Mercury and Lead in pearls?

[Slraep]

It's a question that has been bouncing around my head for a while.

Waters around the globe are increasingly being contaminated with heavy metals, mercury being a biggie.

Pearl molluscs(Akoya especially) filter feed and so ingest large amounts of pollutants which accumulate in their soft bodies and in their shells. Akoya molluscs in particular have been used for pollution monitoring. How does this affect the pearl? If Akoya shells have shown high levels of mercury, lead, cadmium and thullium(just to name a few), it must follow that the pearl is contaminated too. Are there any consequences to wearing pearls? How do the affected pearls affect us?!? I wonder. Some people are super sensitive to heavy metals--especially mercury. Anyway, heavy metals are bad news for anybody.

Any thoughts?

Slraep

 

[knotty panda]

Interesting question indeed especially with so many people placing the pearls in their mouth to see if they're real.

Seafood is closely monitored and would present the same contaminant levels as mollusks. The mollusk by-products would present a lesser amount of contamination. Thallium and cadmium are rapidly decaying contaminants and would dissipate before shells and pearls reach you. Mercury and lead decay at a much slower rate. How much detective work does the Canadian government do to uncover such contaminants? I heard a report on the news this evening that they have found lead contamination in baby bibs imported from China. I don’t know who thought to check baby bibs for contamination, but God bless them! With so many scandalous things happening with Chinese imports, I think they’re scrutinizing every product imported from China. You may have an answer to your question quickly.

 

[Raisondetre]

Another interesting point is that Chinese believe in the use of powdered pearl for medicinal/beauty purposes. The levels of lead would probably be more significant if the powder were ingested.

 

[Slraep]

Seafood is closely monitored and would present the same contaminant levels as mollusks.

No, not necessarily. That's why serious pollution monitoring uses the akoya oyster. The rate at which the mollusc filters water for nutrients is very high.

The mollusk by-products would present a lesser amount of contamination. Thallium and cadmium are rapidly decaying contaminants and would dissipate before shells and pearls reach you. Mercury and lead decay at a much slower rate.

Mollusc by products would have the same amounts of contamination.
The oysters are filtering thulium and cadmium at a constant rate so any decay would not apply if you were ingesting them(no thanks for me) and pearl handlers would be at risk for low to moderate toxicity. Thulium has a half life of 1.92 years, which is not a fast enough decay for contaminated akoya pearl necklaces, in my opinion, anyway.

How much detective work does the Canadian government do to uncover such contaminants?

We do not grow akoya oysters in Canada and we do not have a saltwater pearl industry, so studies were done where akoya oysters normally thrive.

Well. I must admit., my question is just a disguise for thought provocation.

Slraep

 

[Slraep]

Another interesting point is that Chinese believe in the use of powdered pearl for medicinal/beauty purposes. The levels of lead would probably be more significant if the powder were ingested.

Hi Raisondetre,

Scary isn't it !! Get your daily dose of calcium along with a whole slew of contaminants. Even many brands of "coral calcium" coming out of Japan were shown to be contaminated. Sad.

Slraep

 

[CortezPearls]

Hmmm...very interesting question. I will try to find an answer...have some articles about the use of bivalves as pollutant bio-indicators, but those I remember reading have always concerned themselves with the use of the oyster's flesh and never the shell. This could be due to the fact that it is much easier to produce a "pulp" from flesh (for analysis) than from shell, but maybe the natural biomineralization of metals in the shell does not accomodate these pollutants. Porphyrins are metallo-proteins that are a part in natural pearl coloring, but I have never heard or read about a mercury or cadmium based porphyrin, most are iron and copper based.

My first guess is that it is not an issue...let me see if I can find more information.

 

[Slraep]

Hi Douglas,

I would very much appreciate any info you can find and share.

I only know a bit about the lead contamination. If an akoya oyster is purposefully exposed to high doses of lead for a short period, there seems to be no significant contamination. The bivalve probably detects the lead and goes into anaerobic mode for a while. On the other hand, if the exposure is natural and of a prolonged duration then most of it can be detected in the shell. High levels of lead for prolonged periods will impead biomineralization. The molluscs will not grow. Low levels of lead for prolonged periods will actually do the opposite and speed up shell growth.

I know of potassium, and magnesium as a metallo-protein, affecting the colour of nacre to a certain degree, but I have no idea if any of the said contaminants are porphyrin based either.

Mercury contamination seems to affect a mollusc's immune response. Thulium seems to come from illegally dumped mercury. If I'm not mistaken, thulium is added to mercury and used in heavy duty thermometers in northern weather stations. Someone is either illegally recycling the mercury from these or dumping the used material into the ocean. Probably the former because certain dental amalgam mixtures have been found to contain traces of thulium. There really is no limit to what man will do for a buck.

