TEXT SEARCHABLE DOCUMENT UNITED STATES ENVIR~NMENTALPROTECTION AGENCY WASH~GTON,D.C. 20460 I j OFFICEOF PC Code: 035602 DP Barcode: 306855 April 8,2008 MEMORANDUM SUBJECT: Revised Environmental iate and Ecological Risk Assessment for Dazomet TO: Cathryn OConnell, Risk Reviewer Tom Myers, Risk Special Review Division (7508P) FROM: Faruque Khan, Senior entist&> C James Felkel, Wildlife y//g/og Environmental Risk Environmental Fate and dffects Division 17507P) n Approved ah Shamim, Branch Ch By: ~vironmentalRisk Bran Environmental F Attached is the revised EFED E Risk Assessment for the Reregistration of Dazomet. sed to account for 1) removal of the Florida aquatic os for tomatoes and strawberries (these crops are currently registered ), 2) addition of a California strawberry aquatic exposure scenario (incl and 3) corrections to the Pennsylvania turf aquatic exposure scenario. include some new EECs and risk quotients, as well as revisions n and endangered species sections, based on the above changes. QRiae at Pmntian, Pelalddsq and Tawic Substancm Revised ~nvironrnentalFate and Ecological Risk Asbessment for the ~ere~jstrationof Dazomet IUPAC name: CAS name: CAS No: 533-74-4, PC Code: 035602 Table of Contents I. EXECUTIVE SUMMARY ....................................................................................................................4 A. Nature of Chemical Stressor............................................................................................................. 4 B. Conclusions .Exposure Characterization .......................................................................................4 C . Potential Risks to Non-target Organisms ........................................................................................4 D. Conclusions .Effects Characterization ...........................................................................................5 E . Data Gaps and Uncertainties ............................................................................................................5 1. Environmental Fate and Exposure ................................................................................................5 a .Environmental Fate Data Gaps: Dazomet ................................................................................5 b. Environmental Fate data Gaps: MITC .....................................................................................6 c. Uncertainties- Pate and Environmental Exposure ...................................................................6 2. Ecological Effects............................................................................................................................. 7 a .Ecological Effects Data Gaps...................................................................................................... 7 b .Uncertainties Ecological Effects .................................................................................................9 11 .PROBLEM FORMULATION ............................................................................................................11 A. Stressor Source and Distribution ...................................................................................................11 1. Source and Intensity..................................................................................................................... 11 2. Physicochemical, Fate, and Transport Properties ..................................................................... 11 3 . Pesticide Type, Class, and Mode of Action ................................................................................11 4 . Overview of Pesticide Usage ........................................................................................................12 B. Receptors ..........................................................................................................................................12 1. Ecological Effects.......................................................................................................................... 14 a .Aquatic Effects........................................................................................................................... 14 b .Terrestrial Effects .................................................................................................................14 2. Ecosystems at Risk .......................................................................................................................14 C. Assessment Endpoints ......................................................................................................................15 D. Conceptual Model............................................................................................................................ 18 1. Risk Hypotheses............................................................................................................................ 18 2. Diagram ..........................................................................................................................................18 E . Analysis Plan ....................................................................................................................................20 1. Preliminary Identification of Data Gaps ....................................................................................20 2. Measures to Evaluate Risk Hypotheses and Conceptual Model ..............................................22 a .Measures of Exposure ...............................................................................................................20 b. Measures of Effect.................................................................................................................... 21 c. Measures of Ecosystem and Receptor Characteristics ......................................................... 22 111 .ANALYSIS ..........................................................................................................................................23 A. Use Characteruat~on. ....................................................................................................................... 23 B. Exposure Characterization ............................................................................................................. 26 1. Environmental Fate and Transport Characterization ..............................................................26 a .Summary of Empirical Data ....................................................................................................28 b .Degradation and Metabolism................................................................................................... 28 c. Transport and Mobll~ty. ............................................................................................................ 29 d . Field Studies.............................................................................................................................. 30 2. Measures of Aquatic Exposure .......................................................................................................30 a .Aquatic Exposure Modeling ......................................................................................................... 30 b . Aquatic Exposure Monitoring (Field Data) ...........................................................................34 3 . Measures of Terrestrial Exposure .............................................................................................. 35 a . Modeling of Granular Exposure for Terrestrial Animal Exposure..................................... 35 b .Inhalation Exposure Modeling of MITC for Terrestrial Animals........................................ 35 c. Exposure Modeling for Non-Tar rrestrial Plants ......................................................... 38 d .Terrestrial Exposure Monitorin Data) .......................................................................38 C. Ecological Effects Characterizati .................................................................................38 1. Aquatic Effects.................................. .................................................................................39 a .Aquatic Animals ............................ .................................................................................42 b .Aquatic Plants ............................... .................................................................................41 2. Terrestrial Effects ............................ .................................................................................41 a . Terrestrial Animals ....................... .................................................................................43 b . Terrestrial Plants ..................... .................................................................................44 IV . RISK CHARACTERIZATION... .................................................................................45 A. Risk Estimation .Integration of E nd Effects Data ......................................................45 1. Non-target Aquatic Animals ................................................................................47 a .Fish and Invertebrates ........... ................................................................................47 b .Vascular and Nonvascular A s ............................................................................. 49 2. Non-target Terrestrial Animal ...............................................................................48 a .Birds .....................................