Corexit 9500A LC50 data

Species
Inland Silverside................exposure 96 hrs.......LC50 25.2 mg/l
Common Mummichog.......exposure 96 hrs.......LC50 140 mg/l
Turbot...............................exposure 96 hrs.......LC50 75 mg/l
ACUTE INVERTEBRATE RESULTS :
Species
Artemia.............................exposure 48 hrs........LC50 20.7 mg/l
Mysid Shrimp (Mysidopsis
bahia)...............................exposure 48 hrs.........LC50 32.23 mg/l
Acartia tonsa.....................exposure 48 hrs.........LC50 2 mg/l

Can you say ..."What the hell does that mean?"...Let me 'splain.
LC50 stands for "Lethal Concentration - 50%". So take the Inland Silverside for example, 96 hours of exposure at 25.2 mg/l will kill half of your sample size.

So what is the concentration of Corexit in the gulf. Nobody knows, so far there is no Corexit specific water sample data available that I can find. The only data that is available is for Propylene glycol, an ingredient in Corexit. So lets indulge in a bit of extrapolation shall we....

Propylene glycol makes up 1% of corexit. The available data points to a concentration of between 360 and 440 parts per million. So, assuming there are no other sources of Propylene glycol (and that's kind of a big assumption, so I am taking the lower figure), the the Corexit concentration would be 36000 ppm (360ppm X 100). Ppm and mg/l are basically equivalent for pure water (depending on temperature) however ocean water is more dense because of the salt in it (Ocean water at the sea surface is about 1027 kg/m3 while pure water has a density of 1.000 g/ml. ACK!!! all this math hurts my head...). So lets be incredibly generous to BP and take 20% off the 36000 ppm...Call it a BP Blue light special! That gives us a figure of 28,800 Ppm. That's 114285.71 % of the lethal dosage for half of the Inland Silverside exposed for a mere 96 hours. This spill is on day 81 as of this writing, 1944 hours.

Note: I used the Inland Silverside not because I somehow biased toward it. It is considered the "standard" fish for estuary toxicity study. But no, it doesn't live in the gulf.