UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D. C.

OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES June 09, 2006 DP Barcode D293411 PC Code 109702 MEMORANDUM SUBJECT: Response to Comments of Phase 3 Period on the Revised Draft EFED RED Chapter for Cypermethrin FROM: Miachel Rexrode, Fishery Biologist, Senior Scientist Michael Hoffmann, Biologist Ronald Parker, Senior Environmental Engineer José Luis Meléndez, Chemist Environmental Risk Branch V Environmental Fate and Effects Division ( 7507P)

THROUGH: Karen Whitby, Acting Chief Environmental Risk Branch V Environmental Fate and Effects Division ( 7507P)

TO: Dirk Helder, Chemical Review Manager Veronique C. LaCapra, Chemical Review Manager Margaret Rice, Branch Chief, Reregistration Branch II Special Review and Reregistration Division ( 7508P)

The registrants of cypermethrin, and various interested parties, provided comments related to water quality and other matters on the Draft of the EFED Chapter of the Reregistration Eligibility Document ( RED). The purpose of this memorandum is to address those comments. In a separate cover, the EFED RED Chapter, also addressing those comments will be issued.

EFED used a format to address the comments, with abbreviations to identify the party that submitted the comment, side by side with the responses. The comments were sometimes written verbatim, and other times they were summarized, as needed. The Agency also numbered each of the comments in order to streamline and focus Agency responses. 2 Abbreviations:

  SWRCB, State Water Resources Control Board, Division of Water Quality, California Waterboards   CRWQCB, California Regional Water Quality Control Board, San Francisco Bay Region   Supporting Documents: CDFG, State of California Department of Fish and Game o TDC Environmental, Pesticides in Urban Surface Water Urban Pesticides Use Trends Annual Report 2005, Prepared for the San Francisco Estuary Project o UP3P K. Moran, UP3 Project, Sources of Pyrethroids in Urban Runoff o Oros and Werner, Pyrethroids Insecticides: An Analysis of Use Patterns, Distributions, Potential Toxicity and Fate in the Sacramento San Joaquin Delta and Central Valley ( UP3) o WestonSecondUrban: Amweg, E. L., D. P. Weston, et al. ( 2006) " Pyrethroid Insecticides and Sediment Toxicity in Urban Creeks from California and Tennessee." Environ. Sci. Technol. In press ( ASAP article), web release date: January 31, 2006. o Weston ET& C 04 05 corrected: Amweg, E. L., D. P. Weston, et al. ( 2005) " Use and Toxicity of Pyrethroid Pesticides in Central Valley, California, U. S. A." Environ. Toxicol. and Chem. 24( 15): 1300 o WestonFirstUrban: Weston, D. P., et al. ( 2005) " Aquatic Toxicity Due to Residential Use of Pyrethroid Insecticides." Environ. Sci. and Technol. 39( 24): 9778 9784 o Medina, M, et al.( 2002) " Age and sex related variation in sensitivity to pyrethroid cypermethrin in the marine copepod/ Acartia tonsa Dana." Arch. Environ. Contam. Toxicol. 42( 1): 17 22 o Maund, S. J., et al. ( 2002) " Partitioning, Bioavailability, and toxicity of the pyrethroid insecticide cypermethrin in sediments." Environ. Toxicol. Chem. 21( 1): 9 15 o EcoWise Certified Standards for IPM Certification in Structural Pest Management for Structural Pest Control Board Branch 2 Licenses.   CASQA, California Stormwater Quality Association   CSWRCB, California State Water Resources Control Board, Division of Water Quality   CSJESD, City of San José Environmental Services Department   SFE, San Francisco Department of the Environment   FMC, FMC Corporation   OPP USEPA Office of Pesticide Programs   EFED OPP Environmental Fate and Effects Division   HED OPP Health Effects Division   BEAN OPP Biological and Economical Analysis Division   SRRD Special Review and Reregistration Division   PWG, Pyrethroids Working Group 3 SWRCB, State Water Resources Control Board, Division of Water Quality, Waterboards of California Comment 1: The SWRCB, along with nine Regional Quality Control Boards, is the principal state agency with regulatory responsibility for coordination and control of water quality. Recent studies have raised concerns that water quality impairments due to pyrethroids are on the rise. The current draft 2002 California section § 303( d) list contains three recommended listings for pyrethroids.

Response to SWRCB comment 1: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 2: The Board is particularly concerned that environmental risk related to aquatic ecology are not adequately considered in the registration/ reregistration process. They require of the OPP complete an assessment of impacts to water quality.

Response to SWRCB comment 2: The Agency has been conducting national level, aquatic exposure/ risk assessments for the pyrethroid insecticides since the early 1990' s and is continuously working to refine its risk assessment methods and chemical environmental fate and toxicity databases. Please refer to the Agency's response to CRWQCB comment 21.

SWRCB Comment 3: SWRCB are concerned that data gaps in the risk assessment preclude a full evaluation of risks that may have implications on the CWA.

Response to SWRCB comment 3: Please refer to the Agency's response to SWRCB comment 2.

SWRCB Comment 4: SWRCB recommend to forbid use of the chemical above ground outdoors in urban areas and require controls to prevent cypermethrin runoff from preconstruction termiticide applications. This to prevent toxicity to sediment dwelling organisms in urban creeks ( more on this follows).

Response to SWRCB comment 4: The SWRCB comment assumes that it is the aboveground outdoors uses which cause runoff from pre construction termiticide applications and are the direct cause of the toxicity to sediment dwelling organisms in urban creeks. The Agency, however, is required to take a more comprehensive national view of the uses of cypermethrin. Other uses or mis uses may be the cause of exposure and toxicity to sediment dwelling organisms in California and/ or other parts of the nation.

SWRCB Comment 5: Furthermore, since the agricultural use of cypermethrin has increased, SWRCB recommend that sufficient analysis evaluate the potential for impacts due to off site losses from agricultural source areas, where pyrethroids are applied.

Response to SWRCB comment 5: Please refer to the Agency's response to SWRCB comment 2. 4 SWRCB Comment 6: SWRBC requests that the EPA complete a cumulative environmental risk assessment for pyrethroids. The Board does not believe that the Agency will be able to manage the pyrethroids risk adequately without a cumulative approach to environmental risk mitigation.

Response to SWRCB comment 6: The EFED does not conduct cumulative environmental risk assessments with regard to individual REDs; however, at this time, the Division is conducting a comparative assessment of selected synthetic pyrethroids. Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 7: SWRBC requests that the Agency provide another opportunity for public participation in the cypermethrin reregistration process prior to the reregistration elegibility decision. Given the substantial water quality risks, the additional information that the Agency has requested and is receiving, the additional analysis that the Agency will undertake and the additional costs associated with the risk management decision, a full public participation process is warranted.

Response to SWRCB Comment 7: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 8: Pyrethroids are widespread, found in surface water, ground water, surface water sediment, air, rain, and sewage sludge. Some pyrethroids are used primarily in urban areas. As Oros and Werner report indicates, agricultural use of pyrethroids has increased steadily since 1991. Recent studies found pyrethroids in 75% of sediment samples taken in the Central Valley. Recent investigations of sediments in more than 15 Northern California urban creeks found pyrethroids in almost every sample.

Response to SWRCB Comment 8: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 9: The pyrethroids replaced organophosphorous pesticides as the most commonly used pesticide in California urban areas ( after phase out of diazinon and chlorpyrifos). The shift in pesticide use appears to be causing widespread toxicity to sediment dwelling organisms that reside in California urban surface water sediments. Cypermethrin is a significant contributor to the identified toxicity.

Response to SWRCB Comment 9: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 10: These findings are activating EPA's requirements to designate many California waters as impaired in accordance with CWA § 303( d), We anticipate that recently published data will be considered in the next round of listings in 2006.

Response to SWRCB Comment 10: Please refer to the Reregistration Eligibility Decision for Cypermethrin. 5 SWRCB Comment 11: There are three possible outcomes from reregistration decisions:   Few or no changes   Allowable uses of pyrethroids are changed, shifting the market to different pyrethroids, or   Problematic uses of pyrethroids are phased out Response to SWRCB Comment 11: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comments 12: The Agency needs to act in a comprehensive manner:

A. Complete a cumulative environmental risk assessment of pyrethroids.

Response to SWRCB Comment 12A: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

B. Complete an " alternatives assessment" that considers alternative types of pesticides.

Response to SWRCB Comment 12B: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

C. Complete a " cluster assessment" for problematic outdoor urban insecticide applications ( e. g. ant control around buildings, which has been identified as a source of urban runoff).

Response to SWRCB Comment 12C: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

D. Complete laboratory and field studies to fill data gaps that coordinate pyrethroids use patterns ( agricultural and urban) with field chemical measurements at important fish spawning and rearing areas.

Response to SWRCB Comment 12D: Please refer to the Agency's response to SWRCB comment 2. The Agency is continuously working to refine its pyrethroid chemical environmental fate and toxicity databases.

E. Develop best management practices for agricultural and urban uses to prevent pyrethroids from entering the aquatic environments.

Response to SWRCB Comment 12E: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 13: The preliminary risk assessment indicates that urban uses of pyrethroids have the potential to impact aquatic systems.  The SWRCB believes that there is more than a potential risk. The toxicity to sediment dwelling organisms in urban 6 creeks is documented and widespread, and cypermethrin contributes significantly to this adverse impact.

Response to SWRCB Comment 13: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SWRCB Comment 14: The Board is also concerned that the risk of pyrethroid runoff from agricultural areas has been underestimated.

Response to SWRCB Comment 14: The Agency finds this comment difficult to address without having more information. We are unaware that our modeling produces concentration values that underestimate exposure. If the SWRCB has data that would indicate underestimation, we would appreciate that data being presented to us.

SWRCB Comment 15: Simple fate and transport models should be developed to demonstrate the water quality impact of pyrethroid runoff from both agricultural and urban areas.

Response to SWRCB Comment 15: Please refer to the Reregistration Eligibility Decision for Cypermethrin and the Agency's response to CRWQCB comment 21.

SWRCB Comment 16: The Agency should consider, develop, and implement pest control alternatives, other risk mitigation options, best management practices and sustainable farming practices. It should also consider cost benefit analysis for risk management, with the need to address urban as well as agricultural uses and the cost of non compliance with the CWA requirements.

Response to SWRCB Comment 16: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 1: Numerous scientific studies have demonstrated that the use of pesticides in accordance to FIFRA can result in violations of water quality standards. As a result, many waters have been designated as " impaired" in accordance to the Federal Clean Water Act. The CRWQCB has recognized the need for the USEPA to minimize the potential for registered pesticides to impair surface water quality.

Response to CRWQCB Comment 1: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 2: The pyrethroids replaced organophosphorous pesticides. The pyrethroid insecticides are widespread. They have been detected in surface water, ground water, surface water sediments, air, rain, and sewage sludge.

Response to CRWQCB Comment 2: The EFED recognizes the issues brought up by the CRWQCB. The pyrethroids are relatively persistent, and some are highly persistent. For that reason, they may be observed in a variety of locations. The Agency would be 7 happy to have access to any monitored data for use in its risk assessments. Please refer to the Reregistration Eligibility Decision for Cypermethrin for additional information.

CRWQCB Comment 3: Some pyrethroids, including cypermethrin, are used primarily in urban areas. Recent investigations of sediments in more than 15 Northern California urban creeks found pyrethroids in almost every sample.

Response to CRWQCB Comment 3: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 4: The shift from organophosphorous insecticides to pyrethoids appears to be ending the water column toxicity, but it is causing toxicity to sediment dwelling organisms. The CRWQCB predicted this problem in a report published in 2003.

Response to CRWQCB Comment 4: The EFED has been working with the PWG to obtain sediment toxicity data and to strengthen its environmental fate and ecotox database for many years. Concern for both acute and chronic risk to benthic organisms has been identified in the EFED's Science Chapter; all RQs exceed the acute and chronic LOCs for every scenario considered.

CRWQCB Comment 5: The USEPA needs to complete a cumulative environmental risk assessment of the pyrethroids. It is noted that the pyrethroids have a common mode of action and exposure to multiple pyrethroids in surface waters is likely.

Response to CRWQCB Comment 5: Please refer to the Agency's response to SWRCB comment 6 and the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 6: The draft assessment indicates that there is a potential risk   toxicity to sediment dwelling organisms in urban creeks is documented and widespread   and cypermethrin contributes to this adverse impact. The CRWQCB is concerned about the limited analysis of outdoor urban cypermethrin use.

Response to CRWQCB Comment 6: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 7: The Board encouraged California agencies and provided financial support for research on urban uses of pyrethroids. They shared the information with the EPA; however, some important findings were not included in the assessment. The CRWQCB attached abstracts and several publications with information immediately relevant to cypermethrin's environmental risk. It includes sediment toxicity test to Hyalella azteca which has documented in at least 15 Northern California creeks.

