based on an analysis of specific circumstances. PLEASE NOTE: It is strongly suggested that any Sustainable Futures Summary Assessment provide an interpretation of model estimations relative to potential risk for the chemical being evaluated. PLEASE NOTE: The assessment methods described in this document should not be used to assess polymers with MWn <1000. Polymers with MWn <1000 should be assessed as discrete chemicals using EPI Suite, ECOSAR, and other methods in the Sustainable Futures Initiative, as appropriate. The assessment methods described here should be used only as general guidelines for assessment of polymers of similar type. Some polymers may be outside the scope of this document. These estimation methods should not be used in place of measured data on the polymer being evaluated. Please note that data available on structurally similar polymers may be more accurate than assessments based on the estimation methods described in this document. Reference: The main source of assessment methods described in this document is Boethling, Robert S. and Nabholz, J. Vincent "Environmental Assessment of Polymers under the U.S. Toxic Substances Control Act", pp. 187-234, in Ecological Assessment of Polymers Strategies for Product Stewardship and Regulatory Programs. Hamilton, John D. and Sutcliffe, Roger (eds.), (1997) Van Nostrand Reinhold. CONTENTS Availability of Sustainable Futures / P2 Framework Models 2 Three Types of Polymers Grouped by Average Number Molecular Weight (MWn) and Low Molecular Weight (LMW) Material Composition 2 Physical / Chemical Property Estimations 3 Environmental Fate Estimations 4 Aquatic Toxicity Estimations 5 Human Health Hazard Estimations 9 Data Collection Table for Assessment of Polymers 11 1 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 Availability of Sustainable Futures / P2 Framework Models EPISuite: http://www.epa.gov/opptintr/exposure/pubs/episuite.htm ECOSAR: http://www.epa.gov/opptintr/newchems/tools/21ecosar.htm OncoLogic: http://www.epa.gov/oppt/newchems/tools/oncologic.htm E-FAST: http://www.epa.gov/opptintr/exposure/pubs/efast.htm ChemSTEER: http://www.epa.gov/opptintr/exposure/pubs/chemsteerdl.htm NOTE: Due to the dynamic nature of the Internet, the URLs listed in this document may have changed. A search using any of the publicly available search engines may be necessary to the new URL. Three Types of Polymers Grouped by Average Number Molecular Weight (MW) and Low Molecular Weight (LMW) Material Composition Polymers can be grouped into three categories by MWn and LMW material composition. These distinctions are used to determine if the polymer is assessed only as a polymer, or if oligomers may also need to be addressed. Monomers may need to be assessed if there is high content of residual monomer and/or the monomer has known aquatic or human health hazards. The assessment of monomer or oligomer toxicity is in addition to, or in lieu of, any polymer specific assessment. Category 1: Polymers with low molecular weight (MWn <1,000). These polymers may be able to be assessed as a single, discrete structure in EPI Suite and ECOSAR, subject to the normal limitation of the software. This is possible when the composition and structure of the polymer is known. In order to complete the assessment, find a reasonable representative structure of MW <1,000 and use this in the P2 modeling programs. Category 2: Polymers with high molecular weight (MWn >1,000) and large low molecular weight (LMW) material composition (>25% with MW <1,000; >10% with MW<500). These polymers can be assessed for environmental fate and toxicity as the polymer; however, oligomers may need to be assessed in addition to account for any increased toxicity due to these lower molecular weight compounds. Category 3: Polymers with high molecular weight (MWn >1,000) and minimal LMW material (<25% with MW <1,000; <10% with MW <500). These are generally assessed solely as the polymer. However, as stated above, if a high percentage of unreacted monomers with potential health concerns are present, additional assessment may be required to address concerns for the monomer. 