[cichlidfort]

Originally Posted by Ninong

Lee,

Dr. Randy Holmes-Farley touches on the copper toxicity issue in his discussion of toxic metals in tapwater here.

And I would like to remind everyone of the excellent point that greenbean raised and that is that the harmful effects of copper on inverts are cumulative. Even if you don't see any acute symptoms and sudden dieoff, that doesn't mean your inverts are suffering from chronic copper toxicity that takes a little longer to kill them.

Wait...now your saying it takes slow effects for some inverts?

Instead of just pulling up articles form Dr. Randy Holmes-Farley, why can't you explain it yourself?

Not trying to be rude or anything, I just want a debate, not a contest to see who can pull up the most convincing articles.

[leebca]

The authors of those references aren't here to explain it properly. Anything we do will be to mimic what they write/wrote.

Frankly, I read through more than half those references and they contain some theory and reasonable hypothesis. I'm not totally convinced myself until I see relevant data. By 'relevant' I mean data points of detected copper in a glass aquarium after copper use. Then copper detected after washing out the aquarium with common household items (soap for alkaline; vinegar for an acid wash; either; both; etc.)

I hope to get more information from those that wrote the references. But this is the weekend and I don't expect much in the way of immediate response.

[Ninong]

Originally Posted by cichlidfort

Wait...now your saying it takes slow effects for some inverts?

I don't know what you mean by "now you're saying." I have said that copper in the low ppb range, as low as 1-5 ppb, can be toxic to some invertebrates, especially mollusks and polychaetes. Greenbean pointed out that even for invertebrates that may not exhibit acute symptoms right way, the deteterious effects are cumulative resulting in chronic poisoning that may take a relatively long period to develop.

Some inverts are affected almost immediately and others may not exhibit the harmful effects until later on.

Instead of just pulling up articles form Dr. Randy Holmes-Farley, why can't you explain it yourself?

I have already explained it myself, more than once. You seem to think that the fact that copper is adsorbed onto glass "sounds ridiculous." I believe you said the same thing about copper being adsorbed onto live rock. I don't believe we share sufficient common ground to carry on a reasonable discussion.

Not trying to be rude or anything, I just want a debate, not a contest to see who can pull up the most convincing articles.

There is nothing to debate. You are free to believe whatever you choose. If you choose to read the following comments that I lifted from the E.P.A., you may wish to ignore that opening sentence where they mention the fact that copper strongly adsorbs to carbonates, something you said "is ridiculous." Live rock is calcium carbonate. Feel free to ignore references to "chronic toxicity" and the claim that "copper will bioconcentrate in many different organs in fish and mollusks." In particular, pay no attention to the statement that "there is low potential for bioconcentration in fish, but high potential in mollusks" because that is exactly what I have been saying since the beginning of this thread.

Toxicity Profiles:

Copper

Copper is a micronutrient and toxin. It strongly adsorbs to organic matter, carbonates and clay, which reduces its bioavailability. Copper is highly toxic in aquatic environments and has effects in fish, invertebrates, and amphibians, with all three groups equally sensitive to chronic toxicity (USEPA 1993; Horne and Dunson 1995). Copper is highly toxic to amphibians (including mortality and sodium loss), with adverse effects in tadpoles and embryos (Horne and Dunson 1995; Owen 1981). Copper will bioconcentrate in many different organs in fish and mollusks (Owen 1981). There is low potential for bioconcentration in fish, but high potential in mollusks. Copper sulfate and other copper compounds are effective algaecides (free copper ions are the lethal agent). Single-cell and filamentous algae and cyanobacteria are particularly susceptible to the acute effects, which include reductions in photosynthesis and growth, loss of photosynthetic pigments, disruption of potassium regulation, and mortality. Sensitive algae may be affected by free copper at low (parts per billion) ppb concentrations in freshwater.

There is a moderate potential for bioaccumulation in plants and no biomagnification.Toxic effects in birds include reduced growth rates, lowered egg production, and developmental abnormalities. While mammals are not as sensitive to copper toxicity as aquatic organisms, toxicity in mammals includes a wide range of animals and effects such as liver cirrhosis, necrosis in kidneys and the brain, gastrointestinal distress, lesions, low blood pressure, and fetal mortality. (ATSDR 1990c; Kabata-Pendias and Pendias 1992; Ware 1983; Vymazal 1995).


Additional information from:
Kenneth M. Brooks, Ph.D.