Response to CRWQCB Comment 7: The EFED/ OPP appreciates the fact that the CRWQCB has shared the data with the EFED/ OPP. Please see the Agency's Response to CRWQCB Comment 12 and Comment 13. 8 CRWQCB Comment 8: Request a full six phase public participation process for cypermethrin. The Board provides various reasons to support this request.

Response to CRWQCB Comment 8: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 9: Request to use the Water Quality Criteria ( WQC), developed by the Department of Fish and Game, for cypermethrin in accordance with USEPA guidance and available aquatic toxicity data. Cypermethrin Risk Assessment, ppb Waters Criterion Method, ppb Freshwater acute 0.14 0.39 0.002 ( 1 h) Freshwater chronic 0.069 0.14 ( Unable to calc, < 0.002)( 4 days) Saltwater acute 0.00457 0.95 ( Unable to calculate) Saltwater chronic 0.000781 0.34 ( Unable to calculate) Saltwater includes estuarine/ marine.

Response to CRWQCB Comment 9: It was observed that the WQC were incomplete, while the risk assessment toxicity reference values were available. At this time, the methodology described in the EFED's guidelines for a deterministic risk assessment, call for the use of toxicity reference values, not WQC.

CRWQCB Comment 10: Most states, including California, have narrative WQC in addition to, and in the absence of numeric criteria. For example, for San Francisco Bay, it is as follows:   Population and community ecology   " All waters shall be maintained free of toxic substances in concentrations that are lethal to or that produce significant alterations in population of community ecology or receiving water biota. In addition, the health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors."   Sediment   " Controllable water quality factors shall not cause a detrimental increase in the concentrations of toxic pollutants in sediments or aquatic life."   Toxicity   " All water shall be maintained free of toxic substances in concentrations that are lethal to or that produce other detrimental responses in aquatic organisms. The health and life history characteristics of aquatic organisms in waters affected by controllable water quality factors shall not differ significantly from those for the same waters in areas unaffected by controllable water quality factors.

Response to CRWQCB Comment 10: The decision to advance cypermethrin for consideration in establishing a Water Quality Criteria ( WQC) lies within the purview of USEPA Office of Water ( OW). The OPP stands ready to collaborate with the OW within the confines of Confidential Business Information ( CBI). 9 CRWQCB Comment 11: According to these narratives and in accordance with the Federal CWA's statement of national policy " that the discharge of toxic pollutants in toxic amounts is prohibited." Arguments such as the invertebrates are resilient and their population may possibly reintroduces themselves again in time, or diminished invertebrate diversity may not be important for the ecosystem integrity do not agree with the Clean Water Act, nor its costly compliance requirements.

Response to CRWQCB Comment 11: Please see the Agency response to CRWQCB Comment 10.

CRWQCB Comment 12: There are sediment toxicity data for Hyalella azteca available. For cypermethrin, the toxicity is as follows: average sediment 10 day LC50 ( µ g/ g organic carbon) is 0.38.

Response to CRWQCB Comment 12: The EFED is aware of this toxicity endpoint from the Maund et al. ( 2002) paper. In fact, the data from this open literature study had already been submitted to the Agency prior to publication ( MRID 44074402 and 44074406). However, rather than use the average sediment 10 day LC50 ( µ g/ g organic carbon), the EFED used the most sensitive 10 day LC50 ( 3.6 µ g/ kg sediment) to determine risk to aquatic benthic invertebrates in the risk assessment.

CRWQCB Comment 13: The Board appreciates the EPA efforts and the consultation with the Office of Water to come up with the equilibrium partitioning approach. However, now that there are toxicity data available that can be used in the assessment, they request that the analysis be revised to reflect actual potential toxicity.

Response to CRWQCB Comment 13: Toxicity data were used to evaluate acute risk to benthic invertebrates exposed to cypermethrin in the sediment based on what was considered to be the most appropriate and sensitive available data ( as stated above in the Agency's Response to CRWQCB Comment 12). However, the LC50' s were based only on concentrations of cypermethrin in bulk sediment. EFED also estimates risk to benthic invertebrates resulting from exposure to cypermethrin in pore water. Therefore, the equilibrium partitioning approach had to be employed in this instance because toxicity data based on pore water concentrations were not available; in one study pore water concentrations were not measured ( MRID 44074402), and in the other the concentrations were below the LOD ( MRID 44074406). The EFED recognizes that additional sediment toxicity data with LC50' s based on both sediment and pore water concentrations have been submitted by the PWG for use in this assessment. However, these data are currently under review and may be incorporated at a later date if deemed appropriate.

CRWQCB Comment 14: The risk assessment does not include estimates of urban uses of cypermethrin. Probably, they are the major uses nationally. In California, 200,000 pounds of cypermethrin active ingredient were used in 2004 ( almost all in urban areas). Based on data from the California Department of Pesticide Regulation, they know that more than 95% of the cypermethrin occurs in urban areas ( almost all in structural pest control, and some quantities in landscaping and for control of regulated pests). 10 Response to CRWQCB Comment 14: Please refer to the Reregistration Eligibility Decision for Cypermethrin and the Agency's response to CRWQCB comment 21.

CRWQCB Comment 15: Most common reported used labels indicate that cypermethrin may be:   Sprayed in a band around the exterior of the structure to control nuisance insects such as ants.   Injected into the ground ( to control termites).   Sprayed in building interiors to control cockroaches, fleas, ants, and other insects.

Response to CRWQCB Comment 15: As indicated, only the first of these uses has a high potential to be washed into urban creeks.

CRWQCB Comment 16: Cypermethrin labels are mostly applied by professionals and specify application rates; however, they do not specify application frequencies. Based on interviews, it appears that monthly applications are typical.

Response to CRWQCB Comment 16: The number of applications influences the amount of cypermethrin that may reach nearby bodies of water. Please refer to the Reregistration Eligibility Decision for Cypermethrin for additional details.

CRWQCB Comment 17: The environmental risk assessment should use all available scientific data. For example, the ECOTOX database was not used. The CRWQCB has also submitted key relevant literature from their own files.

Response to CRWQCB Comment 17: Data submissions are always welcome. The latest version of the EFED risk assessment included the ECOTOX database.

CRWQCB Comment 18: The aquatic toxicity data set is incomplete. It is important that all data gaps be filled, not only the ones listed in the EFED data request, and that the EPA obtain all aquatic toxicity data necessary to develop water quality criteria in accordance with USEPA methods.

Response to CRWQCB Comment 18: EFED required data under the authority of FIFRA. Please, refer to the Agency's response to CRWQCB comment 10 and the Reregistration Eligibility Decision for Cypermethrin for additional details.

CRWQCB Comment 19: The EPA should ensure that practical methods for commercial laboratories are developed and made widely available in a timely manner.

Response to CRWQCB Comment 19: It is OPP's understanding that new methods have recently been developed by the pesticide registrants. 11 CRWQCB Comment 20: The EPA or the registrant should conduct surveillance monitoring of the nation's surface water ( including sediment) for pesticides, with pyrethroids a priority, and in this case, cypermethrin.

Response to CRWQCB Comment 20: Surveillance monitoring is one possible outcome of reregistration activities. Please refer to the Reregistration Eligibility Decision for Cypermethrin for additional details.

CRWQCB Comment 21: The EPA did not consider urban runoff in its water quality modeling. They indicate that modeling should address the following considerations:   Washoff from urban areas is probably substantially greater than from agricultural fields.   Particle erosion rates for urban land uses have been shown in the literature to correlate with the amount of impervious surface in the watershed ( reference provided).   Standard buildup and washoff equations for sediments on urban impervious surfaces are available and widely used in urban modeling tools ( e. g. Hydrological Simulation Program   Fortran [ HSPF], and Stormwater Management Model [ SWMM].   To complete the urban runoff modeling, the EPA can use simplified scenarios, just as it does for agricultural runoff modeling. For example, a simplified model could be developed for an urban watershed with relatively high impervious surface area, and then evaluated in a range of climatic conditions.   Suggest two websites to select a watershed case study. They also provide a website with weather data.

Response to CRWQCB Comment 21: One of the risk assessment goals of the Office of Pesticide Programs ( OPP) is to estimate pesticide exposure through all significant routes of exposure in both rural and urban areas. For aquatic ecological exposure assessments for pesticides which have urban uses, OPP assumes separate routes for exposure for indoor and for outdoor uses. For indoor uses that may result in pesticide residues in wastewater ( treatments to insects, pets, clothing, etc.), it is assumed that wash water containing pesticide residue flows into a building drain and passes through a sanitary sewer and publicly owned treatment works ( POTW) before being discharged to surface water. For outdoor urban uses ( applications to home lawns, gardens, parks, etc.), it is assumed that runoff water from rain and/ or lawn watering may remove pesticide to storm sewers and then directly to surface water. Simulation of each of these routes of exposure is important to the overall assessment. OPP has developed methods and carried out assessments for indoor uses which ultimately discharge through a POTW to surface water, but has made less progress in estimating discharges resulting from urban outdoor uses. Where applicable, monitoring data from urban areas, such as that collected by the USGS NAWQA program and others, are regularly included in OPP risk assessments. Estimating pesticide in runoff from urban areas through computer simulation modeling has proven more difficult. 12 Developing methods for modeling aquatic ecological pesticide exposure in urban areas is difficult due to lack of a model specifically developed to simulate pesticide fate and transport in a complex urban landscape. Data for model input ( pesticide application amount and timing; physical representation of the urban landscape, storm sewer and receiving water configuration) and for model calibration ( past history of flow and pesticide concentrations) is also generally unavailable. OPP is aware that pesticide aquatic simulations have been performed by the EPA Office of Water ( OW) and has discussed the technical feasibility of their methodology for national scale assessments required under FIFRA. The OW modeling efforts have been extremely time consuming requiring collection of specific use information and extensive data for parameterization for the simulated watershed. OPP has identified limitations and deficiencies in existing models and data as part of the methods development process. These include the following:   OPP conducts national level exposure/ risk assessments for pesticide registration. Supporting models need to be flexible enough to simulate large numbers of sites nationally. Simulations of a single site for which there may be existing data would be unlikely to provide useful information for a national registration. Local, sitespecific exposure assessments are only performed for endangered species risk assessments.   Many urban runoff models were designed primarily as water quantity rather than water quality models and do not have water quality modeling capabilities sophisticated enough to simulate pesticide fate and transport ( e. g. HEC2, SWMM). Models that simulate pesticides need components to handle runoff and leaching as well as chemical degradation, dissipation, volatilization and adsorption/ desorption for both the land and the water components of the model.   Models used for simulating pesticide use in agricultural areas ( e. g. PRZM, GLEAMS, SWRRBWQ, EPIC/ APEX, SWAT, etc) typically do not include features needed to simulate urban areas. Urban settings include impermeable surfaces; storm sewer networks; pumping stations; temporary holding ponds; individual, small scale lawn irrigation systems; and experience multiple, relatively small temporally and spatially variable applications that are not simulated in agricultural models.   Some commonly used models need extensive monitoring data for calibration ( e. g. HSPF included in the OW BASINS platform) and therefore can only be used to simulate sites and pesticides for which extensive flow and pollutant data has been collected in advance. This type of model cannot be used to simulate unmonitored sites or pesticides.   Homeowner application data is not readily available and is difficult to estimate with any degree of confidence. Estimates of the pesticide application area and rate as well as its temporal and spatial distribution are needed to simulate pesticide in runoff in an urban area.   Unlike scenario sites for agricultural simulations; representative, high exposure, urban watersheds and water bodies that can be used in national scale, pesticide exposure assessments in urban landscapes have not been developed. Receiving water bodies developed for use in simulating aquatic ecological exposure of pesticides used in agricultural scenarios were designed based on USDA farm 13 pond construction guidelines. These guidelines were used in the mid 1900s to design and build hundreds of thousands of rural water bodies. These agricultural modeling sites represent a common feature in rural areas.   It is likely that pesticide runoff in urban areas is impacted by inadvertent application of lawn care products to impermeable surfaces ( driveways, sidewalks or road surfaces adjacent to lawns). Crack and crevice applications are specifically designed to be applied to these hard surfaces. Data on deposition/ degradation/ resuspension and washoff from impermeable surfaces are not available.

OPP has, and continues, to consult with other offices within EPA as well as other federal, state and local agencies on available tools and methodologies for assessing aquatic exposure from urban/ suburban pesticide use. However, until such time as a reasonable modeling approach which is appropriate for a national scale risk assessment is developed, OPP will continue to rely predominantly on available monitoring data for characterizing aquatic exposure from urban runoff. Risk assessments indicate that these data provide estimates of a lower bound of potential exposure.

CRWQCB Comment 22: The negative temperature coefficient of the synthetic pyrethroids, in this case, cypermethrin, needs to be addressed. Many of the nation's surface waters have a low temperature, compared to the laboratory temperature.

Response to CRWQCB Comment 22: The EFED is aware that pyrethroids have exhibited a negative temperature coefficient of toxicity and would consider incorporating evidence that substantiates this behavior if such data become available for cypermethrin. However, at this time, acceptable substantive data are not available for quantitative use in this risk assessment.

