In yesterday's column we talked about the product S-200, which is a bioremediation agent specifically designed to take oil from spills and bind it together into clumps and then feed it to a colony of bacteria included with the agent. The process takes several weeks, but during that time, the oil is not able to further pollute and at the end of the time, the oil is gone, the bacteria die off with no more food, and carbon dioxide and water is what's left.
In direct contrast to the current dispersal products being used, bioremediation agents remove the oil - dispersants simply break it up into smaller bits and spread it out in a larger area.
We want to know why BP is
using dispersals instead of bioremediation when the latter promises a
much better result.
S-200 sounded like an answer to everyone's desires, a way to save the Gulf Coast and its wildlife and industries, but we needed to find a way to determine if these claims are indeed true. To that end, I enlisted help from three professionals one a chemist working for the government, another a toxicologist, and the third, a biologist. Oil spills and such technology are NOT their primary fields of work, but they still have ample ability to understand the bulk of the documents we perused. All of us read through multiple documents available including some provided to us by the s-200 manufacturer, as well as spent a lot of time digging on the internet ourselves.
V Below: NASA image of slick on May 17, 2010.
We also reviewed stories related to previous spills
which used this technology. As stated yesterday, there are not a lot of
documents which offer decisive information.
We had specific questions we wanted to answer:
1. Can we find independent evidence that this product works as described?
2. Can we determine what, if any, toxicity there is attached to this product, and compare it to the toxicity of the current kerosene-based dispersant being used?
3. What is the cost compared to the dispersal agent?
4. What exactly is BPs position on this product, and why has it dropped considering it? - This one was addressed to BP but they have not answered, instead simply putting me on a media alert email list.
5. Where have these products been used, and what is their success?
Question 1. Can we find independent evidence that this product works as described?
Answer Yes and no. There are indeed documents which address this and other bioremediation agents but most of them conclude that there hasn't been enough study to determine if they can work all the time in all areas. They did conclude, however, that these products do SEEM to work as described in the limited studies which were done.
The 2004 EPA document (we also referenced yesterday) which talks in general about bioremediation basically says in 61 pages, that it looks like the stuff works but we can't be sure because there are so few studies and everyplace is different anyhow.
Question 2. Toxicity compare S-200 vs current dispersal agents.
Answer There were a number of documents discussing this, but there were contradictory numbers or typos - but it does seem to indicate that there is some degree of toxidity - the "LC50" concentration which means how many organisms are alive at certain time intervals after application looking at survival or death of 50%. A high LC-50 number is good, low is bad. The faster a product attains a low count, the more disastrous it is. One report claimed that S-200 was as toxic as diesel fuel which is pretty toxic - . ALL other reports disputed that finding. The MSDS sheet for the s-200 product states that ingesting it is non-toxic. and that it is a mild skin and eye irritant.
A sub-concern here was whether or not the products over-use the oxygen content in the water and make an aerobic environment turn anaerobic. (Simply put - Aerobic means aquatic life has oxygen and thus can breathe, anaerobic means it suffocates.) Although the subject arose in some papers, there was nothing definitive that we could determine other than a report provided to us by the manufacturer of a study conducted by Severn-Trent Environmental Leadership "A GLP compliant report" titled : "A study of the Aerobic Biodegradation in Seawater of S-200C using the Closed Bottle Procedure." Obviously this could be a very important concern. We quote from this report's Summary:
A figure of 60% degradation within 28 days is usually taken as being indicative of a good potential for degradation in the marine environment. The % of Degradability of S-200C in two different concentrations was 67.2% and 73.1%.
Those are good numbers.
From our team: "As for toxicity, I'm not saying it's
very toxic. It's not. Neither is diesel fuel, for that matter. Their
technical bulletin claimed toxicity values that were also pretty much in
line with their reference toxicant, sodium dodecyl sulfate, which is a
surfactant that's in all sorts of things we use, from shampoos to
toothpaste. So I wouldn't say it's *particularly* toxic, just a bit
more than at least one competitor claims for their product."