Slraep

 

[pernula]

Some mercury may also come from coal power plant. Mercury is present in coal, and when coal is burnt to generate power, the mercury is released into the air and eventually deposited to terrestrial and aquatic systems, including the ocean. Exactly how much is hard to determine and controversial. This is just one of the many references.

www.powerthefuture.com/publications/coalfueled_powerplants_mercury.pdf

pernula

 

[Slraep]

Some mercury may also come from coal power plant. Mercury is present in coal, and when coal is burnt to generate power, the mercury is released into the air and eventually deposited to terrestrial and aquatic systems, including the ocean. Exactly how much is hard to determine and controversial. This is just one of the many references.

Choke, gasp. No wonder cases of asthma are on a steep rise. Cough.

Slraep

 

[Slraep]

Douglas, do you know if any of the metals could possibly be crystal binding as opposed to organic protein binding, or both?

Slraep

 

[knotty panda]

I was confused on your metals. You were talking Thulium, I was talking Thallium. Close but no cigar. Both metals, both toxic, but you're right, Thulium decays much slower than Thallium. Lead and mercury are both detected in background levels so there is no completely escaping them.

There's tons of information on both NIOSH's website and the CDC on lead and mercury.

 

[CortezPearls]

Douglas, do you know if any of the metals could possibly be crystal binding as opposed to organic protein binding, or both?

Slraep

Sorry, my feeble knowledge on biomineralization does not allow me to draw any conclussions on this subject. Have read dozens of scientific articles on the subject, but have not found a single one that will give me any additional insight...most articles are about the use of bivalve fleshy tissue as a bioindicator, none focus on the shell itself.

On our experience farming pearl oysters I can only say that weakened/sick animals will usually display a more yellow (some would say "golden") coloration, because they deposit less nacre and a bit more protein. One of the reasons I think why Japanese Akoya are yellow is due to water pollution...I guess the poor creatures can barely survive under those conditions and produce "sickly pearls".

But I haven't found any real lead (not the metal Lead).

I need more time, sorry.

 

[CortezPearls]

PbSO4 is the common soluble form for lead, the one that causes most common lead toxicity. I don't think this form would be present in salt-water...NaCl (salt) would react with it to form PbCl2 (have to check this, my inorganic chemistry is bad these days) and it is an insoluble compound, would precipitate...but fresh water would be a different thing.

Mercury: nothing can save us. Regardless of salt or fresh, cold or warm, waters...

 

[Slraep]

On our experience farming pearl oysters I can only say that weakened/sick animals will usually display a more yellow (some would say "golden") coloration, because they deposit less nacre and a bit more protein. One of the reasons I think why Japanese Akoya are yellow is due to water pollution...I guess the poor creatures can barely survive under those conditions and produce "sickly pearls".

But I haven't found any real lead (not the metal Lead).

I need more time, sorry.

Hi Douglas,

That's really interesting about the yellowy colour due to pollution. I never thought it might be because the molluscs are sick. Do you think it is the mercury,PCBs or pesticides? These three things seem to be THE major water pollution players.

Can you imagine, on top of everyday survival(tough enough), battling nucleation mortality and being subjected to antibiotics and growth hormones, the poor oyster can't even get a steam of fresh water to filter. It hurts to think about it.

Don't worry, you don't need to get the lead out for me! Anything you can come up with is greatly appreciated. No rush.

Slraep

 

[Slraep]

Mercury: nothing can save us. Regardless of salt or fresh, cold or warm, waters...

At the risk of sounding like a broken CD---we all need to wake up and notice the mercury. You are right, nothing can save us. The US is now starting to tighten regulation of chlorine manufacturing, of which one by-product is mercury. But what about developing countries? Nada.

Slraep

 

[knotty panda]

Dear Slraep: Nothing can save us ... As of Yet! ... Don't give up hope. No one thought air quality could improve and it has. It would improve quicker if there was world-wide implementation of remediation tools. One baby step at a time, unfortunately.