CRWQCB Comment 23: Request that EPA, as part of the Interagency Ecological Program, evaluate the potential that cypermethrin may be a contributor to the sudden decline in San Francisco Bay   Delta fisheries. This is also addressed in one of the supporting documents.

Response to CRWQCB Comment 23: The suggested type of analysis is beyond the scope of this national screening level risk assessment.

CRWQCB Comment 24: The Board recognizes that the EPA has addressed the issue of synergism of PBO with pyrethroids; however, it is not fully acknowledged in this risk assessment. They indicate that they are aware of a study not yet published, of the potential synergism of a pyrethroid and PBO in the overlying water. They ask that the issue be addressed.

Response to CRWQCB Comment 24: The toxicity of pyrethroids and PBO is considered in the individual risk assessments of the pyrethroids, according to the data available. Dr. Weston was contacted on Jan. 5, 2006 regarding two forthcoming papers. The first, to be published in Environmental Toxicology & Chemistry, deals with the 14 occurrence of PBO alone, and indicates little potential for synergism. The second, which has yet to be submitted for publication, indicates some potential for synergism from mosquito spraying of PBO with pyrethrins. Typically, the cypermethrin products employed for agricultural uses that bring major exposure to wildlife do not contain PBO.

CRWQCB Comment 25: The risk management should be implemented including exceedances of water quality criteria and non compliance with NPDES permits. The risk benefit standards of FIFRA require the EPA to ensure that pesticides are used in such a manner that mitigation under the Clean Water Act is minimal or unnecessary. The EPA should not leave states and municipalities in non compliances or needing to prepare and implement costly TMDLs.

Response to CRWQCB Comment 25: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 26: The EPA should prohibit outdoor cypermethrin use in urban areas. There are numerous alternatives to cypermethrin to control pests around structures ( refers to document EcoWise IPM Certification Program).

Response to CRWQCB Comment 26: CASQA also recommend to phase out cypermethrin's outdoor uses. Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 27: Without modeling, it is not possible to know the potential of these chemicals to reach the surface waters ( runoff is unknown).

Response to CRWQCB Comment 27: Please, refer to the Agency's response to CRWQCB comment 21 for information about the feasibility of an urban model at this time.

CRWQCB Comment 28: Should the EPA be unwilling to accept the Board's recommendation to phase out the aboveground outdoor urban uses of cypermethrin, then they recommend limiting the uses to spot treatments and they offer a definition of spot treatment.

Response to CRWQCB Comment 28: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 29: The EPA should require the implementation of control measures for pre construction termiticide applications to prevent cypermethrin runoff from construction sites. They offer the following " best management practices:" ( abbreviated)   Limit the area to be treated to only that can be treated during a normal working shift and backfilled with untreated soil by the end of the work shift.   Treated areas shall be covered as soon as practicable. Backfill and covering must keep rain and runoff from contacting treated soil. 15   On grade spraying should not be conducted during sustained high wind.   Application should not commence within 24 hours of a predicted storm event.   Surface termiticide application is not allowed within 50 feet of any down gradient waterway if there is no vegetative buffer.

Response to CRWQCB Comment 29: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 30: They question if the EPA should allow cypermethrin in swimming pool systems. They were unable to determine if the cypermethrin is in contact with the water of the pool. The risk assessment did not assess this use. If a pool is emptied, usually happens every several years, the discharge would go to the sewer system, controlling such discharges is near impossible.

Response to CRWQCB Comment 30: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CRWQCB Comment 31: The following loose subjects were also mentioned:   Risk Management must ensure that safer alternatives will be used.   Cost Benefit analysis should include state and municipal compliance cost.   Labels should be modified to inform the users of the hazard to aquatic organisms.   Labels should limit the number of applications per year.   Labels should preclude applications prior to rain events.

Response to CRWQCB Comment 31: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

Comments Supporting Document i CDFG: The document is entitled " Hazard Assessment of the Synthetic Pyrethroid Insecticides Bifenthrin, Cypermethrin, Esfenvalerate and Permethrin in the Sacramento San Joaquin River System" It provides information about environmental fate and toxicity of cypermethrin. It also provides use information of the chemical in California and Water Quality Criteria. The interim freshwater final acute value was 0.003 µ g/ L. The interim freshwater criterion continuous concentration for cypermethrin was 0.002 µ g/ L. Calculation of saltwater final chronic value requires paired acute chronic tests from fish, and invertebrate, and an acutely sensitive saltwater species. No monitoring in the Sacramento San Joaquin River system was available.

Response to Supporting Document i CDFG: These data are cited elsewhere in the comments also. The water quality criteria were developed by the California Department of Fish and Game ( DFG), not the EPA. The dataset is incomplete ( no saltwater data). It is noticeable that the document is a hazard assessment of synthetic pyrethroids and there is no monitoring data in the Sacramento San Joaquin River system. 16 Supporting Document ii, Comment UP3P, Moran, K, TDC Environmental, " Sources of Pyrethroids in Urban Runoff": This poster consists of several bits of information.   Eight pyrethroids have been identified as priority chemicals, causing widespread toxicity to sediment dwelling organisms ( Hyallela azteca) in urban creeks draining to the San Francisco Bay Delta Estuary. These chemicals have a variety of uses and a wide range of toxicities.   From 2001 to 2003 the sales of pyrethroids doubled in the Bay area, while three chemicals account for most of the toxic equivalents applied: bifenthrin, cyfluthrin and cypermethrin.   Of the outdoor pyrethroid applications, 72% correspond to structural professional, 8% to other professional, and 20% are non reported. They may include underground applications.   Since pyrethroids are applied to impervious surfaces, they indicate that washoff fractions are greater.   Their conclusion is that the eight pyrethroids are priority chemicals. Outdoor pest control should be the top priority for regulatory agencies. Need to obtain better fate information. Less toxic pyrethroids have higher application rates and substituting one pyrethroid for another may not be the answer.

Response to Supporting Document ii: This poster contains information and conclusions that are stated elsewhere in this comment document. The comments are discussed separately.

Supporting Document iii, Comment Moran, UP3P Project: Pesticides in Urban Surface Water, Urban Pesticides Use Trends Annual Report 2005, Prepared by San Francisco Estuary Project ( SFEP). This is one of three reports. It involved several pesticides. The pyrethroids studied were beta cyfluthrin, bifenthrin, cyfluthrin, cypermethrin, deltamethrin, esfenvalerate, lambda cyhalothrin and permethrin ( note, the pyrethrins were also included).   The general trend was away from the OP's and into the synthetic pyrethroids.   Permethrin and carbaryl were labeled for pet applications.   Urban use of pyrethroids, malathion, fipronil, pyrethrins and PHMB increased from 2001 to 2003. Pyrethroids, fipronil, pyrethrins and perhaps malathion are replacing diazinon and chlorpyrifos in the urban pesticide use market.   Control of pests around buildings by professional pest control operators is the major urban use of pyrethroids.   Tralomethrin is now formulated into non aerosol consumer products with outdoor uses. Soon, it will have the potential to contribute to surface water impacts like other pyrethroids.   The use of beta cyfluthrin grew significantly in 2003.   In 2003, at least half of California pesticide use was in urban areas. As a mitigation recommendation, it was stated to target structural use areas of pyrethroids. And conduct surveillance monitoring of California urban surface water ( including sediment). 17 Response to Supporting Document iii: This document also provides other pieces of information that helps to put the pyrethroids and pyrethrins in context, related to the urban uses. Cypermethrin is noticeably absent in the lists. It may be important to follow the recommendation to do surveillance monitoring of California urban surface waters and sediments. Please refer to the Reregistration Eligibility Decision for Cypermethrin for additional details.

Supporting to Document iv, Comment Oros and Werner ( UP3P): Pyrethroid Insecticides: An Analysis of Use Patterns, Distributions, Potential Toxicity and Fate in Sacramento San Joaquin Delta and Central Valley. This report constitutes an analysis of the use patterns, distributions, potential toxicity and fate in the Sacramento San Joaquin Delta and Central Valley, written by Oros and Werner. It is an extensive report that puts together the current knowledge of the potential role of pyrethroid insecticides in the pelagic organism decline in the upper San Francisco estuary ( Suisun Bay and the Sacramento San Joaquin Delta). Only some of the conclusions are provided here.

Concludes that there are uses of concern:   irrigation return flows from row and orchard crops during summer months   spraying of orchards during the winter dormant season   releasing agricultural tailwater from rice fields during the late spring and early summer   urban areas applications on hard surfaces that occur year round Studies have shown that aquatic and benthic species of concern are present during these events ( see above). Pyrethroids can be found in surface waters and sediments from agricultural areas. There are no urban storm water data to report on the upper San Francisco estuary and the Central Valley Field; studies are needed.

Response to Supporting Document iv: While three of the uses of concern are agricultural related, it appears that the city of San Francisco would like to highlight the last one of the uses of concern: urban areas applications on hard surfaces that occur yearround Responses to comments related to the issue appear in this document elsewhere.

Supporting Document v: Amweg, E. L., et al. ( 2006) " Pyrethroid Insecticides and Sediment Toxicity in Urban Creeks from California and Tennessee." Environ. Sci. Technol. In press, ASAP article. Web release date January 31, 2006. Urban creeks in Sacramento, California, and Nashville, Tennessee were tested on up to four occasions for pesticide residues in sediments, and aquatic toxicity was determined by acute toxicity tests using the amphipod Hyallela azteca.

In California 12 of 15 creeks tested were toxic on at least one sampling occasion, and sediment pyrethroid concentrations were sufficient to explain the observed toxicity in most cases. Bifenthrin was likely responsible for the majority of the toxicity at most sites ( since it is highly toxic). 18 On the other hand, none of the sediments collected from the 12 Tennessee creeks were toxic, and pyrethroids were rarely detectable. Total pyrethroid units ( TU) in all Nashville creeks were consistently below levels expected to cause toxicity to Hyallela azteca.

Precipitation in Nashville ( 119 cm/ yr) is far above that of Sacramento ( 46 cm/ yr), and it occurs year round. Other regional differences are possibly attributable in types of residential development, and pesticide use practices. It is noted that Sacramento does not meter water use, but uses flat rate pricing, which may be a factor contributing to excessive landscape watering and a greater potential for pesticide transport to surface water bodies. Furthermore, in Sacramento, the urban runoff was served by storm drain systems. In Nashville, runoff reached the creeks by flowing across ground surfaces for considerable surfaces.

Response to Supporting Document v: The results of this study show that the problem of pyrethroid contamination may not be " widely spread," as it is indicated in numerous comments. Two cities of similar size in different locations yield contrasting results making the interpretation of the data very difficult. It is rather localized and dependent on factor still to be determined. The EFED/ OPP will continue to gather information as it becomes available, and investigating the extent to which this problem is site specific or more general across pyrethroid usage area.

Supporting Document vi: Amweg, E. L., D. P. Weston, N. M. Ureda ( 2005) " Use and Toxicity of Pyrethroid Pesticides in the Central Valley, California, USA," Environ. Toxicol. And Chem. 24( 15): 1300. This is a corrected manuscript of a previously published article. The paper describes how they were able to determine the acute sediment toxicity values for various synthetic pyrethroids found in sediments in California. These are estimates of LC50 to the amphipod Hyalella azteca. Growth was inhibited typically at levels below the LC50. The results were as follows: Bifenthrin = 0.52 µ g/ goc; cyfluthrin = 1.08 µ g/ goc; cypermethrin = 0.38 µ g/ goc; deltamethrin = 0.79 µ g/ goc; esfenvalerate = 1.54 µ g/ goc; lambda cyhalothrin = 0.45 µ g/ goc; and permethrin = 10.83 µ g/ goc.

Response to Supporting Document vi: The toxicity value reported in this study for cypermethrin appears to come from a previously published paper ( Maund et al. 2002). Please refer to the Agency's response to CRWQCB comment 12 and 13.

Supporting Document vii: Weston, D. P., et al. ( 2005) " Aquatic Toxicity Due to Residential Use of Pyrethroid Insecticides," Environ. Sci. Technol. 39( 24): 9778 9784; Samples were taken from a typical suburban development in Roseville, Sacramento, California. Nearly all creek sediments collected caused toxicity to the amphipod Hyalella azteca, and about half the samples caused nearly complete mortality. Bifenthrin was identified as the primary cause of the toxicity, with contributions of cyfluthrin and cypermethrin. The sources of the pyrethroids are structural pest control by professional applicators and/ or homeowners use of insecticides, particularly lawn care products. The authors believe that Roseville is unlikely to be unique and that other communities may be 19 affected similarly with water and sediment contamination. The authors used LC50 values for individual pyrethroids from the Supporting Document vi.

Response to Supporting Document vii: This is one of various documents by Dr. Weston's team. Their contribution is appreciated. The EFED was working on the issue prior to the publication of the documents. Sediment toxicity and new mobility data had been required to the PWG. These data have been received and are currently in review.

