About those New EPA Dispersant Tests

(10AM EST – promoted by Nightprowlkitty)

Perhaps you heard about the recent EPA Press Release, regarding latest Toxicity Testing results for Dispersants.   Depending on which sound bite you heard, it almost sounded like Corexit got a clean bill of health.

Confused?  I was too.   And since I had previously written a well-received diary,

Corexit Toxicity Tests not so hot, When Mixed with Oil

by jamess  — May 30, 2010

which dove into the Toxicity Data, that the EPA originally cited as credible only 2 months ago, I figured I should try to figure out what was up with the ‘New and Improved’ Dispersant Testing.

What follows is my assessment of what’s happening now, including some relevant links.

I’ll try to keep it brief. (I hate long diaries, lol)

First off, Why did EPA retest the Toxicity these Oil Dispersants when they had perfectly good Test Results on line before hand — like these:

COREXIT: TECHNICAL PRODUCT BULLETIN

COREXIT® EC9500A

TECHNICAL PRODUCT BULLETIN #D-4

USEPA, OIL PROGRAM CENTER

ORIGINAL LISTING DATE: APRIL 13, 1994

REVISED LISTING DATE: DECEMBER 18, 1995

“COREXIT® EC9500A”

(formerly COREXIT 9500)

VII. TOXICITY AND EFFECTIVENESS

a. Toxicity

Material Tested     Species     LC50 (ppm)

COREXIT® EC9500A

Menidia beryllina       25.20  96-hr

Mysidopsis bahia       32.23  48-hr

No. 2 Fuel Oil

Menidia beryllina       10.72  96-hr

Mysidopsis bahia       16.12  48-hr

COREXIT® EC9500A & No. 2 Fuel Oil (1:10)  [ratio of dispersant to oil]

Menidia beryllina         2.61  96-hr

Mysidopsis bahia         3.40  48-hr

Note:  LC50 [Lethal Concentration] means “what it took” for 50% of the test species to die, when exposed to toxic level (in ppm), for the stated time.

The smaller the LC50 number giventhe more Toxic the substance is and the “fewer drops of it” it takes to kill you.   In other words it’s “more Concentrated” — like some brands of Laundry Soap, which tell you to use “smaller capfuls” — it’s Concentrated!

How to interpret LC readings is explained on this EPA FAQ page: http://www.epa.gov/emergencies/content/ncp/index.htm

(and in the diary listed in the intro, where I break it down.)

So once again, if EPA had these LC50 readings Why did they ask for new tests to be conducted?   Well this appears to be the reason — they wanted Toxicity testing from ‘Independent sources’, and not from the Dispersant Manufacturer which was apparently the norm with the previous system:

NCP Product Schedule

NCP Key Provisions

NCP Product Schedule

Subpart J of the National Contingency Plan (NCP) regulates the use of dispersants, other chemical agents, and bioremediation agents to respond to oil spills in U.S waters; it also establishes the NCP Product Schedule, which is a listing of dispersants and other chemical or biological products that may be authorized by EPA for use on oil spills.

Inclusion of a product on the NCP Product Schedule indicates only that the technical product data requirements have been satisfied; listing does not mean that the product is recommended or certified for use on an oil spill. The Federal On-Scene Coordinator managing or overseeing a response determines whether, and in what quantities, a product listed on the NCP Product Schedule may be used to control a particular spill based on the data provided to EPA.

In order to list a product on the NCP Product Schedule, a manufacturer must submit to EPA technical product data (e.g., effectiveness and toxicity data) on the product. EPA reviews the data to confirm that the data are complete and that the procedures specified under Subpart J were followed. The NCP Product Schedule is updated every two months.

So given all that, the EPA apparently wanted “independent peer-reviewed” Toxicity Tests for at least 8 of the listed Dispersants, including Corexit, which BP has been aggressively using. BP claims Corexit is as safe as dish soap.

Next, are the results of the first round of those “independent” Toxicity Tests:

Note: I’ve only included the Corexit results, for improved readability here.  But I would encourage you to read at least the two Tables in the Report, for the others.  (Note 2: “Dispersit” was previously thought to be less toxic and more effective competing Dispersant, when compared to Corexit.)

