Handwipe Method for Removing Lead from Skin

Abstract

Researchers at the U.S. National Institute for Occupational Safety and Health �NIOSH� developed a handwipe removal method for lead �Pb� after field studies showed that workers in lead-acid battery plants had significant risks for dermal-oral lead exposures, despite their attempts to remove the lead by washing with soap and water. Hand washing with soap and water remains the standard recommendation for workers �as well as the public� to clean skin known or believed to be contaminated with toxic metals, such as lead. Despite longstanding recommendations for workers to “wash hands with soap and water,” no efficacy studies show this to be a completely effective removal method for lead. Removal of toxic metals such as lead from skin constitutes a decontamination procedure; it is not, in fact, a hand-washing step. NIOSH scientists conceived and developed a highly effective �nearly 100 %� method for removal of lead from skin. A systems approach was devised incorporating four components deemed necessary for effective metal removal: Surfaction, pH control, chelation, and mechanical effects. The handwipe removal method evolved from a previous NIOSH invention, the handwipe disclosing method for the presence of lead, in the interests of providing complementary techniques for dermal lead detection and decontamination. The method is a patented, award-winning, commercialized technology that has significant potential to prevent occupational and public exposures to lead.

Full text

Eric J. Esswein,1Mark F. Boeniger,2and Kevin Ashley3
Handwipe Method for Removing Lead from Skin*
ABSTRACT: Researchers at the U.S. National Institute for Occupational Safety and Health 共NIOSH兲de-
veloped a handwipe removal method for lead 共Pb兲after field studies showed that workers in lead-acid
battery plants had significant risks for dermal-oral lead exposures, despite their attempts to remove the lead
by washing with soap and water. Hand washing with soap and water remains the standard recommenda-
tion for workers 共as well as the public兲to clean skin known or believed to be contaminated with toxic metals,
such as lead. Despite longstanding recommendations for workers to “wash hands with soap and water,” no
efficacy studies show this to be a completely effective removal method for lead. Removal of toxic metals
such as lead from skin constitutes a decontamination procedure; it is not, in fact, a hand-washing step.
NIOSH scientists conceived and developed a highly effective 共nearly 100 %兲method for removal of lead
from skin. A systems approach was devised incorporating four components deemed necessary for effective
metal removal: Surfaction, pH control, chelation, and mechanical effects. The handwipe removal method
evolved from a previous NIOSH invention, the handwipe disclosing method for the presence of lead, in the
interests of providing complementary techniques for dermal lead detection and decontamination. The
method is a patented, award-winning, commercialized technology that has significant potential to prevent
occupational and public exposures to lead.
KEYWORDS: isostearamidopropyl morpholine lactate 共ISML兲, cleanser, citric acid, decontamination,
dermal, lead, wipe, workplace
Introduction
Occupational and environmental exposure to metals 共e.g., lead 关1兴兲 and other elements inherently toxic to
biological systems 共e.g., cadmium, arsenic, beryllium兲implies 共depending on the degree of exposure兲a
potential for adverse effects on workplace and public health. Exposure to such metals, especially lead, is
a significant problem that affects a large and diverse segment of the population, and workers and their
families are especially at risk 关2–4兴. Exposure to lead 共Pb兲may occur in a wide variety of locations,
including the workplace, homes or schools, or the outdoor environment 关1,2,4兴. Skin contact is a signifi-
cant route for transfer, and exposure to metals such as lead. While hand-to-mouth transfer is understood to
be the most significant route of exposure; 共a兲several researchers have shown that lead ions may be
absorbed through the skin 关5–7兴;共b兲skin can act as a reservoir for metals 关8,9兴;共c兲skin surface deposition
can be an important source of secondary contamination 关3,8,10兴; and 共d兲impairment or loss of skin barrier
function can occur 关6,11兴. Additionally, skin contact with some metals and their compounds 共nickel,
chromium, and beryllium among others兲can cause sensitization and systemic allergic responses which can
result in serious occupational disease and even loss of workers from the working population 关12兴. Unfor-
tunately, many toxic metals are not easily washed off of the skin; finely divided metal particles not only
lodge within the complex interstices of the stratum corneum but also bind to sulfhydryl, carboxyl, and
other groups present in skin proteins 关11兴. Industrial hygiene workplace investigations conducted by
NIOSH and other investigators have shown that lead and other metals remain on the hands of workers
even after they report, or were known to have washed their hands before eating 关13–16兴. In industrial
settings where lead poses exposure risks, significant metal contamination may remain even after washing
关13,14,16,17兴.
Manuscript received October 29, 2010; accepted for publication March 21, 2011; published online May 2011.
1Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, US Department of Health and
Human Services, Western States Office, Denver Federal Center, Bldg 25, Room 2640, Denver, CO 80225, e-mail: eje1@cdc.gov
28380 Jakaro Dr., Cincinnati, OH 45225.
3Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, US Department of Health and
Human Services, 4676 Columbia Pkwy., Cincinnati, OH 45226.
*Presented at the ASTM International Symposium on Surface and Dermal Sampling, October 14–15, 2010, San Antonio, TX. This article was
prepared by U.S. Government employees as part of their official duties and legally may not be copyrighted in the United States of America.