Supporting Document viii: Medina, M. et al. ( 2002) " Age and sex related variations in sensitivity to the pyrethroid cypermethrin in the marine copepod Acartia tonsa Dana" Arch. Environ. Contam. Toxicol. 42( 1): 17 22. This report examines the use of the calanoid copepod Acartia tonsa Dana in the ecological hazard assessment of chemicals released in the environment. It represents an essential link in plankton food incorporation. Cypermethrin is used to treat ectoparasite infestations of salmon.

Acute effects of the chemical were assessed using the calanoid copepod Acartia tonsa. Acartia tonsa has been used in hazard assessments of chemicals in the marine environment, using acute tests, and sex ratio of 1: 1. In this study it was shown that naupliar stages were 28 times more sensitive to cypermethrin than adults after 96 hours of exposure, with LC50' s of 0.005 µ g/ L and 0.142 µ g/ L, respectively.

Significant differences in sensitivity between the sexes were also found during the first 24 hours of exposure, during which males were around twice as sensitive as females. After 24 hours, the difference was not significant. One possible explanation is that there is faster depuration for females through egg production.

They conclude that the standard toxicity analysis with Acartia tonsa are unsatisfactory. It is noted that these studies are conducted with cypermethrin in saltwater and the concentration of cypermethrin is higher at the beginning of the study and lower at the end. They average the values to state the concentration in the exposure vessel.

Response to Supporting Document viii: This study contains some useful information for further characterizing ecological hazard; however, more sensitive data were already incorporated and used to determine risk to estuarine/ marine invertebrates. Therefore, adequate protection has been given to this taxonomic group based on the best available data, and the inclusion of this study would not affect the conclusions of this risk assessment.

Supporting Document ix: Maund, S. J. et al. ( 2002) " Partitioning, Bioavailability, and Toxicity of the Pyrethroid Insecticide Cypermethrin in Sediments," Environ. Toxicol. Chem. 21( 1): 9 15. In this publication, the authors investigate the partitioning, bioavailability and toxicity of cypermethrin in water sediment systems. They found that cypermethrin was rapidly adsorbed, with an overall mean KOC of 350,000 and 99% adsorption occurred in 24 hours. For 1% OM, Koc = 238,000; 3% OM, it was 302,000, and 13% OM, it was 177,000. Measured desorption KOC` s were similar in magnitude to the adsorption ones ( somewhat higher). 20 The bioavailability was measured via body burden of Daphnia magna and Chironomus tentans. Mean biota sediment accumulation factors ( BSAF's), that is, the concentration of the organism as a proportion of the concentration in the sediment decreased with increasing organic carbon content. The BSAF values were 0.31, 0.14 and 0.08 for Daphnia magna and 0.63, 0.19 and 0.08 for C. tentans in 1, 3 and 13% OC sediments, respectively.

The 10 day LC50s of cypermethrin were 3.6, 18, and 32 mg/ Kg for H. azteca and 13, 67, and 62 mg/ Kg for C. tentans in 1, 3 and 13% OC sediments, respectively. Predictions of aqueous concentrations at the LC50 in sediments ( based on KOC) compared well to each other and to the effect concentrations from studies in water alone, suggesting that equilibrium partitioning theory could be used reasonably to predict and normalize the toxicity of cypermethrin across sediments of differing OC content.

Response to Supporting Document ix: Please refer to the Agency's response to CRWQCB comment 12 and 13.

Supporting Document x, EcoWise: Standards for IPM Certification in Structural Pest Management for Structural Pest Control Board Branch 2 Licenses: These are standards adopted as a pilot in the nine San Francisco Bay Area counties and Sacramento County. Overseers: Association of Bay Area Governments ( ABAG), the Sacramento Stormwater Program and Natural Resources Defense Council ( NRDC).   The pilot program will certify an IPM service within a pest control company or branch office.   Certify Branch 2 field representatives and operators through a written exam. Each company or branch office must employ at least one certified individual to oversee its IPM service.   Companies or branch offices submit an application with a written IPM protocol for specific pests and get provisionally certified.   Within a year, applicants must perform 20 IPM service visits for at least 7 different costumers or sites. These visits must be overseen by the company's certified IPM. Practitioner must follow standards, and record the required information on appropriate forms.   After the required service visits, a certification program evaluator will review their record and perform field evaluations to determine if applicants qualify for full certification. The certification program manager will make the final decision on granting certification.   The certification must be renewed after 3 years. Individuals must complete 27 approved continuing IPM education hours every 3 years.   The program includes general pests, but no fumigants or termiticides.   The program emphasizes 3 fundamental elements: o Pest prevention seeks to suppress the pest reproduction, access, shelter/ habitat. Management practices include education to the costumer, prevention of the pest. 21 o Integration of multiple management and tools, such as providing the costumer mechanical and physical controls ( traps, physical barriers), and o Systems approach.   Attachment A is a " prototype" materials list, which is a list of " reduced risk" ( to humans and the environment) pesticides.   Sometimes, a " non safe" pesticide is needed. This is also recorded.   The Pest Management Professional ( PMP) establishes a partnership with the costumer, records a detailed history about the pest problem, and inspects the property. Then the PMP prepares a written list/ map and identifies the pest and proceeds to discuss the findings with the costumer. The PMP provides the costumer with information about IPM and develops a written site specific plan. Finally, the PMP provides inspection records and recommendations, and for ongoing accounts, periodic monitoring program.   There is a record keeping standard, records should have sufficient detail to be understood and audited and demonstrate compliance with the standards of IPM Certification. Records must be kept for at least 3 years, and be available for inspection and reproduction during normal business hours, by authorized representatives. Copies of inspection records must be provided to the costumers, with the recommendation, within a week after each visit.

Response to Supporting Document x: This is an appealing approach to the use of pesticides. The City of San Francisco appears to have gone a long way towards the use of fewer and safer chemicals. Nevertheless, the Agency would be interested in which approach the city has used for termiticides. Please refer to the Reregistration Eligibility Decision for Cypermethrin for additional details.

CASQA   California Stormwater Quality Association Comment 1: CASQA is composed of stormwater quality management organizations and individuals, including cities, counties, special districts, industries, and consulting firms throughout the state, it was formed in 1989.

Response to CASQA Comment 1: This comment is informative and requires no response.

CASQA Comment 2: It is concerned with cypermethrin and other pyrethroids in that they pose a significant risk to water quality in urban and suburban areas. Recent evidence shows that cypermethrin and other pyrethroids are found in urban creeks. They are particularly concerned for the following reasons:   Cypermethrin is used primarily in urban areas.   Recent investigations of sediments in more than 15 Northern California urban creeks found pyrethroids, including cypermethrin in almost every sample.   The same studies have shown widespread toxicity to sediment dwelling organisms in California urban surface water sediments. Cypermethrin is a significant contributor to the identified toxicity.   The State of California is proposing listing several creeks as impaired by pyrethroids as part of the USEPA mandated CWA § 303( d) listing process. 22 Response to CASQA Comment 2: These comments are also concerns common to the CRWQCB and SWRCB. Please, refer to the Agency's response to SWRCB comments 1 and 8.

CASQA Comment 3: CASQA generally supports the Regional Water Board's comments, but emphasizes the following items:   Implement risk management measures to ensure that cypermethrin, when used according to the label, does not interfere with the CWA compliance.   Prohibit aboveground outdoor cypermethrin use in urban areas   Require controls to prevent cypermethrin runoff from preconstruction termiticide applications.   Complete a cumulative environmental risk assessment for the pyrethroids.   Complete an " alternative assessment" that considers alternative pesticides and low risk pest control methods.   Complete a " cluster assessment" for problematic outdoor urban insecticide applications.   Provide another opportunity for public participation in the cypermethrin reregistration process prior to the reregistration elegibility decidion. The proposed truncated public comment period is too short and omits critical steps. Given the complexity and importance of this regulatory action, the EPA should extend the reregistration process.

Response to CASQA comment 3: For comment about a cumulative environmental risk assessment, please, refer to the Agency's response to SWRCB comment 6. For additional details, please refer to the Reregistration Eligibility Decision for Cypermethrin.

CASQA Comment 4: For termiticides, they offer suggestions that would be required in the label and that they indicate are best management practices.   For stormwater protection, the preferred application of liquid termiticide is soil injection near the structure foundation.   If soil injection is not possible, then, limit the size of the treated area to a work shift.   Treated area should be backfilled prior to the onset of precipitation ( rain).   Any treated area that has the potential to come into contact with stormwater should be covered.   On grade spraying should not be conducted during gusty winds.   Application should not commence within 24 hours of predicted precipitation event.   During the rainy season, termiticide application should not be allowed within 50 ft of any down gradient storm.

Response to CASQA Comment 4: Please refer to the Reregistration Eligibility Decision for Cypermethrin. 23 CSJESD   City of San José Environmental Services Department Comment 1: The state that San José is the tenth largest city in the U. S., with approximately 28,000 storm drain inlets. The purpose of the City's Urban Runoff Program is to prevent pollution from entering the storm sewer system and waterways to protect the health of the South San Francisco Bay watershed.

Response to CSJESD Comment 1: This comment is informative and requires no response.

CSJESD Comment 2: Studies have shown that some registered pesticides can cause widespread toxicity in local creeks and urban runoff even when used in accordance with FIFRA requirements.

Response to CSJESD Comment 2: Please, refer to the Agency's response to SWRCB comment 13.

CSJESD Comment 3: The State Water Board and USEPA have found many waters in urban areas in California to be impaired, according to the CWA, § 303( d). as a result of discharges of pesticides registered for use by the USEPA under FIFRA. The CWA requires that the state adhere to resource intensive TMDLs for these waters, which can, in turn, require municipalities to implement expensive programs in hope of restoring designated uses of impaired water bodies. This could be largely avoided if the USEPA more proactively employed its FIFRA authority to reduce the potential for registered pesticides to impair surface water quality.

Response to CSJESD Comment 3: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CSJESD Comment 4: Recent evidence indicates that cypermethrin , as well as other pyrethroids are found in urban creeks at levels of concern. The State of California is proposing listing several creeks as impaired by pyrethroids as part of the CWA § 303( d) listing process.

Response to CSJESD Comment 4: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CSJESD Comment 5: The city is concerned that cypermethrin and other pyrethroids may pose a significant risk to water quality in urban areas because:   It is mainly used in urban areas.   Recent investigations found pyrethroids in sediments in more than 15 Northern California urban creeks in almost every sample. Among the pyrethroids found, cypermethrin was included.   The same studies have shown widespread toxicity to sediment dwelling organisms in California urban surface water sediments. Cypermethrin is a significant contributor to the identified toxicity. 24 Response to CSJESD Comment 5: Please, refer to the Agency's response to SWRCB comment 13.

CSJESD Comment 6: The City of San José supports several of the Regional Water Board's comments. Particularly, they mention the San Francisco Water Quality Control Board letter.

Response to CSJESD Comment 6: Please, refer to the Agency responses to the CRWQCB comments, that appear previously in this report.

CSJESD Comment 7: They emphasize that the USEPA should complete a risk assessment that includes the following:   Implementation of sufficient risk management measures to ensure that the use of cypermethrin according to the label does not interfere with compliance with the CWA.   Forbid use of cypermethrin above ground outdoor in urban areas.   Perform an " alternatives assessment" that considers low risk pest control methods.   Complete a " cluster assessment" for problematic outdoor urban insecticide applications.   Provide additional opportunities for public participation in the cypermethrin reregistration process, prior to the reregistration elegibility decision.

Response to CSJESD Comment 7: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

CSJESD Comment 8: The USEPA needs to improve integration of surface water protection into its pesticide registration and regulatory review programs. The risk benefit standards of FIFRA require USEPA to ensure that pesticides are used in such a manner that mitigation under the CWA is minimal or unnecessary. Full cooperation between the Office of Water and the Office of Pesticides Programs will help the Agency to meet this goal.

Response to CSJESD Comment 8: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 1: The San Francisco Department of the Environment's ( SFE's) mission is to improve, enhance, and preserve the environment, and promote San Francisco's longterm well being. In 1996, the San Francisco adopted an Integrated Pest Management ( IPM) ordinance, which commits the City to a pest management approach on its own property that minimizes the use of toxic chemicals and control pests by methods that pose a lower risk to public and environmental health. They strongly believe that USEPA should use its registration process to protect human health and prevent environmental problems with pesticides. 25 Response to SFE Comment 1: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 2: Most use of cypermethrin is non agricultural. Cypermethrin and other pyrethroids are now the most commonly used urban insecticides. They have been found in " our water, our air, and our bodies," and are of great concern for their toxicity to aquatic organisms, and possible human health effects.

Response to SFE Comment 2: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 3: Researchers have found significant toxicity to sediment dwelling organisms native of Northern California creeks. The toxicity is linked to pyrethroids.

Response to SFE Comment 3: Please, refer to the Agency's response to CRWQCB comment 2 and the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 4: If EPA does not act immediately, the above mentioned finding could have costly regulatory implications to the City.

Response to SFE Comment 4: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 5: SFE has eliminated the use of pyrethroids for control of ants, cockroaches, and landscape insects in their IPM program. They believe that the EPA should emphasize alternatives when seeking to reduce risks.

