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. 2020 Aug 4;64(8):890–896. doi: 10.1093/annweh/wxaa058

Metals and Particulates Exposure from a Mobile E-Waste Shredding Truck: A Pilot Study

Diana Ceballos 1,✉, Michael Zhou 2, Robert Herrick 2
PMCID: PMC7544000  PMID: 32747949

Abstract

The US electronics recycling industry has introduced a novel mobile electronic waste (e-waste) shredding truck service to address increasing needs for secure data destruction of e-waste. These trucks can shred small electronics with data security concerns at remote locations for a wide variety of clients. Shredding jobs usually involve hand-feeding electronic waste (e-waste) for 4–10 h day−1, 1–5 days. Shredding of e-waste has been documented as a source of high metal exposures, especially lead and cadmium. However, no studies have been done to assess exposures on mobile e-waste shredding trucks. We conducted a pilot cross-sectional exposure assessment on a mobile e-waste shredding truck performing a 65-min shredding job (truck back door open and no local exhaust ventilation) in the Greater Boston area in 2019. We collected area air and surface wipe samples for metals along with real-time particulate measurements from different locations. The highest metal air concentrations (e.g. 2.9 µg-lead m−3) were found next and 1.8 m away from the shredder operator inside the semi-trailer. Metal surface contamination was highest near the shredder (e.g. 1190 µg-lead 100 cm−2) and extended to other parts of the truck. Near the shredder, the concentration of ultrafine particles was up to 250 000 particles cm−3 and particulate matter 2.5 mm or less in diameter (PM2.5) was up to 171 µg m−3, and neither returned to background levels after 40 min of inactivity. A diesel-electric generator was used to power the shredder and could have contributed to some of the particulate emissions. We found that mobile e-waste shredding trucks are a source of metals and particulates emissions. We recommend the industry adopts better controls for shredding inside trucks, such as local exhaust ventilation with proper filtration and use of personal protective equipment, to protect workers’ health and the environment.

Keywords: electronics, exposure assessment, heavy metals, lead, new technologies, recycling

Introduction

Rapid technological innovation and market competition have shortened electronic products’ life cycles (Aytac and Wu, 2013). These shorter life cycles have inevitably led to larger amounts of electronic waste (e-waste). Thus, the US electronics recycling (e-recycling) industry has shown tremendous growth. The industry workforce has grown from 6000 fulltime employees in 2002 to 532 000 jobs most recently (ISRI, 2018, 2019). E-recycling processes typically include sorting, testing, refurbishing, repairing, or shredding (Ceballos and Dong, 2016; Li et al., 2017).

The increased need for more secure forms of data destruction (Terry, 2015; Ponemon Institute, 2018), has led e-recycling facilities to introduce mobile e-waste shredding trucks. This service provides onsite shredding of hard drives, solid-state drives, cell phones, laptops, and other media units containing confidential information. Some US e-recycling facilities commonly deploy one or more mobile e-waste shredding truck(s). Shredding jobs vary depending on customer’s needs, but on average small shredders have capacities of 600–800 drives per day, and shredding jobs may span 1–5 days. The design of these novel trucks varies, but the majority consist of a combination of a tractor-unit, a diesel, or hybrid diesel generator to power the shredder, and a semi-trailer with a shredding device (Zeng et al., 2015).

Shredding of e-waste can be a potential source of neurological and cardiovascular toxicants such as lead, cadmium, and airborne particles (Julander et al., 2014; Ceballos et al., 2017). The use of a diesel generator may introduce more particulate emissions (Zhu et al., 2002; Wichmann, 2007). Ultrafine (UFP) and particulate matter 2.5 mm or less in diameter (PM2.5) are efficiently deposited in all regions of the respiratory tract and are associated with respiratory and cardiovascular health outcomes (CONCAWE, 1999; Oberdörster, 2000). One study measured PM2.5 from an e-recycler facility shredder in California and documented an elicited proinflammatory response in exposed mice (Kim et al., 2015).