2 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 PHYSICAL / CHEMICAL PROPERTY ESTIMATIONS Several properties of the polymer are very important and may be required for the assessment of the polymer. These properties are those associated with structure, size, and composition of the polymer to be assessed. In addition, some properties can be estimated based simply on the large size of the material. Properties that fall into these two categories are indicated below. Important physical-chemical properties for polymers include: Monomers from which the polymer is created, and relative mole fraction of each monomer Molecular weight (MW) distribution Number average molecular weight (MWn) in Daltons and how it was determined Oligomer content of the polymer (i.e. percentages with MW <1000 and MW <500) Physical form Equivalent weight of any reactive functional groups (RFG) and/or cationic charge density, which can be determined from the structure. Particle size distribution Swellability Water solubility or dispersability - polymers that form micro emulsions or gels may be mistaken for soluble, but may not be truly soluble. General physical / chemical and environmental fate properties for most polymers with MW >1,000 Vapor Pressure <10"8 mm Hg Henry's Law constant <10"8 atm-m3/mol 3 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 ENVIRONMENTAL FATE ESTIMATIONS The most important parameters to evaluate in the fate assessment of polymers are electronic charge (density being secondary), MWn, and solubility/dispersability. Vapor Pressure - Polymers with MWn >1000 generally have a vapor pressure of <10"8 mm Hg. This indicates that the chemical is likely to exist solely as particulate matter in the atmosphere. As particulate matter, atmospheric oxidation is not expected to be a significant route of environmental removal. Henry's Law Constant - Due to the large size and low vapor pressure of most polymers, those with MWn >1000 generally have Henry's Law constant of <10"8 atm-m3/mol. Due to this, volatilization from water or moist soil is not expected to occur at an appreciable rate, with half-lives for volatilization of >1 year. Bioconcentration Factor (BCF) - Due to the large size and insolubility of most polymers, they are typically of low concern for bioconcentration. Those with MWn >1,000 will typically be of low concern; for estimations that require a numeric BCF (E-FAST), 100, which is within the range of low BCF concern, can be used. Soil Adsorption and Mobility Cationic, amphoteric, nonionic - These polymers will generally absorb strongly to soil and sediment. Anionic polymers - Anionic polymers usually have low sorption to soil. However, due to large size and weight parameters, these materials may still have low mobility in soil. POTW removal - Removal of polymers in sewage treatment is dependent primarily on solubility, but may be influenced by binding potential for sludge. Cationic, Amphoteric, and Nonionic MWn Removal 500 - 1,000 50 - 90% (50% typically used) >1000 90% Anionic ¦ If solubility and/or dispersability are negligible, use table for cationic, amphoteric, and nonionic polymers above. ¦ If soluble and/or dispersible MWn Removal <5,000 0 - 50% (0% typically used) 5,000 - 20,000 50% 20,000 - 50,000 75% >50,000 90% Biodegradation - The vast majority of polymers are essentially non-biodegradable. While some exceptions exist, these polymers are usually specifically designed to be biodegradable materials (to replace more resistant polymers as a more environmentally friendly alternative). Often, to substantiate this claim, biodegradation studies are available on these biodegradable types of polymers. In the case of highly degradable polymers, assessment of the degradation products may be warranted. Hydrolysis - Hydrolysis of susceptible groups on polymers is solubility dependent. Polymers with poor water solubility may have reduced susceptibility to hydrolysis. 4 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 AQUATIC TOXICITY ESTIMATIONS Average Molecular Weight (MWn), Monomer, and Low Molecular Weight (LMW) Material Composition Categories - When assessing polymers that fit into category 1 above, it may be more relevant to find a discrete representative structure with MW of <1,000 and assess this structure using ECOSAR or other methods of aquatic hazards estimation. Polymers that fit into category 2 above may require assessment of the polymer itself, but further assessment of the low molecular weight components of the polymer mixture may also be needed to fully characterize the aquatic hazard. If no data on the compound are available, ECOSAR or other methods for aquatic hazard estimation can be used to assess the LMW components. Lastly, polymers that contain large amounts of residual monomers may require assessment of the monomer to fully characterize the aquatic hazards associated with the mixture. Insoluble Polymers - Insoluble polymers are not expected to be toxic unless the material is in the form of finely divided particles. Most