Research Highlight: Are Chinese Factory Workers at Risk from Exposure to Nanoparticles on the Job?

© 2013, JupiterImages

UW DEOHS PhD candidate Ling Cui defended her dissertation, entitled Exposure Assessments and Inflammatory Responses Among Workers Producing Calcium Carbonation Nanomaterials, on May 15. Her dissertation committee included Center members Harvey Checkoway and Michael Yost (Co-Chairs), Sverre Vedal, and Noah Seixas.

The goal of Ms. Cui's research was to find out whether exposure to nanomaterials during manufacturing results in any adverse health effects. The research took place at the Calcium Carbonate Nanoparticle Factory in Shanxi, China. The nanoparticles manufactured there are used in plastics, ink, and adhesives.

Ling Cui
A nanoparticle is any particle that has at least one dimension equal to or smaller than 100 nanometers. One billion nanometers equals one meter, which puts these particles on the scale of atoms, molecules, and, in living organisms, of DNA and proteins. Their small size allows them to be inhaled deep into the tiny air sacs, or alveoli, of the lungs. Possible health effects of exposure to calcium carbonate nanoparticles include oxidative stress, fibrosis, and inflammation. Ms. Cui stated that workers, consumers and the environment are all at potential risk.

Ms. Cui studied workers who had various roles in the manufacturing of the calcium carbonate nanoparticles. She collected personal samples from workers and area samples from inside and outside the factory. She found that the job with the highest exposure to individual nanoparticles in terms of number and surface area was the modification job in which workers modify the surface of the particles. There was also high exposure in workers who bag the nanoparticles in terms of mass concentration. She observed during her study that some portion of the tiny particles don't settle out of the air and disperse evenly throughout the factory. As a result, many workers might share similar exposure, despite the fact that their jobs are different.

Four biological measurements were used to measure response to nanoparticle exposure: FEV1 (amount of air exhaled in 1 second); Blood Pressure; Exhaled Nitrous Oxide (a marker of inflammation); and sputum biomarkers (proinflammatory cytokines circulated in the lungs). She discovered some of these cytokines were significantly elevated in the high exposure group compared to the low exposure group.

Wearing personal protective equipment was not mandatory for the workers, but some workers wore them voluntarily. Ms. Cui observed that a few workers wore medical masks. Workers in the bagging area, the dustiest area of the factory all wore dual-cartridge half-mask respirators offered by the factory, but they were not replaced frequently enough.

Ms. Cui reported that the factory workers are mostly content with their jobs and turnover at the factory tends to be relatively low. Older workers have lower job turnover than younger workers. Workers in the study had been in their jobs for an average of 6 years.

Ling Cui's research was supported in part by a pilot project grant from the Center for Ecogenetics and Environmental Health. We congratulate her on a job well done!

Event Highlight: CEEH Co-Hosts Educational Workshop on the Duwamish River Superfund Cleanup Proposal

EPA Representative Allison Hiltner answers questions during the Q&A following the presentations, © 2013, J Sharpe

The CEEH and the UW Superfund Research Program (UW SRP) filled the Allen Library Research Commons on April 29th; attendees included UW students and staff, a Duwamish tribal member, staff from EPA, Ecology, the City of Seattle (representing the Lower Duwamish Waterway LDW Group), and the Duwamish River Cleanup Coalition (DRCC). 70 people listened to EPA, Ecology, the LDW Group, and DRCC representatives give their perspectives on EPA's Duwamish River Superfund Cleanup Proposal. Each presenter was given 5 minutes. To assure that each group had equal time, the audience applauded them off the podium when their 5 minutes was up.

You can view videoclips of the presentations on the UW SRP web sitePhotos from the event are also available on Flickr.

Participants listen to panel presentations.
In 2001, a 5.5 mile long stretch of the lower Duwamish River was declared a federal Superfund Site. It is one of the most toxic hazardous waste sites in the United States. 41 different toxicants contaminate the river; the contaminants of highest concern are polychlorinated biphenyls (PCBs), dioxins and furans, carcinogenic polycyclic aromatic hydrocarbons (cPAHs), and arsenic. The contamination is in the river bottom sediment.

Six of the most contaminated areas were designated as Early Action Cleanup Areas. These include Slip 4 near the former Boeing Plant 2; Terminal 117, site of former businesses Duwamish Manufacturing and Malarkey Asphalt Company; Boeing Plant 2 where B-17 bombers were manufactured during World War II; Jorgensen Forge; Duwamish Diagonal, upstream from Harbor Island; and Norfolk Combined Sewer Overflow (CSO) near the south end of Boeing Field.

Cleanups at Slip 4, Duwamish Diagonal, and Norfolk CSO have been completed.

EPA considered active cleanup options ranging from cleaning up from 32 to 302 acres of contaminated sediment. The estimated cost ranged from $210-$810 million. On Feb 28, 2013 EPA released their recommended plan, proposing to:
  • Actively clean up 156 acres of contaminated sediment, including:
  • Dredging 84 acres (54%) to remove contaminated sediment
  • Capping 24 acres (15%) of contaminated sediment with clean material such as sand
  • Pursuing enhanced natural recovery on 48 acres (31%) of contaminated sediment by covering it with 6-9"of clean material, and possibly add activated carbon 
  • Monitoring the natural recovery of 256 additional acres, watching to see whether cleaner sediments are deposited from upriver to sequester contaminated sediment 
Including the Monitored Natural Recovery brings the the total cleanup area to 412 acres. The estimated cost of the Proposed Cleanup Plan is $305 million. Active cleanup would take 7 years. Monitored Natural Recovery would take an additional 10 years.
Dredging is the most thorough and most expensive cleanup method, and monitored natural recovery is the least thorough, least expensive, and least certain method. EPA estimates this cleanup plan will reduce the risk associated with eating contaminated fish and shellfish by 90%.

The Washington State Department of Ecology is responsible for source control and has developed a strategy to mitigate and prevent pollution from upstream roads, residences, farms, forests, and industry from entering the Duwamish River. Upstream source control must be completed before the Superfund Cleanup begins, to prevent new pollution from recontaminating the river.

Kelly Edwards moderated the event.
At the meeting, the representatives had different perspectives on the cleanup. EPA feels they have done a thorough study and that their cleanup proposal will bring about a good cleanup in a reasonable time frame. Ecology stressed the complexity and the importance of preventing upstream pollution from recontaminating the river. The LDW Group feels the EPA goals for how clean the river can be are unachievable since industry will continue on the river, pollution will enter from upstream no matter how good the source control, and Puget Sound itself has pollution. The Duwamish River Cleanup Coalition, on the other hand, feels the cleanup proposal doesn't go far enough to assure a thorough cleanup that is certain to last. They feel strongly that the cleanup should be done right so it doesn't have to be done again down the road.

All the presenters encouraged everybody to make a public comment by June 13th. The comment period is already half over, and this is the only chance for the public to speak up and influence the EPA's Cleanup Plan. EPA must answer all the comments in a public document.

The Duwamish is Seattle's only river, home to 2 historic neighborhoods, South Park and Georgetown, and fishing grounds of the Duwamish, Suquamish, and Muckleshoot Tribes. Seattle and King County residents will help pay for the cleanup through our tax dollars. Now is the time to tell EPA what you think about the Proposed Cleanup.