There are currently to our knowledge no exposure assessments of these mobile e-waste shredding trucks. The main objective of this pilot study was to characterize metals and particulates exposure from a mobile e-waste shredding truck.

Methods

Study design

A cross-sectional exposure assessment pilot study was conducted at a mobile e-waste shredding truck parked at a Greater Boston e-recycling facility in 2019. The shredder was powered by a new hybrid diesel generator. The 65-min shredding job consisted of continuously hand feeding 200 confidential hard drives and solid-state drives for destruction inside the semi-trailer, with worker not moving away from the job during the whole task. There was no local exhaust ventilation and operation relied on natural ventilation with the back door opened. The worker did not use any personal protective equipment (PPE).

Sampling for metals on different locations of the truck included area air sampling during the shredding task and surface wipe sampling. We also collected real-time UFP and PM2.5 at different locations before, during, and after shredding. Samples near the shredder were positioned as close as possible to the worker’s head height. Sampling locations are described in Fig. 1.

Figure 1.

Figure 1.

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Layout of the mobile e-waste shredding truck and locations of the sampling.

Area air and surface wipe sampling and analysis

Active air samples were collected using pre- and postcalibrated AirChek XR5000 air sampling pumps (SKC Inc., Eighty-Four, PA, USA) at 4 l min−1 connected via Tygon tubing to 37-mm cassettes containing 37-mm diameter mixed-cellulose-ester membrane SKC-Solu-CAP filters cat. no. 225-8517—to account for wall deposits (Ceballos et al., 2015).

Surface wipe samples were collected by the same researcher using one premoistened Ghost wipe towelette (SKC Inc., Eighty-Four, PA, USA, cat. no. 225-2414) and a 10 × 10-cm2 disposable template per sample following a standard wiping protocol (Brookhaven National Laboratory, 2014).

Field and media blanks were collected for both area air and surface wipe samples. No blank corrections were necessary. Samples were shipped for analysis to the South West Research Institute Laboratory (San Antonio, TX, USA). Both air and wipe samples were analyzed according to NIOSH Method 7300 (NIOSH, 2018). Sample digestates were analyzed for a panel of 30 elements via Inductively Coupled Plasma Atomic Emission Spectrometry and Mass Spectrometry. Details of the quality assurance and quality control for the analysis method are in Supplementary Information S1, available at Annals of Work Exposures and Health online. A list of elements and detection limits are in Supplementary Table S1, available at Annals of Work Exposures and Health online.

Real-time measurement of particulates

Total UFP (0.01–1 µm) particle number concentrations were measured using a hand-held real-time condensation particle counter (CPC) 3007 (TSI Incorporated, Shoreview, MN, USA). PM2.5 (<2.5 µm) concentrations were measured using a real-time TSI SidePak AM510 PM2.5 monitor. Both devices measured at a time resolution of 1 min, were calibrated annually by TSI, and were blank and quality control checked on the day of sampling.

Statistical analysis

Basic and descriptive statistics were performed using R (3.5.1, R Core Team, Vienna, Austria) and Excel (365, Microsoft, Seattle, WA, USA). Most metals in the analysis were lognormal. Wilcoxon signed ranked test was used to compare production and non-production areas when possible (α = 0.05).

Results

Table 1 shows area air sample results for metals and surface loading for a select group of elements. The highest concentration in air was found next to the shredder or 1.8 m away from the shredder. Specifically, the concentration for most metals next to the shredder was about 1–10 times higher than the concentration of the other locations. The highest level of surface contamination was found on top of the shredder, which showed dust accumulation from old shredding jobs. There were also detectable metals in the non-production area (i.e. generator compartment).

Table 1.

Mobile e-waste shredding truck area air concentrations (µg m−3) and surface wipe loadings (µg 100 cm−2) for selected metals in different sampling locations.

