Sediment Contamination: Protection and Remediation

1. Sediment Contamination: Protection and Remediation Shu-Chi Chang, Ph.D., P.E., P.A. Department of Environmental Engineering National Chung Hsing University

2. Outline • Introduction • Sediment contamination • Protection of sediment • Properties of typical contaminants • Sediment remediation • Conclusion

3. Introduction • What is sediment • A dynamic system • Is it originally pristine • Astatus quo in Taiwan • Why do we care about sediment?

4. What is sediment • Sediments are fragmented materials that originate from weathering and erosion of rocks or unconsolidated deposits and are transported by, suspended in, or deposited by water.(USEPA, 2014) • 底泥：指因重力而沉積於地面水體底層之物質。 • Sediment:those substances, due to gravity, deposited at the bottom of a surface water body. (TWEPA)

5. A dynamic system • Erosion of the surface materials within a water shed • Transport of suspended particles • Deposition of suspended particles • High flow velocity event can re-suspend the deposited particles and re-deposit • During low flow rate period, some may be blown into air • Water chemistry plays a big role at tidal reach sections • How about some contaminants in small quantities • How about some contaminants in large quantities • Microbes and benthic organisms

6. Is it originally pristine • Very hard to judge • Initially eroded particle may be pristine • Litters and organic matter may be present at the middle and downstream section • Human activities may cause higher BOD and exceed the self purification capacity • Farming and industrial activities may introduce persistent organic compounds

7. Astatus quo in Taiwan • Full survey is underway • Selectively monitored heavily polluted rivers for specific contaminants for more than 10 years

8. Why do we care? • An important link in food chain • Estuary areas and continental shelve are traditionally important fishing areas • Heavy metals can enter organismal body and accumulate (El-Moselhy et al., 2014) • Hydrophobic organic compounds may also accumulated and biomagnified through food chain • Comparatively, the cycle time could quite short

9. Protection of sediment • Administrative approach • Guidelines for sediment quality • Implement the guidelines • Review the results and revise the guidelines • Canadian could be the pioneer • Protocol for the Derivation of Canadian Sediment Quality Guidelines for the Protection of Aquatic Life. (CCME, 1995) • EU regulation seemed to be delayed. No single guideline or law dedicated sediment management yet. • US • EPA’s Contaminated Sediment Management Strategy (Farris et al., 1995) • Taiwan • Included into the “Act for soil and groundwater remediation” in 2010 • Specific guideline issued in 2012 • In 2013, a specific regulation requires the government authority in charge of the relevant end-enterprise to finish a first-run sediment survey within 5 years

10. Protection of sediment • Canadian approach as a model • The Sediment Quality Guidelines • How the guidelines work • The No Effect Level: the level of the chemicals in the sediment do not affect fish or the sediment-dwelling organisms.. • The Lowest Effect Level: a level of contamination which has no effect on the majority of the sediment-dwelling organisms. • The Severe Effect Level: At this level, the sediment is considered heavily polluted and likely to affect the health of sediment-dwelling organisms.

11. Protection of sediment • Guideline development • Sediment Background Approach • Equilibrium Partitioning Approaches • Apparent Effects Threshold Approach (AET) • The Screening Level Concentration Approach (SLC) • Spiked Bioassay Approach

12. Sediment contamination (Mulligan et al., 2010)

13. Sediment contamination • Primary minerals • Secondary minerals • Organic matters • Oxides and hydrous oxides • Carbonates and sulfates (Mulligan et al., 2010)

14. Sediment contamination

15. Sediment contamination • Contaminants • Heavy metals • Organic pollutants • Grease and oils • PAHs • PCBs • PBDEs • BPA • Phthalates • Chlorobenzenes • Dioxin and furans • Herbicides and pesticides • etc. • Emerging contaminants NAPL=non-aqueous phase liquid

16. Sediment contamination • Fate and transport (Mulligan et al., 2010)

17. Sediment contamination

18. Sediment contamination • Bio-attenuation and bioavailability

19. Properties of typical contaminants • Molecular weight • Density • Water solubility • Kow • Koc • KH • Vapor pressure • Viscosity • Biodegradability • others

20. Sediment sampling • Sediment sampling method（NIEA S104.31B） • Sediment: usually consists of clay, silt, sand, organic matters, and other mineral mixtures. After long term physical, chemical, and through biological reaction and aquatic transport process, then deposited on the bottom of water bodies. • Surface sediment: the sediment 0 to 15 cm below the surface • Deep sediment : the sediment more than 15 cm below the surface 。 • Sampling devices: trowel or scoop, grab sampler, or core sampler • Considering sampling objectives, sediment, contaminants, and the environments • Samples • Grab sampling • Composite samples • This method describes the apparatus, materials, sampling, sample preservation, safety, and quality controls.

