The Hazards of Nanomaterials and How to Control Exposure
Welcome to Health and Safety to Go! a production of the Canadian Centre for Occupational Health and Safety, broadcasting from Hamilton, Ontario.
CCOHS: Thank you for joining us for this episode of Health and Safety to Go! Today we’re talking to Todd Irick from OCHOW’s Nanotechnology and Health Network, about nanotechnology and its potential adverse health effects on workers. Thanks for joining us today!
Todd Irick: Thanks for having me.
CCOHS: Can you help set the stage for our listeners and explain what nanotechnology is and why it's a cause for concern in the workplace?
Todd Irick: Nanotechnology is a term used to describe a wide range of technologies and materials that create, manipulate, or use particles that have one thing in common: their size.
They’re materials that are extremely small and have dimensions roughly between 1 and 100 nanometers. To get an idea of how small this is, think about a piece of paper or a single strand of hair. The paper is about 100,000 nanometers thick and the diameter of a human hair is about 70 to 80,000 nanometers.
Nanomaterials are incorporated into a wide variety of objects because of their useful properties. Some examples include batteries and computer parts, these use silicon and zinc oxides at the nanoscale, vehicle construction carbon nanotubes that enhance strength without excessive weight); clothing, makeup and cleaners - use silver nanoparticles that provide antimicrobial activity; sunscreen - uses titanium dioxide nanoparticles this allows protection against ultraviolet and it's clear as opposed to the typical white titanium dioxide that use you, that you see that's in a normal size. Also silicon and titanium oxide and substance called graphene are added to cement to increase their flow and stiffness properties.
These desirable properties for manufactured items make them great assets to producers and are used in promotion and marketing campaigns. One database lists over 8,000 products containing Nano materials manufactured by over 2,000 companies located in more than 50 countries. The wide spectrum of products is used in various Industries – cosmetics, textile, petrochemical, medicine, agriculture, electronics, construction, food, even environmental control. However, the same properties that make them desirable from a product performance perspective present the unique potential health hazards that are possible when people are exposed to them. As you can see, they're everywhere and not only is their exposure risk during production and processing but also a product deteriorate that contain nanoparticles if they're ripped or shredded they can become airborne and pose an exposure risk. For this reason, the responsible disposal is also important.
CCOHS: Is it their size that makes them hazardous?
Todd Irick: Well, that's a difficult question to answer since each nanomaterial just like every chemical can have its own unique effects. The effects of nanomaterials are not only based on chemical characteristics, but also the shape, size, crystalline structure, surface coatings, surface texture, surface charge, surface reactivity. And other factors can all impact how the nanomaterials might affect our health. Nanomaterials can have characteristics that are very different from when they are in their larger or normal form. Often, nanomaterials will be stronger lighter more reactive or conduct electricity in a different way, and their appearance like their color may be modified. For example, silver nanoparticles are yellow or brown as opposed to the normal silver color and this small size gives them antiseptic properties. So you might find them in surgical gowns and masks and even athletic socks. Once again, this may not pose an immediate risk if the products remain intact, but if they are torn, worn, ripped, shredded etc., the particles can be released and they can be inhaled ingested or absorbed by people.
CCOHS: What do we know about the possible health effects that may arise from exposure as a result of working with nanomaterials?
Todd Irick: We know there are some common concerns. For example, nanomaterials can enter the body through inhalation ingestion or absorption through the skin. Inhalation is typically the greatest concern since airborne nanomaterials may be difficult to control, and significant amounts of particulates may be readily inhaled. Health effects are influenced by chemical composition, shape, size, surface, texture, charge, and other factors and the retention in tissues may be relatively short or long. These can all influence the toxic effect. They have been found in the lungs, liver, kidney, heart, reproductive organs, brain, spleen, skeleton, soft tissues, and even fetuses. Airborne nanoparticles can be deposited in the deepest part of the respiratory tract, and once deposited they can enter the bloodstream and migrate to other organs like the brain. Some nanomaterials can cause rapid and persistent pulmonary inflammation and fibrosis, lung tumors, and cardiovascular dysfunction, occupational exposure limits for nanomaterials may be much lower that is more stringent than those related to chemicals or materials that are not nano-sized.
CCOHS: What can workplaces do to protect workers?
Todd Irick: Well workplaces can implement nanomaterial management plans similar to what they have for substances such as asbestos, lead, silica, and other hazardous materials. They can screen materials before they enter the workplace but be wary that an SDS or safety data sheet for materials containing nanoparticles may not be revealed as a nanomaterial and the control requirements listed may not be as stringent as they should be. They can monitor for Nano materials as part of their workplace inspections. They can provide worker education and training. Workplaces can use control methods such as elimination or substitution for example using a liquid slurry as opposed to a dry powder during processing where possible.
CCOHS: You just mentioned control methods. How can exposure to nanomaterials be controlled?
Todd Irick: First of all, they need to be identified in the workplace. As with any process workers can be exposed through the manufacturing process, use, and handling as well as the maintenance and cleanup of equipment. The exposure potential depends on the characteristics in the amount of the material whether the particles are dry, in solution, or encapsulated. It also depends on the degree of containment and the duration of use. Control measures can be implemented using the hierarchy of control principle. That is there are four main methods of control, which should be implemented in this order: first elimination, which would include substitution to another product. Second: engineering controls, third administrative controls. And lastly: personal protective equipment commonly referred to as PPE. Engineering controls include enclosing processes with glove boxes, isolating emissions with local exhaust ventilation such as fume hoods and other extraction devices. Ensuring the use of HEPA, high-efficiency particulate arrestor filtration to prevent migration of nanoparticles within the workplace. Administrative controls include housekeeping, for example, keeping surfaces clean, installing warning signs, and restricting access to areas. Protective equipment may include respirators with P-100 filters, another name for HEPA filters, eye, face and skin protection, for example safety glasses/goggles, face shield, lab coat/coveralls depending on the process and the risk of exposure. And how well things are controlled using the first three methods because those are the ones we want to concentrate on and rely lastly on PPE.
CCOHS: Do you have any closing thoughts you want to leave our listeners with today?
Todd Irick: There are a lot of good resources available for workplaces. There are a couple of Canadian Standards Association (CSA) documents that are very useful for the risk assessment and guidelines for controlling exposures to nanomaterials in the workplace. The Exposure Control Program Standard and Occupational Risk Management/Control Banding are very useful documents. Finally, there has been a great deal of effort worldwide to identify hazards associated with exposure to nanoparticles and to recommend suitable control measures to prevent exposures and adverse health outcomes. The best approach is the precautionary principle which implies the need to take prudent action in the face of potentially serious risk, without waiting for the completion of further scientific research. This is a good time to act as the technology emerges to prevent future occupational disease from exposure to nanomaterials.
CCOHS: Thank you for joining us today Todd, and helping to raise awareness of nanotechnology, the importance of protecting workers, and controlling exposure.
For more information on nanotechnology, please visit our website at CCOHS. Thanks for listening everyone.