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Artificial Christmas trees: how real are the lead exposure risks?


Exposure to lead has long been recognized as a major public health issue in the United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area.  and other industrialized in·dus·tri·al·ize  
v. in·dus·tri·al·ized, in·dus·tri·al·iz·ing, in·dus·tri·al·iz·es
1. To develop industry in (a country or society, for example).

 nations. During the late 1980s and early 1990s, it was discovered that lead would cause permanent and irreversible neurological neurological, neurologic

pertaining to or emanating from the nervous system or from neurology.

neurological assessment
evaluation of the health status of a patient with a nervous system disorder or dysfunction.
 damage, especially in infants and young children, at far lower exposure levels than previously believed (McMichael et al., 1988; Sciarillo, Alexander, & Farrell, 1992). Although recent data show that baseline blood lead levels have been declining over the last two decades (Mattuck, Beck, Bowers Bowers is a surname, and may refer to
  • Betty Bowers
  • Bryan Bowers
  • Charles Bowers
  • Claude Bowers
  • Dane Bowers
  • David A. Bowers
  • Elizabeth Crocker Bowers
  • Graham Bowers
  • Henry Francis Bowers
  • Henry Robertson Bowers, (1883 - 1912), polar explorer
, & Cohen cohen
 or kohen

(Hebrew: “priest”) Jewish priest descended from Zadok (a descendant of Aaron), priest at the First Temple of Jerusalem. The biblical priesthood was hereditary and male.
, 2001), lead is still a significant threat to health, particularly in children.

A recent study involving multivariate analysis multivariate analysis,
n a statistical approach used to evaluate multiple variables.

multivariate analysis,
n a set of techniques used when variation in several variables has to be studied simultaneously.
 of 4,853 study subjects ranging in age from 6 to 16 years found reductions in cognitive performance associated with blood lead levels as low as 2.5 micrograms per deciliter deciliter /dec·i·li·ter/ (dL) (des´i-le?ter) one tenth (10minus;1) of a liter; 100 milliliters.
Deciliter (dL)
100 cubic centimeters (cc).

Mentioned in: Hypercholesterolemia
 ([micro]g/dL) (Lanphear, Dietrich, Auinger, & Cox, 2001). Thus, lead-containing products with even moderate potential to cause human exposure are becoming recognized as having public health significance. One particular study found that even children whose blood lead levels (BLLs) never exceeded the Centers for Disease Control and Prevention Centers for Disease Control and Prevention (CDC), agency of the U.S. Public Health Service since 1973, with headquarters in Atlanta; it was established in 1946 as the Communicable Disease Center.  (CDC See Control Data, century date change and Back Orifice.

CDC - Control Data Corporation
) level of concern (10 [micro]g/dL) could have decreases in IQ of 2.6 points per 10 [micro]g/dL increase in BLLs (Winter, 2001). In the most recent study of the neurological effects of low-level lead exposure, Canfield can·field  
n. Games
A form of solitaire.

[After Richard Albert Canfield (1855-1914), American gambler.]

Noun 1.
 and co-authors (2003) found a 7.4-point IQ deficit (with a 95 percent confidence interval confidence interval,
n a statistical device used to determine the range within which an acceptable datum would fall. Confidence intervals are usually expressed in percentages, typically 95% or 99%.
 of 3.2-12.9 points, as measured by the Stanford-Binet Intelligence Scale Stanford-Binet Intelligence Scale

test used to measure IQ; designed to be used primarily with children. [Am. Education: EB, IX: 521]

See : Intelligence
 and the Revised Wechsler Preschool and Primary Scale of Intelligence The Wechsler Preschool and Primary Scale of Intelligence (WPPSI) is an intelligence test designed for children ages 2 years 6 months to 7 years 3 months developed by David Wechsler in 1967. ) as BLLs increased from 1 to 10 [micro]g/dL. This finding strongly suggests that neurological damage may be caused at even lower BLLs. This latest study, which tested 172 children ranging in age from six months to five years and measured nine confounding confounding

when the effects of two, or more, processes on results cannot be separated, the results are said to be confounded, a cause of bias in disease studies.

confounding factor
 factors, further underscores the importance of identifying and addressing even relatively small lead exposure concerns.

