1. Dispersants: Chemistry, Environmental Fate & Effects, and Their Use as a Spill Response Option Ellen Faurot-Daniels California Department of Fish and Wildlife Office of Spill Prevention and Response

2. Objectives for Presentation Review current oil spill response technologies, and discuss why and when we consider dispersants or other ARTs as potential response options Provide background information on dispersants, how they work, and their fate and effects in the environment. Discuss historical barriers to dispersant application, the planning approach used in California, and research and planning activities since the Deepwater Horizon oil spill 2010. Review recommendations on when (and when not) to use dispersants in various response situations.

3. Response Options at the Time of an Oil Spill It is important to have as many tools in the tool box for use in an emergency situation: Some of the contents of the "spill response toolbox” include, in clockwise order from the upper left: Dispersants Boom Skimmers Burning Dispersants would usually be used in conjunction with these other cleanup techniques.

4. Oil Chemistry Types of Oils Persistence of Different Oils

5. Oil Chemistry Review Oil is not one simple “thing”; it is a complex and highly variable mixture of compounds. Crude oil is a mixture of mainly hydrocarbons, with varying small amounts o trace metals. Hydrocarbons (including asphaltenes and waxes) are the most abundant compound in crude oils.

6. Types of Hydrocarbons that are in All Oils LIGHT-WEIGHT COMPONENTS –1 to 10 carbon atoms (low molecular weight) –evaporate and dissolve into the water-column rapidly (within hours) and leave no residue –many of these compounds (such as BTEX: benzene, toluene, ethyl benzene, xylene) are thought to be readily absorbed through skin, and inhaled by animals and humans –BTEX hydrocarbons are carcinogens and/or teratogens –potentially flammable

7. Types of Hydrocarbons that are in All Oils MEDIUM-WEIGHT COMPONENTS –11 to 22 carbon atoms (medium molecular weight) –evaporate and/or dissolve into the water column more slowly (over several days), with some residue remaining. –not as bioavailable as lower-weight components, so less likely to affect animals.

8. Types of Hydrocarbons that are in All Oils HEAVY-WEIGHT COMPONENTS –23 or more carbon atoms (high molecular weight) –undergo little to no evaporation or dissolution –Can cause chronic (long-term) effects via smothering or coating, and as residue in the water column and sediments (such as tar balls)

9. Oil Persistence PERSISTENCE: Refers to an oil or refined product’s tendency to remain in the environment for a long time after discharge. Persistent oils cannot be completely removed from the environment. In general, an oil with a weathering half-life of months to years is considered persistent. The more medium to heavy weight compounds present, the more persistent it becomes.

10. Oil Groups Category Persistence Specific Gravity Typical Examples Group I Non-persistentN/A Gasoline products, condensates. Group II Persistent<0.85Diesel-like products and light crude oils Group III Persistent0.85 < 0.95Medium-grade crudes & intermediate products Group IVPersistent0.95 < 1.00Heavy crudes and residual products Group VPersistent> 1.00Low API gravity products [heavier than fresh water] Persistence as defined by US 33 CFR, Section 155.1029 and CCR.

11. Characteristics and Behavior of Spilled Oil in the Marine Environment

12. Weathering of Oils When oil is spilled on the sea, its physical and chemical properties are changed. This process is known as weathering. Physical ProcessesChemical Processes - Evaporation- Photochemical degradation -Dissolution- Microbial degradation -Emulsification -Spreading -Natural dispersion -Sedimentation

13. Spreading and Advection Spreading: The movement of oil horizontally on water surface due to gravity, inertia, friction, viscosity and surface tension. Advection: The movement of oil due to influences of winds and/or currents. Spreading dominates during the initial stages of a spill.

14. Evaporation Evaporation: The preferential transfer of light and medium-weight components of oil from the liquid phase to the vapor phase. Will vary depending on oil composition 20 - 40% loss by volume for crude oils is considered normal 75 - 100% loss by volume for many light refined products. Evaporation is the primary weathering process in the natural removal of oil from the water surface.