Journal of ASTM International, Vol. 8, No. 5
Paper ID JAI103527
Available online at www.astm.org
Copyright © 2011 by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.

Lead provides a particularly useful illustration of the exposure risks, detection and decontamination
challenges posed by skin exposures. Lead exposure can occur to workers 共and the public兲during and after
removal of lead-based paints and/or the renovation of structures containing lead-based paints 关2兴,to
workers in waste-to-energy plants, manufacture of lead-acid batteries, and other related industries 共e.g.,
radiator repair work, welding, and construction work兲. Adults or children living within or visiting homes
or schools containing deteriorated lead-based paints can be at risk for exposures 关4,10兴. Lead residues on
the skin, especially on the hands, of industrial workers can be a significant health risk since such residues
can be invisible and may be ingested during normal activities 共e.g., eating, drinking, and smoking兲
关7–9,17,18兴. Contaminated clothing 共as well as automobiles兲presents take-home toxics issues for workers
and their families; lead is an especially important metal in this route of exposure 关19兴.
Although screening methods for detecting the presence of lead in workplaces are available 关20–22兴,
validated methods, techniques, and products for highly effective 共⬎99 %兲skin and surface decontamina-
tion are needed. In response to this gap, efforts have been directed to acknowledge the need and impor-
tance of detecting and removing lead from skin and other surfaces 关6,7,23兴. Lead desorption and removal
from contaminated soil using surfactants has been investigated and described 关24,25兴. The physical prop-
erties of liquids and soil permit physical mixing of contaminated liquids or soils with decontaminating
agents 共such as surfactants兲on a microscopic level that cannot be achieved with non-dispersible 共such as,
solid兲matter. As a result, it may be more difficult to contact and remove metal contamination from a solid
surface, especially where the surface has interstices where contaminants can lodge and bind 共such as skin兲.
Moreover, agents suitable for lead decontamination of liquids or soils may cause damage to solid surfaces
and, in particular, may irritate or harm sensitive surfaces such as human skin 关6,26,27兴.
Products that claim to remove lead and toxic metals from human skin often contain active ingredients
such as the chelating agent ethylenediaminetetraaceticacid 共EDTA兲or anionic surfactants 共fatty acid soaps兲
关28兴. EDTA, while a good chelating agent, is a suspected persistent environmental pollutant and a skin
irritant. EDTA may cause reddening or inflammation on prolonged skin contact 关29兴. Anionic surfactants
such as sodium laurel sulfate 共SLS兲are used in many surfactant or soap mixtures but SLS may also cause
skin irritation, including dryness and scaling 关26,30兴. Moreover, anionic surfactants due to their alkaline
pH may not be fully effective in mobilizing and removing lead contamination 关8,24,25,31兴. Therefore,
considering the disadvantages of EDTA and anionic surfactants for removing metals from human skin and
surfaces, safe, reliable and effective compositions are needed for removing metals, notably lead. Of
particular need are compositions and methods that do not substantially damage the treated surface, or
unduly irritate, or sensitize biological surfaces, notably skin 关32兴.
In this work we describe the development and evaluation of treated wipes for decontamination of lead
and other metals from surfaces such as skin. Optimal wipe materials were found to be those that included
a three-dimensionally highly textured absorbent support such a creped surface 共a textured surface com-
prising a succession of ridges and groves; see Fig. 1兲with isostearamidopropyl morpholine lactate 共ISML兲
and citric acid in the absorbent, creped wipe. The amounts of ISML and citrate in the wipe medium were
optimized in order to obtain the best metal-removing capability from dermal surfaces. The metal-removal
(a) (b)
FIG. 1—Creped wipe materials (a) Photo of creped wipe showing succession of ridges and groves and
sample collection within a textured wipe. Photo courtesy of Micrex Corporation. Used with permission B)
Photo of various creped textures that can be imparted into wiping materials. Photo courtesy of Micrex
Corporation. Used with permission.
2 JOURNAL OF ASTM INTERNATIONAL

performance of these wipes from the hands of the researchers as well as volunteers was compared to that
of several other commercially available products and formulations, and also to hand washing with soap
and water. We report herein the results of these investigations, which demonstrate the superior decontami-
nation effectiveness of a textured 共creped兲wipe substrate containing the cationic surfactant ISML and
chelating and pH adjusting agent, citric acid.
Experimental
Materials
Initial formulations of the decontamination wipes were made in NIOSH laboratories in Cincinnati, OH and
Denver, CO. Several rolls of DuPont™ Sontara®were creped by Micrex®共Walpole MA兲and provided to
NIOSH as the absorbent substrate for the initial experimental trials. ISML 共Mackalene™ 426 and
Incromate®ISML兲were obtained from McIntyre Group Ltd. 共University Park, IL USA兲and CRODA Inc.