Several meta-analyses have been done to further investigate the connection between BLLs and IQ deficits. Some researchers (Kaufman, 2001; Pocock, Smith, & Baghurst, 1994) suggest that although there is some evidence that supports the connection, other explanations need considering before definitive conclusions can be drawn on the subject. These researchers fear that recent studies have not adequately allowed for confounding factors and that other shortcomings A shortcoming is a character flaw.

Shortcomings may also be:
  • Shortcomings (SATC episode), an episode of the television series Sex and the City
 in the studies may lead to improper conclusions. Other researchers (Needleman & Bellinger, 2001) argue that meta-analysis shows that lead does indeed have a negative impact on IQ, even when multiple variables have been controlled for in different statistical models.

In addition to intellectual effects, studies have connected lead exposure with behavioral and emotional problems, such as aggressive or anxious behavior, in children (Burns, Baghurst, Sawyer, McMichael, & Tong, 1999). Lead may also affect the growth of children, as was documented in a study that measured decreases in height, head circumference, and chest circumference with increasing lead levels (Kafourou et al., 1997).

Within the past 10 years, it has become recognized that polyvinyl chloride polyvinyl chloride (PVC), thermoplastic that is a polymer of vinyl chloride. Resins of polyvinyl chloride are hard, but with the addition of plasticizers a flexible, elastic plastic can be made.  (PVC PVC: see polyvinyl chloride.
 in full polyvinyl chloride

Synthetic resin, an organic polymer made by treating vinyl chloride monomers with a peroxide.
, or vinyl) plastic products often contain relatively large amounts of lead added as stabilizers. In 1995, it was discovered that imported vinyl mini-blinds contained so much lead that the surface dust produced as a result of direct sunlight and heat was resulting in cases of acute lead poisoning lead poisoning or plumbism (plŭm`bĭz'əm), intoxication of the system by organic compounds containing lead.  of young children who handled and played with them (Norman, 1996; B.C. Lee of U.S. Consumer Products Safety Commission, personal communication to M.F. Toro Toro may refer to:
  • Denominación de Origen Toro, the Spanish wine region
  • Toró, the nickname of Rafael Ferreira Francisco, Brazilian football (soccer) player
, July 24, 1996). Studies conducted in 1997 found that several commonly used children's products, such as PVC raincoats, book bags, and beach bags accumulated high levels of lead on surfaces after exposure to sunlight (DiGangi, 1997; Maas, Smith, Patch, & Thornton, 1997).

Artificial Christmas trees Christmas tree

Evergreen tree, usually decorated with lights and ornaments, to celebrate the Christmas season. The use of evergreen trees, wreaths, and garlands as symbols of eternal life was common among the ancient Egyptians, Chinese, and Hebrews.
 made of PVC have become very common in the United States; out of the 76 million family groups in the country, an estimated 50 million households own and use them (Fields & Casper, 2001). Nearly 20 million of the trees in these households are nine years or older (U.S. Bureau of the Census Noun 1. Bureau of the Census - the bureau of the Commerce Department responsible for taking the census; provides demographic information and analyses about the population of the United States
Census Bureau
, 2000). Thus, there is a potential for lead exposure from the handling of the trees during assembly, disassembly dis·as·sem·ble  
v. dis·as·sem·bled, dis·as·sem·bling, dis·as·sem·bles
To take apart: disassemble a toaster.

, and routine usage, as well as from contact with areas underneath the trees. The purpose of this investigation was to begin to determine the potential lead exposure from typical household usage of these products.


Experiment 1

Eight 7-foot artificial (PVC) Christmas trees, each from a different major manufacturer, were employed for part of this study. Four of these trees were newly purchased, and the other four had been in residential use for periods ranging from 7 to 17 years. The new trees were sent directly from the manufacturer, and length-of-service documentation for the used trees was provided by Foundation E.A.R.T.H. of St. Louis, Missouri. The manufacturer and tree specifications are summarized in Table 1. A sample of the needles (0.25 grams [g]-0.69 g) was cut from each tree for subsequent lead analysis. Tree needle samples were ashed for five hours at 400[degrees]C before acid/hydrogen peroxide peroxide (pərŏk`sīd), chemical compound containing two oxygen atoms, each of which is bonded to the other and to a radical or some element other than oxygen; e.g.  digestion.

