1 / 15

National Descriptive Model of Mercury in Fish Tissue

National Descriptive Model of Mercury in Fish Tissue. Stephen P. Wente Mounds View, MN. U.S. Department of the Interior U.S. Geological Survey. Sampling for Mercury in Fish. Spatial variation Temporal variation Fish consumption advisories. Problem 1: Cost of Information.

verlee
Download Presentation

National Descriptive Model of Mercury in Fish Tissue

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. National Descriptive Model of Mercury in Fish Tissue Stephen P. Wente Mounds View, MN U.S. Department of the Interior U.S. Geological Survey

  2. Sampling for Mercury in Fish • Spatial variation • Temporal variation • Fish consumption advisories

  3. Problem 1: Cost of Information

  4. Possible Sample Designs • Collect fish samples with consistent characteristics • Species confined to definite ranges • Cannot compare to existing data • Use existing data • Must use model to make samples comparable • Variations in quality of existing studies

  5. Problem 2: Difficult Comparisons

  6. Fish Mercury (Hg) Model Details • Regression method (Covariance model) • Accounts for: • Less than detection limit values • Species (Hg increases with trophic position) • Tissues sampled (skin-off fillet > skin-on > whole fish) • Fish length (larger fish are higher in Hg) • Calibrated to national dataset (N=45,605)

  7. High Low Simple yet Realistic Description Log-log Space Arithmetic Space

  8. Largemouth bass No Consumption Limited Carp Bluegill Unlimited Consumption Advisory

  9. Estimate concentration of a standard sample type (e.g. 14 inch skin-off largemouth bass fillets) for all sampling events (specific site and time) Standardize Sample Type

  10. Raw Data Modeled ‘Spatial’ Variation(14 inch Largemouth Bass Skin-off Fillets)

  11. Standard Fish Hg Concentration (mg/Kg) 1965 1965 1990 1990 Date Date Date Northwestern US Fish Hg Trends:NCBP Data 1965 1990 (NCBP = National Contaminant Biomonitoring Program)

  12. Analytical Costs Sample types* Time Sites Analytical Cost Reduction *Sample types is number of species × size classes × tissue types

  13. Fish-Hg Standard Fish-Hg Response Cost Function Uncertainty Fish-Hg Concentration Time Cost $1 $1 $1 $3 $2 $2 $1 Model Reduces Compliance Costs by Reducing Uncertainty

  14. Temporal Trends No Consumption Raw Data Limited Consumption Unlimited Consumption Consumption Advisories “Continuously updated” data & analysis Project Website (emmma.usgs.gov)

  15. Benefits of National Model • Consistent nationwide interpretation of many independent monitoring efforts • More comprehensive fish consumption advisories • Better description of spatial and temporal trends • Reduced analytical and compliance costs Contact: Steve Wente (spwente@usgs.gov)

More Related