共Edison, NJ, USA兲, respectively. Citric acid solutions were made in-house 共NIOSH, Cincinnati, OH,
USA兲. A pre-commercial version of the invention 共MEDTOX®Wipe Lot # 0807兲of LeadTech™ Wipes
was provided for evaluation by MEDTOX®Diagnostics 共Burlington, NC, USA兲. The final formulation of
wipes contained between 0.3 and 2 g 共g兲of ISML and between 0.01 and 0.1 g citric acid per gram of
absorbent support 共exact formulations are proprietary兲. Sampling wipes 共Palintest™ and Ghost Wipes™兲
meeting international voluntary consensus performance standards were obtained from Palintest®共Gates-
head, Tyne and Wear, U.K.兲and Environmental Express 共Mt. Pleasant, SC, USA兲, respectively 关33兴.
D-Lead™ cleansers, both with and without scrubbers, were obtained from Esca Tech 共Milwaukee, WI,
USA兲. Clean-All Heavy Metals Soap™ cleanser came from Sasha International 共Miami Beach, FL, USA兲.
Kresto Select™ cleanser with scrubber, and Kresto Kwik™ wipes, were purchased from Stockhausen
共Greensboro, NC, USA兲. GoJo Multigreen™ cleanser with scrubbers was obtained from GoJo Corp.
共Akron, OH, USA兲. Waxed kitchen paper, paper towels, and food grade corn starch 共Safeway brands,
Pleasanton, CA, USA兲, as well as Pampers Baby Wipes™ and Ivory™ Liquid Soap 共Procter & Gamble
Co., Cincinnati, OH, USA兲, were purchased at a neighborhood grocery store. Disposable nitrile laboratory
gloves came from Fisher Scientific 共Fair Lawn, NJ, USA兲. Acetic acid 共reagent grade兲came from Sigma
Aldrich. Industrial hand soap used was Smart & Final™ Liquid Soap 共Los Angeles, CA, USA兲.
Red lead monoxide powder 共PbO; ⬎99.9 %, particle size ⬍10 micrometer关␮m兴兲was obtained from
Sigma-Aldrich 共Milwaukee, WI, USA兲and was mixed uniformly into corn starch 共used as a mixing
diluent兲by rotary tumbling to yield a concentration of 90.9 mg 共mg兲Pb/gram. Aliquots of this mixture
were weighed into samples of 33 mg each 共to ⫾1mg兲on an analytical balance 共Mettler model AE163,
Greifensee, Switzerland兲. Lead-containing dust 共consisting primarily of PbO collected from a lead-acid
battery manufacturing plant in Texas, USA 关14兴兲 was also weighed into samples of approximately
3000 ␮g each. Polyethylene centrifuge tubes 共Elkay™, 50 mL兲were obtained from Life Sciences Prod-
ucts 共Denver, CO, USA兲.
Procedures
The evaluation of lead dust decontamination from human hands 共the researchers as well as volunteers兲was
approved through NIOSH human subjects review board 关34兴. Skin was contaminated by spiking both
palmer surfaces with weighed quantities of leaded dust 共either lead monoxide powder and corn starch, or
straight PbO from a lead-acid battery plant兲. Skin sampling was performed in accordance with NIOSH
Method 9105 关35兴. To establish if significant lead might have been present as background contamination,
an initial 30-s hand wipe sample was collected on every subject 共researcher or volunteer兲before each of
the experimental trials. Both Ghost Wipes™ and Palintest™ brand wipes were used for skin sampling. To
collect skin samples for the presence of lead, the investigator 共wearing clean nitrile gloves兲opened a wipe
packet and offered the folded wipe to the subject. The volunteer was asked to completely unfold the wipe
and then carefully wipe to sample the palmer surfaces of both hands for 30 s to collect an initial back-
ground sample for the presence of lead. After 30 s, the subject was requested to stop wiping and fold the
wipe with the soiled surface facing inward. The volunteer was asked to place the folded wipe into a 50-mL
ESSWEIN ET AL. ON DECONTAMINATING SKIN FROM LEAD 3

plastic centrifuge tube that was used for sample containment and laboratory transport. After sample
collection, the centrifuge tube was tightly capped and labeled with a discrete sample identification number
using an indelible marker.
To apply the leaded dust to the skin of each volunteer, the investigator 共wearing clean nitrile gloves兲
carefully unfolded the sample weighing paper and poured each pre-weighed leaded dust sample into the
volunteers’ cupped hands while they were held over a clean sheet of wax paper. The wax paper was placed
below the subjects’ hands to capture any leaded dust that fell off the hands during the application, enabling
a mass balance to be established. Subject individuals were asked to carefully rub the leaded dust into the
skin of their hands for 30 s, being careful to keep as much lead dust on their hands as possible.
After the leaded dust was applied to the skin, the investigator changed gloves, removed a decontami-
nation wipe from its container and handed it to each volunteer. Each subject was asked to cleanse his/her
hands for a period of 30 s. Following the 30-s decontamination step, the volunteer was asked to rinse their
hands for 30 s under a laboratory sink with flowing, tepid water to remove the surfactant. After rinsing, the
investigator gave the volunteer two flat paper towels and instructed the volunteer to carefully pat dry their
hands, taking care not to rub their hands with the paper towel.