Each tree was then assembled in the laboratory by an investigator after a thorough handwashing. Before and after assembly, the subject's hands were wiped with a laboratory wipe to remove all metal/dust material present on the hands. Each wipe was hot-block-digested according to according to
1. As stated or indicated by; on the authority of: according to historians.

2. In keeping with: according to instructions.

 National Institute for Occupational Safety and Health National Institute for Occupational Safety and Health, an institute of the Centers for Disease Control and Prevention that is responsible for assuring safe and healthful working conditions and for developing standards of safety and health.
 (NIOSH NIOSH National Institute for Occupational Safety & Health, see there

NIOSH Recommendations for Safety & Health Standards

Agent  NIOSH REL*/OSHA PEL  Health effects
) Method 7082 (NIOSH, 1994) with concentrated nitric acid nitric acid, chemical compound, HNO3, colorless, highly corrosive, poisonous liquid that gives off choking red or yellow fumes in moist air. It is miscible with water in all proportions.  and 30 percent hydrogen peroxide hydrogen peroxide, chemical compound, H2O2, a colorless, syrupy liquid that is a strong oxidizing agent and, in water solution, a weak acid. It is miscible with cold water and is soluble in alcohol and ether. , and the digestate was analyzed for lead.

Following assembly, a new clean laboratory paper surface 120 centimeters (cm) X 120 cm was placed under each tree. Investigators took wipe samples weekly for four weeks by wiping the entire area with a laboratory wipe. They took control samples by wiping an immediately adjacent treeless laboratory paper surface 120 cm X 120 cm. All wipe samples were digested as described above with nitric acid and hydrogen peroxide. The laboratory where the trees were erected had windows only along a long north-facing wall, so no direct sunlight struck the trees. At the conclusion of the four-week experiments addressing surface dust deposition, each tree was disassembled and placed back into its storage box by a subject, with the hands wiped before and after disassembly (as noted above for the assembly procedure) to determine how much lead was transferred to the hands during disassembly.

All digested wipe samples were analyzed for lead according to Standard Method 3113B (Clesceri, Greenberg, & Eaton, 1998) for electrothermal e·lec·tro·ther·mal  
1. Of, relating to, or involving both electricity and heat.

2. Of or relating to the production of heat by electricity.
 atomic absorption spectrometry Absorption spectrometry
A scientific procedure to determine chemical makeup of samples.

Mentioned in: Herbalism, Traditional Chinese
 (EAAS EAAS East Antrim Astronomical Society (Northern Ireland)
EaaS Everything As A Service
). This method basically involves digesting the wipe in a hot concentrated mixture of nitric acid and 30 percent hydrogen peroxide followed by EAAS analysis. Calculations were then made to express the amount of lead on the gloved hands in terms of the total mass (in [micro]g). The lead content in the plastic needles themselves was calculated as micrograms of lead per gram of needle (i.e., [micro]g/g, or ppm), and the lead in the settled dust beneath the trees was expressed as [micro]g/[cm.sup.2] of surface area.

Experiment 2

In this experiment, research testing kits were mailed to 127 households that had ordered the kits from Foundation E.A.R.T.H. The availability of the research kit was announced to the public primarily through a Christmas season evening news story carried by 73 NBC news NBC News (along with NBC News + HD) is the news division of American television network NBC, a part of NBC Universal, which is majority-owned by General Electric. Its current president is Steve Capus. It is the top-rated broadcast news division and has been for a decade.  affiliate stations across the United States. Each testing kit contained instructions, a research questionnaire, sample identification labels, a laboratory wipe, one plastic headspace head·space  
The volume left at the top of an almost filled jar, tin, or other container before sealing.