often, the toxicity of these polymer particles does not depend on a specific reactive structural feature, but occurs from occlusion of respiratory organs such as gills. For these polymers, toxicity typically occurs only at high concentration; acute toxicity values are generally >100 mg/L and chronic toxicity values are generally >10 mg/L (low toxicity). Nonionic Polymers - These polymers are generally of low concern for aquatic hazard, due to negligible water solubility. Two exceptions exist. The first is for nonionic polymers that have monomers blocked in such a way as to use the polymer as a surfactant or dispersant, which may cause toxicity to aquatic organisms. The second is for nonionic polymers with significant oligomer content (i.e., >25% with MW <1,000; >10% with MW<500), which may be a concern on the basis of bioavailability of the LMW material. In this case the LMW oligomers, if they are <1,000 MW, can be assessed using ECOSAR or other methods for aquatic hazard assessment. Anionic Polymers - Polyanionic polymers with MWn >1,000 that are soluble or dispersible in water may pose a concern for direct or indirect toxicity. These polymers are further divided into 2 subclasses: Poly(aromatic acids) and Poly(aliphatic acids). Poly(aromatic acids) - These chemicals are usually poly(aromatic sulfate/carboxylate) structures and generally are of moderate hazard concern to aquatic organisms, with acute LC50/EC50 values between 1 mg/L and 100 mg/L, depending upon the exact structure of the polymer. Monomers associated with toxicity include: carboxylated/sulfonated diphenolsufones, sulfonated phenols, sulfonated cresols, sulfonated diphenylsulfones, and sulfonated diphenylethers. Monomers usually associated with low aquatic toxicity concern include: sulfonated naphthalene and sulfonated benzene. The toxicity of this type of polymer appears to be moderate and not affected by water hardness. Toxicity can be estimated by a nearest analog approach using test data available for polymers of known composition. A collection of data on polymers of this type is available in table 10.4 (pp. 207 - 208) in the Boethling, Nabholz reference cited above. Poly(aliphatic acids) - This type of polymer is made up of repeating carboxylic acid, sulfonic acid, and/or phosphinic acid monomers. At pH 7 this polymer type generally exhibits low toxicity toward fish and daphnid, with LC50 values >100 mg/L. However, there may be toxicity hazard concerns for green algae; toxicity to algae is believed to arise from chelation of nutrients. The toxicity of this type of polymer can be assumed to be low for fish and daphnid. Green algae toxicity can be determined using a nearest analog approach with test data collected for similar polymers of known composition. The toxicity is highly dependent on the structure of the polymer, with space between repeating acid units and addition of non-chelating groups affecting toxicity. A collection of data on polymers of this type is available in table 10.5 (pg. 209) in the Boethling, Nabholz reference cited above. Water hardness has been shown to mitigate the toxicity of poly(aliphatic acid) polymers to green algae. As water hardness increases, toxicity tends to decrease. This is due to the abundance of chelating cations that "fill" the chelation sites of the polymer, allowing more nutrients to remain in the water. In many cases a mitigating factor can be applied to the estimated toxicity values. The 5 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 appropriate mitigating factor, if any, can be discerned from table 10.6 (pg. 212) in the Boethling, Nabholz reference cited above. Cationic Polymers - Cationic polymers that may pose a concern for aquatic hazard are those that have a net positive charge or that may become cationic in the environment. Cationic Atom - The most common atoms that may have net positive charge include, but are not limited to, nitrogen (ammonium), phosphorus (phosphonium), and sulfur (sulfonium); with nitrogen constituting the cationic atom in >99% of polymers. Percent Amine Nitrogen (%A-N) - The percent of amine nitrogen (or other cationic atom) is used in the cationic nitrogen polymer SARs for estimation of aquatic toxicity. Nitrogens directly substituted to an aromatic ring, nitrogens in an aromatic ring, amides, nitriles, nitro groups, and carbo diimides are not counted for determining %A-N. %A-N can be determined using the following equation: %A-N = 100 x [typical wt% of amine subunit in polymer] * [number of cationic nitrogens in subunit] * [atomic wt of N] [MW of amine