Two serial handwipe samples were then collected to evaluate the volunteers’ 共or researchers’兲hands
for the presence of lead on skin. The investigator 共wearing a fresh pair of nitrile gloves兲again opened
packets of Ghost Wipes™ or Palintest™ wipes and offered the folded wipes to the volunteers. The
volunteers were asked to unfold the wipe and wipe the palmer surfaces of both hands for 30 s and then to
fold the wipe together with the “soiled” or sample side facing in. The volunteers placed the wipes into
50-mL centrifuge tubes, which were then capped and labeled. Skin sampling was repeated twice and the
samples combined in a single tube for analysis. A surface wipe sample was collected from the wax paper
that was placed on the laboratory bench below the volunteers’ hands during application of leaded dust to
the hands. This sample was used to account for any lead-containing dust that might have not been rubbed
into the volunteers’ hands or somehow spilled through their fingers during the application process.
Similar protocols as described above were employed to evaluate hand washing with soap and water as
well as various liquid soaps, solutions, wipes and cleanser formulations.
Wipe samples were analyzed at Bureau Veritas North America, 共Novi, MI, USA兲, a facility accredited
by the American Industrial Hygiene Association Laboratory Accreditation Programs, LLC. Analyses were
carried out using NIOSH method 9102 with modifications: lead in collected wipe samples was determined
by means of nitric/perchloric acid hot block digestion and inductively coupled plasma-atomic emission
spectrometry 共ICP-AES兲. Each wipe sample was removed from the centrifuge tubes and placed in a clean
beaker to which 2.5 mL of 12.1Mperchloric acid was added and allowed to stand for 30 min. The beakers
were placed in a hot block and heated at 95°C for 15 min. Samples were removed from the hot block, left
to stand, and allowed to cool to room temperature, and 2.5 mL of 15.6Mnitric acid was then added. The
samples were placed back in the hot block and again heated at 95°C for 15 min. The samples were then
removed, left to stand, and allowed to cool to room temperature and diluted to a final volume of 25 mL
with deionized water. Quality assurance/quality control samples 共blank samples, spikes and spike dupli-
cates兲were digested and analyzed in the same manner. All samples were analyzed using a Perkin Elmer
Optima 3200 XL ICP-AES instrument 共Boston, MA, USA兲. The ICP-AES limits of detection and quan-
titation for lead 共0.3 and 0.86 ␮g per sample, respectively兲were estimated in accordance with ASTM
E1613 关36兴.
Results and Discussion
In initial experiments, the researchers compared the efficacy of a combination of liquid surfactant and
acids alone, with no wipe 共i.e., ISML and acetic or citric acids兲against ISML and citric acid added to a
lightly textured “creped” wipe, against common industrial soap and water to remove leaded dust from the
researcher’s skin. Fig. 2 shows the amount of lead 共in ␮g兲remaining on the palmer surfaces of the skin
after an initial 3000 ␮g Pb loading 共using the PbO–corn starch mixture兲following the four different
methods of cleansing: 共1兲Common industrial soap and water alone 共S&W兲;共2兲liquid only mixtures of
citric acid and ISML 共C-I liquid兲;共3兲liquid mixtures of acetic acid and ISML 共A-I liquid兲; and, 共4兲an
aqueous mixture of citric acid and ISML 共C-I on wipe兲applied onto a commercially available lightly
4 JOURNAL OF ASTM INTERNATIONAL

textured 共Pampers®brand兲baby wipe. In these trials, five replicates were run for each of the above four
experiments.
As is illustrated in Fig. 2, use of common industrial soap and water alone was not effective in
completely removing deposited lead from human skin, as nearly 300 ␮g of lead remained after hand
washing. The alkaline 共pH8–9兲nature of common industrial soap and water, absence of a low pH
surfactant and chelating agent, and lack of mechanical removal effects are understood to be the main
reasons for less complete removal of lead from skin. In contrast, a citric acid and ISML formulation on a
lightly textured “creped” wet wipe was the most effective in this trial, as evidence by the least amount of
remaining lead recovered 共⬍75 ␮g兲after skin decontamination. Mixtures of citric or acetic acids and
ISML applied without a wipe 共C-I liquid and A-I liquid兲were also effective at removing lead 共Fig. 1兲. The
finding that the wipe formulation with citric acid and ISML is somewhat more effective than ISML/citric
acid liquid only indicates that the mechanical action of even a lightly textured wiping material contributed
to the lead-removal process.
In another initial set of experiments also conducted on the researchers’ hands, several variations on the
use of a highly textured “creped” wipe containing aqueous solutions of citric acid and ISML were tested
for efficacy at removing lead from skin. Different cleansing protocols utilizing Micrex®共highly textured,
creped兲Dupont Sontara wiping material were employed after application of 3000 ␮g Pb in leaded dust on
hands, as described previously. These six protocols and hand washing with common soap and water
共which is the most commonly used cleansing protocol兲are outlined in Table 1. Each protocol was done in
FIG. 2—Amount of lead (in
␮
g) remaining on human hands after cleansing with a liquid mixture of citric
acid and ISML (“C-I liquid”), a liquid mixture of acetic acid and ISML (“A-I liquid”), a mixture of citric
acid and ISML on a wipe (“C-I on wipe”), and plain soap and water (“S&W”); n
⫽
5 for each cleanser
method.