Sample locations Al As Ba Be Cd Cr Co Cu Pb Mg Mn Ni Sr Ti Zn
Area air concentrations (µg m−3) during 65-min shredding task
 Air MDC (µg m−3) 9.64 0.193 0.482 0.0385 0.0385 0.482 0.0385 0.482 0.724 4.82 0.482 1.93 0.482 0.482 4.82
  Production
   Table next to shredder (at worker’s head height) 51.1 0.192a 38.8 0.384a 0.384a 1.33 1.64 12.5 2.91 40.3 0.569 5.00 0.807 12.5 8.34
   1.8 m away from shredder 58.0 0.192a 30.1 0.384a 0.384a 1.31 1.21 10.4 2.49 30.0 0.752 4.34 0.691 9.67 10.4
   4.3 m away from shredder outside truck) 13.0 0.195a 4.52 0.3849a 0.3849a 1.07 0.286 3.32 2.43 27.4 0.224a 1.95 0.534 2.14 5.06
   GM(GSD) 34(2) 0.19(1)a 17(3) 0.4(1)a 0.4(1)a 1.2(1) 0.83(3)a 7.6(2) 2.6(1) 32(1) 0.45(2) 3.5(2) 0.67(1) 6.4(3) 7.6(1)
  Non-production
   Generator compartment between trailer and front cabin 14.9 0.192a 1.57 0.384a 0.384a 1.14 0.0385a 1.39 0.192a 29.5 2.11 0.480a 0.588 1.30 4.80a
Surface wipe loadings (µg 100 cm−2)
 Surface wipe LOQ (µg sample−1) 2.50 0.0070 0.050 0.010 0.010 0.125 0.010 0.050 0.188 1.25 0.050 0.500 0.050 0.125 1.25
  Production
   Top of shredder 121 000 125 38 400 0.742 4.45 271 1020 14 500 1190 3010 520 12 700 175 10 800 14 100
    Floor next to shredder & table 3840 0.007b 1520 0.0433 1.79 26.5 105 828 80.3 316 50.2 424 20.8 438 692
   Right inside wall of semi-trailer 314 125 105 0.010b 0.010b 3.60 12.6 47.0 6.62 30.1 3.43 29.7 1.97 30.5 137
   Table next to shredder 185 0.0070b 87.1 0.010b 0.0904 1.97 6.79 30.9 4.72 35.5 3.56 23.1 1.49 30.6 133
   Table on dock outside of truck 285 0.625 99.5 0.010b 0.56 2.97 5.77 36.4 7.22 78.4 13.2 19.2 2.50 32.7 196
   Handles of truck backdoor 413 1.88 98.0 0.010b 0.0573 10.7 27.0 37.5 8.64 96.7 12.6 43.0 2.21 20.8 138
   Top of generator 247 0.0070b 57.5 0.010b 0.01b 2.79 5.71 35.3 2.91 25.0 2.26 32.1 1.55 14.0 117
   GM(GSD) 966(11)c 0.48(83) 314(11)c 0.022(5) 0.16(11) 8.9(6)c 26(7)c 135(11)c 18(8)c 110(5) 14(7) 100(11)c 5.1(6)c 88(11)c 343(6)
  Non-production
   Dashboard of driver seat 174 0.0070b 29.9 0.010b 0.0417 1.56 2.13 20.2 2.37 50.4 4.47 8.97 1.28 9.73 110
   Driving steering wheel and clutch 159 0.0070b 27.7 0.010b 0.142 2.25 2.69 23.5 2.68 56.9 3.58 13.7 1.6 8.42 158
   Dashboard of passenger seat 167 0.0070b 21.2 0.010b 0.0874 1.43 1.98 15.9 2.22 47.8 4.43 7.87 1.16 6.75 97.5
   Door handle to the generator compartment 33.2 0.0070b 3.90 0.010b 0.161 0.614 0.255 7.21 1.75 24.9 0.958 1.77 0.396 2.07 215
   Door handle of driver seat 55.0 0.0070b 6.95 0.010b 0.0253 0.661 0.331 3.50 0.866 33.7 1.52 1.43 0.454 3.06 84.2
   GM(GSD) 97(2) 0.007(1)b 14(2) 0.01(1)b 0.073(2) 1.15(2) 0.99(3) 11(2) 1.8(2) 41(1) 2.5(2) 4.8(3) 0.84(2) 5(2) 125(1)
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Al = aluminum, As = arsenic, Ba = barium, Be = beryllium, Cd = cadmium, Co = cobalt, Cu = copper, GM = geometric mean, GSD = geometric standard deviation, Pb = lead, MDC = minimum detection concentration, Mg = magnesium, Mn = manganese, Ni = nickel, Sr = strontium, Ti = titanium, and Zn = zinc. Bolded numbers represent the highest values per sample media. Note: E-waste sources for the elements measured in the electronics shredded are listed in Supplementary Table S1, available at Annals of Work Exposures and Health online.