Aquatic Environmental Sciences
644 Old Eaglemount Road
Port Townsend, WA 98368


Copper is clearly the metal of most concern in both fresh water and marine environments. From a purely biological point of view, the cupric ion should be maintained below 6 ppb in marine environments. Either the EPA limit of 2.9 ppb, or the Washington State marine standard of 2.5 ppb appear adequate to protect marine life.

His study is mainly concerned with freshwater fish, although salmon live most of their lives in seawater. Here are a few selected quotes:

These studies suggest that coho salmon and rainbow trout (two species in the genus Oncorhynchus) will avoid areas with copper levels elevated above 4.4 ppb and therefore avoid the stress associated with low levels of copper exposure.


McPherson (1976) reported impaired migratory ability at copper levels as low as 5 ppb in coho salmon (Oncorhynchus kisutch).


There are many sites online that give data on copper toxicity to various marine taxa, but I think any further references at this point are unnecessary. Either one accepts the fact that copper in the low ppb range is toxic to marine biota or one doesn't.

For what it's worth, I will post a few typical comments from the advice section of Robert Fenner's www.wetwebmedia.com site:

Question: My question is in regards to copper use in a fish and live rock tank. I had an outbreak of ick a little while back and my LFS gave me some sea cure and told me to put it in my tank as directed. Since then I have discovered that that was not a good idea. Have I completely ruin my live rock and sand? I really want to get a nice coralline covering. Is this still possible or should I start over? I know that the website said that my tank would never be suitable for invertebrates after copper use.

Answer: Afraid so.

Q: I would really like to have some snails and cleaner shrimp. I am in desperate need of some GOOD information.

A: I think it is time to 'fire' this LFS and find another! Using the rock/tank for fish only tank would be OK after removable of all copper in the water column. Use Poly-Filter and carbon and a good test kit to confirm.


Copper and Live Rock
Dear Bob,

<Anthony Calfo in your service>

Q: I wrote to you before regarding my problem with white spot in my tank. I was advised to use MarinOomed which I did to no avail so I used copper and this has worked wonders. Before the use of the copper all my fish had died but I made the mistake of not taking out the live rock so all the life and algae has died on that too. I now have a powder brown tang and a juvenile Koran angel fish in there and they are both doing excellent. The colours are the best I have ever seen!! My Question is that will the live rock eventually get life into it and will the algae start to grow again if I just leave it or do I have to replace it?

A: That depends on your goals and purpose for the live rock. If it's presence is mostly or only biological for a fish only tank, then you may leave it. If you have any hope of putting inverts in there (or going reef) then the rock must be replaced. Copper chemically binds with all calcareous media (sand, gravel, shell, rock) and will contaminate some inverts on contact even when copper is free from the water column.

Q: Also all the parameters are great now to so should I just leave it for nature to take its course or have I already lost the battle and no life will ever grow on the rocks? PS. I have carbon in there also and am told this will remove the copper in time.

A: The carbon absolutely will not remove copper, but a Polyfilter (Poly Bio Marine) will help. Life forms including beneficial algae will certainly return in time... just not all forms that you had previously. Avoid even putting snails or anemones with this rock in the future for the above reasons.

Kind regards, Anthony


More Live Rock/Copper
Mr. Fenner:

<Anthony Calfo in your service with the follow up>

Q: Thanks for the response. However, I do have a few questions on your answers. You indicated it has attached to all of the substrate in the tank live rock, coral gravel, etc..

A: Yes...chemically bound to all calcareous media even when water tests copper free.

Q: After I make sure all of the copper is gone, If I add new live rock will it survive?

A: Significant copper will not be imparted to the new rock...but the old rock/sand/shells/etc is still a problem.

Q: Secondly, can I use the now copper treated rock as base rock or do I throw it away.

A: Fine for fish only systems...but never with invertebrates that can attach or crawl over it (starfish, anemones, coral, etc).

Q: Do I throw the crushed coral gravel away as well and my colored hard corals that made my wife so appreciative of the tank?

A: The crushed coral will be cheaper to replace than neutralize... I'll have to ask around for a refresher on how to chemically liberate the copper adsorbed on your curios so they are not wasted.

Q: Thank you again for your assistance. I did my reading before hand however I relied upon the LFS for backup and I felt he had more experience than I. I guess I had the correct answer and he did not, but I lost the battle hopefully not the war.

A: Agreed...kind regards, Anthony.


Q: can i use copper in a tank with live rocks? if not what can be used?

