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ould your jewelry make you sick?You have probably never givenmuch thought to how much a 25 cent purchase could change your

life. But last summer, a 25 cent purchase mayhave forever changed the life of 4-year-oldColton Burkhart and his family. While on aroutine trip to the local store, Kara Burkhartgave her son a quarter to use in the gumballmachine. For his quarter, Colton’s prize was asmall gold-colored necklace with a medallion… just a small trinket, but highly valued byany 4-year-old.

Unfortunately, Colton, like many youngchildren, could not resist the urge to put hisnew prize in his mouth and swallowed thesmall medallion. Soon after the accidentalingestion, Colton experienced severe stomachpains and flu-like symptoms. After being takento the hospital, X-rays revealed that the toywas lodged in his digestive tract. Other testsindicated that Colton’s blood levels for the ele-ment lead were 12–13 times normal levels …potentially lethal limits for a young child. Thependant was removed, and subsequent analy-sis revealed that the toy contained upward of40% lead! The high levels in Colton’s bloodwere due to lead that was leaching out of the25 cent toy! If doctors had not identified thesource of Colton’s illness, he could have died.

The news of this event sparked a nationaloutcry. Independent testing revealed thatmany of this nation’s leading retail stores wereselling jewelry with dangerous levels of lead.The federal Consumer Product Safety Com-mission also got involved in testing and over150 million pieces of jewelry have since beenrecalled. You might be surprised to learn thatthe jewelry you are wearing even as you readthis article may pose a health risk. If lead poi-

soning is such a serious concern, why wouldmanufacturers use lead in their jewelry andwhy would retailers carry it? Great question …glad you asked.

Lead in historyLead is used in making jewelry because it

is malleable, gives the jewelry some heft, andis inexpensive. The element lead (Pb) derivesits name from the Latin plumbum, from which

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we get our English word plumber, or one whoworks with lead pipes. It is uncommon to findnative lead (elemental form) on the earth butits ores (compounds) are abundant. Lead’sprimary ore, galena (PbS) can be found inmany regions around the world.

Lead is believed to have been the firstmetal extracted from its ore, most likely theresult of heating rock containing galena in acampfire. Lead is a soft metal, easy to workwith and able to resist most corrosive envi-ronments. These characteristics gave leadgreat appeal to early humans. As a result, itwas widely used in a variety of applications.Artifacts in museums around the world showthat lead had appeal to early humans.

Lead use became very common duringthe Roman era. It is a universally agreed uponbelief that the Romans were responsible forpromoting the use of lead throughout theknown world at the time of the RomanEmpire. The Romans, in their attempt to “civi-lize” their empire, used lead in their plumbing.Lead-lined aqueducts (many of which stillstand throughout Europe) brought fresh waterto cities; and lead pipes were used to takewater to and from Roman homes, publicbaths, and fountains. Lead was also usedthroughout the empire as roofing material,wall linings, and other building applications.

Early artisans also found lead to be use-ful. Lead was used to some extent by jewelrymakers, although its dullness made it muchless attractive and less widely used than met-als such as silver and gold. Early pottersenhanced the aesthetic appeal of their cre-ations by adding lead compounds to theirglazes. These compounds gave the potterybrilliant color and served a utilitarian purposeas well. These compounds seemed to preventthe pottery from cracking as it cooled after fir-ing. Lead was also added to glass, which sig-

nificantly improved its clarity. This mixture,known for the “ringing” sound created whenlightly struck, is known as leaded crystal.

Lead compounds even found their wayinto prepared foods. Lead acetate(Pb(C2H3O2)2), known as sugar of lead, iswater soluble and has a sweet taste. This

compound was sometimes used to sweetenwine and other foods. As we will come to dis-cover, this may not have been one of theRoman’s better decisions.

Lead was truly an important metal toearly humans. But its value didn’t come with-out a cost. From the earliest times, humankind

The tin can, invented in England in 1811, could arguably be considered one of thegreatest innovations of all time. The ability to can food allowed early explorers totake enough food supplies to last for long periods of time. The practice of stockingships with canned foods was widely used in the 1800s, an era of exploration. The

cans were formed by placing a tin-coated iron sheet around a cylindrical form, overlappingthe ends, and then soldering to create a seal. Solder is an alloy of metals that when heated,melts (alloying metals can lower melting points) and flows into the joints where two edgesof metal come together. Upon cooling, the solder hardens to produce the seal for the joint.The solder used at the time was about 90% lead and would not flow easily, making it difficult to obtain a perfect seal. Poor quality assurance inthe can-making process could certainly provide an opportu-nity for lead contamination.

One such example can be found on Sir John Franklin’stragic expedition to map the Northwest Passage in 1845. TheFranklin party embarked on their expedition, never to beseen again. Five years into a search for the crew, threegraves were discovered on Beechley Island and on a latersearch an expedition log was found on King William Island350 miles to the south. The log reported that the two ships,the Erebus and Terror, were trapped in ice off King William Island in 1846. The crew hadremained with the ships for two years, but Franklin had died in 1847, along with many of thecrew. In April 1848, 105 survivors started on a journey across the ice for Hudson Bay to thesouth. Debris was discovered along what was thought to be the crew’s path but that was theonly evidence recovered … the remaining crew disappeared.