Noun 1. headspace - the volume left at the top of a filled container (bottle or jar or tin) before sealing
 vial vial

a small bottle.
, and a pair of laboratory gloves. Individuals were instructed, upon receipt of the kit, to open the plastic vial to have it ready to accept their wipe sample. Next, participants put on the gloves and removed and unfolded the laboratory wipe. A Christmas tree branch section approximately 30 cm in length was selected, and the wipe was carefully wrapped around the branch section. The participants took the wipe sample by applying pressure and pulling the wipe over the entire 30 cm section. After the first wipe sample was completed, the wipe was folded in half so that any dust was on the inside of the fold. A second pass was made with the same wipe; it used a second 30-cm branch section following the same methods. The wipe was folded a second time and placed into the plastic vial, which was then capped. A sample identification label was affixed af·fix  
tr.v. af·fixed, af·fix·ing, af·fix·es
1. To secure to something; attach: affix a label to a package.

 to the vial, and the kit was mailed back to the authors laboratory, where the wipes were analyzed for lead. Digestion and analysis of the wipes were conducted with the same methodology as in Experiment 1. Calculations were made to express the amount of lead in each wipe in terms of the total mass (in micrograms).

Participants also were asked to fill out a research questionnaire. The questionnaire was used to determine the number and ages of children in the household, child involvement in handling of the Christmas tree, length of tree ownership, manufacturer of the tree, country of origin, approximate age of tree, and location of tree storage in the off-season. The questionnaire also asked what the participant would do with the tree if it was found to have high lead levels. The choices included "discard tree and buy a real tree," "dispose of tree and buy another artificial tree," or "take extra care to avoid lead exposure when setting up and using the tree."

Results and Discussion

Experiment 1

Table 1 summarizes the metal concentrations found in the vinyl needles themselves. Two of the used trees exhibited relatively high levels of lead, with the used American Tree sample having high levels of lead. The levels of lead were nondetectable in the other six trees. These results suggest that lead was used more commonly as a PVC stabilizer stabilizer: see airplane.  in the past.

The results of dust wipe samples taken beneath the laboratory-erected trees are summarized in Table 2. Only used-tree specimens CH03 and CH06 exhibited relatively high lead levels in the settled dust, which is consistent with the metal-assay results shown in Table 1. A scenario of actual lead exposure for the sample with the highest lead level, American Tree, can be made under the assumption that young children might crawl and otherwise place their hands on the affected under-tree surface (floor, wrapped presents, etc.) once per week during a four-week Christmas tree season and pick up perhaps 25 percent of the total dust in the 1.49 [m.sup.2] area, for a total of 630 [micro]g. The U.S. Consumer Products Safety Commission (CPSC CPSC Consumer Product Safety Commission (US)
CPSC Computer Science (course)
CPSC Canadian Plastics Sector Council (Ottawa, ON, Canada)
CPSC Chemical Processing Safety Committee
) has estimated, based on various behavioral studies, that approximately 50 percent of hand-absorbed material will be ingested in·gest  
tr.v. in·gest·ed, in·gest·ing, in·gests
1. To take into the body by the mouth for digestion or absorption. See Synonyms at eat.

 by a child three years of age or younger (U.S. Consumer Product Safety Commission, 1997), which would entail, in this case, in an approximate acute ingestion ingestion /in·ges·tion/ (-chun) the taking of food, drugs, etc., into the body by mouth.

1. The act of taking food and drink into the body by the mouth.

 of 315 [micro]g. This figure would equate to approximately 0.86 [micro]g/day ingestion spread out over an entire year. California's Proposition 65 requires a warning label if a consumer product results in an average daily lead exposure of 0.5 [micro]g/day or greater. CPSC does not classify a consumer product as hazardous unless it exposes the average user to at least 15 [micro]g/day of lead; neither regulation specifies a limit for acute short-term lead exposures. The dust-wipe data for the Puleo brand tree give an annual exposure estimate of about 0.42 [micro]g/day, just below the Proposition 65 limit, while the remaining products produce estimated daily exposures between 0.02 and 0.16 [micro]g/day. It is important to note that even the six trees with nondetectable lead content produced dust lead levels 4 to 24 times background control levels, which suggests that all of the trees probably contained at least some lead stabilizer. These tests provide only very rough exposure estimates because only a single tree of each brand was tested, but they do suggest at least some lead exposure potential even from new trees.

The mass of lead transferred to subjects' hands during assembly and disassembly of PVC Christmas trees is summarized in Table 3. Again, the results are consistent with the needle lead concentrations shown in Table 1, with trees CH06 and CH03 showing the highest handling transfer levels. Sample CH06 resulted in a total lead transfer from assembly and disassembly of 30.4 [micro]g, which, spread over a four-week Christmas season, translates to a daily exposure of about 1 [micro]g per day and, spread over an entire year, to about 0.1 [micro]g/day. Actual ingestion would most likely be only 10 percent of these amounts for an adult and 50 percent for a young child. Thus, lead exposure from assembly and disassembly would appear to be relatively minor compared with exposure to a child playing around and under a tree.

