1 2 3 4 5 6 7 8 9 10 11 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** 12 13 14 Affiliations: Croucher Institute for Environmental Sciences and Department of Biology, Hong Kong Baptist University, Hong Kong, P.R. China 15 16 17 18 19 Corresponding Author’s emails: * email: sschung@hkbu.edu.hk ** email: mhwong@hkbu.edu.hk 20 21 For journal: Environmental Science and Pollution Research 1 22 Table S1 Description of work processes identified in formal e-waste processing 23 24 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 2 25 Table S2 Exposure factors used in the risk assessment calculations for e-waste 26 recycling workers in Hong Kong (USEPA 1997; USEPA 2002) 27 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 25 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 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 3 52 Table S3 Toxicity and Chemical –specific information used in the risk assessment 53 calculations (USEPA 2013) 54 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 - - - - 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 4 78 79 80 81 82 83 84 85 86 87 88 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. 89 90 91 USEPA (2013) Regional Screening Level (RSL) Summary Table (TR=1E-6, HQ=1) May 2013. 92 93 http://www.epa.gov/reg3hwmd/risk/human/rb-concentration_table/Generic_Tables/do cs/master_sl_table_run_MAY2013.pdf. Accessed 6 November 2013 5