15. Dissolution Dissolution : The transfer of oil component from a slick on the surface into solution in the water column. Light-End Components Tend to the be most soluble Evaporation and dissolution compete for the same oil components Evaporation occurs 10 - 1,000 times faster than dissolution.

16. Natural Dispersion Oil droplet size: Will determine whether droplets re- combine with the slick or stay dispersed in the water column Droplets >0.1mm will likely re-combine and come back to the surface Droplets < 0.1 mm will stay suspended in the water. Following evaporation, natural dispersion is the second most important process. Natural Dispersion: The process of forming small oil droplets that become incorporated into the water column in the form of a dilute oil-in-water suspension.

17. Emulsification Emulsification: The mixing of seawater droplets into the oil spilled on the water surface. Since water is being added to the oil : Emulsification will increase the total volume of oil (mousse) remaining in the environment, often by a factor of 2 or 3.

18. Photo-oxidation Photo-oxidation plays a relatively minor role in the over all weathering of spilled oil (~ to 0.1%/day) Photo-oxidation: The process by which components in the oil are chemically transformed through photo-chemical reactions (in the presence of oxygen), into new by-products.

19. Biodegradation Biodegradation is a significant process but also a slow one. Biodegradation: The process where naturally occurring bacteria and fungi consume hydrocarbons to use as a food source. Carbon dioxide and water are excreted as waste products.

20. Oil Weathering Summary - evaporation - spreading - advection - emulsification - dissolution - dispersion - photo-oxidation - sedimentation - biodegradation

21. Dispersants Surface active agents (surfactants) with hydrophilic and hydrophobic components Used to reduce oil-water interfacial tension Effectiveness varies with weathering, salinity and emulsification Requires addition of energy

22. Dispersants, continued Present formulations of dispersants are less toxic than spilled crude oil Present toxicity concerns are with dispersed oil (dispersant + oil), not dispersants alone, as toxic PAHs from the oil slick now go into the water and expose other organisms A dispersant use decision is a determination of response and environmental trade-offs In general, the lighter the crude, the easier it is to disperse. However, no benefit to use of dispersants on spills of gasoline, diesel, or jet fuel, as these drive toxic parts oil oil into the water instead of letting them evaporate.

23. How Dispersants Work -- A Pictorial The dispersant is applied to the water surface. Molecules of the dispersant attach to the oil, causing it to break into droplets. Wave action and turbulence move the oil-dispersant mixture from the water surface into the water column

24. Dispersant-enhanced Bioremediation Breaking surface oil slicks into small droplets greatly increases the surface area of the oil, and makes the droplets more available to bacteria and other micro-organisms that use it as food source However, dissolved components of oil (PAHs) can cross cell membranes, fish gills, etc., and may create new routes of exposure and toxicity Other contaminants in the oil (e.g., metals) must be broken down as well Ultimate break-down of hydrocarbons is into CO 2 and H 2 O

25. Dispersant Mechanism and Chemistry

26. What are Chemical Dispersants Chemical dispersants are mixtures that contain “surface-active” chemicals (called surfactants) and one or more solvents Surfactants have both hydrophilic and hydrophobic components. At the oil-water interface, surfactants reduce the surface tension. Oil enters the water as tiny droplets.

27. How Dispersants Work First: The dispersant is applied to the water surface; Next: Molecules of the dispersant attach to the oil, causing it to break into droplets; Then:Wave action and turbulence disperse the oil-dispersant mixture into the water column; And:The oil that had been concentrated at the surface is diluted within the water column. Oil is NOT removed from the water, but it is shifted to a part of the spill site where it is expected have fewer long-term environmental impacts.

