A significant threat to marine and shoreline ecosystems is an oil spill caused by ship, pipeline, or oil platform disaster. Booms and skimmer systems have proven an ineffective response. Petroleum based dispersants have proven effective, but they do not work in low salinity and pose health hazards. Until the introduction of Dispersit, the only other approved dispersant products were formulated with petroleum mineral spirits, which were used as a dilutent. Thus, in responding to an oil spill, more petroleum products (up to 40%, of dispersant volume) are added to the spill. Dispersit is a unique blend (patent #6,261,463) of water, water-soluble surfactants and a coupling co-solvent, which is more effective than the petroleum based alternatives. It does not pose the threats that petroleum dispersants do to human health. Unlike petroleum based dispersants, which are ineffective in brackish and fresh water, Dispersit is equally effective in salt and fresh water.
In the United States, the National Contingency Plan List is the final authority for data on dispersants authorized for use in our waters. Until 1999 four products appeared on the list, two manufactured by Exxon (Corexit 9500, 9527) and two of Japanese origin that are not available in the U.S. All are petroleum based. Between 1995 and 1997, 48 products have been removed from the list following E.P.A. review of effectiveness and toxicity testing. Dispersit was included on the NCP list April 22, 1999. Published comparative data offer insight into the relative effectiveness and toxicity of the products. Two crude oils are used for testing effectiveness: South Louisiana, a light crude and Pruhoe Bay, a heavier crude. The dominant Exxon product 9500 tested at 55% for SL and 45% for PB. The average effectiveness was 50%. Dispersit was tested by Battelle Labs, Duxbury, MA. The Dispersit results are 100% for SL and 40% for PB with a blended average of 70%. E.P.A. confirmation testing yielded 50% for SL and 52% for PB with a blended average of 51%. Additional studies have uncovered another advantage of this waterbased product. Vessel based application is a favored response approach which typically uses water eduction application systems. Petroleum based dispersants lose most of their effectiveness when premixed with water. Dispersit shows little loss when premixed (diluted) since it is waterbased. Thus, the new waterbased technology is demonstrated to be at least as effective and, maybe significantly more so, than its petroleum alternative.
COMPARATIVE MARINE TOXICITY
Toxicity is determined by the effect of the dispersant mixed with No. 2 fuel, oil 10:1 on Menidia Beryllina and Mysidopsis Bahia after 96 and 48 hours respectively. The oil itself is toxic at about 11 PPM. Corexit 9500 with oil is toxic at 2.61 PPM upon Menidia and 3.4 PPM upon Mysidopsis. Dispersit with oil is toxic at 7.9 PPM upon Menidia and 8.2 PPM upon Mysidopsis. Thus, the toxicity of the waterbased alternative is one half to one third the toxicity than that of the petroleum based product. Toxicity testing was performed on Dispersit by Coastal Bioanalysts Gloucester, VA.
COMPARATIVE HUMAN HEALTH EFFECTS
A review of the Material Safety Data Sheets (MSDS) of Dispersit and any oil based dispersant illustrates the dramatic difference between the water and oil based effects on human health. Dispersit is essentially water and surfactant (soap). The application of Dispersit via spray should be conducted using goggles, gloves and respirator to avoid discomfort. The potential health effect is "slight to none" with protective equipment. As stated in MSDS, Corexit 9500 can cause central nervous system depression, nausea, and unconsciousness. It can cause liver, kidney damage, and red blood cell hemolysis with repeated or prolonged exposure through inhalation or ingestion according to the MSDS. The threat to human health via exposure is characterized a "MODERATE". In sum, waterbased Dispersit is a material improvement in human health effects when responding to an oil spill.
Dispersit was developed by U.S. Polychemical Corp. in 1998 and the first quarter of 1999. It was introduced to the market at the International Oil Spill Conference in Seattle, WA. on March 3, 1999. Application for inclusion in the national Contingency Plan product list for dispersants was filed on February 24, 1999 and approval was granted on April 22, 1999 making it the only waterbased dispersant on the list and approved for use in U.S. waters. A license to sell and utilize Dispersit was granted by the Government of Trinidad/Tobago on November 22, 1999 by the Ministry of Energy and Energy Industries. Application for approval by The Brazilian Environment and Natural Resources Institute was made on December 1, 2000 and approval is pending. An application for inclusion under the Alternative Response Tool Evaluation System was made May 26, 1999 and the process was successfully completed in September 1999. In commercial application Dispersit has been added to inventory by the Clean Caribbean Coop, the facilities services in Dubai, oil platform manufacturers in Mexico, and for spill response in Thailand. Unitor, the world’s largest marine ship services company, has tested Dispersit against their own petroleum dispersant. As a result of their testing, they have added Dispersit to their product line under the trade name Seacare EPA because of its superior performance and improved operator safety. Since the introduction of Dispersit in March 1999, this product has won wide notice throughout the world and is supplanting other products for use in oil spill remediation in fresh and salt water.