aSamples below MDC or the minimum detection concentration. MDC was calculated as the concentration in air from the reporting mass limits provided by the laboratory over the average air volume of all samples (air volume was calculated from the average airflow during sampling multiplied by the duration of the task).

bSamples below LOQ or the limit of quantitation. LOQ was equal to the reporting mass limits provided by the laboratory in units of µg 100 cm−2 because all samples were taken in an area of 100 cm2.

cProduction areas were significantly higher than non-production areas, determined by Wilcoxon signed rank test at α = 0.05.

Fig. 2 shows the UFP and PM2.5 during the shredding job. Particulates increased rapidly, UFP ≥250 000 particles cm−3 and PM2.5 ≥171 µg m−3, after the shredding began. UFP near and 1.83 m away from the shredder were similar throughout sampling. Unlike UFP, PM2.5 measured higher near the shredder and decreased further away from the shredder. After shredding ended, particulates near the shredder did not return to baseline levels.

Figure 2.

Figure 2.

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Ultrafine (UFP) particulate count concentration (# cm−3) and PM2.5 (µg m−3) concentration during a shredding task in a mobile e-waste shredding truck.

Discussion

In this initial assessment of metals and particulates exposure in a mobile e-waste shredding truck, both air and surface samples suggest that shredding inside a truck is an important source of exposure to toxic metals and particulates in workers.

For most metals, the area air concentrations were low during shredding with the highest levels found near and 1.8 m away from the shredder, confirming poor ventilation conditions. Lead air concentrations during shredding were similar to area air samples in other facilities from other studies that performed shredding in warehouses (NIOSH, 2014, 2015). If air concentrations were maintained for the whole work shift (e.g. 2.9 µg-lead m−3), the lead concentration would not be likely higher than current occupational exposure limits (50 µg-lead m−3) (OSHA, 2020a) but would be higher to the proposed permissible exposure limit (2.1 µg-lead m−3) (CalOSHA, 2020). Although, if we sampled the breathing zone of the worker, lead concentrations would likely be higher than the measured area samples as is typical in the e-recycling industry (Ceballos et al., 2017).

Surface contamination measured in our study was highest on top of the shredder and was comparable to those found in shredders inside e-recycling facilities (NIOSH, 2014, 2015). Surface sampling can provide information about the potential for exposure by other than the inhalation route such as the skin or mouth. The recommended criteria in work surfaces for arsenic, chromium, and lead [100, 50, and 500 µg 100 cm−2, respectively (Brookhaven National Laboratory, 2014)] were all exceeded on the shredder surface (125, 271, and 1190 µg 100 cm−2, respectively). Lastly, although we found low levels of contaminants in the cabin, this suggests some migration to unsuspected areas.

During shredding, particulates reached their peak within minutes with the highest concentrations near the worker. Particulate data suggest that more than natural ventilation is needed to effectively remove or dissipate particulates that are generated from a shredding job. Similar UFP at different locations is likely due to the much lower settling velocity and longer settling time compared with PM2.5 (Tsuda et al., 2013). We would expect particulate concentrations even higher, along other toxic exposures such as carbon monoxide, if the diesel generator was older and not hybrid.