 

[CortezPearls]

Hi Douglas,
That's really interesting about the yellowy colour due to pollution. I never thought it might be because the molluscs are sick. Do you think it is the mercury,PCBs or pesticides? These three things seem to be THE major water pollution players.
Can you imagine, on top of everyday survival(tough enough), battling nucleation mortality and being subjected to antibiotics and growth hormones, the poor oyster can't even get a steam of fresh water to filter. It hurts to think about it.
Slraep

The initial news given to me by a researcher in Japan was that the close proximity of fish farms (mainly of "Fugu" or Sphoeroides) was the main responsible for causing the yellow pearls...he explained that the use of a parasite remover (many fish will have "lice", specially if kept at high densities) was very toxic for shellfish. This substance was Formaldehyde (1%), which was basically just thrown into the fish cages (which are in the ocean). Not a very smart move...there are ways to do this without damaging the environment (but at a monetary cost, of course). I can imagine the Japanese have learned and are no longer using this barbaric method.

In order to really determine if toxic/heavy metals are found in the shell or pearls, we would have to perform a detailed analytical chemistry of shells and pearls. This would allow us to have clear, concise and precise results...no need to draw conjectures.

This goes into the realm of Gem Labs...they have the people, the resources and the tools. It would be interesting to test pearls from different eras: natural, cultured from the early Mikimoto era, then 1950's, 1960's and all the way to present date. It would be an interesting project.

 

[wayne]

Pollution in the Far East

Pollution in the Far East

Pollution in the far east is a widespread problem. Even the most fundamental environmental controls are ignored in favor of profit. Japan's use of mercury and its dumping was captured by an American Photographer about 50 years ago (sorry do not remember his name). The photographs were some of the most heart wrenching I have ever seen. The factories were dumping mercury compounds into the bay, the fish ate the contaminated food, the people ate the fish. The number of birth defects were enormous. While taking the photographs, he was beaten multiple times, injuries from the beatings eventually contribute to his untimely death. The resulting book caused such a loss of face for the Japanese people, they "cleaned up" the bay. I put the word cleaned up in quotes because there a many learned scientific articles which say that decades are required for the elimination of mercury. The current method for cleaning heavy metal contamination is to scoop up the dirt, double seal it in high density polyethylene barrels and hope that future generations will develop a method of cleaning the contaminated material.

Metallic mercury by itself is considered fairly harmless, however, it does have a significant vapor pressure. Mercury vapors are highly toxic and cause many illnesses.

Mercury compounds, especially organo-mercury, are deadly!

Also, while reading this thread, I saw mention of radioactive compounds. The only way to cleanup radioactives is to collect them and any material they have contacted, put it in a lead lined barrel and wait ten half-lives (one half-life is the time for the radioactivity to decrease by 50%). For example, Cobalt-60 has a half-life of 5.3 year, if you house is contaminated with Co-60, it will be 53 year before you can go into you house without being exposed to gamma radiation.

Sorry about climbing on a soap box, but the mindless dumping of waste really get to me.

Wayne Nunn. Ph.D, Chemistry
Virginia Tech, Class of '78

 

[Slraep]

The initial news given to me by a researcher in Japan was that the close proximity of fish farms (mainly of "Fugu" or Sphoeroides) was the main responsible for causing the yellow pearls...he explained that the use of a parasite remover (many fish will have "lice", specially if kept at high densities) was very toxic for shellfish. This substance was Formaldehyde (1%), which was basically just thrown into the fish cages (which are in the ocean). Not a very smart move...there are ways to do this without damaging the environment (but at a monetary cost, of course). I can imagine the Japanese have learned and are no longer using this barbaric method.

Formaldehyde? A known human carcinogen used as a de-licing agent? I guess whenever there is a problem in production(read: profit), man has the natural tendency of going for the quickest, dirt cheapest and most readily available crap as a remedie. It's just mind boggling how no one gives a thought as to the formaldehyde ending up in their own drinking water and food. And their children's and grandchildren's too. And the rest of us.

Slraep

 

[Slraep]

Sorry about climbing on a soap box, but the mindless dumping of waste really get to me.

Wayne Nunn. Ph.D, Chemistry
Virginia Tech, Class of '78

Hi Wayne,

That makes you, me and a WHOLE LOT of other people mad about the mindless use of pollutants too. Anytime you want to climb on a soapbox, we'll be listening.

The use of radioactives and their "problematic" disposal is another maddening issue. Some facilities in the US contain large amounts of contaminated crap -- machine parts, scrap metal and tools, concrete, -- some of which will remain radioactive for years and years and years. How to clean this wonderful stuff up?? Well, the Department of Energy, a couple of years ago, proposed an inceredibly thoughtful way to get rid of the slightly radioactive crap: Recycling and resale, of course!! Both the DOE and the Nuclear Regulatory Commission (NRC) are still revising this plan. The slightly radioactive crap metal could be used to make bicycles, cooking utensils, hot water heaters, window casings.......hmmm, maybe computers and cell phones too. Great idea, eh? Oh those government people are just sooooo smart.

Slraep