Oil spills are a well-documented environmental and economic catastrophe. They present a long-term threat to populations of marine life, birds, aquatic mammals, and plants. The economic loss due to spills can be similarly devastating. Clean up costs can be enormous and the long-term cost of a major spill in a populated or resort area could be incalculable. In the decade since the Exxon Valdez spill many improvements to navigation, ship construction and operational safety have been developed to reduce the probability of an incident resulting in a spill. In spite of these advances, the probability of unfortunate events is still with us and there is no prospect that major spills can be entirely prevented.
On the other hand, the Valdez spill was one of the most studied environmental events of our time. These studies clearly indicate that long-term negative consequences are still being felt on numerous species. The recent Galapagos Island Spill is a perfect example of the continuing threat of spills to our environment. With the prospect of continued spills, the major remaining question is how to respond in a manner that is effective in mitigating the spill, and does not aggravate environmental or human health problems in the process.
PUMPOFF RECOVERY - Recovery via off loading is a most favored approach to a possible spill, but may be limited by weather conditions, location, and condition of the stricken vessel. Even with successful off loading some spillage is likely to occur, which requires another response.
CONTAINMENT / RECOVERY - Great sums have been invested in this approach since the Exxon Valdez incident. Unfortunately, field results have demonstrated that actual recovery is less than 10% of the spilled oil. In order to be nominally successful the incident must be near stored equipment, in a location amenable to containment and in benign weather conditions. In short, conditions must be near perfect for the containment/ recovery approach to be even a nominal success.
IN SITU BURNING - The burning off of oil in a damaged tanker may have some application in special circumstances but recent studies have demonstrated that burning may be seldom appropriate. A study of 141 spills since 1967, with losses over 10,000 barrels determined that only 14 would have passed criteria for acceptability and 12 would have been "marginal". (Gary Yoshioka, Past In Situ Burning Possibilities, 1998). Other studies have found some oils will not readily ignite or burn efficiently, which renders the burning option moot. (James McCourt, S.L. Ross Environmental Research Ltd., Operational Parameters for In Situ Burning of Six U.S. Outer Continental Shelf Crude Oils, 1998). Thus, the process of burning has limited application and in the process reduces one environmental problem and supplants it for another. In situ burning does not render the problem benign, rather it trades a sea and shore problem for an airborne problem.
DISPERSANTS - Dispersants by their nature and ease of application offer the best all around response to spills of all types. Dispersants have been the first line of defense throughout the world but not so in the U.S. This is because dispersants present toxicity threats and health threats to those applying the products. Development of Dispersit, a waterbased dispersant, commenced in 1998 and was introduced to the market in March 1999. It addresses and eliminates the shortcoming of the previous generation of dispersants. The remaining sections of this presentation address the benefits and breakthroughs of the Dispersit technology. It is an effective and non-toxic oil spill dispersant combining a predominately oil-soluble surfactant with a predominately water-soluble surfactant and a co-solvent for coupling a mixture of the predominately oil-soluble surfactant and the oil spill, with the predominately water-soluble surfactant. Water is included in the combination to help advance the interaction between the predominately oil-soluble surfactant and the predominately water-soluble surfactant, as well as, the co-solvent. The water component also helps reduce the viscosity of the dispersant to allow it to be pumped under pressure. The resulting product performs to a superior degree in both fresh and salt water. It does not pose a threat to human health.
One of the continuing difficulties of relying on dispersants for remediation is their lack of effectiveness in fresh and brackish water. A recent study has demonstrated the dramatic drop-off of effectiveness of petroleum dispersant as salinity declines from salt to fresh water. Using ten test oils, salinity was varied from 35 ppm to 0 ppm and effectiveness of the two dominant petroleum based dispersants was graphed. Both demonstrated maximum dispersion at 25-35 ppm salinity. In every test, oil effectiveness declined by over 50% and in some cases 90% as salinity was reduced. (G. Blondina, Influence of Salinity on Petroleum Accommodation by Dispersants, Spill Science & Technology Bulletin, May 1999). Because Dispersit is waterbased, it has proven its effectiveness in these conditions. In side by side testing, conducted by S.L. Ross Environmental Research Ltd., against the dominant petroleum dispersant; Dispersit SPC 1000 performed in a consistently superior fashion in fresh and brackish water. "In tests on South Louisiana crude oil with varying water salinity, the dispersant maintained much of its effectiveness in brackish water and notable effectiveness even in fresh water. For example, with South Louisiana Crude, Dispersit performed better in brackish water than Corexit 9500 did in full salt water. The relative decline in performance at dispersing Prudhoe Bay crude oil was more pronounced with decreasing salinity, but the product still retained some effectiveness in brackish and fresh water. In full salt water (35 ppt), Polychem Dispersit SPC 1000 compared favorably to Corexit 9500, being more effective at dispersing South Louisiana crude oil, but less effective with the heavier Prudhoe Bay crude oil. This result is reasonable since the effectiveness of any dispersant product is greatly influenced by the composition and physical properties of the candidate oil". Thus, Dispersit promises an effective response to a spill in any water condition.
In summary, Dispersit in relation to other products available today, is:
- More effective
- Less toxic to marine life
- Works in fresh, brackish, and salt water
- Completely safe for people who contact it during application