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Supplementary Data
Title:
Human health risk assessment based on trace metals in suspended air
particulates, surface and floor dust from e-waste recycling workshops in Hong
Kong, China
Authors:
Winifred Ka Yan Lau, Peng Liang, Yu Bon Man, Shan Shan Chung*, and Ming Hung
Wong**
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Affiliations:
Croucher Institute for Environmental Sciences and Department of Biology, Hong
Kong Baptist University, Hong Kong, P.R. China
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Corresponding Author’s emails:
* email: sschung@hkbu.edu.hk
** email: mhwong@hkbu.edu.hk
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For journal:
Environmental Science and Pollution Research
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Table S1 Description of work processes identified in formal e-waste processing
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workshops in Hong Kong (Lau et al. 2013)
Work Process
Description
1. Office
2. Repair
General administrative work
Checking of machine by knowledgeable personnel for reparability.
Those that can be fixed are repaired while those that cannot are
designated for dismantling. Useful parts may be retained as spare
parts for use in the future
3. Dismantling Breaking down or opening of e-waste by manual processes such as
hammering or prying using hand held tools to assess components
which are then sorted for further recycling
4. Storage
Temporary storage areas for e-waste waiting to be processed or for
processed materials waiting to be sent off for further recycling
5. Desoldering Use of a desoldering machine to remove solders on PCBs. May
need to hammer and smash down large PCBS prior to feeding into
machine
6. Loading
Where e-wastes are unloaded from trucks either by manual
forklifts or forklift trucks. Equipment usually arrives on wooden
pallets wrapped in vinyl shrink-wrap or in boxes, bins or as
7. Cable
shredding
8. Chemical
waste
individual equipment. Personnel in the area first identifies the
content, weighs the load, and sort receiving equipment to
downstream processes.
Use of shredder for size reduction of cables and enabling materials
to be sorted according to size and type for efficient separation.
Reclamation of refrigerant and drainage of motor and compressor
oil
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Table S2 Exposure factors used in the risk assessment calculations for e-waste
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recycling workers in Hong Kong (USEPA 1997; USEPA 2002)
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Exposure Factors
Worker
Ingestion rate, InR (mg/day)
Exposed skin area (cm2)
Skin adherence factor, AF (mg/cm/day)
Body weight, BW (kg)
Exposure time, ET (hours/day)
Exposure frequency, EF (days/yr)
Exposure duration, ED (yr)
50
3300
0.2
60
8
300
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Averaging time (AT)
For non-carcinogens, AT (days) = (ED x 365 days/yr)
For carcinogens, AT (days) = (70 yr x 365 days/yr)
9125
25550
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Table S3 Toxicity and Chemical –specific information used in the risk assessment
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calculations (USEPA 2013)
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Non-cancer risk
Ingestion
Dermal
Cancer risk
Inhalation
Ingestion
Contact
Metal
Dermal
Inhalation
Contact
RfDo
RfDo*GIABS
RfCi
SFO
SFO /GIABS
IUR
(mg/kg-day)
(mg/kg-day)
(mg/m3)
(mg/kg-day)-1
(mg/kg-day)-1
(µg/m3)-1
Cd
1.0 E-03
2.5 E-05
1.0 E-05
-
-
1.8 E-03
Cr (VI)
3.0 E-03
7.5 E-05
1.0 E-04
5.0 E-01
2.0 E+01
8.4 E-02
Cu
4.0 E-02
4.0 E-02
-
-
-
-
Hg
-
-
3.0 E-04
-
-
-
Ni
1.1 E-02
4.4 E-04
1.4 E-05
-
-
2.4 E-04
Zn
3.0 E-01
3.0 E-01
-
-
-
-
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References
Lau W, Chung S (2012) A Preliminary Study on Occupational Safety and Health
Risks of E-waste Recycling Workers in Hong Kong. IJCEES 3: 49 – 58.
USEPA (1997) Exposure Factors Handbook, National Center for Environmental
Assessment, Washington, D.C.
USEPA (2002) Supplemental Guidance for Developing Soil Screening Levels for
Superfund Sites, OSWR 9355.4 – 24, Solid Waste and Emergency Response,
Washington D.C.
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USEPA (2013) Regional Screening Level (RSL) Summary Table (TR=1E-6, HQ=1)
May 2013.
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http://www.epa.gov/reg3hwmd/risk/human/rb-concentration_table/Generic_Tables/do
cs/master_sl_table_run_MAY2013.pdf. Accessed 6 November 2013
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