Journal of Environmental Protection, 2011, 2, 379-386
doi: 10.4236/jep.2011.24042 Published Online June 2011 (http://www.SciRP.org/journal/jep)
379
Preliminary Risk Assessment Posed by
Formaldehyde Residues in Clothing to Vietnamese
Consumers
Van Nam Thai, Akihiro Tokai
Osaka University, Division of Sustainable Energy and Environmental Engineering, Osaka, Japan.
Received January 19th, 2011; revised February 26th, 2011; accepted April 6th, 2011.
ABSTRACT
The assessment of potential health risks posed by formaldehyde in clothing to consumers is of increasing concern
worldwide. Because of this, it is necessary to develop an exposure model that can realistically mimic clothes wearing
conditions. This study aims to preliminarily develop a health risk assessment model for formaldehyde in clothing, and
then to assess the potential health risk posed by formaldehyde in textiles to adults and infants in Vietnam using the
model. Finally, this study aims to exam ine the plausibility of the adopted permissible values for fo rmaldehyde in cloth-
ing in Vietnam. In the model, two exposure factors for dermal exposure and overall exposure routes, i.e. sweat type and
perspiration area, were considered. The margins of exposure (MOE) were calculated to estimate the health risks from
worst case and average exposures. The assessment shows that acute exposure via inhalation can pose health risks to
Vietnamese consumers in both cases. In regards to chronic exposure, dermal exposure is about four (for infants) and
seven (for adults) times higher than exposure via inha lation, but no risks were found for averag e exposure . If a MOE of
100 is defined as ‘safe’ used, dermal and total chronic exposure to worst case cause potential risks, whereas no health
risks were found for exposure to average case. With the model, the adopted Vietnamese permissible values for forma l-
dehyde in clothing were assessed as not posing a health risk to Vietnamese consumers, hence they are accepted.
Keywords: Formaldehyde, Health Risk, Exposure Model, Clothing, Vietnamese Consumers
1. Introduction
In 2004, the International Agency for Research on Can-
cer (IARC) classified formaldehyde as a human carcino-
gen [1] as well as highly toxic, and irritating. Subsequent
to this classification, the first serious exposure event oc-
curred in New Zealand (2007) [2 ] from Chinese imports.
Many countries then carried out analytical studies of
formaldehyde in clothes and set limits, e.g. the European
Union (EU) (2007) [3], Australia (2007), Netherlands
(2008), the US (2008) [4], and the US (2010) [5]. Thus,
formaldehyde residue in clothing has become a hot issue
for imported textiles.
China Daily (2009) reported that 46.5% of clothing
produced in Guangdong provin ce, the most indu strialized
province in China, which exports clothing to Vietnam,
exceeded the permissible levels of formaldehyde in tex-
tiles. To control this substance in imported clothing and
textiles (mainly from China, 36.6% of total imports)
(Vietnam Statistics Office, 2009), the Vietnam Ministry
of Industry and Trade (MOIT) issued a contemporary
regulation for formaldehyde limits [6]. However, there
has been no demonstrated research in terms of risk as-
sessments of Vietnamese consumer’s health when using
such contaminated textiles. In addition, although the
adopted permissible values, based on those of the EU
Flower Label and Oeko-tex 100, are appropriate to ex-
port textiles, the question ‘Are they suitab le for domestic
consumers?’ should be quantitatively answered in terms
of scientific grounds. Therefore, it is necessary to create
a model to identify any health risks to Vietnamese con-
sumers and to check the plausibility of the adopted val-
ues.
Some recent studies on formaldehyde in clothing have
focused on measuring formaldehyde in clothes (both free
and extracted partly through hydrolysis), and then com-
paring these measurements with standard values [2,5,7].
Others have extensively studied the human health risk
assessment from dermal exposure, but there is little in-
formation concerning the exposure via inhalation. In gen-

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers 380
eral, these studies have not considered certain factors that
could influence formaldehyde transfer from clothes into
human body, e.g. sweat type [3] or specific contact areas
such as respiration zones [8]. The EU Federal In-stitute
for Risk Assessment also states that a more realistic es-
timate of exposure should be developed to include these
two factors [9]. Therefore, a developed model for human
health risk assessment, not only for formaldehyde resi-
dues but also for other hazardous substances (such as
heavy metals and dyestuffs) clothing needs to be devel-
oped.