subunit] For smaller polymers, where the total number of nitrogens per polymer molecule is known, or non-polymers that may have toxicity similar to cationic polymers, the %A-N can be determined as: %A-N = 100 x [number of amines in compound] * 14.01 [atomic wt of N] [MWn of polymer] Polymer Backbone - In addition to the cation-producing group, polymers of this type are assessed according to their backbone, which can be carbon-based, silicone-based (i.e., Si-O), or natural (chitin, starch, tannin). Cationic Polymer SARs - The SARs for determination of aquatic hazard from cationic polymers are based on the %A-N. At high %A-N (typically 3.5% or 4.3%), it has been found that the aquatic hazard no longer correlates with increasing %A-N and is essentially constant. At this point the aquatic hazard is based on the geometric mean of similar polymers with measured data. 6 of 11 ------- Interpretive Assistance Document for Assessment of Polymers SAR Equations for Estimating Aquatic Toxicity of Polycationic Polymers Apr. 2008 Carbon-Based Silicon-Based Natural-Based Fish Acute* If %A-N <3.5; Log [Fish 96-hr LCso] = 1.209 - 0.462 x %A-N If %A-N >3.5; Fish 96-hr LC50 = 0.28 mg/L If %A-N <3.5; Log [Fish 96-hr LCso] = 2.203 - 0.963 x %A-N If %A-N >3.5; Fish 96-hr LC50 = 1.17 mg/L Data indicate that acute toxicity toward fish will be similar or less than that for carbon-based backbone polymers. SAR analysis should employ the nearest analog method. Daphnid Acute* If %A-N <3.5; Log [Daphnid 48-hr LCso] = 2.839 - 1.194 x %A-N If %A-N >3.5; Daphnid 48-hr LC5o = 0.10 mg/L Data indicate that acute toxicity toward Daphnids will be similar or less than that for carbon- based backbone polymers. SAR analysis should employ the nearest analog method. If %A-N <4.3; Log [Daphnid 48-hr LCso] = 2.77-0.412 * %A-N If %A-N >4.3; Daphnid 48-hr LC50 = 11 mg/L Green Algal Acute* If %A-N <3.5; Log [Green Algae 96-hr ECso] = 1.569 - 0.97 x %A- N If %A-N >3.5; Green Algae 96-hr EC5o = 0.040 mg/L Data indicate that acute toxicity toward green algae will be similar or less than that for carbon-based backbone polymers. SAR analysis should employ the nearest analog method. Data indicate that acute toxicity toward green algae will be less than that for carbon-based backbone polymers. SAR analysis should employ the nearest analog method. Fish Chronic* Acute to Chronic Ratio (ACR) of 18 Acute to Chronic Ratio (ACR) of 18 Acute to Chronic Ratio (ACR) of 18 Daphnid Chronic* Acute to Chronic Ratio (ACR) of 14 Acute to Chronic Ratio (ACR) of 14 Acute to Chronic Ratio (ACR) of 14 Green Algal Chronic* If %A-N <3.5; Log [Green Algae ChV] = 1.057- 1 x o/0a-N If %A-N >3.5; Green Algae ChV = 0.020 mg/L Use the SAR for methodology above for carbon-based backbone polymers Data indicate that chronic toxicity toward green algae will be less than that for carbon-based backbone polymers. SAR analysis should employ the nearest analog method. *Please note conditions for application of Mitigation Factors (MF) on page 8, for certain scenarios and cationic/amphoteric polymers. This may affect the quantitative results of polymer profile. Amphoteric Polymers - These polymers contain both positive and negative charges in the same polymer. The toxicity of these polymers is dependent on cation-to-anion ratio (CAR) and the overall cationic charge density. Toxicity increases with cationic charge density and, when charge density is constant, increases with CAR. The toxicity of these polymers may be reduced by a toxicity reduction factor (TRF) calculated for each endpoint. In cases where chronic endpoints are estimated using an acute to chronic ration (ACR), apply the ACR after the TRF is applied to the acute endpoint, no further TRF is applied to the chromic endpoint. The toxicity of these polymers is predicted in 4 steps: Step 1: a. Calculation of the %A-N: this is done as for cationic polymers above. b. Calculation of the CAR; this calculation is as follows: CAR = ratio of cations to anions in the chemical = [total number of cations] [total number of anions] Step 2: Estimate the aquatic toxicity from the %A-N as if the polymer were polycationic. Step 3: Calculate the TRF from the CAR for each end point from the following equations: Fish Acute TRF (96-hr LC50): Log [TRF] = 1.411 - 0.257 x CAR Daphnid Acute TRF (48-hr LC50): Log [TRF] = 2.705 - 0.445 x CAR Green Algae Acute (96-hr EC50): Log [TRF] = 1.544 - 0.049 x CAR Green Algae Chronic (96-hr ChV): Log [TRF] = 1.444 - 0.049 x CAR 7 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 Step 4: The predicted value from Step 2 is