28. Dispersant Formulations Modern formulations based on mixture of solvents and surfactants. Latest generation of dispersants designed to disperse oil with minimal toxicity. Three groups based on solvent class: –Water-Based Solvents –Hydrocarbon-Based Solvents –Solvent-based with lower surfactants (limited number in general use)

29. Water-Based Solvents Can be diluted with water for application Developed for light-distillate fuels and low-viscosity crudes and products Least effective all of dispersant types

30. Hydrocarbon-Based Solvents Hydroxy solvents: These are miscible in water (e.g., glycol ethers) and/or with hydrocarbons May have over 50% surfactant composition Can be used neat or diluted in water stream Enhances mixing and penetration into more viscous oils Majority of dispersants are in this category (including Corexit 9500)

32. Summary: Mechanism and Chemistry Dispersants are chemicals which have hydrophilic and hydrophobic components. They lowers the surface tension at the oil-water interface. They allow oil droplets to move into the water column. Energy is required for mixing to occur. Once oil is dispersed, it is distributed throughout the water column by tides and currents.

33. Fate and Transport Processes When Using Dispersants Effects of weathering processes once dispersants are applied

34. The Effects of Dispersants on Weathering of Oil Evaporation becomes a secondary weathering process Natural dispersion Emulsification rate Photo-oxidation Sedimentation/stranding Spreading Natural dissolution Biodegradation Reduced Effects Enhanced Effects

35. Dispersant Toxicity Laboratory Test Information from Deepwater Horizon spill

36. Short-term Toxicity Short-term exposure is described using LC 50 and EC 50. LC 50 The concentration that causes mortality in 50% of test organisms in a specified time period (usually 48 or 96 hrs) EC 50 The concentration that causes a specific effect (such as reduced growth or immobility) in 50% of test organisms in a specified time period. NOEC: No Observable Effects Concentration: The concentration at which no effects of any kind are observed

37. The greater the LC 50 or EC 50 value, the lower the toxicity (higher numbers are better) The range in LC 50 values results from biological and laboratory variability Lab tests are either spike test (California) or static tests (EPA) Most toxicity data available have been from 96-hr static test, which significantly over-estimates exposure (NRC,1989 and 2005) Acute Toxicity

38. Factors Affecting the Aquatic Toxicity of Dispersed Oil Toxicity is dependent on many variables, such as species, life stage of the species, and water temperature Concentration and duration of exposure of organisms to dispersed oil will vary, and is critical in determining when, and to what organisms and habitats, the greatest risks will occur Chemical composition of the dispersant also affects toxicity

39. California Spiked Test In an attempt to make a more realistic test, Singer et al. developed a flow-through system that creates a declining (spiked) exposure that more realistically simulates oil spill conditions.

40. Species & Lifestage Standard Test (24 - 96 hrs) Calif. Test (24 - 96 hrs) (static test) (spiked exposure) LC 50 or EC 50 ppm Crustaceans Juvenile and adult 3.5 to 35.9 158 to 1,038 Early life stages 1 48 ---- 2 Molluscs Juvenile and adult 42.3 ---- Early life stages --- 12.8 to 19.7 Fish Juvenile and adult 50 to >400 --- Early life stage 25.2 to 74.7 >1,055 Algae Adult 20 --- Early life stage 0.7 --- 1 zoospores, embryos, larvae; 2 no data available Aquatic Toxicity Data for Corexit 9500

41. Types of Effect and Exposure Acute Effects vs Chronic Effects Short-Term vs Long-Term Exposure

42. What will be Affected? Untreated Spill Chemically-Dispersed Spill Sea Surface Marine birds, furred mammals, fishing activity) Water Column Seabed (offshore) Seabed (nearshore) Benthic species, mariculture Shoreline Marshes, shorelines Sea Surface Water Column Plankton, pelagic fish Seabed (offshore) Seabed (Nearshore) Benthic species, mariculture, corals, seagrasses, seawater intakes Shoreline

43. Fate and Effects of Dispersed Oil in the Marine Environment Water Column Bioaccumulation Sediments

45. Concepts of Dispersed Oil Fate

47. California Dispersant Plan

48. California Dispersant Plan: Policy Development RRT IX tasked each of California’s 6 area committees to recommend a policy for dispersant use in federal waters (3 – 200 nm from shore), within each Area Committee’s zone of operation. Used a Net Environmental Benefit Analysis (NEBA) process to evaluate risks and benefits of using any response approach, including “no response”, mechanical recovery, dispersants, and in- situ burning. (These NEBAs were very similar to the Ecological Risk Assessment conducted in 2006 for Mexico-US Pacific Coastal Border Region). Zone recommendations from each Area Committee forwarded to USCG and RRT for their approval. With modifications as necessary, RRT approved all the dispersant- use plans and they became a part of the RCP and NCP.