A: Uh, no, not really... many of the live rock organisms will be killed... and the copper would be readily absorbed... and regarding the second question...what are you intending to use the copper for?

Bob Fenner


Live Rock & Copper
Q: Is live rock, when used in a quarantine tank with CopperSafe to treat marine ich, still "live"? Or does the copper kill off all the little critters in the live rock, essentially turning it into inert but porous rock? Once your copper treatments have been completed, does restoring the live rock to freshly made salt water, without copper, restore its live qualities? (if they were ever gone...?)

A: NO! The calcium carbonate the rock is principally made from fixes and absorbs the copper making the rock unsafe for further use with invertebrates, etc.

Craig


Q: I am using a stainless steel mesh in the system and I notice it started rusting about 1 week back.

A: GET THAT OUT NOW! God only knows what metals are leaching into the system. You need to find a Polyfilter or equivalent product and use it right away, this can pull a lot of the toxins out of your tank. See if you can find a copper test kit and check your water. If you have had copper contamination, then your tank is permanently hostile to inverts. Time to start over if that's the case.

Q: I cannot think of anything that causes the death of my shrimps.. I have not add anything to the system.. is it the rust? If yes, can I still keep shrimps in the future? Does the rust change anything in the water? My worm and fishes are still doing fine after 4 days my shrimps died.

A: I think I already answered that one. Hopefully there's been no copper leached into your system.


Q: I am slowly trying to convert my 155L tank to a reef system by firstly adding small amounts of live rock each month. I started this wonderful hobby in December 04 and had a case of ich (February) and was foolishly advised to treat with copper in my display tank by my LFS which worked.

A: Well... good for the fish!

Q: I have performed numerous water changes to reduce the level of copper in the system and thought about taking out the substrate and adding live sand with a large water change to eliminate all the copper readings (which are low 0.01-0.02). Can I add cured live sand straight into my tank and will it survive?

A: I'd try to remove even more copper by the use of absorptive media such as Poly Filter, which changes color to show that it's absorbing the copper.

Q: Will treating the tank previously with copper reduce the chance of successfully running a reef system?

A: Well, Brad, copper will continue to leach from substrate, rocks, and the tank itself over time, but the continued use of the aforementioned absorptive media and regular frequent water changes should help dilute the remaining copper to even lower levels. I'd employ these methods for several weeks, then, after continued water testing indicates undetectable copper levels, begin slow and judicious stocking of invertebrates in the system. Proceed with caution. Good luck!

P.S. -- I don't agree fully with that last bit of advice. I don't believe the tank will be 100% safe for all invertebrates after only a few weeks of running polyfilters. Polyfilters cannot remove adsorbed copper. They can only remove the copper as it is released over time. It could continue to leach copper for many months, even years, and this will not be picked up by copper test kits. The test kits cannot measure copper that is adsorbed and none of the test kits can measure copper in the low ppb range. It is OK to use such a tank as a fish-only tank but I wouldn't want to use it as a reef tank unless it had been properly decontaminated with hydrochloric or nitric acid wash, followed by rinses with distilled water, followed by an acetone wash and then several rinses with either distilled or R.O./D.I. water.

Furthermore, the makers of polyfilters, Poly-Bio-Marine, claim that their polyfilters will NOT remove ALL copper. Their filters are incapable of removing copper below ~30 ppb. That's just not good enough. That level would be capable of chronic toxicity for many invertebrates. Dr. Randy Holmes-Farley discusses the polyfilter issue in this thread on Reef Central. In reviewing the manufacturer's website, I found a statement that their polyfilter is designed so as NOT to remove all trace elements. I also found a claim that they had removed copper down to 40 ppb and that they considered that level acceptable for invertebrates. Well, they're wrong! Obviously the invertebrates didn't die right away, so they jumped to the incorrect conclusion that 40 ppb Cu was an acceptable level. It's not! They didn't bother to describe exactly what "invertebrates" they employed to test their 40 ppb Cu hypothesis.

[leebca]

I've been in contact with friend Bob Goemans. I'd like to post his reply, since he has given his permission to do so.

Hi Lee,
Now keep in mind that I’m not a scientist, however, I’ve only been in this hobby for 60 years! Furthermore, my scientific knowledge of copper and its affect on various parameters/mediums is quite limited. Yet I believe silicon dioxide (glass) is an oxygen source, and since copper is a conductor, copper will/can react with its oxygen molecules and be retained by the glass to some extent. What that extent is, I don’t know, nor do I know which type of copper, chelated or ionic, have the most impact. Yet I would think ionic. Furthermore, this would/could be termed ‘plating’ which is an adsorption method/process. I doubt very much there is an absorption situation here!