In this context, this study aims to (1) develop a health
risk assessment model for formaldehyde in clothing that
integrates dermal and inhalation exposure and incorpo-
rates the factors of sweat type and specific contact areas,
(2) assess the potential consumer health risk of formal-
dehyde in imported tex tiles, which are stipulated to com-
ply with the regulation issued by MOIT [6] and (3) ex-
amine the plausibility of the ad opted Vietnamese permis-
sible values for formaldehyde in clothing for infants and
adults. To do this, a model with th e two factors based on
typical characteristics of Vietnamese consumers is first
proposed. This model is then applied in assessing the
health risk of formaldehyde in imported clothing to
Vietnamese consumers and by examining the p lausibility
of the adopted permissible values of formaldehyde in
clothing.
2. Methods
2.1. Framework
Formaldehyde in clothing poses two key health risks: (1)
dermal exposure resulting in allergic contact dermatitis;
and (2) chronic inhalation exposure, which may cause
cancer [5,10]. The method proposed in both the European
Technical Guidance Document on Risk Assessment [11]
and the Human and Environmental Risk Assessment
(HERA) Guidance Document [12], which assumes a
percent weight fraction of a chemical being transferred
from clothing and absorbed into the skin via dermal ex-
posure, has primarily been used for the estimation of
total exposure. For exposure via inhalation, the exposure
concentration was limited to the maximum amount ac-
cording to the ideal gas law. Because of a lack of avail-
able relevant data, many studies relied on single-point
estimates for the exposure term using average case, worst
case or maximum legal values.
In this study, exposure is calculated as a total body
dose including dermal and inhalation exposure for dif-
ferent users (infants and adults). Such exposures were
then modelled using worst case and average case. The
average and worst cases are similar in all respects except
for the concentration levels of formaldehyde in clothing.
The model differs from the previous research in two re-
spects: (1) it includes the factors of sweat type and spe-
cific contact area (respiration zones) for dermal exposure
and (2) it is designed for assessing the health risks to
Vietnamese consumers. Sweat types and specific contact
areas can influence the weight faction of formaldehyde
that is transferred and absorbed into skin [9]. For esti-
mating health risks, margins of exposure (MOE), the
ratio of no observed adverse effect level (NOAEL) to the
actual exposure, selected from previous dose-response
assessment bioassays and exposure concentrations were
calculated for individual routes and for the total of all
routes. Figure 1 schematically shows the framework in
detail. In addition, we also assessed the health risk to th e
maximum permissible legal values for formaldehyde for
adults and infants using the proposed model.
2.2. Data Collection
When the Directive of Formaldehyde Limits in Imported
Textiles was promulgated, from November, 2009 to
January, 2010 there were 16 instances of formaldehyde
exceeding the limit out of 800 batches sampled. They
were mainly exports from China [13]. Formaldehyde is
analysed after extraction from clothing by water. Table 1
shows the concentration of formaldehyde in water, Cwater,
for 16 samples that exceeded the limit. These values
were obtained from the Cen tre for Stand ard s, Qu ality an d
MeasurementsBranch 3 in Ho Chi Minh (HCM) City
commissioned by the Ministry of Industry and Trade
Figure 1. Risk assessment for exposure to formaldehyde in clothing for consumer’s health (*Worst case and average point
estimates for two exposure routes).

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers381
Table 1. Analytical data for formaldehyde in imported textiles (mg/kg fabrics).
Nov., Dec., 2009 Jan., 2010 No
Sample Value (Cwate r )
No
Sample Value (Cwate r )
1 F27 2,619 11 F623 812
2 F38 750 12 F690 1,337
3 F65 3,517 13 F699 463
4 F96 384 14 F728 784
5 F99 2,035 15 F747 359
6 F113 806 16 F791 982
7 F357 1,334 Formaldehyde limits in textiles [6]
8 F389 872 Infant (<3 year-old) 30
9 F487 397 Direct contact 75
10 F539 537 Indirect contact 300
Mean = 1,124; Max value = 3 ,517; SD = 889 with the 95% confidence interval being  474. Accordingly, formaldehyde concentration = 1,124  474 (mg/kg
textile).
with the support of a recommendation letter from the
HCM Environmental Protection Ag ency.