Experiment 2

A total of 127 in-service trees were tested in this part of the experiment, and 42 trees, or 33.1 percent, were observed to have detectable levels of lead in their PVC needles. The lower limit for the analytical method was 1.5 [micro]g of lead. Analysis of the questionnaire data showed that 66.7 percent of the households with detectable levels of lead had children living in the household. Of this number, 47.6 percent had children five years of age or younger, while 23.8 percent had children two years of age or younger in the residence. Many volunteer participants were not able to determine the tree manufacturer or manufacturer location, and thus no conclusions regarding the relationship between the amount of lead in the tree and the trees manufacturer or country of origin can be made from the data.

Of the 47 trees with detectable lead levels, 35.7 percent were stored in the basement, 28.6 percent were stored in the attic In the Attic can refer to:
  • In The Attic (webcast)
  • In the Attic (band)
, and 14.3 percent were stored in the garage. Christmas tree storage location was considered a relevant questionnaire inquiry; it had been hypothesized that trees stored in locations with higher temperatures might display greater lead levels since heat encourages the breakdown of PVC materials. The data, however, do not support this hypothesis. The attic was assumed to be the hottest storage location, but of the 40 trees that were stored in the attic, only 30 percent had detectable lead levels. Of the 15 trees that were stored in the garage, 40 percent had detectable lead levels. In the basement storage location, which was assumed to be the coolest, 37 percent of 41 trees had detectable lead levels.

Table 4 shows the number of trees in several tree age categories. The mean lead concentration found in kit wipe samples, by tree age category, as well as the percentage of trees in each age category with lead levels that exceeded the detection limit, are shown. Fifteen trees had ages that were listed on the questionnaire as unknown, and results for those trees were not included in the analysis. The data shown in Table 4 suggest that, while the percentage of artificial trees manufactured with at least some lead stabilizer has decreased only modestly, the amount of lead stabilizer used has apparently been reduced to a much larger extent.

The last two columns in Table 4 deal with possible lead exposure from the artificial Christmas trees. Direct mouthing exposure was calculated on the assumption of once-daily 100 percent transfer of lead from a 30-cm tree branch to a child's mouth over a 30-day Christmas season. The scenario that was used for estimating exposure from hand-to-mouth transfer was a once-daily handling of a 30-cm tree branch with a 50 percent transfer rate over a 30-day Christmas season. A young child might likely handle more than one tree branch per day. A typical daily exposure might more commonly involve the handling of three branches per day on a 10-15 year old tree; with this amount of physical contact, the child would be exposed to 6.72 [micro]g/day of lead, or 201.6 [micro]g over the Christmas season.

On average, the data collected from the wipe samples showed that exposure risks are generally relatively low. Some percentage of young children, however, will come into physical contact with their Christmas tree more than once a day, and some children will touch much more than just one tree branch per day. These factors combined suggest that it is possible for a child to be exposed to a far greater amount of lead than the data immediately suggest. For instance, if perhaps the worst-case scenario worst-case scenario nSchlimmstfallszenario nt  of child exposure involves a child who mouths 10 tree branches per day on trees that are 20 years old or greater, and in addition handles a total of 300 cm of branch per day, the exposure for this child could be as great as 225.6 [micro]g per day, or 6,768 [micro]g over the 30-day Christmas season (or nearly 20 [micro]g/day averaged over the entire year). When one applies the Food and Drug Administration (FDA FDA
Food and Drug Administration

FDA, See Food and Drug Administration.

FDA, the abbreviation for the Food and Drug Administration.
, 1993) 0.16 factor for converting [micro]g/day of lead exposure to [micro]g/dL increases in BLL BLL Blood Lead Level
BLL Bovis Lend Lease
BLL Business Logic Layer
BLL Buraku Liberation League (Japan)
BLL Billund, Denmark - Billund (Airport Code)
BLL Base Locator for Linkage
, this value translates to a BLL increase of over 3.0 [micro]g/dL. Extrapolation (mathematics, algorithm) extrapolation - A mathematical procedure which estimates values of a function for certain desired inputs given values for known inputs.