TABLE 1—Cleansing protocols tested in evaluating efficacies of treated, textured wipes.
Protocol Description
A
Wipe containing 10 mL of 0.5 % citric acid and
12.5 % ISML solution and a final water rinse
B
Wipe containing 10 mL of 0.25 % citric acid and
18.75 % ISML solution with a final water rinse
C Protocol B but without a final water rinse
D
Protocol B but with use of a second wipe prior to
rinsing with water
E
Use of a wipe wetted with water only, followed by a
water rinse
T
Protocol B followed by a second citric acid/ISML
wipe, but with no water rinse
S&W Soap and water hand washing
ESSWEIN ET AL. ON DECONTAMINATING SKIN FROM LEAD 5

replicates of five.
As shown in Fig. 3, Protocols A and B 共using two different concentrations of citric acid and ISML兲
were essentially equally effective at removing lead from skin, with ⬇15 ␮g Pb of an initial 3000 ␮gPb
load measured on the hands after cleansing in this manner. With Protocol C, 共same as A&B but without a
water rinse兲about 100 ␮g Pb remained on the hands, indicating that a final water rinse is recommended
for removal of solubilized lead. Protocol D 共use of a second citrate/ISML creped wipe兲illustrates that use
of a second citric acid and ISML treated wipe removes almost all lead, with only 2.5 ␮g Pb remaining on
skin. Use of a second wipe but without a final water rinse 共Protocol T兲indicates that lead removal is
effective 共⬇35 ␮g Pb remains after the cleansing protocol兲. Protocol T could be used in remote locations
where water for rinsing is not available.
In contrast to each of the protocols involving one or more citrate/ISML wipes, the use of a wetted,
creped wipe with no surfactant or citric acid 共i.e., Protocol E兲was less effective for lead removal from
skin, with nearly 200 ␮g Pb remaining 共see Fig. 3兲indicating that the mechanical action of the creped
wipe has an effect in dislodging lead from skin. Use of common industrial hand soap and water as cleaning
agents 共S&W兲resulted in over 250 ␮g Pb remaining on the hands thereby demonstrating the relative
ineffectiveness of this widely used method for lead removal from dermal surfaces.
The efficacy of lead removal using textured creped wipes containing citric acid and ISML was com-
pared side-by-side with other commercial products in described in Fig. 4. In this set of experiments,
Dupont Sontara™ creped by Micrex®共20 cm⫻20 cm兲were fortified with 10 mL of aqueous solution
containing 0.5 % citric acid and 12.5 % ISML. Fourteen volunteer’s hands were spiked with 3000 ␮g
leaded dust prior to cleansing. Commercial products tested included those listed in Table 2. These com-
parison products were selected as among the most widely used on the commercial market for lead and
other heavy metal decontamination. The scrubbers in some of these products may consist of ground walnut
shells, plastic beads, or crystalline silica 共comparable to the consistency of beach sand兲.
The citric acid/ISML wipe 共Cleanser A兲provided statistically significant superior lead cleansing from
human hands when compared to Cleansers F, U, N, H, and G 共cleansers listed in Table 2兲. The citric
acid/ISML wipe also removed more lead from skin than did Cleanser I 共16 ␮g Pb versus 27 ␮gPb
remaining on hands: Fig. 3兲, but this difference was not statistically significant. It is noted that scrubbers
contained in some of the commercial products may irritate the skin with repeated use 关32兴.
As a follow-on to the previous investigations, a blind comparison between citric acid/ISML wipes and
representative liquid cleansers was also conducted using another fourteen volunteer participants. In this
investigation, the participants were not informed of the identities of the test products. Each subject was
provided with a randomly selected cleanser, and each product was used twice by each participant. As in
previous trials, volunteers’ hands were spiked with 3000 ␮g Pb leaded dust prior to cleansing. The liquid
FIG. 3—Amount of lead (in
␮
g) remaining on human hands after cleansing protocols involving one or
more citrate/ISML wipes, as described in Protocols A, B, C, D and T; or a wipe wetted only with water
(Protocol E); or hand washing with soap and water (S&W). 95 % confidence limits are shown
共
n
⫽
5
兲
. (See
text and Table 1 for description).
6 JOURNAL OF ASTM INTERNATIONAL

cleansers that were compared to the citric acid/ISML wipe 共Cleanser A兲included: 1. D-Lead®liquid soap
without scrubbers 共Cleanser B兲; 2. Clean-All Heavy Metal™ liquid soap 共Cleanser C兲; and 3. Ivory®liquid
soap 共Cleanser D兲. In carrying out these tests, 2 mL of each of the liquid soaps were applied to the palms.
The results from these comparisons are shown in Fig. 5. It is demonstrated that the citric acid/ISML
wipe system removed more lead from the hands than each of the other products; these results are statis-
tically significant. One of the products advertised to be effective for removal of lead as well as other toxic
metals 共Clean-All Heavy Metal Soap™兲in fact did not decontaminate hands any better than 共the non-
industrial兲Ivory®liquid soap.