In August 1984, Owen Beattie and a team of scientists from the University of Albertadug up the three graves on Beechley Island … those of John Torrington, John Hartnell, andWilliam Braine, the first crew members to die on Franklin’s expedition. Routine studies car-ried out on bone fragments of Franklin sailors, as well as those of Inuit Eskimos found in thesame area, revealed one striking difference. The lead content of the Eskimo bones waswithin normal limits, while that of the English sailors examined was 20 times higher. Furtheranalysis on tissue and hair samples confirmed the original findings … dramatically high lev-els of lead. On the basis of the evidence, the University of Alberta scientists concluded thatthe increase in lead content had occurred during the expedition. The crew could have beenexposed to a number of sources of the lead, but attention was soon focused on the thou-sands of tin cans … enough canned food to last for three years! As strange as it mightseem, many of Franklin’s crew may have died from complications associated from lead poi-soning … the result of eating food from tin cans soldered with lead solder (3)!

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has been aware of lead’s toxic nature. By the1st century, the Greek physician Dioscoridesnoted the relationship between exposure tolead and its toxic manifestations. Notingintestinal problems and swelling as well asparalysis and delirium, he is quoted as saying,“lead makes the mind give way.”

Lead in the modernworld

Tetraethyl leadBefore the 1970s, most gasoline con-

tained an additive known as tetraethyl lead,which decreased the amount of engine“knocking”.

As the U.S.population grewduring the 1970sand 1980s, so toodid gasoline con-sumption. To keeppace, the manufac-

ture of tetraethyl lead also rose. At one point,approximately 20% of all lead produced inthe United States was used as a gasolineadditive (1). However, car exhausts releasedlead directly into the atmosphere makingleaded gasoline a major contributor to theamount of lead in the environment. An entirepopulation was beingexposed to dangerouslevels of lead.

Tetraethyl lead isconsidered to be a neu-rotoxin … a chemicalthat directly affects thenervous system. Whenlead enters the body,whether through inges-tion, inhalation, orabsorption (the threemost common routesof entry into the body),it is rapidly absorbedinto the bloodstream.From there, it’s a quickand costly trip to thebrain and central ner-vous system. Symp-tons of exposure arelethargy, tremors, andmuscle fatigue. Chronicexposure can evenresult in brain damageand/or death.

The goodnews is that timeshave changed. Datacollected over thepast 20 yearsshows a positivetrend. Atmosphericlead levels havedeclined by 90%and not surpris-ingly, so have theinstances of leadexposure. The pro-hibition of tetraethyllead as a fuel addi-tive has greatly bene-fited both theenvironment and the public’s health.

Lead paintLead compounds were also commonly

used in the manufacture of house paints. Ifyou were to take a trip to your local hardwarestore today, you would find it next to impossi-ble to find lead-based paints. But before 1978,lead-based paints lined the shelves! Basic leadcarbonate, PbCO3·Pb(OH)2, when pure, is abrilliant white substance that makes an excel-lent paint pigment, called white lead. While theuse of white lead has been banned, manybuildings still have significant levels of lead-

based paints. This hasprecipitated the U.S.Centers for DiseaseControl and Preven-tion to set a “level ofconcern” for childrenat 10 µg per deciliterof blood (2). The vastmajority of leadabsorption in childrenis through the gas-trointestinal tract …small children tend toput things into theirmouths — the gate-way to this system!And once an object,such as chip of leadpaint, is placed in themouth, there is agreat chance that theobject will be swal-lowed. Let’s not forgetthat lead paint chipsdo have a sweet taste,which might addition-

ally encourage a small child to put them intotheir mouths. This places small children in thehigh-risk group for lead poisoning. But theyare not alone. Anyone who ingests objects withhigh lead content can absorb significant levelsof this toxic heavy metal. Now let us direct ourattention to the most recent concern for newcases of lead poisoning … jewelry.

Lead is a cumulative poison, building upin the body until it reaches toxic levels. Oncethe body is exposed, lead is quickly distrib-uted to blood, soft tissue (kidney, bone mar-row, liver, and brain), and mineralized tissue(bones and teeth). Part of lead’s toxicity canbe explained by how it interferes with the pro-duction of heme, needed for red blood cellhemoglobin. An enzyme called ferrochelataseis responsible for inserting the iron (II) ioninto the heme molecule. Lead ions interferewith this process, and abnormal red bloodcells are formed. These abnormal red bloodcells are destroyed, but the body may not beable to produce replacement red blood cellsquickly enough. Bone marrow attempts to doits part by ramping up production of red bloodcells; however, these red blood cells are notsufficiently mature and are likely to bedestroyed in the spleen (1). These processescause the anemia that is associated with leadpoisoning, as there is both decreased red cellproduction and increased red cell destruction.Lead also affects the intestines and vascularsmooth muscles. Intestinal spasms due to thecontraction of vascular smooth muscle are thecause of some very painful cramps that tendto characterize extreme lead exposures.