If the desired input is outside the range of the known values this is called extrapolation, if it is inside then
 from the recent work of Canfield and co-authors (2003) produces an estimated IQ deficit for this scenario of about 2.5 points. Although no studies have ever addressed the range of hand-to-mouth contact a young child might have with an artificial Christmas tree, clearly many children will have much higher exposure than was estimated as typical in this study. With an estimated 50 million out of 76 million families owning and using artificial Christmas trees in the United States, and with almost 11.5 million children two years of age and younger living in the United States (U.S. Bureau of the Census, 2000), if even 50 percent of these children lived in a home with an artificial Christmas tree, the most exposed 1 percent of this population (a combination of the most dangerous child behavior and the trees with the highest lead content) would have a much higher exposure level than estimated for the typical child; mathematically, this percentage would translate to about 57,500 children.


The experiments conducted in the first phase of the research do not support the contention that the PVC Christmas trees currently being manufactured represent more than a relatively small lead exposure hazard across the entire population of U.S. children. This conclusion is tempered by the fact that only one tree of each major brand was tested.

In contrast, two of the four older used trees that were tested contained relatively high levels of lead (1,527 and 7,184 [micro]g/g) in the PVC needles. These levels are well in excess of the less than 400 [micro]g/g that CPSC recommends children's products contain, and ingestion calculations indicate that trees of these two types probably expose young children to lead levels at least in the range of California Proposition 65 limits.

While clearly not an acute toxicity acute toxicity Pharmacology Illness caused by a single exposure to a toxic substance  threat by themselves, a significant fraction of older artificial trees are probably exposing children and adults to enough lead to be at least a noteworthy public health issue. The experiments described in this paper indicate that it is probably appropriate to caution families--especially families with older PVC Christmas trees, but even families with new ones--to thoroughly wash hands immediately after tree assembly and disassembly, and especially to limit the access of children to areas under erected trees. Direct mouthing contact, frequent branch handling, or both by young children would appear to have the potential for causing lead exposures of considerably greater health significance.

Data collected from the second phase of the authors' research generally confirm that on average, lead exposure from artificial Christmas trees is relatively low. A worst-case scenario, however, would result in very harmful lead exposure. For the safety of all children, it is probably appropriate to request that PVC Christmas tree manufacturers formally commit to banning the use of lead in the PVC formations employed in these products. Until they do so, it would be wise to limit the amount of physical contact that children have with artificial Christmas trees.
TABLE 1 Lead Content of Artificial Christmas Tree Needles

ID     Type  Manufacturer           Length of Service  Pb
                                    (Years)            ([micro]g/g)

CH 01  New   The Christmas House     0                 *ND
CH 02  New   Holiday Tree and Trim   0                 ND
CH 03  Used  Puleo                  13                 1,527
CH 04  New   Christmas Direct        0                 ND
CH 05  New   Tree Classics           0                 ND
CH 06  Used  American Tree          17                 7,184
CH 07  Used  Hudson Valley Tree      8                 ND
CH 08  Used  General Form Plastic    7                 ND
Blank                                                  ND

*ND: less than 25 [micro]g/g.

TABLE 2 Lead in Settled Dust Beneath Standing Christmas Trees

ID     Manufacturer           Week 1
                              ([micro]g/100 [cm.sup.2])

CH 01  The Christmas House    0.127
CH 02  Holiday Tree and Trim  0.0538
CH 03  Puleo                  0.424
CH 04  Christmas Direct       0.114
CH 05  Tree Classics          0.298
CH 06  American Tree          2.43
CH 07  Hudson Valley Tree     0.0807
CH 08  General Form Plastic   0.0129
Blank                         0.0107

ID     Week 2                     Week 3
       ([micro]g/100 [cm.sup.2])  ([micro]g/100 [cm.sup.2])

CH 01  0.0980                     2.66
CH 02  0.0258                     0.157
CH 03  1.71                       4.98
CH 04  0.207                      0.107
CH 05  0.0893                     0.157
CH 06  3.20                       5.39
CH 07  0.109                      0.133
CH 08  0.475                      0.0635
Blank  0.0151                     0.0258