What's more, for the adsorbed copper to be released, it’s my belief it would take a very severe reduction in pH to release the copper, e.g., a pH of 2! And that’s why an acid bath is used in laboratories needing to reuse glass enclosures for further testing.

And in looking back ‘decades’ where I’ve or others have use it in glass aquariums, and thoroughly washed out the glass tanks and reused them for invert aquariums, I do not know of one single invert being harmed! And as I’ve often said in these type situations, if the tank is going to be reused for inverts, wash it out thoroughly and keep activated carbon or a Poly-Filter in the tank as a precaution.

Additionally, I have a good friend who owned one of this country’s finest aquarium stores and who faithfully quarantined all his animals. And he used ionic copper in glass tanks, which were thoroughly washed and often reused to house inverts, with ‘never’ a sign of invert stress. In fact, he used a LaMotte DC-1600 colorimeter and never registered the slightest amount of copper in any of those reused glass tanks!

Hope this helps, and if you would like to post it, you have my permission.
Cheers
Bob Goemans

[Ninong]

Now keep in mind that I'm not a scientist...

I figured as much when I read Goemans' promotional piece for the Eco-Aqualizer.

I doubt very much there is an absorption situation here.

I didn't think so either until I read Dr. Randy Holmes-Farley's article where he states that copper IS absorbed by glass, although very slowly. It is quickly adsorbed onto glass. I was aware that it is adsorbed onto glass but I wasn't aware that any copper was actually absorbed by glass. However, since Randy has a Ph.D. in Chemistry, and I don't, I will accept his expert opinion.

What's more, for the adsorbed copper to be released, it's my belief it would take a very severe reduction in pH to release the copper, e.g., a pH of 2!

We're all entitled to our own beliefs but not our own facts. I suggest that the belief that it would take a pH of 2 to cause the copper to desorb is not substantiated by the facts.

And that's why an acid bath is used in laboratories needing to reuse glass enclosures for further testing.

An acid bath is used to immediately remove all traces of copper because otherwise the copper would be slowly released over time, affecting the outcome of the future experiments. If the adsorbed copper were not released unless the pH was down to 2, then there would be no need to clean the vessels as no toxicity experiments are conducted at a pH of 2.

And in looking back 'decades' where I've or others have use it in glass aquariums, and thoroughly washed out the glass tanks and reused them for invert aquariums, I do not know of one single invert being harmed!

How would one know if an invert was harmed or not? If there is only a small amount of copper (low ppb range) being released gradually, this copper would be accumulated in the organs of the mollusks and other sensitive invertebrates resulting in premature death. Without doing a necropsy to measure the levels of copper in the deceased animal's tissues, there is no way to know what caused its early demise.

In this Reefland thread one of our members describes losing all of her newly purchased snails and hermit crabs within about a week after placing them in her tank. Nothing else seemed to be affected, just snails and hermits. Her water was tested for copper by her LFS and they reported zero copper. Hobby test kits cannot measure copper in the low ppb range. It was determined that the previous owner used this tank as a freshwater tank and used a product by Jungle called Fungus Guard (it contains copper sulfate).

That is not the only thread like that. I remember reading several threads exactly like that over the past six years on the various reefkeeping bulletin boards.

Previously in this thread I have copied selected comments from Robert Fenner's website, www.wetwebmedia.com , that warned of the dangers of using a tank that had previously been used with copper as a reef aquarium. So the advice of Bob Fenner and his associates would seem to be at odds with Goemans' advice on this matter.

I won't bother to link to any comments of Dr. Randy Holmes-Farley or Dr. Ron Shimek because I have already done that in this thread.

And as I've often said in these type situations, if the tank is going to be reused for inverts, wash it out thoroughly and keep activated carbon or a Poly-filter in the tank as a precaution.

The activated carbon will not help much and the Poly-filter, by design, CANNOT remove copper below ~30 ppb!

[cichlidfort]

Ok, Copper is not absorbed. Glass is not microporous. If it was like your saying it is, then water is absorbed also thus water would leak through glass.

[Ninong]

Originally Posted by cichlidfort

Ok, Copper is not absorbed. Glass is not microporous. If it was like your saying it is, then water is absorbed also thus water would leak through glass.