The main limitation of this study is the limited sampling time in only one facility that makes results not generalizable. Due to privacy and data security concerns typical of outside clients, we were unable to travel with employees to a remote location to sample a longer session. However, these preliminary data are important to create awareness of potential health and safety issues with the use of this novel technology. In future studies, it would be interesting to measure air and surface levels of other metals such as mercury. Besides, since shredding can generate particles with diameters in the range of 100 µm, a comprehensive assessment of the size distribution of the airborne particle personal exposures (including inhalable and total) dust exposures should be conducted. Our preliminary findings show that personal exposure assessments of the inhalation and dermal exposures of the operators, and other workers involved in the mobile shredding processes are needed.

Mobile e-waste shredding truck services are relatively new in the e-recycling industry, and many of these trucks have not been retrofitted with ventilation to accommodate a shredder in the semi-trailer. Our findings suggest that an e-recycling facility with shredding operations inside a truck(s) should develop health and safety procedures striving, as a minimum, to use the same controls typically recommended for shredding inside e-recycling facilities (e.g. local exhaust ventilation, PPE, and housekeeping). Other safety and health considerations should also be in mind with shredding operations inside a truck. Rotating parts could create an injury or a spark in an area that could be inadvertently closed (back door could close with a worker inside) and generate a hazardous temporary confined space—confined space is defined as a space large enough for an employee to enter and perform work; with limited or restricted means for entry or exit; and not designed for continuous occupancy (OSHA, 2020b). Dangerous conditions can be further exacerbated if the truck was parked for long periods exposed to extreme weather conditions at a client’s remote location. There are also potentials for noise and non-ergonomic workstations, among other hazards typical of the industry (Ceballos et al., 2014; OSHA, 2020c). Future research is necessary to further characterize exposures and other health and safety issues in these trucks to assure the health of both workers and the environment.

Funding

Funds for this project were provided by grant National Institutes of Health (NIH)/ National Institute of Environmental Health Sciences (NIEHS) 2R25ES023635-04 supplement, the Harvard JPB Environmental Health Fellowship, and the Harvard Hoffman Program on Chemicals and Health. Michael Zhou’s time in this project was also partially funded by the Harvard Education and Research Center fellowship.

Supplementary Material

wxaa058_suppl_Supplementary_Materials
Click here for additional data file. (22.3KB, docx)

Acknowledgements

We would like to acknowledge the facilities and businesses that participated in our study. We would also like to thank Mimi Ton, Gretel Poliakova, Shangzhi Gao, Matthew Schaefer, Jose Vallarino, Jaime Hart, Francine Laden, David Christiani, Mike Wolfson, Jose Guillermo Cedeno Laurent, Gary Adamkiewicz, and Alice Yau for their assistance.

Conflict of Interest

The authors declare no conflict of interest.