21. Samplers Gravity corer） Ekman dredge Trowel Sampling kit Van Veen dredge

22. Other samplers Smith McIntyre sampler Open core sampler (Mulligan et al., 2010)

23. Sampling points selection

24. Others • Weather • Temp, wind, tide, wave, storm? • Transportation • Mass transport, rental cars, rental boats, rafts, or wading • Special needs • Climbing • Taking boats • Diving? • Safety • Insurance • safety rope • Life jackets • Physical training

25. 3-13 QA/QC • Blanksamples • Fieldblanksample • Tripblanksample • Equipmentblanksample

26. 3-13 Blanks • Fieldblanksample • Meaning：if contaminated during sampling process • Prep： • Amount：every batch. One of twenty samples and if not enough at least one balnk. Air：filter paper groundwater：reagent water or dilution water sediment ：soils Without the target pollutant(s).

27. Blanks • Tripblanksample • Meaning：To judge if the samples were contaminated • Prep • Amount：every batch and at least one per 20 samples

28. Blanks • Equipmentblanksample • Meaning：also called rinse blanks. To judge if samplers are contaminated • Prep：Collect the reagent water or solvent at the very last step of rinsing • Amount：every batch and at least one per 20 samples

29. Method selection • Analytes characteristics • Feasibility • Convenience • Accuracy and precision • Sensitivity

30. Methods and instruments • Instruments • Gas chromatography • Suitable for chemicals that are thermally stable (will not decompose or change chemical structure). The boiling point should be lower than 350°C. • Liquid chromatography • Suitable for semi-volatile and non-volatile compoundsand those thermally decomposable analytes but the analytes have to be dissolved in solvents. • Higher molecular weight • Ionic chromatography • Inductively coupled plasma optical emission spectrometry (ICP-OES) • Atomic absorption spectroscopy

31. OA/QC for detection • Surrogate Standard • Methodblanksample • Qualitychecksample • Duplicatesample • Spikedsample

32. Pretreatment • All samples have to be determined for their water contents • Digestion • Extraction

33. Extraction Using accelerated solvent extraction to recover a 40-ml sample with solvent Using vacuum to Concentrate the sample to a specific volume GC-or LC 濃縮 圖6　真空減壓濃縮機 Using GC for analysis Column: depends定樣品Injection: 1 µL Carrier gas: Nitrogen 圖5Speed Extractor （Speed Extractor E-916, BÜCHI Labortechnik AG, Switzerland） 3 steps： • Concentrate sulfuric acid • Copper powder • Acidic silica gel column Vacuum concentrate to a specific volume. 圖7　氣相色層分析儀 圖6　真空減壓濃縮機

34. Heavy metal analysis (I) • Atomic absorption spectrometry (AA)

35. Ignitor Assembly Burner Head Burner Mixing Chamber AUX Oxidant Line FUEL Nebulizer Capillary Tube Drain Tube NEB Oxidant Line

36. Heavy metals (II) • inductively coupled plasma-optical emission spectrometry • Can quantify more than 60 different metals • No need to change lamps • Higher sensitivity

37. ICP-OES

38. Heavy metals

39. Biological analysis • Total cell • fluorescent in situ hybridization (FISH) • polymerase chain reaction – denaturant gradient gel electrophoresis (PCR-DGGE) • Real-time PCR

40. Remediation • Remedial technologies • Engineering practice • An example • Current research

41. Remedial technologies • Physical:separation, rinsing, floatation, ultrasonic • Chemical/thermal treatment：oxidation, electrokinetic, solidification, plasma vitrification, thermal desorption • Biological：Slurry reactor, land farming, compositing, bioleaching, biotransformation, phytoremediation

42. Engineering practices (Adriaens et al., 2006)

43. Dredging (Palermo et al, 2008)

44. Treatment of dredged materials (Mulligan et al., 2010)

45. Confined disposal (Netzband, 2002)

46. Contained aquatic disposal (Thomas and Concord, 2005)

47. Capping (Aldrich, 2010)

48. Active capping • Organic clay • Activated carbon • Ash • Apatite • reactive mat

49. Monitored natural recovery (MNR) (Mulligan et al., 2010)

50. MNR (Mulligan et al., 2010)