I have said all along that copper is adsorbed onto glass. In researching this topic further, I found that Dr. Randy Holmes-Farley states that copper is also absorbed by glass, but very slowly. Randy states that it is quickly adsorbed onto glass. Since Randy graduated Summa Cum Laude in Chemistry and Biology from Cornell and has a Ph.D. in Chemistry from Harvard, I will accept his word that copper is very slowly absorbed by glass and quickly adsorbed onto glass.

Randy's comments on that point can be found in this Reef Central thread. Bryan asked Randy the following question: "Hi Randy, Why would glass absorb copper. I thought it was almost impossible for glass to absorb anything."

Randy's reply to Bryan:

Bryan:
Glass is very slow to absorb things, but fast to adsorb them. Adsorbed things sit on its surface, or in the very thin hydrated layer on the surface of the glass. At tank pH, many of the oxygen atoms will carry a negative charge:

Glass-Si-(O-)

It is the negatively charged oxygen atom that binds to the positively charged copper ion (actually, probably more than one oxygen to each copper). Copper quite likes to bind to oxygen ligands, and hence sticks.



In that thread somone was asking about cleaning copper from a tank that had previously been used as a freshwater tank with copper. Randy's second reply in that thread was as follows: "Washing plastic parts is probably adequate, IMO. Glass, rock, and sand are much harder to clean of copper."

P.S. -- I asked Randy for clarification on what he meant by absorption, in addition to adsorption, and he told me there may be a very thin hydrated layer where absorption might apply as well, like magnesium does on calcium carbonate.

[Ninong]

For those who may not realize that very low levels of copper can be toxic to aquatic biota, I present the following:

10.5.1.2 Overview of toxicity data

Copper exhibits significant toxicity to some aquatic organisms,
although the degree of toxicity is highly variable and the
bioavailability of copper dictates its toxicity to a large extent.

Some algal species are very sensitive to copper. EC50 values as
low as 47 µg/litre total dissolved copper have been reported for 96-h
growth rate experiments, but for other algal species EC50 values up
to 481 µg/litre have been found. However, it is possible that many of
the high EC50 values in the literature are the result of the growth
rate experiments being carried out in culture media containing
copper-complexing agents such as silicate, iron, manganese and EDTA,
which reduce the bioavailability of copper.

Acutely lethal copper concentrations to aquatic invertebrates
range from several µg/litre to several mg/litre. The 48-96-h LC50s
of copper ranged from 7 to 54 µg/litre for Daphnia magna, 37 to 183
µg/litre for amphipods, 58 to 112 µg/litre for gastropods and 50 to
100 µg/litre for crab larvae. Sublethal effects and effects on
longer-term survival have been reported in a variety of invertebrate
species for copper concentrations from about 1 µg/litre to a few
hundred µg/litre. For high bioavailability waters, effect
concentrations for several sensitive taxa can be < 10 µg Cu/litre.

Acutely lethal copper concentrations for fish range from a few
µg/litre to several mg/litre, depending greatly both on the test
species and exposure conditions. Acute LC50s less than 50 µg
Cu/litre for fish generally are associated with test waters with low
DOC, low hardness, and neutral to slightly acidic pH. Sublethal
effects and effects on longer-term survival have been reported from 1
µg/litre to a few hundred µg/litre, with effects less than 50 µg
Cu/litre being reported for several species. Again, lower effect
concentrations are generally associated with test waters of high
bioavailability.

Because of the variability of toxic effects concentrations among
different biological taxa and exposure conditions, the expected
response of aquatic communities will be highly site specific. Table
25 provides a general summary of the nature of response expected for
various concentration ranges at sites with moderate to high
bioavailability similar to water used in most toxicity tests.


P.S. -- Notice that I have highlighted statements in bold that say that acutely lethal concentrations for some invertebrates can range from several ppb to several ppm and that concentrations as low as 1 ppb can be harmful to fish and that concentrations less than 50 ppb are reported as harmful for several species.

[leebca]

Ninong,

I don't think I am questioning that low copper levels are hazardous to fish life. What I'm having difficulty with is believing there is copper being adsorbed onto the glass and subsequently releasing into the aquarium water.

If it's that difficult to 'clean' the adsorbed copper off, then why worry about it coming off? If it hasn't shown itself to be a problem for decades of washing and rinsing tanks, why now?

I have checked the hits you had posted. Thanks. None provide me with a chemical equation for the adsorption process. Do you know of the actual chemistry involved? Randy's post gives some anecdotal chemical information, but I can find no hard balanced chemical equation for the adsorption process.

