Date: 9 Dec 1997
From: Ian Forster <ian@host.or.jp>
To: AQUA-L@killick.ifmt.nf.ca
QUESTION:
I am seeking information regarding the breakdown products of ozone in seawater. (Unfortunately my access to libraries etc. is difficult at the moment!)
I was under the impression that some oxygen radicals and perhaps hydroxyl radicals might be generated in the breakdown process. However, I readily admit my ignorance on the topic.
I would be very interested to hear if anyone has experience with the
effects of ozone (and, therefore, its breakdown products) on abalone,
particularly with gonad development.
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COMMENTS 1:
One of the breakdown products is peroxide which can stimulate various aspects of prostoglandin production and has been demonstrated to stimulate the release of gametes (at very low -seemingly impossibly low - concentrations) by several species of bivalves - and probably gastropods too! I will try and dig up some references on the biochemical pathways for you.
Robert B. Rheault, Ph.D., <oysters@ids.net>
Moonstone Oysters
Narragansett, RI, USA
Consultants on hatchery design, and shellfish aquaculture
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COMMENTS 2:
Ozone breaks down in seawater, or anywhere else, simply to oxygen.
2O3 = 3O2.
Roy Drinnan, <rdrinnan@netcom.ca>
RR#1 Musquodoboit Harbour.
Nova Scotia, Canada, B0J 2L0.
Phone: (902) 889-3432
Fax: (902) 889-2905
e-mail: rdrinnan@netcom.ca
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COMMENTS 3:
I'm relatively a novice with ozone use, but in seawater an additional
problem is the combination of ozone with bromide which must be removed from the water with items such as charcoal filters.
Name: Bill Daniels
E-mail: wdaniels@dsc.edu
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COMMENTS 4:
Because of the presence of bromine in natural seawater, hydrobromic acid is formed which is very toxic. I have gathered that many people use ozone in seawater with no known repercussions. Others avoid it like the plague.
Paul Hundley
AAquatics@aol.com
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COMMENTS 5:
While the "breakdown" products of ozone may be oxygen, ozone oxidizes halide ions in seawater. Bromide, iodide and chloride are all oxidized. People have focused attention primarily on the products with bromide and chloride. For a brief overview and references on these interactions, along with references, you can read my column on
www.aquariumfrontiers.com on bromide. It is one issue back at this
point. The reference by Spotte gives more detailed information.
Briefly, the initial products are X+ ions, Br+ and Cl+, which are then
hydrolyzed to HOBr and HOCl. (and I can't recall the pKa values in
seawater, but I think they are both appreciably ionized.) All of these
products are more persistent than O3, and are potent oxidants of
biological molecules. At excessive concentrations, they can have adverse effects on life in the system.
The Spotte reference in the column gives more detail on this topic.
Craig Bingman <cbingman@netcom.com>
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COMMENTS 6:
Add hyperbromous acid to your list of byproducts when applying ozone to seawater. This acid has a half life of 48 hours, and if not managed properly can rapidly become toxic in recirculation systems.
Michael H. Schwarz,
Aquaculture Specialist
Virginia Seafood Research and Extension Center
Virginia Tech
PO Box 369
Hampton, VA 23666
757-727-4861 Fax: 757-727-4871
mschwarz@vt.edu
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COMMENTS 7:
Ozone breaks down to pure oxygen, in theory, with pure distilled water. However, this is not the case with anything else. Bromide radicals can be formed, hydroxyl radicals, and breakdown products from any organics. Alkalinity and pH can affect ozonation, the presence of metals, etc. There is a large book available on the use of ozone in water and wastewater treatment that is a summary of a literature review. It describes a lot of the different reactions and interactions of ozone used for water treatment. I don't have the book with me now, but I can post the complete title later.
Suffice it to say there are a lot of different things happening when ozone is used, and there is still a limited knowledge of everything that is happening.
Mike Christensen <mchris@unix1.sncc.lsu.edu>
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COMMENTS 8:
The differences that have emerged in discussing this topic are, I suggest, a matter of language. I took the original enquiry too literally!
Later respondents have been closer to what was sought.
Ozone is a powerful oxidizing agent. It reacts chemically with the
components of the chemical soup which makes up the average seawater to produce a complex of compounds, including bromates, peroxides, etc. Some of these are biologically very significant.
I still maintain that 'breakdown products' are the result of the decay, decomposition or breakup of the substance in question alone, not the
results of 'chemical reaction' with other substances, and therefore my
statement is still valid, though, in this case, largely irrelevant to the
intent of the original enquiry.
Roy Drinnan
RR#1 Musquodoboit Harbour.
Nova Scotia, Canada, B0J 2L0.
Phone: (902) 889-3432
Fax: (902) 889-2905
e-mail: rdrinnan@netcom.ca
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COMMENTS 9:
I just discovered an interesting H2O2 web site:
http://www.h2o2.com
Paul Hundley, <AAquatics@aol.com>
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