Most of lead’s neurological effects aredue to its ability to mimic and inhibit theactions of calcium ions. Calcium ions play animportant role in the nervous system; theyhelp convert the electrical pulse into a chemi-

ChemMatters, APRIL 2006 13

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14 ChemMatters, APRIL 2006 http://chemistry.org/education/chemmatters.html

cal signal. Cells absorb lead ions using thesame channels through which they absorbcalcium ions. High levels of lead ions areknown to cause these channels to uptakemore lead ions into the cell, as well as inhibitthe transport of calcium ions. Lead ions, evenat low concentrations, can both promote andlimit the release of the specific neurotransmit-ters, which are chemicals that regulate thebrain. This can have serious consequences onthe developing nervous system of an infant ora child. It is believed that this is one of thecauses of learning and behavioral problemsthat occur in children.

In the central nervous system, lead alsoincreases the permeability of the blood–brainbarrier, which produces brain edema, anaccumulation of fluid in the brain that causesextreme swelling. Lead exposure causes adisruption in this barrier, and the resultingchanges in osmotic pressure cause the con-centration of water to be altered, and ulti-mately, edema of the brain and intracranialpressure. With the increased pressure, theneurological development of a maturing childcan be altered. As you can see, lead exposurecan have severe immediate and long-lastingeffects. So what can be done to treat a 4-year-old whose blood contains 12–13 timesthe normal amount of lead?

Chelation therapyA chelator (means “claw-like”) is a

chemical substance that acts to bind metalions and take them out of solution. Designinga chelating agent for treatment of lead expo-sure can be challenging, because it should notremove essential metal ions (in this instancecalcium or iron ions) from the blood, but itshould remove the lead ions. Thus, the chela-tor must have a higher affinity (likes it better)

for the lead ions than for the calcium ions. Itmust also have a higher affinity for the leadions than the binding sites in the body. Thinkof this therapy as a microscale tug-of-war …if the chelator can remove the lead ions, thechelator wins; if not, the lead ions remainbound to the cells and the chelator won’twork. Also complicating matters is the varietyof heavy metal binding sites—with both highand low affinities—within the body. Thelonger the lead ions are in the body, there is agreater chance that they will migrate from thelower-affinity binding sites to the higher-affin-ity binding sites. This makes it even more dif-ficult for the chelator to pry it loose. As aresult, early chelation therapy is best. CalciumEDTA (Calcium disodium edetate) is the nearlyperfect chelator for lead ions. It is water solu-ble and can be administered intravenously orby injection. Calcium EDTA has a greater affin-ity for lead ions than for calcium ions; there-fore, when lead ions are encountered by thecalcium EDTA, the calcium ion “pops” off thechelator and is replaced by the lead ion. Whenthis happens, the lead is not metabolized, iseliminated through the urine, and has fewtoxic effects.

Are U.S. teens atrisk from toxic jewelry?

So you’re a teen, you go to the mall, yousee some costume jewelry that you like, andbecause it’s inexpensive, you buy it withoutgiving it much thought. It looks good, youlook good, life is good. But a careful inspec-tion reveals thatmuch of this jewelryis manufactured inChina, India, Korea,and other countrieswhere labor ischeap, making thejewelry affordable.

The hidden costs might have to be paid forwith your health and not with your money! Asof July 2004, more than 150 million pieces,found in vending machines and in low-enddiscount stores nationwide, were recalled.The problem also extends to fine jewelryavailable at many retail outlets, includingmalls and jewelry stores. Buyer beware …your jewelry may be the source of potentiallyharmful levels of lead.

Currently, there are no federal or statelaws that regulate lead content in jewelry.(California may be the exception by publica-tion of this article). Although efforts over thepast 20 years have done much to eliminatelead from U.S. food, water, air, etc., the leadcontent of jewelry seems to have snuck inunder the radar! Costume jewelry is cheapenough to attract teen buyers and thereforepotentially poses some risk of lead exposure.There is little risk in just wearing this jewelry.The real risk comes when the lead gets intoyour system. To be safe, be sure you keepyour jewelry out of your mouth and out ofreach of children, such as younger brothersand sisters.

A happy ending?Colton Burkhart, now 5 years old, has

undergone extensive chelation therapy toremove the lead from his system. So far, theresults have been good, but even a year later,lead levels in his blood remain higher thannormal. Only time will tell if his lead exposurewill have any long-lasting effects on hisdevelopment.

References1. Heavy Metal, www.dartmouth.edu/

~rpsmith/Heavy_Metals.html.2. Department of Health and Human

Services, Center for Disease Control(CDC), http://www.cdc.gov/.

3. Beattie, Owen and John Geiger. Frozenin Time. Saskatoon: Western ProducerPrairie Books, 1987. www.redlandsfort-nightly.org/papers/jfrnklin.htm

4. Anjali Patel, How Does Lead Affect theNervous System?, 2000.http://serendip.brynmawr.edu/bb/neuro/neuro00/web2/Patel.html

Tim Graham teaches chemistry at Roosevelt HighSchool in Wyandotte, MI. His most recent article“Secrets of the Samurai Sword Revealed”appeared in the December 2005 issue ofChemMatters.

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