[Randy Holmes-Farley]

Here are my thoughts on copper:

1. Copper in a reef aquarium is going to be strongly bound to organic materials. That is known to be true in natural seawater at normal copper levels. Maybe when you initially blast seawater with unbound copper there is substantial free copper for some period of time, until the copper concentration eventually drops, or the free copper has a chance to find organics to bind to.

2. While free copper may or may not bind much to glass (and likely none to silicone, IMO), organic bound copper will bind to both glass and silicone surfaces. Not into it, but onto it. It would be an interesting experiment to put some clear cured silicone into a copper/water solution to see if it turns blue. My expectation is that it will not, but I've not done the experiment.

3. It is my opinion that it is not too difficult to remove copper from all plastic and glass objects in an aquarium, but specifically not those that are calcium carbonate. A little bleach will remove organics and copper along with them. A little acid (like vinegar) will remove inorganic copper and some of its precipitates (like copper carbonate or oxide/hydroxide). I think all such objects can be reused after such cleaning.

4. Calcium carbonate surfaces are a much bigger concern. Just as magnesium gets onto and actually into calcium carbonate surfaces, copper and other similar ions would be expected to do the same thing. It is not trivial to clean live rock and sand. In most cases, I'd recommend tossing it. If that is just not an option, cleaning it in acid so that you actually dissolve some of the surface away is a reasonable thing to try, and some folks in my forum have done that.



"Why all the countless years have we not seen dying inverts in tanks where we used copper medications?"


I discuss copper toxicity here:

Tap Water in Reef Aquaria
http://www.advancedaquarist.com/issues/jan2004/chem.htm

from it:

"Toxic Metals in Tap Water: Copper

One of the biggest concerns for aquarists considering the use of tap water is copper. Copper is more toxic to marine invertebrates than it is to humans, so the EPA allows more in tap water than an aquarist would want in an aquarium. Specifically, the EPA has an action level at 1.3 ppm copper in tap water, and it is only a big problem (to the EPA) if more than 10% of the homes on the water supply exceed that level. For that reason, water supplies typically report the 90% level, meaning that 10% of homes exceed that stated value. Many also report the maximum level in any home tested.

Table 5 shows copper levels for a small selection of homes for all of the cities in this study. The reason that copper must be tested at the home tap is that most of the copper in public water supplies comes from the pipes in the home itself. Further, newer does not necessarily mean better, as fresh copper pipes might be even more inclined to release copper to the water than those that have had decades to build up protective coatings.

How much copper is too much? That is difficult to say, and certainly varies from organism to organism. In a recent test,5 Ron Shimek added copper to natural seawater and looked at the effect on sea urchin larvae. He found that concentrations above 10 ppb decreased the larval survival after 48 h, and that concentrations above 100 ppb killed all of them. Whether that translates into particular copper levels to be concerned about in typical reef aquaria is open to discussion. Nevertheless, it points out that copper is potentially toxic at levels well below the EPA action level of 1.3 ppm. That hypothesis is well supported by the literature on copper toxicity.6 Canadian Water Quality Guidelines for the Protection of Aquatic Life suggest that copper be kept to less than a few ppb in fresh water, but they do not provide a salt water recommendation. "

[Randy Holmes-Farley]

In terms of chemistry of inorganic copper adsorption, bare glass is likely to carry a net negative charge in seawater (from silicate) and can bind copper as a copper silicate complex. This is well established in the scientific literature:


Adsorption of some divalent cations from aqueous solution on precipitated silica. Bye, Gerald C.; McEvoy, Michael; Malati, Mounir A. Mid-Kent Coll. Higher Further Educ., Chatham, UK. Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases (1983), 79(10), 2311-18.
Abstract

The adsorption of Co2+, Ni2+, Cu2+, Zn2+, and Cd2+ on the K+ form of a pptd. silica is reported. The adsorption isotherms of Co2+ and of Ni2+ at pH 7.0 and different temps. follow the Langmuir isotherm. The endothermic apparent heats of adsorption, 2 and 10 kJ/mol, resp., are compared with those of Cu2+ and Cd2+. The limiting amt. adsorbed, Xm, of the 4 ions decrease as the pH is lowered. An ion-exchange mechanism between hydrated K+ ions in the outer Helmholtz layer and metal, M2+, ions in soln. is proposed. The results also suggest that (MOH)+ ions are adsorbed at the higher pH values. A plot of Xm at pH 6.0 and 323 K for the 5 ions studied against at. no. exhibits the Irving-Williams sequence. At pH 3.0, i.e. close to the point of zero charge of SiO2, the adsorption results were used to calc. the free energy of specific adsorption, DG, using the Grahame equation. The DG values were -11.1, -10.7, -13.4, -13.3, and -12.1 kJ/mol for Co, Ni, Cu, Zn, and Cd, resp. Specific adsorption is tentatively ascribed to the formation of surface coordination complexes.

