1. California Sediment Quality Objectives Bioaccumulation Methods A Presentation to the SQO Scientific Steering Committee July 27, 2005

2. Presentation Summary Background and Conceptual Model Background and Conceptual Model –Three Lines of Evidence Technical Issues With Each Line of Evidence Technical Issues With Each Line of Evidence

3. Conceptual Model Chemical uptake via diet, respiration Effects Thresholds For Wildlife/Fish Effects Thresholds For Humans Exposure Assessment Effects Assessment

4. Multiple Lines of Evidence Approach Chemical uptake via diet, respiration Effects Thresholds For Wildlife/Fish Effects Thresholds For Humans Exposure Assessment Effects Assessment

5. Indirect Effects Multiple Lines of Evidence (MLOE) Fish Concentration Sediment Concentration Laboratory Bioaccumulation Concentration Fish Concentration Sediment Concentration Laboratory Bioaccumulation Concentration Human Lines of Evidence Fish and Wildlife Lines of Evidence

6. Fish Concentration Sediment Concentration Laboratory Bioaccumulation Concentration Tissue contaminant concentration in field captured fish Tissue contaminant concentration in field captured fish –Assesses beneficial use impairment. –Does not directly implicate sediments: Other sources (water column, watershed loading)Other sources (water column, watershed loading) Fish movementFish movement 1. Fish Line of Evidence

7. 2. Sediment Line of Evidence Fish Concentration Sediment Concentration Laboratory Bioaccumulation Concentration Contaminant concentrations in sediments Contaminant concentrations in sediments –Assess whether sediments are a potential source. –Does not assess variations in bioavailability Physical parameters, e.g., soot carbon, paint chips.Physical parameters, e.g., soot carbon, paint chips.

8. 3. Bioaccumulation Line of Evidence Fish Concentration Sediment Concentration Laboratory Bioaccumulation Concentration Contaminant concentrations in laboratory bioaccumulation tests Contaminant concentrations in laboratory bioaccumulation tests –Are sediment contaminants bioavailable? –Has limitations Difficulty achieving equilibriumDifficulty achieving equilibrium Laboratory extrapolationLaboratory extrapolation

9. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

10. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

11. Target Species Arrow Goby Black Surfperch California Corbina California Halibut California Killifish Dwarf Surfperch English Sole Leopard Shark Longfin Sanddab Pacific Sanddab Pacific Staghorn Sculpin Species previously monitored in CA Bays and Estuaries with sediment linkage in adult lifestyle: Saddleback Sculpin Shiner Surfperch Slender Sole Speckled Sanddab Spotted Sandbass Starry Flounder Striped Mullet Walleye Surfperch White Croaker White Surfperch Yellowfin Goby

12. Prey For Humans and Wildlife Sediment Linkage Limited Variation in Diet or Home Range Target Species

13. Bold indicates significant r^2 value and positive slope Target Species - Sediment Linkage

14. Evaluate different species using mechanistic model simulations –Gobas model parameterized for San Francisco Bay Includes dietary and respiratory uptake –Run simulations setting water vs. sediment input to zero to estimate relative influence of waterborne vs. sediment contaminants –Approach may be used locally wherever food web data are available

15. Target Species - Sediment Linkage

16. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

17. Standard risk assessment approach –Threshold Fish Concentration = Function of (Toxicity Reference Value, Dose, Body Size) Threshold choice is in large part a policy decision –Target population to protect (e.g., consumption rate) –Allowable Risk Level Fish Tissue Thresholds For Protecting Humans

18. Comparison of thresholds using different assumptions: Federal or state recommended policies Two additional thresholds represented more or less conservative assumptions Fish Tissue Thresholds For Protecting Humans

19. Thresholds vary greatly depending on assumptions Fish Tissue Thresholds For Protecting Humans

21. Human thresholds generally lower - will drive the SQO DDT is an exception Chlordane generally does not exceed thresholds Effects thresholds vs. organic contaminant concentrations in three sportfish species (Shiner Surfperch, California Halibut, and White Croaker) Exceedances Using Different Thresholds

22. Appropriate Assumptions for Thresholds Bioaccumulation Work Group Also Many BTAG Members

23. General approach: –Threshold Fish Concentration = Function of (Toxicity Reference Value, Dose, Body Size) Dose based on body mass allometry equation Statewide based on generic species classes Local regulators refine with site-specific data for individual water bodies Fish Tissue Thresholds For Protecting Wildlife