References

  1. Aytac B, Wu SD (2013). Characterization of demand for short life-cycle technology products. Ann Oper Res; 203: 255–77. [Google Scholar]
  2. Brookhaven National Laboratory (2014) IH75190: surface wipe sampling procedure [Online]. Available at https://www.bnl.gov/esh/shsd/sop/pdf/ih_sops/ih75190.pdf. Accessed 6 March 2019.
  3. CALOSHA (2020) Health-based permissible exposure limit for lead [Online]. Available at https://www.cdph.ca.gov/Programs/CCDPHP/DEODC/OHB/OLPPP/CDPH%20Document%20Library/LeadStdPELRec.pdf. Accessed July 2020.
  4. Ceballos D, Beaucham C, Page E (2017) Metal exposures at three U.S. electronic scrap recycling facilities. J Occup Environ Hyg; 14: 401–8. [DOI] [PubMed] [Google Scholar]
  5. Ceballos D, Chen L, Page E  et al. (2014) Evaluation of occupational exposures at an electronic scrap recycling facility. Health hazard evaluation report. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. [Google Scholar]
  6. Ceballos DM, Dong Z (2016) The formal electronic recycling industry: challenges and opportunities in occupational and environmental health research. Environ Int; 95: 157–66. [DOI] [PubMed] [Google Scholar]
  7. Ceballos D, King B, Beaucham C  et al. (2015) Comparison of a wipe method with and without a rinse to recover wall losses in closed face 37-mm cassettes used for sampling lead dust particulates. J Occup Environ Hyg; 12: D225–31. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. CONCAWE (1999) The health effects of PM2.5 (including ultrafine particles). Brussels: CONCAWE. [Google Scholar]
  9. ISRI (2018) The Scrap Recycling Industry: electronics [Online]. Available at https://www.isri.org/docs/default-source/commodities/electronics-fact-sheet_2018.pdf?sfvrsn=18. Accessed 13 February 2019.
  10. ISRI (2019) ISRI quantifies economic might of US recycling [Online]. Available at https://resource-recycling.com/recycling/2019/10/01/isri-quantifies-economic-might-of-us-recycling/?utm_medium=email&utm_source=internal&utm_campaign=Oct+1+RR. Accessed October 2019.
  11. Julander A, Lundgren L, Skare L  et al. (2014) Formal recycling of e-waste leads to increased exposure to toxic metals: an occupational exposure study from Sweden. Environ Int; 73: 243–51. [DOI] [PubMed] [Google Scholar]
  12. Kim YH, Wyrzykowska-Ceradini B, Touati A  et al. (2015) Characterization of size-fractionated airborne particles inside an electronic waste recycling facility and acute toxicity testing in mice. Environ Sci Technol; 49: 11543–50. [DOI] [PubMed] [Google Scholar]
  13. Li J, He X, Zeng X (2017) Designing and examining e-waste recycling process: methodology and case studies. Environ Technol; 38: 652–60. [DOI] [PubMed] [Google Scholar]
  14. NIOSH (2014) In Beaucham CC, Kawamoto MM, Brueck SE, editors. Health hazard evaluation report: evaluation of exposure to metals at an electronic scrap recycling facility. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. [Google Scholar]
  15. NIOSH (2015) In Page E, Ceballos D, Oza A, Gong W, Mueller C, editors. Health hazard evaluation report: metal exposures in an electronic scrap recycling facility. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health. [Google Scholar]
  16. NIOSH (2018) NIOSH manual of analytical methods (NMAM). 5th edn.  Method 7300. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH). [Google Scholar]
  17. Oberdörster G. (2000) Pulmonary effects of inhaled ultrafine particles. Int Arch Occup Environ Health; 74: 1–8. [DOI] [PubMed] [Google Scholar]
  18. OSHA (2020a) Permissible exposure limits: OSHA annotated table Z-1 [Online]. Available at https://www.osha.gov/dsg/annotated-pels/tablez-1.html. Accessed July 2020.
  19. OSHA (2020b) Safety and health topics: confined spaces [Online]. Available at https://www.osha.gov/SLTC/confinedspaces/. Accessed July 2020.
  20. OSHA (2020c) Recycling: consumer electronics [Online]. Available at https://www.osha.gov/SLTC/recycling/recycling_consumer_electronics.html. Accessed July 2020.
  21. Ponemon Institute (2018) Second annual study on the IoT: a new era of third-party risk [Online]. Available at https://sharedassessments.org/wp-content/uploads/2018/04/2018-IoTThirdPartyRiskReport-Final-04APR18.pdf. Accessed 13 February 2019.
  22. Terry K. (2015) HIPAA BREACH. Secure data & prevent fines—here’s how. Med Econ; 92: 26–8, 30–2. [PubMed] [Google Scholar]
  23. Tsuda A, Henry FS, Butler JP (2013) Particle transport and deposition: basic physics of particle kinetics. Compr Physiol; 3: 1437–71. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Wichmann HE. (2007) Diesel exhaust particles. Inhal Toxicol; 19: 241–4. [DOI] [PubMed] [Google Scholar]
  25. Zeng X, Song Q, Li J  et al. (2015) Solving e-waste problem using an integrated mobile recycling plant. J Clean Prod; 90: 55–9. [Google Scholar]
  26. Zhu Y, Hinds WC, Kim S  et al. (2002) Study of ultrafine particles near a major highway with heavy-duty diesel traffic. Atmos Environ; 36: 4323–35. [Google Scholar]

Associated Data

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Supplementary Materials

wxaa058_suppl_Supplementary_Materials
Click here for additional data file. (22.3KB, docx)

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