Ion-exchange adsorption of zinc and copper ions on silica. Kozawa, A. Univ. Nagoya, Japan. Journal of Inorganic and Nuclear Chemistry (1961), 21(3/4), 315-24.
Abstract

Ion-exchange adsorption of Zn and Cu ions on silica were examd. in 2M NH4Cl contg. ZnO or ZnCl2 and in M NH4OAc contg. 0.05M CuCl2, resp. The ion-exchange adsorption attains equil. in about 2 hrs. at 25°. The adsorption of Zn++ increases with the pH of the soln. up to pH 7.12, then decreases. Between pH 5.48 and 6.38 the mole-ratio of H+ released Zn2+ adsorbed is const. at .apprx.3.0. Zn++ adsorption on heated silica decreases markedly with increase in the heating temp. For Cu++ adsorption, the mole-ratio, H+ rel./Cu2+ ads., is 4.0. The infrared absorption spectra of silica samples, heated silica, and silica treated with Zn2+, Cu2+, and Na+ solns., were taken. A decrease in the absorption intensities for the bending vibration of OH groups on the silica is discussed. A surface complex mechanism for metal ion adsorption of silica is proposed; the silica surface is acting as tridentate ligands for the Zn++ adsorption. A new method for detg. the surface acid and the surface area of silica is suggested.



Reaction of silica gel with copper ions in acetate solutions. II. Rak, R. V.; Dushina, A. P.; Aleskovskii, V. B. Leningr. Tekhnol. Inst. im. Lensoveta, Leningrad, USSR. Zhurnal Prikladnoi Khimii (Sankt-Peterburg, Russian Federation) (1971), 44(5), 1068-73.

Abstract

Sorption of Cu ions by silica gel from acetate solns. was studied under 2 different conditions: (a) contact time from 1 min to 24 hr using 4.7 ´ 10-2M Cu(NO3)2 in M AcONa; and (b) contact time from 2 to 120 days with 4.25 ´ 10-4-4.8 ´ 10-2M Cu(NO3)2 in M AcONa. The soly. of the polysilicate salts and the hydrated Cu silicates, in the form of activity products, Kp = aCu2+aSiO32- and Kc = aCu2+aSSiO32-, was (0.8 ± 0.1) ´ 10-19 and 1.9 ´ 10-19, resp.

[leebca]

Thanks Randy. I appreciate the thoroughness and in depth responses to the issues. Can't beat that.

After all is said and done, I'd wash out the glass aquariums with soap and vinegar and bleach then over rinse before using it for an invertebrate marine tank.

[cichlidfort]

Wow, Randy's responce was overwhelming. My brain hurts now. lol

Although, I do remember a method someone had on the other thread about cleaning copper of glass. It was much more complex.

Remembering anything Ninong?

[Ninong]

Originally Posted by cichlidfort

Although, I do remember a method someone had on the other thread about cleaning copper of glass. It was much more complex.

Remembering anything Ninong?

That method was linked to in the first response in this thread by leebca to my post in a previous thread here. That is the method that was employed when Dr. Ron Shimek supervised the lab at the University of Washington. It is the method recommended in the scientific literature for removing all traces of copper from glass. I believe I mentioned the same thing in this thread. It requires an acid wash using either hydrochloric or nitric acid, followed by rinses with either distilled or R.O./D.I. water, followed by an acetone bath, followed by more rinses. If you follow the link I just posted, you can read Dr. Shimek's detailed explanation of this decontamination method.

It is certainly not something that I would be interested in performing myself. It sounds too hazardous and too labor intensive. Obviously this is not something that can be done with live rock or calcareous sediments. Those should be discarded.

The compromise would be something like what leebca is suggesting. A wash with a mild acetic acid followed by rinses. That may remove much of the copper but probably not absolutely all of it. Whether this is sufficient depends on your perspective. The point to remember is that tanks like the one brooke purchased from a freshwater hobbyist, who used a product containing copper sulfate, that were not properly decontaminated have proven to be lethal to snails and hermits, in her case at least. I don't know if a simple wash with vinegar followed by rinses with R.O./D.I. water would have prevented her losses or not. In her case, it is obvious that there was enough copper being released to result in acute toxicity that resulted in the death of snails and hermits within one week. Had that tank been subjected to a vinegar wash, what would have happened? Would it still have released some copper but not as much, or would it have released none at all? I don't know.