ID     Week 4                     Total
       ([micro]g/100 [cm.sup.2])  ([micro]g/100 [cm.sup.2])

CH 01  0.171                       3.06
CH 02  0.539                       0.775
CH 03  1.16                        8.28
CH 04  0.170                       0.596
CH 05  0.114                       0.658
CH 06  5.94                       17.0
CH 07  0.157                       0.479
CH 08  0.151                       0.701
Blank  0.0732                      0.125

TABLE 3 Lead on Hands After Assembly and Disassembly of Artificial
Christmas Trees

ID#              Assembly                Disassembly
       Blank         Wipe Transfer  Blank       Wipe Transfer
       ([micro]g)    ([micro]g)     ([micro]g)  ([micro]g)

Ch 01    <0.1            0.7        <0.1            0.5
Ch 02    <0.1            0.8        <0.1            0.3
Ch 03    <0.1            6.9        <0.1            2.3
Ch 04    <0.1            0.2        <0.1            0.8
Ch 05    <0.1            0.3        <0.1            0.9
Ch 06    <0.1           15.0        <0.1           15.4
Ch 07    <0.1            4.4        <0.1            1.2
Ch 08    <0.1            0.8        <0.1            0.5

TABLE 4 Mean Lead Mass and Estimated Lead Exposures from In-service
Artificial Christmas Trees

                                     Age of Trees (Years)
                             0-5     5-10     10-15    15-20    >20

Number of trees              61       21       16         9      5
in age category
Percentage of trees          26.2     23.8     37.5      33.3  100
above detection limit
(1.5 [micro]g Pb)
Mean lead mass on             1.45     0.91     4.48      2.92  11.28
wipe ([micro]g)
Estimated mean total direct  43.5     27.3    134.4      87.6  338.4
mouthing exposure over
Christmas season ([micro]g)
Estimated mean total         21.8     13.7     67.2      43.8  169.2
hand-to-mouth transfer
exposure over Christmas
season ([micro]g)


Burns, J.M., Baghurst, P.A., Sawyer, M.G., McMichael, A.J., & Tong, S. (1999). Lifetime low-level exposure to environmental lead and children's emotional and behavioral development at ages 11-13 years: The Port Pirie Port Pirie (pĭr`ē), city (1991 pop. 14,110), South Australia, S Australia, on an inlet of Spencer Gulf. It is a railroad center and has uranium refineries and smelting works for the silver-lead mines at Broken Hill.  Cohort Study A cohort study is a form of longitudinal study used in medicine and social science. It is one type of study design.

In medicine, it is usually undertaken to obtain evidence to try to refute the existence of a suspected association between cause and disease; failure to refute
. American Journal of Epidemiology, 149(8), 740-749.

Canfield, R.L., Henderson, C.R., Cory-Slechta, D.A., Cox, C., Jusko, T.A., & Lanphear, B.P. (2003). Intellectual impairment in children with blood lead concentrations below 10 [micro]g per deciliter. New England Journal of Medicine The New England Journal of Medicine (New Engl J Med or NEJM) is an English-language peer-reviewed medical journal published by the Massachusetts Medical Society. It is one of the most popular and widely-read peer-reviewed general medical journals in the world. , 348(16), 1517-1526.

Clesceri, L.S., Greenberg, A.E., & Eaton, A.D. (Eds.). (1998) Standard methods for the examination of water and wastewater (20th ed.). Baltimore: United Book Press, Inc.

DiGangi, J. (1997) Lead and cadmium cadmium (kăd`mēəm) [from cadmia, Lat. for calamine, with which cadmium is found associated], metallic chemical element; symbol Cd; at. no. 48; at. wt. 112.41; m.p. 321°C;; b.p. 765°C;; sp. gr. 8.  in vinyl children's products: A Greenpeace expose (Report No. 38). Washington, DC: Greenpeace USA.

Fields, J., & Casper, L.M. (2001) America's families and living arrangements: March 2000 (Current Population Reports, 20-537). Washington, DC: U.S. Bureau of the Census.

Kafourou, A., Touloumi, G., Makropoulos, V., Loutradi, A., Papanagiotou, A., & Hatzakis, A. (1997). Effects of lead on the somatic somatic /so·mat·ic/ (so-mat´ik)
1. pertaining to or characteristic of the soma or body.