2.3. Exposure Scenarios
To approach the three purposes described in the intro-
duction, a health risk assessment model for dermal and
inhalation exposure was first devised. The calculations of
the estimated exposures were performed twice: once
based on the highest relevant concentrations (i.e. the
worst case) and once based on average concentrations
(average case) that consumers could be exposed to. Con-
siderations of the individual exposure routes and their
respective concentration s, i.e. skin exposur e (Expskin) and
inhalation exposure (Expinhalation), led to the expression
for the overall exposure (Exptotal) shown in Equation (1):
totalskin inhalation
ExpExp Exp (1)
2.3.1. Skin Exposure
Consumers can be directly exposed to formaldehyde
dermally by wearing clothing processed with it (perma-
nent press fabrics or anti-wrinkle/crease fabrics). Equa-
tion (2), based on the HERA Guidance Document [12],
but modified to suit exposure is as follows. (The HERA
Guidance Document proposed an exposure model for
esterquats, fabric conditioners, that remain in clothes
washed and softened with such substances, but not for-
maldehyde).
12skin
ExpCSFDFFNBW  (2)
where
Expskin.:dermal (skin) systemic consumer exposure
(mg/kg of bod y weig ht/ day )
C: formaldehyde concentration in clothing (mg/kg tex-
tile) (also called Cwater in this paper)
S: surface area of exposed skin (m2)
FD: fabric density (g/m2)
F1: percent weight fraction of formaldehyde trans-
ferred from clothing to skin (migration ratio) (%)
F2: percent weight fraction of formaldehyde absorbed
by the skin (penetration ratio ) (%)
N: exposure frequency (day1)
BW: body weight (kg)
2.3.1.1. Parameter Estimations
C (mg/kg) was assigned average and maximum values
(worst case) from the measured formaldehyde concentra-
tion in Table 1. The total body areas (S) for an adult an d
a child were assumed to be 18,150 cm2 and 6,700 cm2,
respectively [3]. The exposed area was taken to be 85%
of a person’s total body area [3], g iving Sadult = 15,430 cm2
and Schild = 5,695 cm2. Cotton and cotton/polyester
blended fabrics are the most predominant in Vietnam;
hence, the average FD (g/m2) was assigned to be 200 g/m2
[14]. The bases for the assessment of formaldehyde ex-
posure from clothing are the migration ratio (F1) and the
penetration ratio (F2). The value of F2 is determined by
the octanol water partition coefficient (Kow)1. Since
log(Kow) of formaldehyde is 0.35 [1], formaldehyde is
categorised as hydrophilic. Based on the HERA Guid-
ance Document [12]2, we selected F1 as being 100% and
F2 as being 5% in normal areas and 10% in high contact
1If a chemical has log (Kow) [3, 1), it is hydrophilic; [1, 4), rela-
tively hydrophobic and  [4, 7], very hydrophobic.
2Penetration ratios of hydrophilic textile auxiliaries are 5% and 10%
f
or normal and respiration zones, respectively.

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers 382
areas (perspiration areas) [9]. It was assumed that con-
sumers wear clothes for the entire day (N = 24 hours)3.
The standard BW of a 3-year-old child (BWchild) was
assumed to be 13.9 kg [15], while the average weight of
a Vietnamese adult (BWadult) was calculated as being
56.0kg. This latter calculation used the following algo-
rithm: BWadult (kg) = BMI × H2 (BMI: Body Mass Index,
average BMI = 22; H: the height of a Vietnamese adult,
average H = 1.59 m [16]).
2.3.1.2. Exp osure Factors
Temperature (t, ˚C) and humidity were assumed to be
constants with t being 25˚C. We excluded the pH of
washing water owning to unavailable data and high un-
certainty. Ryan et al. [17] stated that areas with high
contact with specific parts of the body (specific contact
areas or perspiration areas) are the most allergic to for-
maldehyde. The authors studied diagnosis of allergic
contact dermatitis from formaldehyde irritation and ob-
served that the common eruption sites, such as around
the neck, the lateral thorax, the flexor surfaces and the
waistband were those highly exposed to clothing. It was
concluded that these areas can influence the absorption
of formaldehyde into skin. To calculate the perspiration
areas we utilised into allergic contact dermatitis by Ryan
et al. above and the proportions of the skin surface iden-
tified by Mathieu [18]. Using these, perspiration areas
were estimated to be 30% of the total exposure area. The
penetration ratio in these areas was assigned the variable
F2 sweat.