It doesn't take very much copper to affect some inverts, especially mollusks. I think what we have here is Dr. Ron Shimek telling us what is required to make a tank with adsorbed copper completely safe for all invertebrates. He explains why each step is required. If we do anything less, we may end up with a tank that doesn't kill anything right away but perhaps releases just a tiny bit of copper over the next several months, or longer, that is accumulated in the organs of various inverts, even fish, and results in shortened lifespans. How would we know?

It is quite possible that hobbyists who say they have never experienced harmful effects from using tanks that were previously dosed with copper just haven't recognized the harmful effects. Unless animals start dying right away or start looking bad, how would they know? What if their animals just don't live as long as they otherwise would?

There is another thread on this board that discusses what can happen when copper gets into a brand new 220-gal reef aquarium and what the owner decided to do about it. In this case, the problem was caused by a couple of brass plumbing fittings and the effects were much more pronounced but the thread makes for interesting reading nonetheless. I suggest you read it to see what symptoms the owner reported and what my immediate response was in assessing the probable cause. Here is that thread. The owner decided to take down the entire system and decontaminate the tank following the method described by Dr. Shimek. Anything less in his situation may have been a waste of time because his tank already had a lot of adsorbed copper that would have been desorbing for years to come.

[Ninong]

I would like to thank Dr. Randy Holmes-Farley for taking the time to respond directly in this thread.

Dr. Ron Shimek does not post outside his own forum on Marine Depot other than to respond to questions about his RHO articles in our RHO forum; however, he is willing to discuss this topic with anyone who wishes to post their questions in his Marine Depot forum. I thank him for his willingness to accomodate anyone who may have additional questions about copper adsorption on glass or questions about his recommended decontamination method.

[Steven Pro]

Originally Posted by Ninong

The point to remember is that tanks like the one brooke purchased from a freshwater hobbyist, who used a product containing copper sulfate, that were not properly decontaminated have proven to be lethal to snails and hermits, in her case at least. I don't know if a simple wash with vinegar followed by rinses with R.O./D.I. water would have prevented her losses or not. In her case, it is obvious that there was enough copper being released to result in acute toxicity that resulted in the death of snails and hermits within one week. Had that tank been subjected to a vinegar wash, what would have happened? Would it still have released some copper but not as much, or would it have released none at all? I don't know.

I have read that thread, Snails and hermits dying! It proves no such thing. Her pH was low ranging from 7.7-8.0 and there is no mentioned whatsoever regarding salinity. It could have just as easily been low salinity killing those invertebrates.

Not to mention that she was a newbie with all of 4 months experience. Inexperienced hobbyists kill all sorts of animals for a variety of reasons. To conclude that it must have been copper contamination is a real leap.

[Randy Holmes-Farley]

Although, I do remember a method someone had on the other thread about cleaning copper of glass. It was much more complex.

Ron's tolerance of heavy metals is notoriously low.

[zhenya]

Originally Posted by Steven Pro

I have read that thread, Snails and hermits dying! It proves no such thing. Her pH was low ranging from 7.7-8.0 and there is no mentioned whatsoever regarding salinity. It could have just as easily been low salinity killing those invertebrates.

Not to mention that she was a newbie with all of 4 months experience. Inexperienced hobbyists kill all sorts of animals for a variety of reasons. To conclude that it must have been copper contamination is a real leap.

Steven,

I don;t want to sound controversial.., but why would you think that dosing that particular tank with almost entire bottle of copper sulfate wouldn't have anything to do with brooke's problems with keeping snails and hermit crabs? I also don;t think that 4 month experience in reefkeeping is a problem, too. I could understand if one or two snails died and attribute this to her messing up acclimation on some of them, but all of them?
I had kept numerous snails and shrimp when I had only few month of experience without incident or death of the animals.
I believe she stated in another thread that her sp.gravity were 1.024, which even if low a tad is not dangerously low to present problems for gastropods or any other invert. Many people keep their reef tanks at that level and have no issues with snails deaths. I think there had to be something else involved and I'm personally leaning towards that copper sulfate in the form of Fungus Guard by Jungle.

Randy, nice seeing you here!