multiplied by the correct TRF to generate the final toxicity value. Cationic and Amphoteric Polymers: Mitigation of Toxicity - Standard aquatic hazard testing media (OECD) usually has a low total organic content (TOC) which may result in artificially high toxicity of polycationic and amphoteric polymers in those media. Surface waters tend to have higher total organic content (TOC) and dissolved organic content (DOC) than what is used in standard (OECD) aquatic toxicity testing media. It has been shown that DOC, particularly humic and other acidic compounds, reduces the toxicity of cationic and amphoteric polymers to the aquatic environment. Due to this, the aquatic hazard may be over estimated in laboratory testing of this type of polymer, which, in large part is what the SAR methods are based on. In order to correct for TOC in actual surface water versus that in laboratory testing media, a mitigating factor (MF) has been calculated, based on testing done with standard media compared to testing done with media containing a standard 10 mg/L TOC as humic acid, to apply to the aquatic effect levels estimated using SAR equations. The MF is dependent on the overall charge density, calculated as %A-N, for the polymer. Several conditions and/or structural features have been shown to affect the mitigation factor, which are discussed below. Mitigating Factor (MF) for Polymers that are formed by the random reaction of monomers and have minimal oligomer content (i.e., <25% with MW <1,000; <10% with MW<500): For charge density where %A-N is >3.5: MF = 110 For charge density where %A-N is 3.5 - 0.7: Log [MF] = 0.858 + 0.265 * %A-N For charge density where %A-N is <0.7: Do not use a MF for these cases; MFs have not been established, but are expected to be <7. Conditions effecting Mitigation Factor (MF) value: It has been shown that as LMW component composition increases, the MF decreases. For compounds with high LMW component compositions, do not apply a mitigation factor. The mitigating factor has been shown to be decreased by the addition of ethoxy groups, or ethoxy ether groups, substituted directly on the nitrogen i.e. N(CH2CH20)n, with the mitigations factor being decreased for each additional group of this type bonded to the nitrogen. If a single ethoxy group is attached, the MF is multiplied by 0.67 If two ethoxy groups are attached, the MF is multiplied by 0.33 If three ethoxy groups are attached, the MF is essentially 0 8 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 HUMAN HEALTH HAZARD ESTIMATIONS Non-Cancer Human Health Hazard - The approach for assessing potential human health concerns posed by a polymer depends on the type and availability of toxicity data. In most cases, there is a paucity of data, which precludes adequate evaluation of the polymer itself, and requires an assessment based on information available for, e.g., close analogs, chemical class, or the constituent monomer(s). The following text presents a hierarchical approach often used in evaluating the human health effects of polymers. Assessment Based On Toxicity Data For The Polymer Or Analog- For some polymers, adequate toxicity data exist in the literature or are supplied by the submitter for assessing the potential health effects of the polymer. In this case, systemic effects, as well as portal of entry effects, are thoroughly evaluated based on data for the polymer itself. In the absence of adequate data on the polymer, or to fill specific data gaps, the assessment will be based on structurally related analog(s) that have adequate toxicity information. Assessment Based On Chemical Class Information - Often, either no toxicity data are available or the data may be inadequate for thorough evaluation of the health effects of the polymer. For these polymers, several lines of evidence are used in parallel. The assessment may be based on the toxicity information available for the chemical class. For example, if a polymer has a structure similar to that of amphoteric surfactants, the toxicity of the polymer may be assessed based on information available for such surfactants. The toxicity of a polymer may also be evaluated based on its intended use. For example, if the polymer is a chelating agent, the assessment will consider the toxicity information available for such agents based on their functional effect. The evaluation should also take into consideration the presence of reactive functional groups (RFGs) on the side chains. A key consideration is whether these side chains are likely to have biological functions in the context of their presence