As described previously formaldehyde is usually ex-
tracted by water (refer to Cwater shown in Table 1. How-
ever, according to research by the European Commission
[3], it is better to mimic the real extraction conditions in
which consumer sweat (either acid or basic) extracts the
formaldehyde than using water. The research shows that
formaldehyde concentrations after extraction by ba-
sic/acid sweat solution are on average 1.3 times higher
than those after extraction by a water solution. As a result,
a better estimate of concentrations of formaldehyde in
the F2 sweat area is Csweat =
 × Cwater (  = 0.8 - 2.5 with an
average of 1.3,
 = 2.5 in the worst case [3]). Using this,
Equation 2 can be written as follows:

22
1
0.7 0.3
s
kin watersweatsweat
ExpCS FCSF
FDFN BW


(3)
2.3.2. Inhalation Exposure
Exposure via inhalation is expressed as the concentration
of formaldehyde in the air in a breathing zone and is
given as an average concentration over a reference period.
The vapour immediately produces local irritation in mu-
cous membranes, including the eyes, nose and upper res-
piratory tract (acute exposure) [1,17] and recently it has
been reported that inhaled formaldehyde may cause can-
cer (from chronic exposure) [5]. Because buildings in
Vietnam commonly have minimal use of external win-
dows and openings, and poor natural and mechanical
ventilation [19], the ventilation of a given room is as-
sumed to be insufficient. It is also assumed that formal-
dehyde is released instan taneously to the entire roo m and
distributed homogenously. Equations (4)-(6) are based on
the European Technical Guidance Document on Risk
Assessment [11], modified to suit clothing contact and
were used to estimate formaldehyde entering the body
via inhalation. For the calculation of theoretical maxi-
mum concentration of formaldehyde in the air (Cvapour),
the ideal gas law was utilised (see Equation 6).
3inhalationinhair breathed
ExpCVFn BW

 (4)
clothing
inh vapourroom
Q
CC V  (5)
273
22.4 101325
a
vapour watera
P MW
CC TEM   (6)
where
Expinhalation: formaldehyde intake to the body via mu-
cous membranes (mg/kg of body weight/day)
Cinh: formaldehyde concentration in air at specific sites
(mg/m3)
Vair breathed : the volume of air that a person breathes per
day; 15 m3 for an adult, 6 m3 for a child [20]
F3: fraction of formaldehyde inhaled or respired (%)
(F3 = 100%) [10,21]
n: exposure frequency; according to the study by Shin
et al. [22] an adult stays indoor for 20 hours (13.7 hours
at home, 6.4 hours for working) while a child is also in a
room for 20 hours (8 hours at h ome, 12 hours at school).
Assuming that if they are outdoor, there is no effect by
inhalation of formaldehyde from clothing. Hence, nadult =
20/24 (day1) and nchild = 20/24 (day1).
BW: body weight (kg). BWchild = 13.9 kg and BWadult =
56 kg (see Section 2.3.1).
Qclothing = S × FD (kg); hence, Qclothing for adults and
children is 0.3 1 (k g) and 0. 1 1 (kg ), res pect i v el y .
Cvapour: concentration of formaldehyde vapours from
clothing at the examined temperature of 25˚C (mg/kg). It
is estimated from Cwater (the concentration of formalde-
hyde in clothing as shown in Table 1).
Vroom: the volume of a closed room in which people
stay/work; 30 m3 for an adult, 18 m3 for a child (m3) [8].
MW: molecular weight of formaldehyde (30.03 g/mole);
TEMa and Pa are the actual temperature in K and the va-
pour pressure in Pascals (3,466.4 Pa at 25˚C) f or formal-
dehyde, respec t ively [1].
3Actually, consumers can change their clothes, but it is as
s
umed that
S
and FD are constants.

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers 383
3. Results and Discussion
2.4. Acute and Chronic Exposures
Many people have a habit of wearing new clothing
without washing it first [23,24]. Accordingly, we distin-
guished between acute exposure while wearing new
clothes with a possibly higher migration rate and chronic
exposure during the whole course of usage. Based on
Equations (3) and (4), we first estimated acute exposure
by using the first migration data, and then undertook a
risk assessment of acute exposure and allergic reactions.
