1 / 32

Soil Geochemical Survey of Florida

Soil Geochemical Survey of Florida. Ming Chen, PhD. Quality Assurance Officer University of Florida, IFAS Belle Glade, FL 33430. ACKNOWLEDGEMENT. Univ. Florida - Soil & Water Dept. Lena Q. Ma Willie G. Harris Tait Chirenje Florida Cooperative Soil Survey

bonnie
Download Presentation

Soil Geochemical Survey of Florida

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. Soil Geochemical Survey of Florida Ming Chen, PhD Quality Assurance Officer University of Florida, IFAS Belle Glade, FL 33430

  2. ACKNOWLEDGEMENT • Univ. Florida - Soil & Water Dept. • Lena Q. Ma • Willie G. Harris • Tait Chirenje • Florida Cooperative Soil Survey • Florida Center for Solid & Hazardous Waste Management • Florida Power and Light • Florida DEP

  3. What We Did in Florida? • Background of 21 Elements in Soils. • Determination (total vs. total-recoverable) • Interpretation (baseline vs. taxonomy) • Geochemical Survey of As in Urban Soils • Sampling protocol • Golf course study • Soil Digestion - Method Development • USEPA vs. Europe • Hotplate vs. Microwave

  4. SOIL BACKGROUND STUDY

  5. Pristine Agricultural Urban What is Background ? • Natural Background (NB) • Concentrations of chemicals in soils without human influence(USEPA, 1995) • AnthropogenicBackground (AB) • AB= NB + Anthropogenic input from non-point sources

  6. Sample Size Consideration • NB-variability & soil taxonomy: N = [(S x t0.05)/R]2 • AB - sample distribution & land use: To obtain 95th quantile at =0.05

  7. Ways to Interpret • Geometric Mean vs. Arithmetic Mean • Pattern of Distribution • Upper Percentile Level (UPL) • UBL-97.5% Upper Percentile of data (USGS, 1993) • UBL = GM  GSD2 • Large database • Upper Confidence Level of Mean(UCL) • Site specific cases • Small database

  8. No. of Occurrences Upper confidence limit (UCL) When sample size is big enough, … Upper baseline limit (UBL) AM GM / GSD2 GM X GSD2 Baseline (95%) UCL vs. UBL GM

  9. Sample Selection • Near Pristine Soils - N = 448 out of 7000 Soil Survey Archives • Undisturbed Soil (n =266) - with native vegetation • Disturbed Soil (n=182) - by plowing or clearing • Representative of Samples • 7 orders - 19 suborders - 33 Great Groups • 51 counties - 80% acreage • Verification Samples

  10. Geographical vs. Taxonomic

  11. Quality Assurance System • QA Plan: Florida DEP approval • NELAP Certification • Digestion Method: • EPA 3051a – HNO3/HCl • EPA 3052 – HNO3/HCl/HF • QA/QC sample: every 20 samples • regent blank ------- MDLs • certified standard soil --- method validation • spiked soil ---- precision • duplicate soil ----- accuracy

  12. Statistical Consideration • Test Sample Distribution for Normality: • Normally distributed datasets: t- UCL • Log-normally distributed datasets: H - UCL • Neither normally nor log-normally distributed datasets: Non-parametric tests (Pro- UCL) • Reduce Number of Non-detects • Updated procedure or instrument to low MDL. • Use 0.5 MDL for non-detects (< 20 %) • Outliers: Q-Q Plot

  13. As Distribution Pattern

  14. Is It a Real Soil Background- Q/Q Plot ? Undisturbed Soils (n=266) Disturbed Soils (n=182) Urban Soils (n=197)

  15. As Values in Florida & World Soils

  16. Wet soils (73) GM=1.28 Upland soils (293) GM=0.18 Borderline(82) GM=0.29 As vs. Soil Suborders

  17. Total Fe & Al PCA : explained 29% of variation (Chen et al., 1999) Partial regression <0.05 (Chen et al., 2002) Phosphate Deposit Total P: partial regression <0.05 (Chen et al., 2002) Distribution paralleled P rock: 7-121 vs. non- P rock: 2- 6.6 mg As /kg Wetland/vegetation – no direct evidence Factors Contribute to As

  18. Limestone 3-13 mg/kg: Everglades (Chen et al., 2000) 40 mg/kg: Avon Park limestone (Levy County) Sea snail and other marine animals Database: 61.2- snail, 38.1-mollusk shells. 144-484 mg/kg – marine snail shells (vs. 0.2 for land snail) 3.6-63 mg/kg - meat, wet weight Factors Contribute to As

  19. GEOCHEMICAL SURVEY OF AS IN URBAN SOIL

  20. Why Arsenic? • Toxicity • No. 1 priority hazardous substance (275) (ATSDR, 1999) • Class A human carcinogen (USEPA, 1998) • Taiwan • Bangladesh • Florida • Drinking Water Standard • USEPA 10 ppb (2006)

  21. Survey: As - Herbicide Usage on Golf Courses - (Chen & Ma, 2000)

  22. Lysimeter Study: As Held by Surface Soil (Chen & Snyder, 2002)

  23. Daytona Beach/ Volusia Gainesville/Alachua Ft.Lauderdale/ Broward Miami/Dade As in Urban Soils

  24. Sample Selection

  25. As in Urban Soils with Different Land Uses Gainesville, FL (N=201)

  26. METHOD DEVELOPMENT Soil Digestion Procedures

  27. Why Methods Development ? • Worldwide Geo-chemical Survey needs Unified Methodology and Standards • Standard Operation Procedure (SOPs): data comparison • Certified Reference Materials (SRM): Data validation. • Digestion Methods are lab-dependent • Europe: Aqua regia (HNO3/HCl =1:3) + HF • USEPA Methods (3050, 3051, 3051a and 3052) (HNO3/HCl =3:1) • Microwave vs. Hotplate

  28. USEPA Digestion Procedures • EPA 3051a is an overall better procedure in replacing the regulatory method 3050. • 3051a and 3050 only get partial recoveries for Ba, Cr, Mo, Ni, K, and Al in NIST SRMs.

  29. USEPA vs. Aqua Regia Methods • Aqua regia procedures are more aggressive than the relevant EPA procedures.

  30. CONCLUSION • Florida soils generally have low elemental backgrounds, which are based on: • soil type • soil property • land uses • Certain soil has naturally high As background: • marl soil (wet) • muck soil (wet) • P deposit soil • Fe coated soil • marine shelly soil • contaminated soils

  31. CONCLUSION • UBL value of soil Suborder is a better approach for soil As screening in a state level. However, • there is not a single magic number for regulatory uses. • Pilot study and method development can address issues like: • soil sampling protocol • soil digestion procedure • certified standard soils

  32. MING CHEN 561-993-1527 mchen@mail.ifas.ufl.edu THANK YOU

More Related