on a larger molecule (since they may not be available for interaction with the same cellular targets as a small molecule would be with the same structure). Additionally, if the polymer is expected to undergo hydrolysis (in the environment, under physiological conditions such as the acidic pH of the stomach, or enzymatically), the evaluation of the health effects should take into consideration the toxicity data available for the hydrolysis product(s). If hydrolysis is expected, then the toxicity assessment may also need to consider potential toxicity of the hydrolysis products. In other instances, the size or chemical properties (e.g., solubility) of the polymer will raise the question regarding its bioavailability. Typically, polymers with molecular weight > 1000 are considered to be of limited bioavailability. If it is known, or if there is evidence to suggest that the polymer is not bioavailable, the evaluation will be limited to consideration of portal of entry effects. Assessment Based On Residual Monomers - It may also be appropriate to develop an assessment based on the toxicity information of the low molecular weight species or residual monomers if they exist in a product at significant quantities (e.g., >10%). Lung Effects Of High Molecular Weight Polymers - Polymers with MWn of >10,000 are generally of concern only for lung effects. For concerns specific to lung toxicity, these polymers are typically divided into 3 classes; soluble, insoluble, and swellable. The associated hazard concerns are qualitative, rather than quantitative, and are used to identify inhalation concerns. Additional guidance on the human health assessment of high molecular weight polymers is available at: http://www.epa.gov/opptintr/newchems/pubs/hmwtpolv.htm. Soluble - Soluble polymers of MWn 10,000 - 13,000 are not expected to exhibit lung toxicity because they can rapidly clear from the respiratory tract, preventing lung overload. However, soluble polymers of MWn >13,000 may have the potential to cause lung overloading effects. Polymers that are soluble as well as swellable (tea bag test shows loss of material) are considered soluble for the determination of lung effect concerns. Insoluble - There are concerns for insoluble polymers with MWn >10,000 for the potential to cause lung overloading. Studies have shown irreversible lung damage as a result of respiration of polymer particles with MWn >70,000. Additional concerns exists for ultra-fine particles with significant amounts of <10 micron material. 9 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 Swellable - Polymers of this type that can absorb their weight or greater in water have serious health concerns for fibrosis and/or cancer. Cancer Human Health Hazard - OncoLogic may be used to assess the potential human health cancer concerns for polymers. The assessment uses input on basic properties, structural features, and components of the polymer; not all of these properties are required, however, more data input will lead to a more accurate assessment of the potential carcinogenic effects. In addition, the software goes through several yes or no questions to help in the assessment. The data needed, as well as many of the questions that will be asked, are listed below. Average molecule weight (MWn) Is the polymer made of covalently linked repeating units? Does the polymer contain >2% residual monomer? Does the polymer contain >2% material with MW <500? Does the polymer contain any of the following atoms: Beryllium (Be), Cadmium (Cd), Chromium (Cr), Nickel (Ni), Arsenic (As), Antimony (Sb)? Is the polymer crosslinked? Any reactive functional groups (RFGs) on the polymer or unreacted monomers should be included. Water solubility of the polymer. Is the polymer expected to be inflammatory? Is the polymer expected to accumulate in soft tissues? What routes of exposure (ingestion, injection, and/or inhalation) are expected? Is the polymer going to be in a form that is easily respirable? 10 of 11 ------- Interpretive Assistance Document for Assessment of Polymers Apr. 2008 Data Collection Sheet for Assessment of Polymers This data collection sheet can be used to collect data important to the assessment of polymers. Polymer Representative Structure Mole Ratio (or Percent) of each monomer Are the monomers blocked? MWn %<1000, % <500 Residual Monomer(s) (Wt %) Solubility/ Dispersability/ Swellability Particle size Overall Polymer Charge Reactive Functional Groups (RFGs, if any) Wt % of RFGs Cation Generating Groups (if any) Percent of Amine Nitrogen (%A-N) 11 of 11 ------- |