US EPA Dispersant Toxicity Testing June 30, 2010 (pdf)

US EPA Dispersant Toxicity Testing

June 30, 2010

Comparative Toxicity of Eight Oil Dispersant Products on Two Gulf of

Mexico Aquatic Test Species


U.S. Environmental Protection Agency

Office of Research and Development

U.S.EPA/ORD Contributors

National Health and Environmental Effects Research Laboratory

Michael J. Hemmer, Mace G. Barron and Richard M. Greene

— pg 9 —

Table 1. Results of mysid 48-hr static acute toxicity tests with eight dispersants. LC50 values (ppm), 95% confidence intervals [in brackets] and the toxicity classification of dispersant LC50s derived in the present study. NCP Product Schedule listing of dispersant LC50s and 95% confidence intervals [in brackets] shown in right column for comparison.

Dispersant

Corexit 9500A

This Study LC50 (ppm) [95% CI]

42 [38-47]c

Toxicity Category1

Slightly Toxic

NCP Product Schedule LC50 (ppm) [95% CI]d

32.2 [26.5-39.2]

footnotes:

1 Toxicity classification per USEPA 2010 applied to results of present study

c Estimated by binomial method

d Values as reported in NCP Product Schedule documentation by manufacturer

[…]

— pg 10 —

Table 2. Results of Menidia 96-hr static acute toxicity tests with eight dispersants. LC50 values (ppm), 95% confidence intervals [in brackets] and the toxicity classification of dispersant LC50s derived in the present study. NCP Product Schedule listing of dispersant LC50s and 95% confidence intervals [in brackets] shown in right column for comparison.

Dispersant

Corexit 9500A

This Study LC50 (ppm) [95% CI]

130 [122-138]b

Toxicity Category1

Practically Non-Toxic

NCP Product Schedule LC50 (ppm) [95% CI]d

25.2e [13.6-46.6]

footnotes:

1 Toxicity classification per USEPA 2010 applied to results of present study

b Estimated by Spearman-Karber method

d Values as reported in NCP Product Schedule documentation by manufacturer

e Classified as slightly toxic according to values provided in NCP Product Schedule

[…]

5.0 Conclusions

The present study provided an independent, quantitative assessment of acute toxicities of eight dispersants to two aquatic species inhabiting Gulf of Mexico waters

[…]

Given the expected range of inter-laboratory variability, the results of the present study were consistent with test results reported in the NCP Product Schedule, with the exception of two dispersants for each test species which yielded higher LC50s (i.e., lower toxicity) than reported in the NCP. The rank order toxicity of the eight dispersants was generally similar to the information provided in the NCP Product Schedule. For both test species, Dispersit SPC1000 was the most toxic and JD-2000 the least toxic.

[…]

Corexit 9500A, the dispersant currently applied offshore at the surface and underwater, falls into the slightly toxic category for mysids and the practically non toxic category for Menidia.

Short-term acute toxicity tests using consistent methodologies and test organisms provide important and fundamental information on oil spill dispersants and other toxicants. The next phase of testing will examine the acute toxicity of Louisiana sweet crude oil and dispersant sweet crude oil mixtures […]

Some of my quick observations:

In the case of Opossum shrimp, Mysid (tiny shrimp) Corexit alone, was found to be slightly less toxic, than previous NCP ratings [National Contingency Plan]

42 vs 32.2    (The LC50 ppm needed for 50% Lethality.)

Corexit was 3rd in Toxicity out the 8 tested. Dispersit was the 1st most Toxic.

In the case of Inland silverside, Menidia (tiny fish) Corexit alone, was found to be much less toxic, than previous NCP ratings

130  vs. 25.2      (The larger the LC number, the LESS Toxic it is.)

Corexit was 7th in Toxicity out the 8 tested. Dispersit was the 1st most Toxic.

That’s good news for Corexit — SORT OF.  At least at the sound bite level:

“Corexit found less Toxic than previously thought!”  woo hoo.

One BIG Problem thoughDispersants generally become MORE Toxic when mixed with Oil — These new “independent tests” SO FAR have only tested the Dispersants ALONE.  

Unfortunately, that is NOT HOW the Gulf Creatures will have to deal with this more “user friendly” Corexit — all by itself, like simple “soap suds” in the sink.

No instead they will be greeted with millions of gallons of Oil + Dispersants MIXTURE, which I shown in my previous diary, for Corexit at least, the Mixture is at least 3 TIMES MORE TOXIC, than either pollutant ALONE. (and that Combined rating, is based on the Manufacturers Numbers!)