49. California (Marine) Dispersant Use Zones Pre-Approval Zones –Federal marine waters 3-200 nm from the coast or island shorelines except: Waters part of a National Marine Sanctuary, or within three miles of the CA/Mexico border (These may change pending results of ESA Section 7 consultations for use of dispersants in offshore pre-approval zones). RRT Incident-Specific Approval Required Zones and Uses –State marine waters (0 – 3 nm miles from shore) –Waters part of a National Marine Sanctuary –Waters within three miles of the CA/Mexico border –Marine waters one mile from anadromous fish streams during times of emigration and immigration. –Subsea use or use at surface for more than 4 days

50. California Dispersant Plan  Single document for the evaluation of dispersant use in California FOSC checklists and flow charts for both zone and use types Appendices for ease of referencing

51. Dispersant Delivery Platforms Information regarding all dispersant resources available in or to California (dispersant stockpiles, application platforms) is in the California Dispersant Plan

52. Embedded Plans and Protocols Special Monitoring of Applied Response Technologies (SMART) –Conducted in real time, generally by Pacific Strike Team –Looks for presence of dispersed oil; does not give oil concentrations. Wildlife Spotting Protocols Seafood Safety Public Communications Short and Long-Term Monitoring for Environmental Concentrations: Dispersed Oil Monitoring Plan (DOMP) –Goal: Determine where and when monitoring should take place. –Data can be used for fishery closures, for NRDA and for validating assumptions made during the NEBA process for dispersant pre- approval

53. Both aerial spraying and subsea injection used Aerial spraying on surface waters April 22 - May 26: About 682,808 gallons Corexit 9527A and 9500A May 27 - July 19: About 293,436 gallons Corexit 9500A Sub-Total: 976,244 Subsea injection at the source May 9 - May 15: About 15,151 gallons of Corexit 9500A (2 tests) May 15 - July 19: About 771,000 gallons of Corexit 9500A Sub-Total: 786,151 Grand Total: 1,762,395 gallons Dispersants: During and After Deepwater Horizon Spill

54. DWH Dispersant Use: Fate and Effects Oil Budget (August 4, 2010 numbers): –Directly recovered from wellhead:17% –Mechanically skimmed: 3% –Evaporated or dissolved:25% –Naturally dispersed:16% –Chemically dispersed: 8% –In-situ burn: 5% –Residual:26%

55. DWH Dispersant Fate and Effects, continued Dispersants were applied consistent with all policies FOSC directed the response and use of dispersants, not the RP Extensive monitoring for dispersant effectiveness, impacts on human health, and impacts on water and wildlife were employed Additional EPA dispersant components analysis validated initial toxicity effects data; FDA analysis indicated components commonly used in foods, cosmetics and OTC medications, and many are Generaly Recognized as Safe (GRAS) Dispersant use (surface and subsea) greatly reduced shoreline and wildlife impacts Seafood safely samples indicated uptake of oil by organisms did not reach levels of concern for human consumption Even with the extensive “loading” of dispersants in this response, the dispersants behaved as expected and there was a determination of net environmental benefit for their use

56. Dispersant Lessons Learned by California from Deepwater Horizon Spill Subsea use, and surface use of dispersants for more than 5 days, had not been previously evaluated as part of NEBA Subsea use and use of surface for >5 days will need RRT incident-specific approval Rest of NEBA assumptions still seem to apply Biological Assessment for ESA Section 7 submitted to NMFS and USFWS, currently under review Once ESA consultations complete, will update CDP

57. Summary and Conclusions Dispersants have toxicity, but most toxicity associated with its use is that of the oil. In looking at dispersant-oil toxicity and potential environmental effects, it is important to clearly review mechanism of exposure, duration of exposure, species sensitivity and type of effects and weight this against same for undispersed oil. A lot is known scientifically; however, there will never be perfect or complete information. Net Environmental Benefit trade-off decisions should be made using best available information at the time.