Response to SFE Comment 5: Please refer to the Reregistration Eligibility Decision for Cypermethrin.

SFE Comment 6: Human health risks:   6B. Cumulative risk of pyrethroids needs to be assessed  The EPA stated that no determination of a common toxic mode of action has yet been made. SFE recognizes that pyrethroids are divided into two distinct types. This research is important because all pyrethroids are neurotoxicants, and several of them may be carcinogens. In addition, they are widely used in and around homes. It is their view that EPA should take the precautionary approach of assuming cumulative risk exists. o Response to 6B: Please, refer to the Agency's response to SWRCB comment 6 and the Reregistration Eligibility Decision for Cypermethrin for additional details. SFE Comment 7: Environmental risks:   7A. Use Water Quality Criteria ( WQC) to assess risks to aquatic life   The Agency has used toxicity reference values, based on the most sensitive species; however, SFE recommends to use WQC, like the ones developed by the California Department of Fish and Game ( DFG), using Office of Water ( OW) 26 methods. These WQC are representative of a range of species that are exposed to pollutants in surface waters. If EPA does not use the criterion, it will not ensure compliance with the CWA, and will leave municipalities like San Francisco with the responsibility for complying with the water quality criterion, but without funding or regulatory authority to manage the problem. o Response to 7A: Please, refer to the Agency's response to CRWQCB comment 10.   7B. Assess urban runoff risks   There is evidence that pyrethroid toxicity due to urban runoff is higher than in surface water receiving agricultural runoff. Furthermore, USGS NAWQA monitoring data shows that there are higher insecticide concentrations in urban surface waters than in agricultural surface waters. EPA assumes that agricultural modeling covers the risk in urban environments, an argument that the SFE considers untenable. Urban runoff modeling is needed. o Response to 7B: Please, refer to the Agency's response to CRWQCB comment 21.   7C. The EPA needs to evaluate cumulative effects of cypermethrin with other pyrethroids and with synergists. o Response to 7C: The EFED does not do cumulative environmental risk assessments. The toxicity of pyrethroids and PBO is considered in the individual risk assessments of the pyrethroids when data are available; however, the cypermethrin products employed for agricultural uses that bring major exposure to wildlife do not typically contain PBO.

SFE Comment 8: Risk Management:   Restrict above ground, urban, outdoor uses of cypermethrin   These applications include applications around buildings and applications on lawns and in gardens. Preconstruction termiticide applications may also be subject to washoff if treated surfaces are not covered and protected from rain and runoff before the next storm. These applications have not been necessary in San Francisco, which proves that there are safer alternatives to cypermethrin.   Complete an alternatives assessment   Need to ensure that alternatives for cancelled pesticide uses are indeed safer for human health and the environment. A cursory alternatives assessment will reveal a wide range of effective, safer alternatives, which should provide the Agency with solid justification for restricting the use for ant control in urban areas.   Include local government costs in benefit assessment   The Agency should consider the costs that cypermethrin reregistration decision could create, such as waste disposal and health care costs are potentially significant, they could change the outcome of a benefits assessment.   Label should limit the number of applications per year   This applies to all the pyrethroids.   Labels should preclude outdoor applications prior to forecasted rain.

Response to SFE Comment 8: Please refer to the Reregistration Eligibility Decision for Cypermethrin. 27 FMC Response ( MRID# 467759 01)

FMC Comment 1: The Science Chapter notes that cypermethrin and other pyrethroids have been found in sediments of urban streams, possibly resulting from runoff from lawn care uses. It is appropriate to raise the issue of urban uses in the Problem Formulation. This would also be an appropriate place to state that urban uses will not be addressed in the risk assessment.

Response to FMC Comment 1: EFED acknowledges that FMC is correct in its recommendation about inclusion of urban issues in the problem formulation. Perceptions of the issue have changed since the chapter was written. However, rewriting the problem formulation to include these additional issues will not impact the risk characterization or the risk mitigation. The Agency did raise the issue of pyrethroid contamination of urban streams in the problem formulation. However, at this point the Agency is limited in its ability to assess the risk to these aquatic communities adjacent to urban developments.

FMC Comment 2: With respect to the paragraph summarizing Dr. Weston's work on urban monitoring III. C. 1. a ( 4) a. Residue Monitoring ( non agricultural), the FMC poses the following questions: 1) How widespread is this condition in space and time? 2) How do pyrethroids get into the sediments of urban streams? 3) Are species affected other than Hyallela azteca?

Response to FMC Comment 2: At this early stage, Dr. Weston's work poses as many new questions as it provides answers. As cypermethrin is widely used in urban areas, there is a possibility that concentrations in sediments are widespread. Pyrethroids typically get to surface water through some combination of spray drift, washoff and adsorbed to eroding soil. There is no reason at this time to expect that the route would be different in this case. The work done by Don Weston was a preliminary study to see if future research should be conducted. The study was limited to one urban community and samples were generally taken close to points of entry ( culvert opening etc). There was no attempt to assess spatial and temporal distribution of contaminants. It is assumed that pesticides reached the urban streams as a result of runoff from impermeable surfaces ( walkways, streets, etc.) and/ or runoff or erosion from irrigated lawns. Weston did not specify impacts to aquatic communities. The studies were set up to evaluate in situ toxicity ( toxic units) of prevalent pyrethroids that were found in the sediments.

FMC Comment 3: Section II. B. 3. Ecosystems at Risk. The FMC contends that this section does not address ecosystems at risk. It simply reiterates the list of taxonomic groups " of potential concern." It could be simplified to state that " all aquatic and terrestrial organisms could potentially be exposed to cypermethrin." It does not state, for example, the relationship between aquatic or terrestrial exposure, and proximity to sites of cypermethrin use, or the factors that determine whether exposure will be dominated by spray drift or erosion. 28 Response to FMC Comment 3: EFED typically does not address the relationship between aquatic or terrestrial exposure, but clearly there are linkages that could be explored. Preliminary work by the PWG would indicate that exposure in agricultural areas may be dominated by spray drift in some locations and erosion in others. Routes of exposure in urban areas have yet to be positively determined. Ecosystem at Risk was a general assessment of the potential for cypermethrin exposure and toxic risk to aquatic organisms.

FMC Comment 4: The EPA has adopted a tiered approach to conduct aquatic and terrestrial risk assessments. The predicted concentrations reflect the cumulative effect of numerous conservative assumptions used in the analysis, for example, the input parameters " exaggerate" persistence, use of maximum label rate, use of standard pond ( closed system), many of the Tier II crop scenarios over estimate soil erosion, high spray drift loadings are assumed with every event. Many of these factors are being examined by the PWG at this time.

Response to Comment 4: The Agency's tiered approach is designed to estimate exposure at a few " high exposure" sites where occasional combinations of factors may produce high end concentration values. If high exposure sites can be shown to be safe, it will reduce expenditure of Agency resources in investigating the extent of lower exposure sites. If safety cannot be demonstrated at high exposure sites, additional work may need to be done. The Agency together with the PWG is exploring those factors that would lead to lower concentration values in some locations. When PWG completes their evaluation, the Agency may possibly refine its assessment.

FMC Comment 5: These uncertainties impact the EFED's preliminary ( screening level) aquatic risk assessment.

Response to FMC Comment 5: The Agency agrees. This screening level assessment does represent exposure at high exposure sites. The PWG work is expected to give a distribution of concentration values for pyrethroids across a broader range of sites.

FMC Comment 6: The EFED said under " Source and Intensity" that there are four different cypermethrin products ( alpha, beta, theta, and zeta cypermethrin). The FMC indicates that the EFED should state whether all isomer mixtures will be treated as a single group, or whether distinctions will be made among them. FMC noted that several trv's were from beta cypermethrin. This should be addressed in the Problem Formulation. The PWG ecological assessment is expected to include an evaluation of the relative toxicity of the pyrethroid isomers.

Response to FMC Comment 6: As a screening level assessment, the cypermethrin isomer data were treated as bridging data ( the registrants requested a waiver on toxicity studies for the different isomers). Since, the range in cypermethrin ( isomers) toxicity to non target organisms was considered to be similar enough ( 1X   4X), the Agency used all of the available information in the cypermethrin RED. 29 FMC Comment 7: The FMC states that the definitions of measures of effect and assessment endpoints are confusing ( p. 15 of FMC report). They indicate that measures of effect are better defined as " attributes of an ecological entity ( the assessment endpoint or a surrogate) that are actually measured, and from which effects on assessment endpoints are inferred." They indicate that the assessment endpoints are at the population and community level; the measures of effect are at the individual level. They state that Table 3. Summary of Assessment and Measures of Effect for Cypermethrin is also inconsistent in its reference to individuals, populations and communities.

Response to FMC Comment 7: Table 3 is not inconsistent. Measures of effect reflect the parameters evaluated in the toxicity studies that are routinely submitted to the Agency ( e. g., acute studies: LC50, LD50, EC50; Chronic studies reproduction studies, early life stage studies, full life cycle: NOAEC). The toxicity values derived from these laboratory derived measurements of effect are used in the risk assessment in order to predict potential risk to non target organisms in the environment. The assessment endpoints represent the environmental relevant system that the measures of effect could show potential impact. For example, the chronic studies that indicate significant reproductive effects for invertebrates( measure of effect) may be used to extrapolate the potential for a decrease in invertebrate community diversity ( assessment endpoint) and the secondary effects ( e. g. fish grow) to organisms that are dependent upon invertebrates as a food source.

FMC Comment 8: The Conceptual Model is too generic and at a minimum should address the following items:   Aquatic exposure scenarios ( farm pond adjacent to treated field)   Use factors influencing drift, runoff and erosion   Climate and soil factors influencing drift, runoff and erosion   Landscape factors influencing drift, runoff and erosion   Environmental fate processes in receiving water   Partitioning to sediment   Bioavalability and bioaccumulation in water column and sediment   Food chain transport   Direct acute and chronic effects in water column   Direct acute and chronic effects in sediment, and   Indirect effects For each of these elements, the conceptual model should specify assumptions and uncertainties about the process.

Response to FMC Comment 8: The Conceptual Model is intended to be relatively general, especially for a document as large and complicated as a RED. Clarity is the intent of the Conceptual Model. However, the Agency agrees that some of the points could be added to include direct acute and chronic effects in water column, direct acute and chronic effects in sediment, and indirect effects through food chain depletion and bioaccumulation. However, these additions would not ultimately affect the conclusions of this risk assessment. 30 FMC Comment 9: Risk in Sediments   The use of the EqP approach depends on reliable estimates of the KOC. The PWG and others are developing methods to measure more accurately the freely dissolved pore water pyrethroids, using SPME ( Solid Phase Microextraction) techniques. However, in the end, the EFED did not use the method described in the problem formulation ( EqP approach) and used existing sediment toxicity testing.

Response to FMC Comment 9: It is true that toxicity data were used to evaluate acute risk to benthic invertebrates exposed to cypermethrin in the sediment based on the appropriate most sensitive available data ( as stated above in the Agency's Response to CRWQCB Comment 12 and 13), and that the EqP method is typically used by the Agency in the absence of appropriate sediment toxicity data. However, EFED also typically estimates risk to benthic invertebrates resulting from exposure to a chemical in pore water. Therefore, the equilibrium partitioning approach had to be employed in this instance because cypermethrin toxicity data based on pore water concentrations were not available. In one study pore water concentrations were not measured ( MRID 44074402), and in the other the concentrations were below the LOD ( MRID 44074406). The EFED recognizes that additional sediment toxicity data with LC50' s based on both sediment and pore water concentrations have been submitted by the PWG for use in this assessment. However, these data are currently under review and may be incorporated at a later date if deemed appropriate.

FMC Comment 10: There seems to be no scenario description ( pp. 34 37 of the Science Chapter). The standard pond scenario assumes a 1 ha pond, 2 m deep, receives drift and runoff/ erosion from a 10 ha watershed, consisting entirely of treated crop. Other assumptions, such as constant pond volume also affect the EEC's.

Response to FMC Comment 10: The assumptions of the standard pond scenario are usually described in each risk assessment.

FMC Comment 11: The risk to benthic organisms can be presumed to be due to potential chronic effects rather than acute effects because the concentrations in the pore water are much lower than in the water column.

Response to FMC Comment 11: This is only a presumption made by FMC. Acute effects may not be precluded if the concentrations of cypermethrin reach certain levels. Pore water RQ values suggest that acute and chronic risk from sediment exposure can potentially impact benthic invertebrates.

FMC Comment 12: The Science Chapter did not include quantitative exposure in an estuarine/ marine environment. The standard farm pond EEC's was used as surrogates in lieu of the exposure of estuarine/ marine environment. Because this assumption is tenuous and largely untested, the assessment does not support conclusive statements about risk to estuarine/ marine organisms. 31 Response to FMC Comment 12: The standard pond scenario is currently accepted by the EFED and used to generate EEC values for estuarine/ marine organisms.