Chronic exposure depends on experimental tests using
si mulated wash, wear cycles, pH of detergents, etc, which
are not readily available. Hence, alternatively, to deter-
mine chronic exposure for the risk assessment of chronic
toxicity, the Danish Ministry of Environment [8] and the
EU Federal Institute for Risk Assessment [9] recommend
using a safety factor of one-tenth (1/10) of the acute ex-
posure estimates. This study concentrates on both acute
and chronic exposures.
3.1. Assessment of Human Health Risk from
Formaldehyde
From the monitored concentrations of formaldehyde
(Cwater), we estimated Csweat for dermal exposure and Cva-
pour for exposure via inha lation.
The results of the exposure calculations are given in
Table 2 for dermal, inhalation and total exposure. Der-
mal exposure is about four times (for infants) to seven
times (for adults) higher than exposure via inhalation,
meaning dermal exposure is the dominant route. This
result agrees with the existing medical literature, i.e. the
greatest concern for human health associated with for-
maldehyde in clothing is allergic contact dermatitis that
stems from dermal exposure [5].
It is apparent that the potential dermal exposure of a
child is higher than that of an adu lt owning to lower BW
of children. The results show that the average (and worst
case) dermal uptakes were 0.46 (2.13 worst case) and
0.68 (3.17 worst case) mg/kg bw/day for an adult and for
a child, respectively. These exposures are similar to those
in the worst case research by Ellebak et al. for Danish
consumers, i.e. 0.31 (adult) and 1.10 (child) mg/kg bw/day
[27] and slightly lower than those in a study for European
consumers (1.2 and 3.1 mg/kg bw/day, respect- tively, in
the worst case). However, the maximum dose of formal-
dehyde in imported clothing in Vietnam (3,517 mg/kg) is
very much higher than that in Europe (162.5 mg/kg).
This difference is because the research for Dan- ish and
European consumers used F2 = 100% owning to absence
of data, whereas we used F2 = 10% for perspire- tion
zones and 5% for other zones based on the latest discus-
sion for garment textiles of the EU Federal Institute for
Risk Assessment [9] and the fact that that the weights of
Vietnamese people are less than those of Europeans. Re-
garding exposure via inhalation, estimated formaldehyde
concentrations in the room sizes assumed are higher than
the recommended threshold li mit value (TLV) for indoor
conditions (0.15 mg/m3) [8] by three times in the average
case and ten times in the worst case. Rumchev et al. [28]
state that children exposed to a formaldehyde level of
60 gm3 are at increased risk of contracting asthma; in
contrast, the average inhalation exposure for children in
2.5. Preliminary Risk Assessment
As mentioned in the method section, MOEs can be used
to assess whether formaldehyde contained in clothing has
a potential adverse health effect when using such cloth-
ing. To do this, data on NOAEL has been selected from
available literature, where the focu s has typically been on
the skin’s ability to absorb formaldehyde and inhalation
of it through mucous membranes (via th e eyes, throat and
nose). In this study, the two lowest NOAELs were used,
namely NOAELoral (chronic) = 10 (mg/kg.day) established
on the basis of a 24-month oral toxicity study of total
exposure (including dermal and inhalation routes) and
NOAELinhalation (acute) = 1.3 (mg/m3) based on a 3-con-
secutive-day inhalation exposure [25]. The latter was
also considered because many studies show that the in-
halation of formaldehyde can immediately cause local
irritation in mucous membranes when consumers are in
contact with formaldehyde. By using MOEs it is possible
to assess the human health risk to consumers from for-
maldehyde in monitored clothing. The values of MOEs
are calculated by Equation7, i.e. MOEtotal = NOAELo-
ral/Exptotal while MOEinh = NOAELinhalation/Expinhalation
[26].
M
OENOAEL Exp (7)
Table 2. Worst case and average exposure estimates for users via each route and as a total.
Route Inhalation (mg/m3) Inhalation (mg/kg/day)1 Dermal (mg/kg/day)2 Total (mg/kg/day)1 + 2
User Adult Child Adult Child Adult Child Adult Child
Average 0.49  0.21 0.29  0.12 0.11  0.05 0.10  0.04 0.46  0.19 0.68  0.29 0.57  0.24 0.78  0.33
Worst case 1.53 0.90 0.34 0.32 2.13 3.17 2.47 3.49
Values in this table are acute exposures. Chronic exposures are estimated to be one-tenth of acute exposures

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers 384
this study for children was about 290 gm3, five times
higher than the level suggested by Rumchev.
With respect to chronic exposure, almost all exposure
routes and users have MOEs much larger than 1, even for
the worst cases. Most exposure is again via the dermal
route. For acute exposure, e.g. consumers wearing new
clothes without washing, after ironing or hot washing
(which can generate free formaldehyde from formalde-
hyde carriers), MOEs are around 1, suggesting potential
health risks, e.g. histopathological effects or increased
cell proliferation in the nasal cavity. Since formaldehyde
is highly absorbed in the respiratory and gastro-intestinal
tracts [29], acute exposure via inhalation plays an impor-
tant role in assessing the health risk of formaldehyde. To
reduce the risk of acute inhalation exposure, washing
new clothes (which results in a 90% decrease in formal-
dehyde levels after one wash and a further decrease to
5% of original levels after several washes [30] and/or
living in a well-ventilated room [22 ,28,31] are two of the
best solutions that past studies have demonstrated. For
chronic exposure, some studies report that while formal-
dehyde levels may decline initially after washing, the
levels may start increasing again after multiple washes.
This can be explained by noting that during washing and
ironing, resins fixed on clothes are broken down, be-
coming more ingrained in th e fabrics [5]. This underpins
the assumption that one is exposed to formaldehyde
dermally and via vapours in the room during the long-
term exposure.
Average and worst case exposure approaches such as
those in this research are often used for the screening of
risk. Estimated MOEs are only a rough guide for assess-
ing the health risks of formaldehyde. It has to be taken
into account that exposure levels obtained from such
approaches might be 10 to 100 lower than the actual ex-
posure, i.e. the MOEs estimated in th is research might be
10 - 100 higher than they actually are [32,33]. A MOE of
100 is considered for defining a safe level in risk as-
sessment [34] because of inter- and intra-specie varia-
tions or any inherent uncertainty in databases. If a MOE
of 100 is considered as ‘safe’, then one can examine Ta-
ble 3 and see that for chronic exposure via inhalation,
even in the worst case, and chronic dermal exposure in
average cases poses no potential risks. However, the fur-
ther research on the accumulation of formaldehyde in the
human body should be considered to understand when
formaldehyde could cause potential health risk. On the
other hand, especially for the worst cases of dermal and
total exposure, they are potential health risks. In short,
the clothing examined in this study could cause local
irritation in mucous membranes, including the eyes, nose
and upper respiratory tract (owning to acute exposure via
inhalation), and create health risks for Vietnamese con-
sumers with chronic dermal exposure to the worst case
concentrations.
The advantage of the proposed model is that two fac-
tors, perspiration zones and the sweat type, which were
not modelled in the previous studies, are included. Fur-
thermore, the model deals with the penetration ratio
based on latest studies. In addition, the model combines
two exposure routes (inhalation and dermal exposure),
whereas past research in the EU, New Zealand and
Denmark only considered dermal exposure. However,
the research presented on this pape r has so me li mitation s :
(1) it only uses point estimates and (2) it assesses health
risks associated with imported clothing only. The former
should be replaced by probabilistic estimates where suf-
ficient information is available and the latter by domes-
tically made clothes. With such enhancements, a more
detailed and comprehensive picture of the health risk
associated with formaldehyde in clothing could be made.
However, since this study is the first study in terms of
health risk of household produ cts in Vietnam, the lack of
relevant data has limited this research.
The validity of the proposed model comes from the
fact that it is based on exposure models for health risk
assessment developed by the European Commission (EC,
2003). The latest research by the EC on the release of
formaldehyde from textiles [3] concludes that it would be
better to mimic real textile usage conditions b y replacing
the present water extraction analysis of formaldehyde
with a modified method using artificial perspiration solu-
tions. This was the reason that we changed Cwater to Csweat
for the perspiration zones, thereby describing more real-
istic conditions. We also based the model on the latest
dermatological studies [17,18] to identify the perspiration
zones where there is a high risk of irritation caused by
formaldehyde. The usage of a more acute penetration
ratio (F2) and inhalable ratio (F3)—as compared to past
research is also appropriate, as exposure studies state that
close to 100% of formaldehyde is readily absorbed in the
respiratory and gastro-intestinal tracts while dermal ab-
sorption of formaldehyde appears to be less [29].
3.2. Plausibility of Adopted Legal Values of
Formaldehyde
The third purpose of this study is to examine the plausi-
bility of the adopted Vietnamese permissible values for
formaldehyde exposure for adults and children. They are
set in terms of maximum legal values, being Cchild = 30
and Cadult = 75 (mg/kg textile) [6] (for comparison to ac-
tual values, see Table 1). Exposure estimates and MOE
values derived from the maximum legal permissible
concentration are shown in Table 4.
The results in Table 4 show that there should be no
health problems connected with chronic exposure to the

Preliminary Risk Assessment Posed by Fo rmaldehyde Resid ues in Clothing to Vietnamese Consumers385
Table 3. MOEs based on worst case and average exposure estimates by each route and as a total of all routes.
Route Inhalation (acute) Inhalation (chronic) Dermal (chronic) Total (chronic)
User Adult Child Adult Child Adult Child Adult Child
Average 2.6 4.5 909 1,000 217 147 175 128
Worst case 0.85 1.4 294 312 47 32 40 29
MOE = NOAEL/Intake (exposure)
Table 4. Exposure estimates (chronic) and MOE values based on maximum legal values.
Exposure (mg/kg.day) or concentration (mg/m3) MOE
User Inhalationacute Inhalation Dermal Total Inhalationacute Inhalation Dermal Total
Adult 0.03 0.007 0.046 0.053 43 14,286 2,174 1,887
Child 0.01 0.003 0.027 0.030 130 33,333 3,704 3,333
MOE = NOAEL/Intake (exposure); Inhalationacute (mg/m3)
maximum permissible legal concentrations, as the MOEs
are far greater than 100. Furthermore, the corresponding
legal maximum formaldehyde concentrations for adults
and children are 0.03 and 0.01 mg/m3, respectively for
acute inhalation, which are 5 and 15 times below the
TLV of 0.15 mg/m3, respectively. In other words, the
adopted permissible values of formaldehyde in clothing
for Vietnamese consumers are justified.
It should be remembered, however, that formaldehyde
can be found in numerous consumer products besides
clothing, for example, other textiles such as carpet and
curtain, disinfectants, pressed wood, paper, etc. Formal-
dehyde vapours can be given off by any of these products,
and therefore it is necessary to assess and establish total
permissible formaldehyde exposure levels. In this context,
the permissible level of formaldehyde vapours from
clothing would be less than the present values. For exam-
ple, Japan has the most stringent limits on formaldehyde
in infant clothing, i.e. 20 mg/kg textile [4]. The propo sed
model could be adapted to include the contributions of all
major sources of formaldehyde and establish new limits
in Vietnam.
4. Conclusions and Implications
This study serves as a preliminary risk assessment to
Vietnamese consumers from formaldehyde in clothing.
The proposed model could be applied to assess the health
risk from other chemicals in clothing as well, such as
dyestuffs and heavy metals if the relevant data is avail-
able.
The assessment of risks caused by formaldehyde in
imported clothing carried out by using the model shows
that the potential risk of overall chronic exposure stems
mainly from the dermal route. For average exposure, the
chronic total exposure (inhalation and dermal exposure)
does not pose a risk to Vietnamese consumers, whereas
acute exposure could pose a risk if a MOE of 10 or
higher are needed. For worst case exposure (with a MOE
of 100) dermal and total exposure could cause potential
health problems for Vietnamese consumers. In addition,
the acute exposure via inhalation can also pose potential
health risks. By utilizing the model, the adopted permis-
sible values of formaldehyde in clothing for children and
adults are assessed not to pose any health risks and are
considered acceptable f or Vietname se consumers.
5. Acknowledgements
We express our gratitude to the members of the Depart-
ment of Environmental Management in HoChiMinh City,
who helped with the data collection. Special thanks are
due to the Rotary Foundation for the Ph.D. course in
Osaka University, Japan.
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