User’s Guide and Technical Documentation KABAM version 1.0 (KOW (based) Aquatic BioAccumulation Model) April 7, 2009 Environmental Fate and Effects Division (EFED) Office of Pesticide Programs U.S. Environmental Protection Agency Washington, D.C. 1 of 123 Acknowledgements Author Kristina Garber Technical Reviewers Brian Anderson Lawrence Burkhard Paige Doelling Keith Sappington Thomas Steeger Editorial Reviewer Karen McCormack QA/QC Officer Nick Mastrota QC Testers Oak Ridge National Laboratories 2 of 123 Table of Contents 1. Introduction................................................................................................................................. 5 1.1. Model Description ............................................................................................................... 5 1.2. When to use this model........................................................................................................ 6 1.3. Conceptual model ................................................................................................................ 6 1.4. Model Application ............................................................................................................... 7 2. Input parameters.......................................................................................................................... 8 2.1. Chemical Specific Inputs ..................................................................................................... 8 2.2. Ecosystem Inputs ............................................................................................................... 13 3. Parameters & Calculations........................................................................................................ 17 4. Model Results ........................................................................................................................... 18 5. Assessing pesticide concentrations in fish tissues for human consumption............................. 24 6. Model assumptions, limitations, and uncertainties................................................................... 24 Appendix A. Description of bioaccumulation model ................................................................... 26 A.1. Calculation of fraction of chemical in the water column that is freely dissolved (Ф)...... 28 A.2. Calculation of chemical concentration in sediment .......................................................... 30 A.3. Calculation of respiration uptake (k1) and elimination (k2) rate constants ....................... 30 A.4. Calculation of growth rate constant .................................................................................. 37 A.5. Calculation of dietary uptake (kD) rate constant ............................................................... 38 A.6. Calculation of dietary elimination (kE) rate constant........................................................ 43 A.7. Overall sensitivity of body concentration of chemical (CB) to individual input parameters ................................................................................................................................................... 57 Appendix B. Explanation of defaults and alternative values representing abiotic characteristics of aquatic ecosystem ......................................................................................................................... 72 B.1. Particulate organic carbon (XPOC) and dissolved organic carbon (XDOC) ......................... 72 B.2. Concentration of dissolved oxygen (COX)......................................................................... 72 B.3. Water temperature (T)....................................................................................................... 73 B.4. Concentration of suspended solids (C SS).......................................................................... 74 B.5. Sediment organic carbon (OC).......................................................................................... 74 Appendix C. Explanation of default values representing biotic characteristics of aquatic ecosystem, including food web structure...................................................................................... 75 C.1. Phytoplankton.................................................................................................................... 75 C.2. Zooplankton ...................................................................................................................... 78 C.3. Benthic invertebrates......................................................................................................... 79 C.4. Filter feeders...................................................................................................................... 84 C.5. Fish (small, medium and large sizes)................................................................................ 86 3 of 123 Appendix D. Selection of mammal species of concern and corresponding biological parameters ....................................................................................................................................................... 91 D.1. Descriptions of mammal species....................................................................................... 91 D.2. Determination of mammalian default parameters for KABAM ....................................... 92 Appendix E. Selection of bird species of concern and corresponding biological parameters...... 97 E.1. Bird family descriptions .................................................................................................... 97 E.2. Detailed conceptual model .............................................................................................. 102 E.3. Determination of daily food intake.................................................................................. 103 E.4. Definition of default parameters to represent birds in KABAM..................................... 104 Appendix F. Description of equations used to calculate the BCF, BAF, BMF, and BSAF values. ..................................................................................................................................................... 107 F.1. Bioconcentration.............................................................................................................. 107 F.2. Bioaccumulation.............................................................................................................. 108 F.3. Biomagnification ............................................................................................................. 109 Appendix G. Description of equations used to calculate dietary-based and dose-based EECs, toxicity values, and RQs for mammals and birds consuming contaminated aquatic organisms 110 G.1. Food ingestion rates ........................................................................................................ 110 G.2. Drinking water intake rates............................................................................................. 110 G.3. Dose-based EECs............................................................................................................ 111 G.4. Dietary-based EECs ........................................................................................................ 111 G.5. Adjusted dose-based toxicity values............................................................................... 111 Appendix H. Methods for estimating metabolism rate constant (kM) ........................................ 113 H.1. Use of Equation A1......................................................................................................... 113 H.2. Use of Arnot et al. 2008.................................................................................................. 114 H.3. Assumptions and uncertainties........................................................................................ 114 Appendix I. References Cited..................................................................................................... 116 4 of 123 1. Introduction 1.1. Model Description KABAM (KOW (based) Aquatic BioAccumulation Model) is used to estimate potential bioaccumulation of hydrophobic organic pesticides in freshwater aquatic food webs and subsequent risks to mammals and birds via consumption of contaminated aquatic prey. This model can also be used to estimate pesticide concentrations in fish tissues consumed by humans. The model was designed for use by the U. S. Environmental Protection Agency Office of Pesticide Programs’ Environmental Fate and Effects Division (EFED) scientists. KABAM is composed of two parts: 1) a bioaccumulation model estimating pesticide concentrations in aquatic organisms and 2) a risk component translating exposure and toxicological effects of a pesticide into risk estimates for mammals and birds consuming contaminated aquatic prey. The bioaccumulation portion of KABAM is based on an aquatic food web bioaccumulation model published by Arnot and Gobas (2004). This model was originally published in 1993 by Gobas (Gobas 1993) and was modified by Arnot and Gobas (2004). The Arnot and Gobas (2004) model was selected for estimating pesticide bioaccumulation based on the following reasons: 1) the Gobas 1993 model underlying the Arnot and Gobas 2004 version is generally accepted by the scientific community as a reasonable approach for estimating bioaccumulation of persistent hydrophobic organic compounds in aquatic systems (Burkhard