58. Summary and Conclusions cont. California has developed a dispersant-use policy, using scientific data, with input from all stakeholders within a given area planning area. Used a process similar to an ERA to categorize risk and trade-offs associated with that risk within the offshore planning areas. Developed policies and decision-making processes that clearly designates zones, address trustee and public concerns, and ensure timeliness of response. Similar process/product completed in 2006 for spill scenario at US/Mexico border

59. Summary and Conclusions cont. Dispersants not recommended for: Spills of gasoline, jet fuel, diesel or similar light-weight hydrocarbons Spills of heavy crude oils that have low initial dispersibility and weather quickly Oil sheens Over shallow waters (<30-60’ deep) Over calm waters where mixing is insufficient (sea state < ~3’) Small spills When conventional mechanical removal or In-situ burn can be used to remove most of the oil When extremely sensitive species and habitats are not threatened by surface oil When it is unsafe for operations When you do not know enough about the product used (fate and effects once applied, toxicity) On shorelines or streams/rivers/lakes Over marine mammals or near birds If the spill will go offshore If there is no expectation of a “Net Environmental Benefit”

60. Summary and Conclusions cont. When dispersants are worth considering: The spilled oil is a medium-weight crude, considered dispersible, and has a “window of opportunity” that allows enough time for the dispersants to work You have the right application platforms, equipment, and trained personnel You have the right oceanographic and weather conditions You cannot get sufficient oil removal using more conventional/mechanical options Ocean conditions are too rough to allow safe or efficient mechanical recovery operations You know where the oil is going, and that it will impact sensitive resources that you cannot otherwise protect You can do the effectiveness and water quality monitoring that you will need You know enough about your dispersant product, and what the relative benefits and consequences will be of its use You are prepared to handle government and public relations You can demonstrate that you expect there to be a “Net Environmental Benefit”

61. Department of Fish and Wildlife Office of Spill Prevention and Response Response Support Unit Ellen Faurot-Daniels ellen.faurot-daniels@wildlife.ca.gov 831-649-2888 (office) 831-235-7320 (cell)

63. What is in Corexit 9500? Propylene glycol Common uses include commercial foods, drugs, cosmetics, and personal care products (e.g. toothpaste, shampoo, mouthwash). Approved by FDA as a Generally Recognized As Safe (GRAS) ingredient, direct and indirect food additive. Dipropylene glycol monobutyl ether Common uses include as a solvent for industrial and residential cleaners/degreasers, paints and plasticizers. Propylene glycol ethers as a class are rapidly absorbed and exhibit low acute toxicity by oral exposure. Dioctyl sodium sulfosuccinate (DOSS) Common uses include wetting and flavoring agent in food, industrial, and cosmetic applications, and a medicinal stool softener in over-the-counter use (e.g., docusate). FDA has approved this compound as a GRAS ingredient, and as indirect and direct food additives under prescribed conditions of use.

64. What is in Corexit 9500? Petroleum distillates, hydrotreated light fraction Common uses include as a solvent for paints, varnishes, polishes, and lubricants, and general purpose cleaners and degreasers. FDA has approved similar odorless light petroleum hydrocarbons as indirect and direct food additives. Numerous chemical synonyms and trade names are used for these materials (such as Span 80, Tween 80). Common uses are as wetting agents, solubilizing agents, or emulsifying agents in cosmetic and personal care products. Widely used in food products, oral pharmaceuticals, and parenteral products. They include GRAS ingredients and direct and indirect food additives commonly known as polysorbates. Sorbitan, mono-(9Z)-9-octadecenoate Polyoxy-1,2-ethanediyl derivatives of sorbitan, mono-(9Z)-9-octadecenoatePolyoxy-1,2-ethanediyl derivatives of sorbitan, mono-(9Z)-9-octadecenoate Polyoxy-1,2-ethanediyl derivatives of sorbitan, tri-(9Z)-9-octadecenoate