FMC Comment 13: Sentences in III. B. 1. a. Summary of Empirical Data, and III. B. 1. d. Bioaccumulation, are inconsistent with respect to the characterization of the bioaccumulation and depuration in fish of cypermethrin.

Response to FMC Comment 13: The EFED appreciates the identification of this error; however, this is a minor error that does not compromise the quality, conclusions, or the integrity of the risk assessment.

FMC Comment 14: Data selection: FMC indicates that the reviewer may have overlooked a Daphnia magna acute toxicity study ( MRID 43293501; Wheat and Evans, 1994), with 48 hr EC50 = 161.5 ppt = 161.5 ng ai/ L [ not µ g a. i./ L as it was reported in the Chapter]. This value is lower than the lowest value reported in the Science Chapter.

Response to FMC Comment 14: MRID 43293501 was not overlooked in the document and was correctly not used to calculate risk to freshwater invertebrates; rather, MRID 43293501 was misclassified in the RED. The individual data evaluation record for the study indicates that it was not scientifically sound because there was significant contamination of the controls. The study report itself also states that the measured " residues from the cypermethrin exposure  did not follow a serial dilution pattern" and that the " analysis of test samples failed to yield useful results." Therefore, the study should have been classified as Invalid and should not have been discussed in the RED.

FMC Comment 15: EFED's rationale to reject EPAIDENT 00089047 does not apply to the calculation of the NOEC for the most sensitive endpoint ( refer to p. 19 of 58 of FMC report).

Response to FMC Comment 15: Unfortunately the study in question had several problems that included the following: negative control contamination; delivery lines for treatment 1 and 2 were switched for 4 days; mortality in 2 of the 4 replicates for solvent controls exceeded 30%; Dissolved oxygen levels were not maintained above 60% throughout the test. Because of these problems the Agency deemed this study invalid and has required that a new study be conducted.

FMC Comment 16: The chronic NOAEC for waterflea calculated using the acute: chronic ratio resulted in a NOAEC 4 11 fold higher than measured values. There is uncertainty in the applicability of the acute: chronic ratio method, particularly considering the large difference in acute sensitivity of the two species.

Response to FMC Comment 16: The Agency understands the uncertainty in calculating a NOAEC using an acute: chronic ratio. However, the measured values from the daphnid life cycle study were not acceptable as noted previously. 32 FMC Comment 17: The trv for estuarine/ marine fish was 0.95 µ g a. i./ L ( sheephead minnow, MRID 90075). FMC did not examine the study 44546033 that reports a third sheephead minnow study because FMC does not have access to this study ( it was conducted with beta cypermethrin).

Response to FMC Comment 17: EFED defers this issue to the SRRD. The responsibility of data compensation belongs to the SRRD. However, the value used by the Agency is 0.95 ug ai/ L and is the worst case.

FMC Comment 18: The acute to chronic ratios should be calculated with trv's of the same species, if available, not the lowest trv.

Response to FMC Comment 18: The Agency agrees. However, the availability of data on the same species or even genus, is rare. Therefore, the Agency will use the best information that is available in order to make necessary extrapolations. This is done with a complete understanding and acknowledgment of the inherent uncertainties.

FMC Comment 19: EFED considers data from water only studies with benthic organisms to be representative of organisms living in the water column. In the analysis of effects on estuarine/ marine invertebrates, toxicity data from benthic and open water species were combined. Yet in the analysis of effects on freshwater invertebrates, the Science Chapter separated toxicity data for benthic species from data for Daphnia magna, and used Daphnia magna as a surrogate for all freshwater water column invertebrates. Data from water only studies with freshwater invertebrate species considered to be benthic were not used in the effects characterization for the water column. ( Not all of the test organisms listed as benthic in Table E 4 are actually sediment dwellers; for example, adult whirligigs ( Gyrinus), backswimmers ( Notonecta), water boatmen ( Corixa), and water mites ( Piona).) The segregation of benthic from water column species was not discussed, and no justification was presented. By segregating data from benthic and water column species this assessment deviates from EPA's stated practice of basing screening level RQs on the most sensitive species in each category of organisms. Daphnia magna is in fact the least sensitive of the five freshwater crustacean species for which water only toxicity data are presented in Appendix E. As has been found for other synthetic pyrethroids, amphipods ( Gammarus and Hyalella) are substantially more sensitive than Daphnia magna. If data from all water only toxicity tests with freshwater invertebrates were used to characterize effects on water column species, the Toxicity Reference Value would have been 0.0036 µ g/ L ( Hyalella azteca, 96 h LC50, p. E 38) rather than 0.42 µ g/ L ( Daphnia magna, 48 h EC50, p. E 23). RQs for freshwater invertebrates would have been approximately 100 times greater than those calculated in the Science Chapter. Use of Daphnia magna data to represent all water column invertebrates reduces the apparent risk of cypermethrin. Attention is drawn to it here for two reasons: Inconsistent application of data selection strategies for screening level assessments leads to confusion and subjectivity in what should be a transparent process. 33 Response to FMC Comment 19: The Agency acknowledges that some of the species listed in the table referring to Freshwater Benthic Invertebrates are not benthic ( e. g., adult whirligigs ( Gyrinus), backswimmers ( Notonecta), water boatmen ( Corixa), and water mites ( Piona)). EFED also agrees that the data for aquatic invertebrates would have been most transparently separated based on water column toxicity ( studies with water only systems) data and sediment toxicity ( studies with water sediment systems) data.

The two most important considerations when selecting toxicity data to characterize risk to a specific taxonomic group are whether the data are the most sensitive available and whether the exposure scenario under which the endpoints were derived are appropriate and representative of that group of organisms. The RED explicitly states in Appendix E:

" In the water system studies, organisms were exposed only to cypermethrin in overlying water; there was no sediment in the test chamber. Thus, while data from these studies provide information regarding the sensitivity of benthic organisms to cypermethrin in surface water, no data from these studies regarding exposure to cypermethrin in sediment are available. Therefore, data are insufficient for use in quantifying risks to benthic organisms," and " studies using the water sediment system more accurately depict the environmental exposure of benthic organisms than the water system studies."

Therefore, only those studies that exposed sediment dwellers to cypermethrin in a watersediment system were considered appropriate for determining risk to benthic organisms. The only two studies that met these criteria were MRID 44074402 and MRID 44074406.

EFED agrees that it may be appropriate to use the study with Hyallella ( MRID 44423501) to characterize risk to freshwater water column dwelling species because this species can spend time in both the water column and benthos and because the study was conducted in a water only system. However, the EFED reviewer exercised best professional judgment and chose the Daphnia measurement endpoint because the use of this endpoint allows for a comparative analysis of toxicity to most other chemicals. Although the 96 hour LC50 value of 0.0036 µ g a. i./ L for Hyalella azteca ( based on a water only system) may be appropriate for determining risk to all freshwater water column dwelling organisms, freshwater invertebrate RQs still exceeded all acute LOCs ( RQ range= 0.4  4.8) when based on the 48 h EC50 value of 0.42 µ g a. i./ L for Daphnia magna. If based on the endpoint for Hyalella, RQs would be approximately 100 times higher and range from 49.4 to 558.3.

In addition, chronic RQs for freshwater invertebrates would also increase if the Hyalella measurement endpoint is used. Because no chronic data were available for freshwater invertebrates, a surrogate NOAEC toxicity value was derived to calculate chronic RQs for this taxonomic group. Previously, the chronic NOAEC estimated for freshwater invertebrates was based on the acute to chronic ratio method, determined by using the acute Daphnia measurement endpoint and the following mathematical relationship: 34 Estuarine/ marine invertebrate LC50 ( 0.00475 µ g a. i./ L) / Estuarine/ marine invertebrate NOAEC ( 0.000781 µ g a. i./ L) = Freshwater invertebrate LC50 ( 0.42 µ g a. i./ L)/ X ( estimated value for Freshwater invertebrate NOAEC), where X = 0.069 µ g a. i./ L.

Based on this derived NOAEC for freshwater invertebrates, chronic RQs exceeded chronic LOCs and ranged from 0.5 to 2.8. However, because a more sensitive endpoint has now been identified, a chronic NOAEC can be estimated for freshwater invertebrates using the acute Hyalella measurement endpoint and the following mathematical relationship:

Estuarine/ marine invertebrate LC50 ( 0.00475 µ g a. i./ L) / Estuarine/ marine invertebrate NOAEC ( 0.000781 µ g a. i./ L) = Freshwater invertebrate LC50 ( 0.0036 µ g a. i./ L)/ X ( estimated value for Freshwater invertebrate NOAEC), where X = 0.00059 µ g a. i./ L.

Based on this newly estimated NOAEC value, chronic RQs for freshwater invertebrates would be approximately 100 times higher and range from 57.6 to 325.4. Therefore, while use of the Daphnia EC50 value may foster a comparative analysis, its use may also result in RQs that underestimate acute and chronic risk to freshwater water column dwelling invertebrates.

This issue was also addressed in the Addendum to the EFED RED Chapter for Cypermethrin.

FMC Comment 20: The analysis based on Daphnia magna leads EFED to the erroneous conclusion that estuarine/ marine invertebrates are substantially more sensitive to cypermethrin than freshwater invertebrates. Section III. C. 1. Aquatic Effects Characterization ( p. 51). The EFED states that for estuarine/ marine invertebrates, the lowest LC50 value reported is 0.00475 µ g a. i./ L, which is 100 times lower than reported for other aquatic animals. The FMC states that, data for freshwater amphipods was ignored ( e. g. Hyalella azteca and Gammarus species), which are approximately 100 times more sensitive than Daphnia magna. Moreover, the relative sensitivities would be better represented by means, medians or Entire Sensitivity Distributions. The EFED statement also says that estuarine/ marine invertebrates are expected to be the species at greatest risk. The FMC believes that the statement may be incorrect, and based on studies not yet published, freshwater and marine invertebrates are approximately equal in their sensitivity to cypermethrin.

Response to FMC Comment 20: The EFED does not use means, medians, or Entire Sensitivity Distributions in screening level risk assessments, but rather, bases risk conclusions on the most relevant and sensitive data available. The EFED acknowledges that it may be considered appropriate to use the study with Hyallella ( MRID 44423501) to characterize risk to freshwater water column dwelling species ( Please refer to the Agency's response to FMC comment 19), and that based on such an analysis, the sensitivity of and risk to estuarine/ marine invertebrates is on par with freshwater 35 invertebrates. However, while the EFED cannot comment on the unpublished data mentioned above, the increased sensitivity of estuarine/ marine invertebrates does appear to be consistent among other pyrethroids and may be correlated with osmoregulation.

FMC Comment 21: Even if marine invertebrates were more sensitive than freshwater invertebrates, the final part of the statement   " Thus, estuarine/ marine invertebrates are expected to be the species at greatest risk for acute effects ( lethality)." would be inappropriate unless accompanied by valid exposure estimates for the estuarine/ marine environments.

Response to FMC Comment 21: Please refer to the Agency's response to FMC comments 12, 19, and 20.

FMC Comment 22: Laskowski established that the KOC for cypermethrin is 310,000. Use of the Laskowski ( 2002) Koc value in this calculation and in PRZM/ EXAMS would reduce the estimates of cypermethrin concentrations in pore water. If this value is used, the estimates of toxicity of Hyalella azteca LC50 for Florissant sediment in units of OC are as follows: Florissant ( 0.99% OC)   Bulk sediment LC50 3.6 µ g ai/ Kg sediment   OC normalized LC50 364 µ g ai/ Kg sed OC)   Pore Water LC50 0.00257 µ g ai/ L FMC provides the values for Mississippi 3.1% OC and Duluth 13.3% OC. The results show that cypermethrin is more toxic in the Florissant sediment when represented in Bulk Sediment LC50; however, the chemical is more toxic when represented in units of OCnormalized LC50 or Pore Water LC50.

Response to FMC Comment 22: The Agency used the Koc = 141, 700. This value represents the average from Koc = 20,800   328,500. Although the EFED chose to select the most sensitive measurement endpoints based on the measurement endpoints represented in bulk sediment, RQs for benthic organisms would still exceed the acute risk LOCs regardless of whether they were calculated using the most sensitive bulk sediment toxicity values or the most sensitive OC normalized pore water toxicity values.

FMC Comment 23: As noted in the Science Chapter, the PWG submitted new cypermethrin sediment toxicity studies with benthic organisms to EFED. The results will provide a broader understanding of the toxicity and bioavailability of pyrethroids in sediments.

Response to FMC Comment 23: These studies have been received by EFED and are still in review.

FMC Comment 24: III. C. 1 Aquatic Effects Characterization ( p. 32). It is stated that in most studies, the NOAEC is 2 to 3 fold lower than the LC50 ( exception rainbow trout and bluegill sunfish). III. C. i. a( 3) Sublethal Effects ( p. 62) The NOAEC values cited for Bluegill sunfish and Rainbow trout are incorrect. The NOAEC units are mg/ L instead of µ g/ L; therefore 36 Rainbow trout LC50 = 0.8 µ g a. i./ L NOAEC = 0.68 µ g/ L Bluegill sunfish LC50 = 2.2 µ g a. i./ L NOAEC < 2.2 µ g/ L Response to FMC Comment 24: The Agency will address this units correction in an addendum to the EFED Science Chapter.

