Golden Pearls & Copper

[JeremyR]

Dr. Ron,

This is a link to a thread discussing golden pearls and copper content, and I was wondering if you could comment as your results on food testing are being used as a reference.

Thanks :)

http://www.reefs.org/ubb/ultimatebb.php?ubb=get_topic&f=1&t=031704

[rshimek]

Hi Jeremy,

I make it a rule not to follow links to other threads. etc.

[JeremyR]

This is the gist... it's being discussed that your food analysis report showed 22ppm copper in golden pearls, and that feeding this food to inverts/fry will cause a toxic buildup of copper in the animals. I feed heavily and have not noticed this, even when feeding pellets of the stuff. So my question is.. is it 22ppm, or 22ppb... and what your thoughts in general are on this topic. I noticed on the food table that lancefish/silversides have significantly more copper, and have been using them as coral/anemone food for far longer than I have used GP's and have never seen trouble with them either.

Thanks,

[JeremyR]

Btw, if you have posted somewhere on this topic before, my apologies for missing it. Owning an LFS, I try to stay up on things,I don't want to be giving bad advice/product to my customers.

Thanks,

[rshimek]

Hi Jeremy,

I didn't post on it before.

Yes, many - maybe all - foods are high in some toxic materials, typically metals. This occurs in nature, and in all foods made from natural sources.

Generally, these materials are chemically bound to some substance in the foods (bones, structural proteins, etc). That being the case, they are relatively insoluble and don't make it into the general tank circulation, at least not immediately.

Nonetheless, after prolonged feedings they may indeed build up. In many cases, the salt mixes are also quite high in some metals relative to sea water.

These toxic materials, primarily heavy metals, such as copper, cadmium, silver, etc., are often necessary for metabolitic processes in very small amounts, and are often quite toxic at levels only marginally above that.

Presumably many of these materials get processed in a normal fashion, through the animals normal metabolism. Then they get passed into the general tank circulation. What happens to them there, we simply don't know.

I am in the midst of an analysis of the water from some 25 tanks of varying ages and sizes to see if there some evidences of toxic build ups. Those samples are presently being analyzed and I hope to have the data before long. After that I hope to get some analyses done of various methods of nutrient removal - skimmates, algae, etc. From this, I hope to be able to come up an approximate tank "budget" for many of these chemicals. With some luck, I will present those data and results at next year's MACNA in Dallas/Ft. Worth.

So... in answer to the unstated questions of fate and potential toxicities of metals in foods and additives... I think it is potentially a serious problem (I think "toxic trace element buildup" is the cause of "old tank wipeout syndrome"), but I also think I don't have the data to say conclusively yet what may be going on.

:frog: