Subscriber access provided by University of Newcastle, Australia
Letter
Phthalate esters on hands of office workers: Estimating influence of touching surfaces Wei Shi, Jing Guo, Yubin Zhou, Dongyang Deng, Zhihua Han, Hongxia Yu, Xiaowei Zhang, and John P. Giesy Environ. Sci. Technol. Lett., Just Accepted Manuscript • DOI: 10.1021/acs.estlett.6b00458 • Publication Date (Web): 20 Dec 2016 Downloaded from http://pubs.acs.org on December 20, 2016
Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Environmental Science & Technology Letters is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.
Page 1 of 16
Environmental Science & Technology Letters
1
Phthalate Esters on Hands of Office Workers: Estimating Influence
2
of Touching Surfaces
3
Wei Shi,† Jing Guo,† Yubin Zhou,† Dongyang Deng,† Zhihua Han,† Xiaowei Zhang,†,*
4
Hongxia Yu,†,* and John P. Giesy,†,§,║,#
5
†
6
Environment, Nanjing University, Nanjing 210023, People’s Republic of China
7
§
8
Saskatchewan, Saskatoon, Saskatchewan S7N 5B3, Canada
9
║
State Key Laboratory of Pollution Control and Resource Reuse, School of the
Department of Veterinary Biomedical Sciences and Toxicology Centre, University of
Department of Zoology, and Center for Integrative Toxicology, Michigan State
10
University, East Lansing, MI 48824, USA
11
#
12
City University of Hong Kong, Kowloon, Hong Kong SAR, China
Department of Biology & Chemistry and State Key Laboratory in Marine Pollution,
13 14
1
ACS Paragon Plus Environment
Environmental Science & Technology Letters
Page 2 of 16
15
ABSTRACT
16
Phthalate esters are known to be transferred to hands by contact with surfaces,
17
however, little is known about associations between masses on hand wipes and
18
frequency or duration of touching surfaces, especially surfaces in office environments.
19
Relationships between PAEs on hands and multiple surfaces in offices were
20
investigated. Wipes of hands, computers, and mobile phones as well as dust on
21
furniture were collected from 55 offices in China.
22
between masses of di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DnBP),
23
benzyl butyl phthalate (BBP) and di-n-octyl phthalate (DnOP) on wipes of hands and
24
wipes of keyboards of computers. When workers used keyboards with polymer
25
covers (dust covers), masses of these lipophilic PAEs on hands were significantly
26
correlated with masses on keyboards rather than dust on furniture.
27
used keyboards without polymer covers, masses on hands were related to masses in
28
dust on furniture.
29
could increase the mass of exposure via hand to body of office workers, which could
30
further result in as much as 10-fold greater hazard.
31
less use of polymer products containing PAEs were recommended for office workers
32
to reduce exposures.
Positive associations were found
For workers who
Use of polymer covers containing PAEs and less washing of hands
Thus, more hand washing and
33
2
ACS Paragon Plus Environment
Page 3 of 16
Environmental Science & Technology Letters
34
INTRODUCTION
35
Phthalate esters (PAEs) are used as plasticizers to enhance flexibility in a variety
36
of household and building materials, including cables, wires, silicone films, screen
37
guards, vinyl flooring and polyvinylchloride (PVC) tubing 1.
38
including di-2-ethylhexyl phthalate (DEHP), dibutyl phthalate (DnBP), dimethyl
39
phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP) and
40
di-n-octyl phthalate (DnOP) (Table S1)2, 3 are not chemically bound within products
41
and can be slowly emitted into indoor environments. In a study that analyzed 89
42
organic chemicals in 120 homes, phthalate esters were one of the most abundant
43
indoor pollutants 4.
44
Phthalate esters
Recently, indoor exposure of humans to PAEs on skin and especially on hands 5, 6
45
has been shown to be non-negligible
.
Phthalate esters that are transferred to
46
hands by contact with surfaces and direct air-to-skin transport, can represent a
47
significant proportion of total accumulation 6.
48
skin, PAEs on hands can result in inadvertent ingestion, by biting of nails, sucking of
49
digits or eating finger foods 7, 8.
Besides direct absorption through
50
Since previous studies of PAEs have focused on residential exposures, little is
51
known about exposure in offices, although studies have shown greater concentrations
52
of PAEs in dust from offices than those from apartments 9. Phthalate esters which
53
tended to be strongly adsorbed to indoor surfaces, such as protectors of computer
54
screens, keyboards, furniture, floor and desks, are commonly touched by hands of
55
office workers
56
penetration through hands and further increase the health risk was unknown.
10
.
Whether and how touching surfaces in offices can increase
57
It was hypothesized that PAEs in office furniture might result in exposure of
58
office workers through touching surfaces. The main objectives of the present study
59
were to examine relationships between PAEs on hands of people and on probable
60
touched surfaces in offices by determining amounts of PAEs on surfaces in offices,
61
including computers, mobile phones and dust on furniture. Another objective was to
62
better understand the role of behaviors of workers, including use of polymer covers
63
and habits of hand washing to these relationships and also to the hazards of exposure 3
ACS Paragon Plus Environment
Environmental Science & Technology Letters
64
via hand to body.
65
MATERIALS AND METHODS
66
Collection of samples.
Page 4 of 16
Samples were collected from April to June 2014.
67
Participants for this study consisted of 55 adults who worked at least 20 h a week in
68
an office and were healthy, nonsmokers in the cities of Huaian (n=12), Zhenjiang
69
(n=31) and Nanjing (n=12) in East China.
70
buildings, and only one person per office participated in the study. Questionnaires
71
were also completed at the time samples were collected (see study design in SI).
72
Within-individual variability was estimated by collecting samples in triplicate from
73
four participants.
74
including dust on desks, chairs, bookcases and personal accessible furniture by use of
75
a standardized protocol that used a mini vacuum cleaner.
76
Offices were located in ten different
Samples of dust were collected from each participant’s office,
To avoid contamination of hands from sources other than the offices, participants
77
were asked to wash their hands before entering the office.
Samples of PAEs on
78
hands were collected by use of wipes applied at close of business.
79
sterile gauze pad pre-cleaned with dichloromethane and acetone was immersed in 3.0
80
mL of isopropyl alcohol (Tedia Co. Ltd, Fairfield, OH, USA) and then used to wipe
81
the palm and back of the hand from wrist to fingertips, including sides.
82
computer keyboards and mobile phones were collected from participants in their
83
office after collection of wipe samples of hands and at least 1 day after the last time
84
the computer, phone or furniture was cleaned.
A 7.6×7.6 cm
Wipes of
85
To confirm sources of PAEs, wipes of keyboards were further collected from
86
twelve computers in six offices. In each office, there were two keyboards, one with a
87
polymer cover and one without a polymer cover. Polymer keyboard covers are
88
removable polymer plastic sheets that are placed on keyboards and left in place while
89
typing. Keyboards and polymer covers were cleaned with isopropyl alcohol in the
90
morning and they were kept in offices without disruption for 5 days. More
91
information for collection of samples is given in supporting information (SI).
92 93
Preparation of samples and quantification of PAEs. extracted by use of accelerated solvent extraction (ASE). 4
ACS Paragon Plus Environment
PAEs in samples were
PAEs were quantified by
Page 5 of 16
Environmental Science & Technology Letters
94
use of a Thermo TSQ Quantum Discovery triple-quadrupole mass spectrometer (San
95
Jose, CA, USA) in multiple-reaction monitoring (MRM) mode.
96
information for instrumental analysis, procedural blanks and other QA/QC procedures
97
is listed in SI, Table S1 and Table S2.
98 99
More detailed
The concept of relative cumulative hazard
Assessment of cumulative hazard.
quotient (HQ), developed previously, was employed to incorporate cumulative
100
exposure into the assessment 11.
101
hands was divided by tolerable daily intake values for each PAE (TDIi value) and the
102
HQ for individual PAEs (HQ-PAEi) were summed to obtain total hazard quotients
103
(HQs) including BBP, DBP, DEP and DEHP.
104
n
n
i =1
i =1
HQs = ∑ HQ-PAE i = ∑
The daily intake (DI) of PAEs through exposure on
DI i (µg/kg bw/day) TDI i (µg/kg bw/day)
(1)
105
Where: DIi is daily intake (exposure through hand) of individual PAEs, and n is the
106
number of PAEs considered. DIi is the sum of exposure through hand-to-mouth
107
contact (µg/kg bm/day) and absorption through the dermis of the hand (µg/kg bm/day)
108
(More detail is shown in SI and Table S3).
109
Data analysis. We used Spearman correlations (SPSS statistics software package,
110
V. 17.0) to determine associations between continuous variables while minimizing the
111
influence of outliers. To minimize effects of skewed data and outliers, we created
112
categorical variables from surfaces and hand wipe data: Two-level variables (lesser,
113
and greater) were created using the median as a cut-point (detail is in SI).
114 115 116
RESULTS AND DISCUSSION Phthalate esters on wipes of hands.
Phthalate esters were detected in all
117
wipes of surfaces of hands (Table S4).
As expected, DEHP was the predominant
118
compound, followed by DnBP and DnOP.
119
with the pattern observed in serum of people from China for DEHP, DnBP and DnOP,
120
although no study has previously reported masses of DnOP on wipes of hands
121
Few studies have examined phthalates in wipes of hands (Table S5). Generally,
122
DEHP and DnBP are among the most widely detectable PAEs on wipes of hands in
This pattern for skin wipes is consistent
5
ACS Paragon Plus Environment
12, 13
.
Environmental Science & Technology Letters
Page 6 of 16
123
Korea, Beijing in China and also East China detected in the present study 14, 15. DEP
124
was not detected on wipes of hands of Koreans, while a frequency of detection of less
125
than 20% was observed in the study of people in Beijing, which is approximately the
126
same as the frequency of 52% observed in the present study.
127
its greater vapor pressure, which results in a greater partition coefficient 16.
128
Phthalate esters from surfaces in offices.
This might be due to
PAEs were detectable on surfaces
129
of furniture, keyboards and phones, which based on the results of questionnaires, were
130
the most touched surfaces (Table S4).
131
detection frequency for all types of surface samples.
132
predominant compound, with geometric means (GM) of 148 µg/g, 83.6 µg and 10.2 µg
133
for dust, keyboards and phones, respectively.
134
were 3- to 8-fold greater than those on phones, which might be due to the large area of
135
keyboards and limited variation indicated similar sources for PAEs on keyboard and
136
phone.
137
wipe samples had similar variability (Figure S1), and masses not concentrations on
138
wipes of hands, surfaces of computer keyboards and phones were used in the
139
following studies. Concentrations and masses of PAEs in repeated samplings of dust
140
and wipes over a three month period are mostly consistent (See repeated
141
measurements in SI and Figure S2).
142
DnBP, BBP, DEHP and DnOP had a greater DEHP was the most
For all PAEs, masses on keyboards
Distributions of masses and normalized concentrations of PAEs measured on
Associations of PAEs on hand wipes with indoor surfaces.
Total masses of
143
PAEs on wipes of hands were positively correlated with masses on wipes of surfaces
144
of computer keyboards, with a Spearman correlation coefficient (R) of 0.59 (p