FMC Comment 25: II. B. 3. Ecosystems at Risk, p. 12, EFED states that several aquatic field studies are available and will be incorporated into the risk characterization. III.. C. 1. a.( 4) Field Studies, p. 64 EFED states that the results are not sufficient for use in quantitative assessments, but will be used qualitatively. There is a discrepancy between the two statements. The FMC indicates that the field studies are useful for rounding out the description of effects and for adding perspective to the interpretation of standard toxicity data, rather than the dose response relationships. Information such like comparison of magnitude of effects on different species, on populations as individuals, and short term versus long term impacts.

Response to FMC Comment 25: The Agency agrees and included a qualitative statement in the risk assessment. In general the studies found that some species of invertebrates were impacted and that opportunistic species increased in numbers. However, the increase in biomass of species that are not a viable food source for fish was also mentioned. Keystone species were generally impacted and the diversity of communities was affected in several cases. Recovery was a great uncertainty. Some species recolonized the area within a few weeks while others did not. The studies looked at one application. Spatial and temporal assessment of community impact and recovery was not achieved, which raises more uncertainty as to the realistic impact of cypermethrin on aquatic ecological systems over time.

FMC Comment 26: III. C. 1. a.( 4) Field Studies, p. 64. The EFED stated that sublethal effects were observed for 8 days following application ( 0.0012 0.089 lb a. i./ A) and were attributed, in part to exposure to cypermethrin from ingestion of dead and dying invertebrates. The FMC observes that three studies show no sublethal effects at rates from 0.0012 to 0.089 lb a. i./ A. The study discussed above is inconsistent with the other evidence and additional analyses should be made to determine if food chain exposure is plausible ( presumed bioconcentration).

Response to FMC Comment 26: The Agency agrees that an evaluation of food chain exposure would be beneficial. However, based on the currently available data from Davies and Cook ( 1993), the Agency cannot discount the possiblity that the sublethal effects ( fish lethargy) noted in the study were the result of the consumption of cypermethrin residues in dying or dead invertebrates.

FMC Comment 27: IV. A. 1. b. Sediment Exposure   Acute and Chronic Risk ( p. 72). The EFED indicates that the acute RQ for pore water and chronic RQ from sediment and pore water were derived from a sediment toxicity study that had considerable uncertainty surrounding it. The system was not at equilibrium. FMC considers that equilibrium is unlikely in a sediment toxicity test system. Other source of error in the EqP approach is 37 the natural variability of KOC and sediment organic matter. However, the FMC believes that the best approach is the EqP approach because the percent OC may be different in the sediment toxicity study vs. the PRZM/ EXAMS run.

Response to FMC Comment 27: Equilibrium in the sediment can be achieved in the laboratory (> one month for pyrethroids) and has been verified by the EPA laboratory at Duluth, Minnesota ( Dave Mount, personal communication). The Agency will use actual sediment toxicity tests values when they are available. However, the EqP approach is an acceptable method for deriving an estimated toxicity value ( normalized to organic carbon levels).

FMC Comment 28: IV. B Risk Description, p. 81. The EFED says that there is the potential for direct acute and chronic toxic risk to aquatic life in the water column and the benthos, as well as indirect sublethal risk to fish through food chain alterations that can affect freshwater and estuarine/ marine fish year classes. This potential risk is predicated on the data pertaining the sediment toxicity. The FMC says that there is no data to support these " conjectures" based on general ecological principles.

Response to FMC Comment 28: Based on general ecological, toxicological, and risk assessment principles, the decline of aquatic invertebrate populations will affect aquatic communities, especially fish year class strength, fish species distribution, possible fish pathology, as well as the general energetics of a balanced system. This has been noted from several field studies that showed a decline in certain invertebrate species ( keystone species) and the increase in other opportunistic species followed by a decline in fish growth. Given the available information for a screening level assessment, the Agency has made assumptions based on sound scientific principles that are accepted in the science community with regard to pyrethroid effects on aquatic organisms.

FMC Comment 29: IV. A. 1. c. Use of Buffer Zones, p. 75. The RQ in NC changed little with an increase of the buffer zone. In a CA scenario, the RQ changed substantially. It is indicated that the NC scenario has a small component of drift, while the CA scenario has a large component of drift. The FMC indicated that the mandated vegetated filter strip was not taken into consideration in the model. The filter strip is expected to decrease the level of erosion.

Response to FMC Comment 29: Maintained buffer strips are a way to decrease the level of erosion, but it cannot be quantified.

FMC Comment 30: At this time, the EFED does not have any tools to do quantitative measurements of the vegetated filter strip to decrease the level of erosion.

Response to FMC Comment 30: We agree that unfortunately there are no models to measure quantitatively the decrease in levels of erosion due to maintained vegetated filter strips suitable for national assessments. 38 FMC Comment 31: IV. B. Risk Description, p. 81. The Agency has identified acute and chronic risk concerns  includes  aquatic snails, clams. FMC indicates that this is the first reference to mollusks in the chapter. The toxicity data in Appendix E do not support the conclusion of risk to snails and clams. Based on data for estuarine/ marine mollusks, the Science Chapter concluded that " results of these studies indicate that mollusks are less susceptible than shrimp and crustaceans to cypermethrin toxicity on an acute basis."

Response to FMC Comment 31: Although it is true that based on the limited data on a few oyster species alone mollusks may be less susceptible than shrimp and crustaceans to cypermethrin toxicity, these data still suggest that cypermethrin can be classified as moderately to highly toxic to mollusks. However, the cypermethrin database does not currently contain toxicity values for aquatic snails, aquatic clams, or any freshwater mollusk, so it is not possible to preclude risk at this time to these organisms. It is a standard approach of the EFED to assess risk to entire taxonomic groups based on the most sensitive toxicity data available. To a certain extent, using the most sensitive data available helps to address the issue of interspecies variability and the likelihood that laboratory tests do not account for all variables that could influence species sensitivity in the environment. Since the most sensitive data for both the freshwater and estuarine/ marine invertebrates taxonomic groups suggested the potential for risk, a general statement of risk to all aquatic invertebrates was made.

FMC Comment 32: IV. B. 4. Endocrine Effects, p. 91. In the study of reproductive effects in aquatic invertebrates, there may be many causes for the effects, such as general toxicity ( e. g. egg mortality or feeding inhibition). Equating those to reproductive effects is incorrect.

Response to FMC Comment 32: The endocrine effects criteria for a screening level assessment is reproductive effects. The Agency is very aware that different environmental components can contribute to effects on reproduction, but will use broad assumptions at this time. In the future a more refined evaluation for endocrine effects will be possible as appropriate testing is developed.

FMC Comment 33: Section on endangered and threatened ( listed) species ( IV. B. 5., pp. 92 97) reflects the current uncertainties and ambiguities about how the guidance will be put into practice. Section IV. B. 5. a. Action Area begins with the observation that the screening level assessment assumes all listed species inhabit the pesticide treatment area. This assumption avoids to define the action area. Then it continues with a summary of OPP's endangered species assessment process, rather than explaining the relevance or application of the action area concept to the assessment.

Response to FMC Comment 33: This is a screening level assessment. Specific information on listed species is provided for refined assessments when identified.

FMC Comment 34: Section IV. B. 5. b ( Taxonomic Groups Potentially at Risk): The section begins by noting the registrant's responsibility for providing data on the proximity of listed species to cypermethrin use sites. The section then provides a table 39 with numbers of taxa in proximity to various crops in each state with no indication of how such information was obtained or what it implies to the assessment. Furthermore, it includes clams and snails, for which no RQs were calculated, and are not generally sensitive to pyrethroids.

Response to FMC Comment 34: The goal of the analysis for co location is to determine whether sites of pesticide use are geographically associated with known locations of listed species. At the screening level, this analysis is accomplished using the LOCATES database. The database uses location information for listed species at the county level and compares it to agricultural census data for crop production at the same county level of resolution. The product is a listing of federally listed species that are located within counties known to produce the crops upon which the pesticide will be used. For additional details regarding the inclusion of clams and snails, please refer to the Agency's response to FMC comment 31.

FMC Comment 35: In a section named " Probit Slope Analysis", a brief statement about calculation of the probability of individual mortality at the listed species acute LOC is introduced. The results are presented only for freshwater fish. The utility of these calculations is not apparent.

Response to FMC Comment 35: The Probit Analysis is used to estimate the chance for individual effects and was part of an agreement with the Alternative Consultation for evaluating risk to listed species. The application of these analyses occurs as a species specific assessment is advanced to the determination of the likelihood of adverse effects.

FMC Comment 36: Section IV. B. 5. c. Critical Habitat, describes an approach to evaluate risk to pesticide effects on designated critical habitat, based on screening level RQs. However, no analysis is presented.

Response to FMC Comment 36: At present, the information reviewed by the Agency does not permit use of either analytical approach to make a definitive identification of listed species that are potentially impacted indirectly or critical habitats that are potentially impacted directly by the use of pesticides. The screening level assessment for critical habitat only provides a listing of potential biological features that, if they are constituent elements of one or more critical habitats, would be a potential concern. This corresponds to the taxa identification as being of potential concern for indirect effects.

FMC Comment 37: In many places of the Science Chapter, the word " endangered" appears to have been replaced to " listed." This results in anomalies such as " the Listed Species Act," p. 17.

Response to FMC Comment 37: These minor errors do not compromise the quality or conclusions of the risk assessment, the results, or the actual species in the list of endangered/ threatened species. The risk assessment will not be revised. 40 FMC Comment 38: Assumptions and Uncertainties: Exposure Analysis must be approached with an understanding of the assumptions and limitations of the model:   Input parameters may exaggerate persistence ( by means of safety factors).   The maximum label rate is used.   Standard pond scenario is very conservative ( it is closed with no flow).   Many PRZM/ EXAMS combinations overestimate soil erosion and consequently runoff of chemicals like cypermethrin.   Natural and engineered landscape features to attenuate and reduce pesticide transport in runoff and drift are neglected ( e. g. buffer strips).   High spray drift loadings are assumed to occur.

Response to FMC Comment 38: This is a screening level assessment. Actual monitoring data are not available. Models are used in an attempt to assess the potential for toxic exposure to non target organisms. Currently PRZM/ EXAMS scenarios prove to be adequate for this type of assessment. However, if the registrant has a more accurate model the Agency would gladly provide it's evaluation.

FMC Comment 39: IV. C. 4. Assumptions, Limitations, Uncertainties, Strengths and Data Gaps Related to Effects Assessment, pp. 101 102. There is a discussion of two effects analysis: " differences in the sensitivity of individuals depending on their age class, and differences in sensitivity among species. In both cases, the screening level assessment is intended to " err" on the conservative side. These are techniques to account for species sensitivity differences in a refined ecological risk assessment.

Response to FMC Comment 39: The Agency agrees.

FMC Comment 40: The analysis of the risk of the pyrethroids to sediment dwelling organisms is subject to several other assumptions and uncertainties. The equilibrium partitioning is taken into account. The partition coefficient is highly variable in natural sediments.

Response to FMC Comment 40: The partition coefficient was found to have a range ( Koc = 20,800   328,500 L/ Kg). It is the EFED's policy to use the average of the available Koc values when running PRZM/ EXAMS to generate water column, pore water, and sediment EECs. Therefore, the Agency used an average value when it derived toxicity values using the EqP Theory calculations as well, since the derived toxicity values would be compared to those EECs.

FMC Comment 41: In Appendix 3, the FMC provides a revised Tier 1 avian risk assessment. Cypermethrin is practically non toxic to birds with all of the calculated avian RQs for the target crops ( cotton, lettuce and pecans) being below the LOCs for acute endangered species ( 0.1). Several of the chronic RQs are above the LOC ( RQ range 0.16 2.65; LOC= 1). However, since the chronic toxicity was reported as greater than ( NOAEC> 50 mg/ Kg diet), the actual RQs are potentially lower than those reported. The refinement was done by using actual residue data from cotton and lettuce field trials. 41 Response to FMC Comment 41: The EFED has revised the terrestrial risk assessment in an addendum to the EFED's Science Chapter to demonstrate that risk to avian species from cypermethrin exposure is low. Please, refer to the addendum for additional details.

FMC Comment 42: The FMC is also providing a revised Tier I risk assessment. Acute RQs are below the LOCs for acute high risk ( LOC= 0.5) and acute restricted use ( LOC= 0.2), except for the 15 g mammal feeding on short grass ( RQ= 0.23). The endangered species LOC ( 0.1) is exceeded for various scenarios. The LOC for chronic risk ( LOC= 1) for all modeled crop uses and mammalian weight classes was exceeded based on dose based RQs. No dietary chronic RQs exceeded the chronic risk LOC.