In a final evaluation, the efficacy of lead removal using straight, lead-acid battery plant dust 共as 99 %
PbO兲, of a licensed, converted 共commercially manufactured and packaged兲, Beta version of the invention
was evaluated using nine volunteers. Results from these experiments are summarized in Table 3. The
spiking, sampling, and decontamination investigative protocol was similar to the previous investigations
but Palintest™, rather than Ghost Wipes™ were used for skin sampling. Differences in sampling effi-
ciency using Ghost Wipes™ and Palintest™ brand wipes has been investigated and no significant sample
collection efficiency differences were found 关37兴. Not unexpectedly, all background handwipe samples
revealed some lead, likely from handling lead-containing brass keys, or touching other brass/lead contain-
ing environmental surfaces. Dermal lead concentrations ranged from trace levels 共detectable but not
quantifiable兲to 2.6 ␮g Pb/handwipe. An average of 670 ␮g of lead was recovered in surface wipe
samples from the wax paper suggesting the application technique varied considerably in the successful
loading of lead dust onto the skin. The average calculated amount of Pb applied to the skin was
⬇2,300 ␮g. Calculated percent removal for pre-commercial lot 0807 ranged from 99.7 to 99.9 %, indi-
cating that the MEDTOX™ Wipe 共which uses a slightly different but highly textured wipe material from
FIG. 4—Amount of lead remaining on hands following 3000
␮
g Pb initial loading and after cleaning with
a citric acid/ISML wipe (Cleanser A) and various commercially available industrial hand cleansers
(Cleansers F, U, N, H, I and G), as described in text and Table 2; n
⫽
5 for each cleanser method.
TABLE 2—Cleansing products tested in comparison study with treated, textured wipes containing citric
acid and ISML.
Cleanser Product Description
A
Wipe containing 10 mL of 0.5 % citric acid and
12.5 % ISML solution
F Clean-All Heavy Metal Soap
G Kresto Kwik Wipes
H Kresto Select with scrubber
I GoJo Multigreen with scrubbers
N D-Lead with scrubbers
U D-Lead without scrubbers
ESSWEIN ET AL. ON DECONTAMINATING SKIN FROM LEAD 7

that supplied to NIOSH by Micrex®兲was as effective as the original citric acid/ISML creped wipes
evaluated previously 共creped DuPont™ Sontara®wipe material supplied by Micrex®兲. Similar experiments
using Hygenall®brand licensed and commercialized wipes have also demonstrated 99.2 % lead removal
efficiency with five trials using 6,000 ␮g palmer skin loadings and of straight PbO 共99 %兲from a
lead-acid battery plant.
Conclusion
A novel and highly effective method for removing toxic metals 共notably lead兲from skin has been con-
ceived, developed, evaluated, patented and licensed from the government to the private sector. The tech-
nology consists of a three-dimensionally textured absorbent wipe treated with proportions of a cationic
surfactant 共ISML兲and a weak organic acid 共citric acid兲. Published research has shown that the method
does not damage the skin 关6兴. The technology design criteria involved developing a system of metal
removal incorporating contributing effects of surfaction, chelation, pH adjustment and mechanical re-
moval. This technology was developed to complement a previous NIOSH invention involving colorimetric
chemistry that detects lead collected from skin and workplace surfaces. Used serially, the two technologies
are envisioned to “close the loop” on detection and decontamination of skin contaminated with lead.
Decontamination of workers’ skin should improve with the use of this technology and the commercial
FIG. 5—Amount of a 3000
␮
g Pb initial load remaining on the hands of 14 blinded study participants
after using a citric acid/ISML wipe (“Cleanser A”), D-Lead liquid soap without scrubbers (“Cleanser
B”), Clean-All liquid soap (“Cleanser C”), or Ivory liquid soap (“Cleanser D”).
TABLE 3—Lead dust removal efficacy (hands) from a pre-commercial lot of textured citric acid/IMSL wipes.
Volunteer No.
Background
Handwipe Pb
共␮g兲
Initially Weighed
Pb Amount
共␮g;asPbO兲
Pb 共␮g兲
Recovered from
Wax Paper
Calculated Pb Mass 共␮g兲
Applied to Hands
Final Pb 共␮g兲
Collected After 2
Serial Handwipes
Calculated %
Pb Removeda
1 2.5 2868 830 2038 4.6 99.7
2 0.31b2978 310 2668 6.6 99.7
3 2.0 3238 1500 1738 2.1 99.8
4 2.5 2830 660 2170 2.7 99.8
5 0.65b3146 270 2876 3.3 99.8
6 2.6 2960 600 2360 1.8 99.9
7 0.77b3006 790 2216 1.9 99.9
8 1.2 2997 470 2527 1.6 99.9
9 0.71b3053 600 2453 3.5 99.8
aAccounts for initial hand contamination measured 共background兲and losses onto wax paper that occurred during loading of lead oxide dust onto
hands.
bEstimated amount: Above detection limit but below quantitation limit.
8 JOURNAL OF ASTM INTERNATIONAL

versions of these wipes, which have been shown to be more effective than hand washing using soap and
water.