2. pertaining to the body wall in contrast to the viscera.

 growth of children. Archives of Environmental Health, 52(5), 377-383.

Kaufman, A.S. (2001) Do low levels of lead produce IQ loss in children? A careful examination of the literature. Archives of Clinical Neuropsychology Clinical neuropsychology is a sub-specialty of clinical psychology that specialises in the diagnostic assessment and treatment of patients with brain injury or neurocognitive deficits. , 16 (4), 303-341.

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Maas, R.P., Smith, R.M., Patch, S.C., & Thornton, L.R. (1997). Assessment of potential lead exposure from children's vinyl products (Tech. Rep. No. 97-043). Ashville, NC: UNC (Universal Naming Convention) A standard for identifying servers, printers and other resources in a network, which originated in the Unix community. A UNC path uses double slashes or backslashes to precede the name of the computer.  Asheville Environmental Quality Institute, 18.

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Needleman, H.L., & Bellinger, D. (2001). Studies of lead exposure and the developing central nervous system: A reply to Kaufman. Archives of Clinical Neuropsychology, 16(4), 359-374.

National Institute for Occupational Safety and Health (1994). Lead by flame AAS method 7082, i.2. Manual of Analytical Methods (4th ed.). Washington, DC: United States Department of Health and Human Services United States Department of Health and Human Services (USDHHS), a cabinet-level government organization comprising 12 agencies, including the Food and Drug Administration and the Centers for Disease Control and Prevention.

Norman, E. (1996.) Imported, plastic mini-blinds identified as potential source of lead poisoning. North Carolina Department of Environment and Natural Resources The North Carolina Department of Environment and Natural Resources (NCDENR) is the state's leading stewardship agency for the preservation and protection of natural resources and public health. . (7 Sept. 2004).

Pocock, S.J., Smith, M., & Baghurst, P. (1994). Environmental lead and children's intelligence: A systematic review of the epidemiological evidence. British Medical Journal The British Medical Journal, or BMJ, is one of the most popular and widely-read peer-reviewed general medical journals in the world.[2] It is published by the BMJ Publishing Group Ltd (owned by the British Medical Association), whose other , 309(6963), 1189-1197.

Sciarillo, W.G., Alexander, G., & Farrell, K.P. (1992). Lead exposure and child behavior. American Journal of Public Health The American Journal of Public Health (AJPH) is a peer reviewed monthly journal of the American Public Health Association (APHA). The Journal also regularly publishes authoritative editorials and commentaries and serves as a forum for the analysis of health policy. , 82(10), 1356-1360.

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U.S. Consumer Product Safety Commission. (1997). CPSC staff report on lead and cadmium in children's polyvinyl chloride (PVC) products. Washington, DC: Author.

U.S. Food and Drug Administration. (1993). Lead in Food, Part II, 58 Federal Register 117 (codified cod·i·fy  
tr.v. cod·i·fied, cod·i·fy·ing, cod·i·fies
1. To reduce to a code: codify laws.

2. To arrange or systematize.
 at 21 CFR CFR

See: Cost and Freight
 [section][section] 109, 189).

Winter, M. (2001). Heavy metal: It doesn't take nearly as much lead as the CDC thought to lower a child's IQ. Human Ecology Human ecology

The study of how the distributions and numbers of humans are determined by interactions with conspecific individuals, with members of other species, and with the abiotic environment.
, 29(4), 10-12.

Richard P. Maas, Ph.D.

Steven C. Patch, Ph.D.

Tamara J. Pandolfo

Corresponding Author: Richard P. Maas, Co-director, UNC-Asheville Environmental Quality Institute, CPO (Chief Privacy Officer) An individual who manages the privacy issues within an organization. Arising out of the privacy regulations in finance and health care in the late 1990s, the CPO position eventually crossed over to all industries.  #2331, One University Heights University Heights, city (1990 pop. 14,790), Cuyahoga co., NE Ohio, a residential suburb E of Cleveland; inc. 1925. It is the seat of John Carroll Univ. , Asheville, NC 28804. E-mail:
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Title Annotation:FEATURES
Author:Pandolfo, Tamara J.
Publication:Journal of Environmental Health
Geographic Code:1USA
Date:Dec 1, 2004
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