Response to FMC Comment 42: The Agency has revised the terrestrial risk assessment in an addendum to the EFED's Science Chapter and has also identified acute endangered species and dose and dietary based chronic LOC exceedances for mammals. A foliar dissipation half life based on measured total residues on plants ( internal plus dislodgeable) in the field ( Willis and McDowell 1987) was used to determine upperbound exposure levels and risk to terrestrial organisms. Please, refer to the addendum for additional details.

FMC Comment 43: Honeybees do not frequent lettuce or pecans. There is a slight risk through exposure to treated cotton, which needs proper monitoring. FMC concludes that cypermethrin poses minimal risk to earthworms and to honeybees when used according to label requirements.

Response to FMC Comment 43: Please, refer to the Agency's response to comment Appendix 4 below.

FMC Comment 44: Avian NOAEC datagap. Based on FMC assessment, chronic RQs ranged from 0.020 to 0.078, and since there is no anticipated risk to birds, the study is not required.

Response to FMC Comment 44: Based on the EFED's analyses, the non definitive NOAEC value of > 50 ppm could not be used to preclude chronic risk to avian species, and the NOAEC value for permethrin was used to demonstrate low risk to birds resulting from cypermethrin use. Permethrin data are considered to be suitable surrogate data for cypermethrin because both chemicals are pyrethroids, they are structurally similar compounds with similar modes of action, and both are expected to be of low chronic toxicity to birds. Based on the NOAEC for permethrin, there appears to be no chronic risk to birds. Therefore, at this time, additional avian reproductive studies are not being requested. Please, refer to the addendum for additional details.

FMC Comment 45: Three data gaps were identified by EFED for aquatic organisms, namely, 1) Acute and chronic freshwater sediment, 2) Chronic estuarine and marine sediment and 3) Aquatic freshwater invertebrate life cycle study. The FMC indicates that the first two were addressed through the PWG and reports were submitted to the Agency. 42 The third study was submitted under EPAIDENT 00089047, 21 day D. magna toxicity study. It was listed as invalid because only one test chamber per test concentration was used ( should have used replication for statistical analysis). The FMC notes that growth was more sensitive than reproduction in this study, based on measured lengths of 10 individuals at each concentration in each trial. Thus, EFED's rationale for rejection of the study does not apply for the calculation of the NOEC for the most sensitive endpoint. FMC believes that the study is valid and the data requirement would be fulfilled.

Response to FMC Comment 45: In recent revisions to the chapter, the EFED has acknowledged the submission of studies by the PWG to address data gaps 1 and 2 above. The submitted studies have been received but are still in review and have not been discussed in the RED. With respect to the third data gap, it has been mentioned in a previous response that the study in question had several problems that included the following: negative control contamination; delivery lines for treatment 1 and 2 were switched for 4 days; mortality in 2 of the 4 replicates for solvent controls exceeded 30%; Dissolved oxygen levels were not maintained above 60% throughout the test. Because of these problems the Agency deemed this study invalid and has required that a new study be conducted.

FMC Comment 46: There are existing mitigation measures for crop uses, for example, the buffer zones ( 25 ft for ground applications, 150 ft for aerial applications, 450 ft for ULV, a 10 foot vegetative buffer strip for ground boom applications). These buffer zones and filter strips mitigate erosion and spray drift. Cypermethrin's physical chemical properties result in strong binding to soil and organic matter, as a result, cypermethrin exhibits only a limited expression of its inherent toxicity to aquatic organisms during labeled use.

Response to FMC Comment 46: Unfortunately, there are no models to measure quantitatively the decrease in levels of erosion due to maintained vegetated filter strips suitable for national assessments.

FMC Comment 47: FMC concludes with a series of remarks. Generally, these remarks are the positive aspects of cypermethrin or the pyrethroids as a class. They are abridged as follows:   Several issues discussed in the Science Chapter apply to synthetic pyrethroids as a class and are the subject of ongoing investigation by the Pyrethroid Working Group ( PWG), of which FMC Corporation is a member.   According to FMC, pyrethroids, including cypermethrin, are critically important agricultural and residential use insecticides. The pyrethroid class of chemistry controls a wide variety of pests that cause direct harm to people and agriculture. In aquatic environments, the inherent toxicity observed in clean water systems in the laboratory is ameliorated under field conditions, since the bioavailability of cypermethrin is restricted by its physical chemical properties. For cypermethrin, the exposure risk to terrestrial species is generally low. 43   Certain aspects of the implementation of standard approaches in this cypermethrin risk assessment could be improved.   The Problem Formulation should be more specific in its identification of ecosystems and organisms at risk, assessment endpoints, and measures of effects. The conceptual model is too generic to guide the risk assessment.   Aquatic exposure is estimated using EFED's standard pond scenario, which is not described in the Science Chapter.   Use of the equilibrium partitioning ( EqP) approach for evaluating the risks of pyrethroids in sediments is appropriate. This approach makes several important assumptions which should be applied consistently throughout the assessment.   The Problem Formulation acknowledges recent reports of cypermethrin and other pyrethroids in sediments of suburban streams, presumably originating from nonagricultural uses such as lawn care. FMC, through the PWG, is aware of these reports and will consider measures to address specific issues as they are raised by federal and state regulatory agencies.   The Science Chapter includes no quantitative estimate of exposure in estuarine/ marine environments. An implicit assumption is made that exposure in estuarine/ marine environments is similar to exposure in farm ponds. Because this assumption is tenuous and largely untested, the assessment does not support conclusive statements about risk to estuarine/ marine organisms.   Data selection should be more accurate and transparent. In several cases, the Science Chapter selects and misinterprets toxicity data based on errors concerning concentration units. In other cases, data are rejected without adequate explanation, or data from unreliable studies are used in the analysis.   By segregating toxicity data for " benthic" freshwater invertebrates from the standard Daphnia magna, the Science Chapter underestimates the sensitivity of freshwater invertebrates to cypermethrin. This also leads to erroneous conclusions about the relative sensitivity of freshwater and estuarine/ marine invertebrate species.   Due to a transcription error regarding test concentration units, the Science Chapter reaches the erroneous conclusion that " sublethal effects [ on fish] can occur at exposure levels far below the concentrations that cause lethality." On the contrary, all data from studies with freshwater fish demonstrate that sublethal effects ( such as loss of equilibrium or altered swimming behavior) occur at concentrations only slightly below acute lethal concentrations.   EFED construes observations of reproductive effects of cypermethrin in estuarine/ marine invertebrates as an indication of effects on the endocrine system. Reproductive effects in aquatic invertebrates ( and other taxa) can have many causes other than endocrine disruption ( e. g., egg mortality or feeding inhibition).   The Science Chapter includes a description of " assumptions, limitations, uncertainties, strengths, and data gaps" affecting the assessment. Most of the assumptions and uncertainties identified are interpreted as potential causes of underestimation of risk. Assumptions that lead to overestimation of risk are generally ignored. Many implicit assumptions need to be stated explicitly.   The PWG and FMC continue to actively evaluate and refine potential aquatic risk. Aquatic exposure evaluations include environmental fate studies and reviews, 44 small and large scale runoff studies, a review of vegetative filter strips, and freshwater and marine acute and chronic sediment studies ( APPENDIX 1). Ongoing evaluations include preliminary endangered species assessment, evaluation of SPME ( solid phase micro extraction) analytical techniques for pore water, national proximity/ vulnerability assessments, and a revised ecological risk assessment.   FMC contends that existing mitigation measures are protective. Cypermethrin crop use labels require a no spray buffer zone distance of 150 feet with a 10 foot vegetative buffer strip for aerial and 25 foot buffer with a 10 foot vegetative buffer strip for ground boom applications. The purpose of this distance is to mitigate potential spray drift into water bodies. Buffer zones and filter strips also provide mitigation from soil erosion. Cypermethrin's physical/ chemical properties result in strong binding to soil and organic matter; as a result, cypermethrin exhibits only a limited expression of its inherent toxicity to aquatic organisms during labelled use.   FMC's revised risk assessment concludes that cypermethrin poses a minimal risk to terrestrial ( avian and mammalian) species. EFED demonstrated a minimal acute risk, and a potential chronic risk to birds and mammals. However, when real field residue data from cotton and lettuce were utilized to assess the risk, there was minimal risk to both birds and mammals with quotients ranging from 0.0001 to 0.013 for acute and 0.013 to 0.431 for chronic RQs in birds and mammals combined.   FMC's revised risk assessment for honeybees concludes no concern to honeybees in lettuce or pecans since honeybees do not generally frequent these crops during treatment periods. FMC notes a slight risk to honeybees through exposure to treated cotton. However, mitigation is possible though appropriate monitoring of cotton fields, i. e., safe to use when honeybees are not active ( e. g., at night or during non flowering seasons).   Cypermethrin applied as a foliar application to target crops is not a risk to earthworms.

Response to FMC Comment 47: Comment 47 is a summary of the comments submitted by FMC. They have been responded to previously; therefore, no additional response is necessary.

FMC, Comment Appendix 1: It is a list of studies submitted by the PWG.

Response to Comment Appendix 1: The EFED appreciates the submission of the list.

FMC, Comment Appendix 2: It is a note that a review of aquatic risk assessment is submitted jointly with Syngenta Crop Protection, separately.

Response to Comment Appendix 2: EFED acknowledges the information submitted in the appendix. 45 FMC, Comment Appendix 3: It is an assessment of the potential risk to birds and mammals from cypermethrin applications.   FMC indicates that it provides a more realistic potential exposure, using the same timing than the one of PRZM/ EXAMS model ( e. g. application interval).   FMC noted that the RQs in the model were different in the T REX model vs. those in the RED.   Assumption 1 is that birds spend 100% of their time in treated fields. Crocker, et al., ( 2001) provide data for four species of passerine birds in the U. K. Most songbirds spend < 10% in crops while a few birds spend 90% or more in crops.   Assumption 2, RQs calculated using LD50s ( bolus dose) misrepresent the potential dietary ( dose over time) toxicity to birds. Birds consume food items over many hours of the day and the exposure characteristics are more similar to a dietary LC50 toxicity test.   Assumption 3: 100% of the avian diet contains residue. Very few birds will spend more than 90% of their time in one field.   Assumption 4: Risk to birds is assessed using one food source while bird diet consists of a variety of food sources.   Assumption 5: Even for a screening level process, it is unreasonable to promote the vegetation eating scenario. Few birds are specialized herbivores.   The EFEDs RQs do not reflect a realistic exposure scenario for avian species, according to the FMC.   The FMC says that, in addition, the toxicity reference values are reported as greater than [ e. g. LC50 > 20,000 mg/ Kg bw, and LD50 > 2000 mg/ Kg bw. The RQs are potentially lower.   After recalculation of the chronic RQs for birds, several of them were above the LOC for chronic risk ( range 0.16 2.65; LOC= 1).   The chronic toxicity reference value ( trv) was reported as greater than for both mallard duck and bobwhite quail ( NOAEC> 50 mg/ Kg diet). RQs are potentially lower.   The EFED found that the acute RQs for mammals are below the LOC for acute risk ( 0.5) and restricted use ( 0.2), except for 15 g mammal feeding on shortgrass ( RQ= 0.23). The endangered species LOC ( 0.1) was exceeded in several scenarios for cotton, lettuce and pecan.   FMC believes that EFED exaggerated the estimates of exposure because mammals were assumed to spend 100% of the time in the treated field and it was assumed that 100% of the diet contains cypermethrin residue.   The chronic risk dose based RQs for mammals exceeded the LOC ( 1) for all modeled crop uses and weight classes for exposure via short grass, tall grass and broadleaf plants/ small insects. None of the chronic dietary based RQs for mammals are exceeded. FMC believes that dietary RQs are more relevant, since mammals are potentially more likely to obtain cypermethrin through their diets over the longer term rather than through single bolus doses.   FMC believes that EFED's assessment may be revised by incorporating the avian and mammalian RQs using field residue data. In this case, the resulting RQs are well below EFED's LOC for both acute and chronic risks. 46   Birds   Acute oral RQs range from 0.0005 to 0.002, and acute dietary RQs range from 0.00005 to 0.0002. Chronic RQs range from 0.020 to 0.078 when calculated at maximum field value ( 3.4 ppm), obtained from up to 15 applications per trial residue studies.   Mammals   Acute RQs range from 0.0004 to 0.013 and chronic RQs range from 0.013 to 0.431 when calculated using the maximum EEC field value obtained from up to 15 applications per trial residue studies.

Response to Comment Appendix 3: Many of the comments above have been addressed in a recently completed revised terrestrial risk assessment for birds and mammals and in a number of responses to previous comments. In addition, while FMC contends that a number of the " exaggerated" assumptions outlined above do not reflect a realistic exposure scenario and that actual exposure to terrestrial organisms may be lower for some organisms, it is standard policy of the EFED to be as protective as possible of the most sensitive/ vulnerable species and endangered species in screening level risk assessments by taking a conservative approach. Because pesticide regulatory decisions involve potentially widespread uses of pesticides, EFED believes that conservative assumptions are necessary to account for the potential variability and uncertainty associated with exposure of a diverse array of receptors to pesticides applied to a wide variety of use sites under a variety of environmental conditions.