Acknowledgments
The authors would like to thank Ms. Tami Wise, NIOSH, DART for her expert assistance in preparation of
a proportion of the treated wipes used in this study, and careful weighing of lead dust samples. The authors
also thank Dr. Cynthia A.F. Striley, NIOSH, DART, for her assistance with resolution of graphics used in
the manuscript. The authors also thank the volunteers who agreed to participate in this study. Finally, the
authors thank Mr. Richard Walton of Micrex Corporation for donating creped wipe material and for
consistently generous and wise council regarding all things webbed, creped and converted.
References
关1兴US Agency for Toxic Substances and Disease Registry 共ATSDR兲,Toxicological Profile for Lead,
ATSDR, Atlanta, GA, 2007.
关2兴Sussell, A., Ed., “Protecting Workers Exposed to Lead-Based Paint Hazards: A Report to Congress,”
DHHS (NIOSH) Publ. No. 98-112, CDC/NIOSH, Cincinnati, OH, 1997.
关3兴Weber, A., Ed., “Health Hazard Evaluations: Issues Related to Occupational Exposure to Lead,
1994–1999,” DHHS (NIOSH) Publ. No. 2001–113, CDC/NIOSH, Cincinnati, OH, 2001.
关4兴Whelan, E. A., Piacitelli, G. M., Gerwel, B., Schnorr, T. M., Mueller, C. A., Gittleman, J., and Matte,
T. D., “Elevated Blood Lead Levels in Children of Construction Workers,” Am. J. Public Health, Vol.
87, 1997, pp. 1352–1355.
关5兴Stauber, J. L., Florence, T. M., Gulson, B., and Dale, L., “Percutaneous Absorption of Inorganic Lead
Compounds,” Sci. Total Environ., Vol. 145, 1994, pp. 55–70.
关6兴Filon, F. L., Boeniger, M., Maina, G., Adami, G., Spinelli, P., and Damian, A., “Skin Absorption of
Inorganic Lead 共PbO兲and the Effect of Skin Cleansers,” J. Occup. Environ. Med., Vol. 48, 2006, pp.
692–699.
关7兴Sun, C.-C., Wong, T.-T., Hwang, Y.-H., Chao, K.-Y., Jee, S.-H., and Wang, J.-D., 2002, “Percute-
anous Absorbtion of Inorganic Lead Compounds,” Am. Ind. Hyg. Assoc. J., Vol. 63, pp. 641–646.
关8兴Esswein, E. and Boeniger, M., “Preventing the Toxic Hand-Off,” Occup. Hazards, Vol. 67, 2005, pp.
53–61.
关9兴Far, H. S., Pin, N. T., and Kong, C. Y., “An Evaluation of the Significance of Mouth and Hand
Contamination for Lead Absorption in Lead Acid Battery Plant Workers,” Int. Arch. Occup. Environ.
Health, Vol. 64, 1993, pp. 439–443.
关10兴Piacitelli, G. M., Whelan, E. A., Sieber, W. K., and Gerwel, B., “Elevated Lead Contamination in
Homes of Construction Workers,” Am. Ind. Hyg. Assoc. J., Vol. 58, 1997, pp. 447–454.
关11兴Hostynek, J., “Factors Determining Percutaneous Metal Absorption,” Food Chem. Toxicol., Vol. 41,
2003, pp. 327–345.
关12兴Hostýnek, J., Hinz, R. S., Lorence, C. R., Price, M., and Guy, R. H., “Metals and the Skin,” Crit. Rev.
Toxicol., Vol. 23共2兲, 1993, pp. 171–235.
关13兴Esswein, E. J. and Tepper, A., NIOSH Health Hazard Evaluation Report No. 91-0366-2453, Dela-
ware County Resource Recovery Facility, Chester, PA. CDC/NIOSH, Cincinnati, Ohio, 1991.
关14兴Esswein, E. J. and Boeniger, M. F., NIOSH Health Hazard Evaluation Report No. 94-0268-2618,
Standard Industries, San Antonio, TX, CDC/NIOSH, Cincinnati, OH, 1996.
关15兴Durgam, S., Aristeguieta, C., and Achutan, C., NIOSH Health Hazard Evaluation Report No. 2007-
0201-3086, Sanmina-SCI®Corporation, CDC/NIOSH, Huntsville, AL, 2009.
关16兴Mattorano, D., NIOSH Health Hazard Evaluation Report No. 94-0273-2556, Bruce Mansfield Power
Station, Shippingport, PA, CDC/NIOSH, Cincinnati, OH, 1996.
关17兴Chavalitnitikul, C., Levin, L., and Chen, Lung-Chi, “Study and Models of Total Lead Exposures of
Battery Workers,” Am. Ind. Hyg. Assoc. J., Vol. 45, 1984, pp. 802–808.
关18兴Chuang, H.-Y., Lee, M.-L T., Chao, K.-Y., Wang, J.-D., and Hu, H., “Relationship of Blood Lead
Levels to Personal Hygiene Habits in Lead Battery Workers: Taiwan, 1991–1997,” Am. J. Ind. Med.,
Vol. 35, 1999, pp. 595–603.
