On Thu, 08 Jan 2004 22:15:02 -0500, Mike Patterson
wrote:

Really like my new pond, finally seem to have the surrounding drainage
problem and the Mysterious Water Loss After Heavy Rain problem fixed,
so now I'm thinking...

How about if I run black gas pipe out to the the back end of the pond,
put on a valve there, then something like icemaker tubing into the
pond so that gas bubbles up near the center, then light it.

I wouldn't run it all the time, but it'd be a cool effect for parties.

Would there be any adverse repercussions to the fish?



Replying to my own post here as an FYI for those interested.
The following excerpt is from the Material Safety Data Sheet on
propane. http://www.vmpropane.com/pdf/safetydata.pdf

QUOTE:
Section X TOXICOLOGICAL INFORMATION

OSHA Carcinogen Classification (29 CFR 1910) Not
listed/applicable___X___

U.S. Department of Health (21 CFR 184.1655): Generally recognized as
safe (GRAS) as a direct human food ingredient when used as a
propellant, aerating agent and gas as defined in Section 170.3
(o)(25).
END QUOTE

Note especially the term "aerating agent" in regards to using propane
on human food.

I am inclined to conclude from this that propane would not harm de
little fishies in term of toxicity.

As for it being absorbed into the water and "suffocating" the little
water-breathers, everything I've found so far indicates that propane
will not absorb or mix with water. I guess the molecules are just too
light, they go to the surface and fling themselves skyward.


Now as for mercaptan, the stuff they add to make the gas smell bad:
http://www.matheson-trigas.com/msds/MAT14620.pdf

The "water solubility rate" is 2.4%. I wish I knew what that actually
meant... haven't found a definition yet.

This part is interesting:

QUOTE:
SECTION 12 ECOLOGICAL INFORMATION
ECOTOXICITY DATA:
FISH TOXICITY: 500 ug/L 5 hour(s) (Mortality) Spotfin shiner (Notropis
spilopterus)
INVERTEBRATE TOXICITY: 50000 ug/L 48 hour(s) (Mortality) Midge
(Chironomus sp)
END QUOTE

This page lists common composition of residential-quality gas:

http://www.test-lab.com/gasone.htm

Quote:

Propane-Propylene grades: Commercial (i.e. residential fuel) grade
liquid propane (LP) is predominantly propane &/or propylene. HD-5
Grade (special duty engine fuel) has a more tightly defined
composition that is 90+% propane, 2 - 5% propylene & lower amounts of
other C2-C5 alkane/alkene hydrocarbons. Ethyl Mercaptan or thiophane
(tetrahydrothiophene) are typical LP odorant additives.

The only reference I've found that comes close to specifying the
amount of mercaptan used is this:
http://www.gasco.net/Files/faq.html

QUOTE
Propane's distinctive odor comes from the injection of no less than
1.5 pounds of ethyl-mercaptan per 10,000 gallons of liquid propane.
END QUOTE

Numerous other sources say it is added at rates from 0-50 ppm.


I have to leave for a busines trip tomorrow, so can't spend any more
time on this for a few days, but if anyone wants to play with the
numbers, there you go.

I'm guessing I could get a ball park idea of toxicity by figuring how
much mercaptan is in gas, factored with the absorption rate, volume of
the gas flow, volume of water exposed, and the stated toxicity levels
for fish. Oi, I hate math. I'll do it, but I'll not like it. :-)

Mike


Mike Patterson
Please remove the spamtrap to email me.