25. Toxicity Reference Values: –DDTs, PCBs, Hg - Using USEPA Region 9 BTAG TRV-Low –Dieldrin - USEPA ECO-SSL values –Chlordane - no consensus values available –Mammals - Khasawinah and Grutsch 1989 –Birds - Stickel et al. 1983 –Recall that chlordanes do not exceed thresholds for any fish (N = 192)

26. Fish Tissue Thresholds For Protecting Wildlife Avian results lower Small animals lower

27. Among wildlife, small birds would drive the SQO for PCBs and DDTs Comparison of organic contaminant concentrations in three sportfish species (Shiner Surfperch, California Halibut, and White Croaker) to wildlife and human effect thresholds Exceedances Using Different Thresholds

28. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

29. Macoma nasuta is a good species for Laboratory Bioaccumulation test - Recommended for bed sediment testing (EPA guidance) -Deposit feeder with high contaminant tolerance -Large California database available Methods Guidance: Target Species - Lab Test Organisms Species with existing data in SQO database

30. ContaminantSF Central Bay San Pedro Bay Tomales Bay San Diego Bay Total DDTsn = 137n = 77n = 12ND R2R2 0.56 * 0.13 * 0.12 Total PCBsn = 63ND n = 14 R2R2 0.39 * 0.93 * Total HPAHsn = 137n = 77n = 11n = 14 R2R2 0.19* 0.39 * 0.52 * 0.80 * Chlordanesn = 137n = 78n = 12ND R2R2 0.64 * 0.34 * 0.27 Summary of regression analysis of summed contaminant concentrations in sediment and Macoma nasuta tissue. * = significant linear relationship (p<0.05) ND = No Data Available Target Species - Macoma nasuta

31. Macoma nasuta tissue data indicate different results for different water bodies. BSAFs vary among waterbodies 22.533.544.555.56 Sediment Concentration (log x+1, ug/kg, dry wt.) Bivalve Tissue Concentration (log x+1, ug/kg, dry wt.) San Diego San Pedro SF Tomales Linear (SF) Linear (San Diego) Linear (Tomales) Linear (San Pedro)

32. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

33. Bioaccumulation Line of Evidence: Methods of Evaluation How establish threshold with this line of evidence? Potential methods: 1. Test for any bioavailability –Organism tissue concentrations above concentrations in control organisms 2. Test for bioaccumulation –BSAF > 1 3. Test for tissue effects threshold exceedance –Use test organisms as surrogates for dietary exposure to fish, wildlife, and humans –With 28-day test, must correct for lack of equilibrium in short time frame B

34. Bioaccumulation Line of Evidence: Methods of Evaluation 3. Test for tissue effects threshold exceedance –Correcting for lack of equilibrium in 28 day time frame More conservative approach: multiply laboratory results by 4 (USEPA Ocean Disposal Testing Manual 1991) Less conservative approach: multiply laboratory results by factor between 1 and 3, depending on compound Kow (USEPA Inland Testing Manual 1998; McFarland 1994) Use longer time frame e.g., 45 day test (very costly) B

35. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold? S

36. Fish have variable home ranges and are often not captured where sediment data available. Approach: Fish concentrations compared with sediments in a disk centered at each fish sampling location. Disk size ranged from 0.5 - 15 km (0.5 km increments) No a priori assumptions about fish home range Fish Movement S

37. Identify best spatial scale to combine fish and sediment data.

38. Diagnose spatial association between fish and sediment contamination for a given water body.

39. Technical Issues Fish Line of Evidence Fish Line of Evidence –What are appropriate target species? –What assumptions to use in calculating tissue thresholds? Consumption rateConsumption rate Risk levelRisk level Bioaccumulation Line of Evidence Bioaccumulation Line of Evidence –What are the most appropriate tests? –What are appropriate thresholds? Sediment Chemistry Line of Evidence Sediment Chemistry Line of Evidence –How address fish movement? –How translate from fish threshold to sediment threshold?

40. Translating From Fish Threshold To Sediment Threshold S Effects Thresholds For Wildlife/Fish Effects Thresholds For Humans ?