ESSWEIN ET AL. ON DECONTAMINATING SKIN FROM LEAD 9

关19兴Hipkins, K. L., Materna, B. L., Payne, S. F., and Kirsch, L. C., “Family Lead Poisoning Associated
with Occupational Exposure,” Clin. Pediatr. (Phila.), Vol. 43, 2004, pp. 845–849.
关20兴Esswein, E. J., Boeniger, M. F., and Ashley, K., “Handwipe Disclosing Method for Lead,” U.S.
Patent No. 6,248,593 共2001兲.
关21兴Ashley, K., “Field-Portable Methods for Monitoring Occupational Exposures to Metals,” J. Chem.
Health Saf., Vol. 17, 2010, pp. 22–28.
关22兴2003 U.S. National Institute for Occupational Safety and Health 共NIOSH兲, Lead in Dust Wipes by
Chemical Spot Test Method, 共Colorimetric Screening Method兲9105, NIOSH Manual of Analytical
Methods, CDC/NIOSH, Cincinnati, OH, www.cdc.gov/niosh/nmam 共Last accessed 20 Sept. 2010兲.
关23兴Askin, D. P. and Volkmann, M., “Effect of Personal Hygiene on Blood Lead Levels of Workers at a
Lead Processing Facility,” Am. Ind. Hyg. Assoc. J., Vol. 58, 1997, pp. 752–753.
关24兴Kornecki, T. S., Brown, G. O., Allred, B., and Basta, N., “Cationic Surfactant Feasibility for Use in
Removal of Lead from Soil,” Envir. Geosciences, Vol. 5, 1998, pp. 29–38.
关25兴Kornecki, T. S., Brown, G. O., and Allred, B., “Saturated Column Feasibility Study Using Cationic
Surfactants for In Situ Removal of Lead from Soil,” Envir. Geosciences, Vol. 6共1兲, 1999, pp. 42–52.
关26兴Froebe, C., Simion, F., Rhein, L., Cagan, R., and Kligman, A., “Stratum Corneum Lipid Removal by
Surfactants: Relation to In Vivo Irritation,” Dermatologica, Vol. 181, 1990, pp. 277–283.
关27兴Schleupein, R. and Ross, L., “Effects of Surfactants and Solvents on the Permeability of the Epider-
mis,” J. Soc. Cosmet. Chem. Vol. 21, 1970, pp. 853–857.
关28兴2010 Esca Tech Inc., D-Wipe®, Esca Tech, Milwaukee, WI, www.esca-tech.com 共Last accessed 14
Aug. 2010兲.
关29兴Mallinkrodt Baker Inc., Material Safety Data Sheet (MSDS): EDTA Disodium Salt, Mallinkrodt
Baker, Phillipsburg, NJ, 2009.
关30兴Frankild, S., Andersen, K., and Nielsen, G., “Effect of Sodium Laurel Sulfate on In Vitro Percuta-
neous Absorption of Water, Hydrocortisone and Nickel,” Contact Dermatitis, Vol. 32, 1995, pp.
338–345.
关31兴Esswein, E. J., Boeniger, M. F., and Ashley, K., “Wipes and Methods for Removal of Metal Con-
tamination from Surfaces,” US Patent No. 7,604,997 共2009兲.
关32兴Klotz, A., Veeger, M., and Röcher, W., “Skin Cleansers for Occupational Use: Testing the Skin
Compatibility of Different Formulations,” Int. Arch. Occup. Environ. Health, Vol. 76, 2003, pp.
367–373.
关33兴2003, ASTM E 1792, “Standard Specification for Wipe Sampling Materials for Lead in Surface Dust,
ASTM International, West Conshohocken, PA.
关34兴U.S. National Institute for Occupational Safety and Health 共NIOSH兲, “Development and Evaluation
of a Novel Skin Cleansing System for Removing Lead and Other Toxic Inorganics,” HSRB 04-
DSHEFS-01XP, CDC/NIOSH, Cincinnati, OH, 2004.
关35兴U.S. National Institute for Occupational Safety and Health 共NIOSH兲, “Lead in Dust Wipes by
Chemical Spot Test Method, 共Colorimetric Screening Method兲9105,” NIOSH Manual of Analytical
Methods, CDC/NIOSH, Cincinnati, OH, 2003, www.cdc.gov/niosh/nmam 共Last accessed 20 Sept.
2010兲.
关36兴ASTM E1613-04, 2004, “Standard Test Method for Determination of Lead by Inductively Coupled
Plasma Atomic Emission Spectrometry 共ICP-AES兲, Flame Atomic Absorption Spectrometry 共FAAS兲,
or Graphite Furnace Atomic Absorption Spectrometry 共GFAAS兲Techniques,” Annual Book of
ASTM Standards, Vol. 04.11, ASTM International, West Conshohocken, PA.
关37兴Boeniger, M., “A Comparison of Surface Wipe Media for Sampling Lead on Hands,” J. Occup.
Environ. Hyg., Vol. 3, 2006, pp. 428–434.
10 JOURNAL OF ASTM INTERNATIONAL