NOTE: This was where Dispersit as supposed to excel, vs Corexit — under ‘real world’ conditions — in Combination with Oil.

So the next questions, WHY did the EPA save the MOST TOXIC substance testing til last?  (the combination tests of Oil and Dispersants)

Maybe they wanted to establish good scientific base lines?  Maybe they have limited resources?  Maybe they’re just making the most of a bad situation?

Well at least they got some seemingly “positive news” into an otherwise Sea of Misery, for a day or two.  And if you weren’t paying attention, you might even think using Corexit all this time was a “good idea” afterall, after hearing about this [1st round] report, in passing:

EPA Releases First Round of Toxicity Testing Data for Eight Oil Dispersants

EPA Releases First Round of Toxicity Testing Data for Eight Oil Dispersants

Release date: 06/30/2010

WASHINGTON -The U.S. Environmental Protection Agency today released peer reviewed results from the first round of its own independent toxicity testing on eight oil dispersants. EPA conducted testing to ensure that decisions about ongoing dispersant use in the Gulf of Mexico continue to be grounded in the best available science.

EPA’s results indicated that none of the eight dispersants tested, including the product in use in the gulf, displayed biologically significant endocrine disrupting activity. While the dispersant products alone – not mixed with oil – have roughly the same impact on aquatic life, JD-2000 and Corexit 9500 were generally less toxic to small fish and JD-2000 and SAF-RON GOLD were least toxic to mysid shrimp. While this is important information to have, additional testing is needed to further inform the use of dispersants.

“EPA is performing independent tests to determine the potential impacts of various dispersants. We will continue to conduct additional research before providing a final recommendation, ” said EPA Administrator Lisa P. Jackson. “We want to ensure that every tool is available to mitigate the impact of the BP spill and protect our fragile wetlands. But we continue to direct BP to use dispersants responsibly and in as limited an amount as possible.”

[…]

EPA tested these eight products for endocrine disrupting activity and potential impacts on small fish and mysid shrimp. The testing found:

None of the eight dispersants tested displayed biologically significant endocrine disrupting activity.

— While all eight dispersants alone – not mixed with oil – showed roughly the same effects, JD-2000 and Corexit 9500 proved to be the least toxic to small fish, and JD-2000 and SAF-RON GOLD were the least toxic to the mysid shrimp.

The next phase of EPA’s testing will assess the acute toxicity of multiple concentrations of Louisiana Sweet Crude Oil alone and combinations of Louisiana Sweet Crude Oil with each of the eight dispersants for two test species.

I hope there are still some species left to save, by the time Round 2 and 3 are done! Too bad the EPA didn’t order the test the most Toxic combinations, FIRST!   Go Figure.

I guess well just have to wait and see what those next rounds of independent test results say, before we really know how bad it is.

For many of us, however, THAT Ship already sailed — a long time ago.

It’s about as bad, as it can get.  

Dispersants only hide the damage, they don’t make the cleanup any easier.

In my opinion, ALL use of Dispersants, should have ended a long time ago.

AND they should be ended NOW, before Dispersants end up starving the entire Gulf of Dissolved Oxygen, and turn it into one giant Dead Zone!  

Many Scientists have noted the extreme levels of Dispersants (and Methane gas too) are having an effect of speeding up the Biodegradation process, WHICH IS depleting all the the Oxygen, and which in turn causes the Biodegradation process, to HALT, before finishing it purification.  But alas that is a story, for another day.

Thanks all for reading … sorry for the lengthy diatribe, once again,  Doooh!

4 comments

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    • jamess on July 3, 2010 at 5:44 am
      Author

    the EPA …

    Only want to use one Independent Lab —

    and that lab has limited capacity.

    But what galls me — is

    Why not run concurrent tests?

    by using more labs, or bigger labs?

    Why be stingy on this?  

    They’re going to end up paying for it anyways.

    This is kind of an emergency isn’t it?

    I hate to say it, but it looks like either,

    intentional stalling, or sheer incompetence to me —

    which is better?

    neither.

  1. a reliable source at all, any more, on anything,  in any way.  

    There’s numerous other studies on Corexit/Dispersants one of which is why Corexit is banned in the UK.

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