41. Potential Approaches: 1.BAF and BSAF 2.Regression Model 3.Mechanistic Model 4.Combine 1 and 3 S Translating From Fish Threshold To Sediment Threshold

42. Focus of Effort  Non-ionic organic compounds with extensive exposure and effects data  PCBs  Legacy Pesticides (DDTs, Chlordanes, Dieldrin)

43. 1. BSAF = Lipid-normalized tissue conc./ organic carbon-normalized sediment conc. 2. BAF = Tissue conc. / sediment conc. Both methods use paired samples from multiple locations, pooling data from a representative range when necessary 1. BAF and BSAF

44. DDTs in San Francisco Bay Macoma clams vs. sediment R 2 = 0.6585 R 2 = 0.2541 0.1 1 10 100 1101001000 Sediment DDT (ug/kg) Tissue DDT (ug/kg) BAF BSAF BAF vs. BSAF

45. Using the shiner surfperch dataset from San Francisco Bay, calculated the BAF for each sample (N = 43) Determined distribution to be log- normal Determined geometric mean BAF and used it to backcalculate sediment thresholds from tissue thresholds –Less conservative Determined 95% CI to estimate high-end BAF and backcalculate low end sediment thresholds –More conservative BAF Example Application

46. Example results in three thresholds More conservative threshold - 95%ile BAF using CTR tissue criteria Intermediate threshold - GeoMean BAF using CTR Less conservative threshold - GeoMean using US EPA Screening Value for general population

47. 0 2 4 6 810 Sediment Concentration 0 10 30 40 Biota Concentration 20 4 2 High toxicity Threshold Low toxicity Threshold 2. Regression Modeling

48. Total Chlordanes - Shiner Surfperch - San Francisco Bay R 2 = 0.2627 0 0.5 1 1.5 2 2.5 00.511.5 Sediment Chlordanes (logx+1) ug/kg (dry wt.) Fish Tissue Chlordanes (logx+1) ug/kg (dry wt.) F

49. 2. Regression modeling Cannot predict well outside data range High data requirements High uncertainty

50. Uptake Dietary Gill Loss Excretion Egestion Gill Elimination Metabolism Growth Chemical properties (e.g., K ow ) important Translating From Fish Threshold To Sediment Threshold 3. Mechanistic Modeling

51. Calculate BAFs for pesticides in San Francisco Bay Using Gobas (1993) model, as updated by Arnot and Gobas (2005) Inputs required –Contaminant Kow –Quantitative representation of food web structure –Animal body mass, lipid content, feeding strategy –Water body chemistry (temperature, DO, TSS) Mechanistic Model Example Application

52. Sediment Shiner Surfperch White Croaker Jacksmelt Zooplankton Algae Grass Shrimp MollusksPolychaete Worms Amphipods Input food web data

53. Model outputs BAFs for modeled Species Can estimate Uncertainty using Monte Carlo

54. 4. Combine BAF/BSAF With Mechanistic Model Corroborate mechanistic model results with field BAF data If results don't fit, reevaluate model assumptions, and/or collect more data Requires same data as mechanistic model, but also requires field data to confirm BAFs –Contaminant concentrations in water and sediments –Contaminant concentrations in biota of interest

55. Compare results to: Sediments Biota

56. Combined Approach For San Francisco Bay Pesticides

57. Source: Gobas and Arnot, 2005 Combined Approach For San Francisco Bay PCBs

58. Ease of Implementation

59. Indirect effects relies on MLOE: fish tissue chemistry, bioaccumulation tests, and sediment chemistry Fish tissue thresholds are driven by policy decisions. Modify assumptions to accommodate State decision. Bioaccumulation - Macoma nasuta an applicable test. Sediment contamination - number of methods available, depending on time, data, and expertise. BSAF or BAF Mechanistic modeling using Gobas model Bioaccumulation Methods Summary Bioaccumulation Methods Summary

60. Develop approach to integrate lines of evidence Equal weighting? Tiered implementation? Continue case studies - Newport Bay Develop approaches for other contaminants Mercury PAHs Develop guidance manual Future Steps

61. Contact Information Ben Greenfield: ben@sfei.org Mike Connor: mikec@sfei.org www.sfei.org Acknowledgements Ned Black, Michael Anderson, Laurie Sullivan, Katie Zeeman, Robert Brodberg and other members of Bioaccumulation Work Group Beckye Stanton, Regina Donohue, Julie Yamamoto, and othe BTAG members Frank Gobas and Jon Arnot, Simon Frasier University

62. Supplemental Information

63. California Toxics Rule gives explicit guidance as to fish tissue risk assessment assumptions in developing state water quality objectives: –"EPA assumes 6.5 grams per day of contaminated fish and shellfish consumption…for a 70 kilogram person in calculating the criteria….For carcinogens, the risk assessments are upper bound one in a million (10 -6 ) lifetime risk numbers….EPA maintains an electronic database which contains the official Agency consensus for oral RfD assessments and carcinogenicity assessments which is known as the Integrated Risk Information System (IRIS)." Fish Tissue Thresholds For Protecting Humans

64. Methods Guidance: Target Species - Small Home Range Spatial patterns in total PCB concentrations and stable isotope signatures suggest site fidelity for shiner perch in the San Francisco Estuary Total PCBs