  |
|
|
Dental offices across Washington State create a wide variety of waste during the course of a normal business day. These dental wastes need to be properly managed to avoid negative environmental impacts. This is easy to achieve following the guidelines below:
Which dental wastes are of environmental concern?
How harmful is mercury and mercury waste?
Mercury is a highly toxic, persistent and bio-accumulative neurotoxin. Once released, mercury will remain in the environment for years, dispersing over a wide area and accumulating in the tissues of plants, insects, and animals, concentrating on creatures higher up the food chain (e.g., humans). Health effects of mercury can be severe, particularly to a fetus in utero and to younger children.
What are the major sources of mercury waste in a dental office?
Where else are mercury and mercury wastes found in a dental office?
There are non-mercury alternatives available for medical equipment and thermostats, and also bulbs and lamps available that contain lower amounts of mercury. Dentists should utilize these choices when starting an office or replacing items.
Why should I install an amalgam separator?
Washington State Law requires that all businesses handling hazardous materials determine whether they are generating hazardous waste. Determination may require testing. This compliance includes dental offices. National and state tests indicate that dental wastewater contains as much as 100-2,000 parts per million (ppm) of mercury which greatly exceeds the state regulatory dangerous waste limit of 0.2 ppm. Wastewater containing more than the legal limit of mercury should not be disposed to the sewer. Because these tests are so well documented, Ecology has agreed to bypass testing and potentially other restrictions if the dentist chooses to install and maintain a separator. Ecology established this policy because ISO 14011 certified amalgam separators can capture the fine amalgam particles and dissolved mercury in wastewater that is not removed by chair-side traps. They can remove up to 99% of the mercury in dental wastewater, if maintained properly. Ecology believes this alternative will save dentists both money and time, as long as they maintain the system properly." (note: an uncertified separator may lead to non-compliance and liability.)
What is an amalgam separator and what is it’s purpose?
An amalgam separator is designed to remove waste amalgam from the rinse water in the vacuum line before discharge to sewer. These separator systems are used to capture scrap amalgam which is too fine to be removed by a trap or a screen. There are a number of separator manufacturers that offer a variety of models. Which separator to use depends on the amount of water discharged or the number of dental chairs operated at the dentist’s office. These systems are usually installed by the suppliers and maintenance agreements are common. Amalgam separators can remove up to 99 % of the mercury from the wastewater before it is discharged from the dental office. Many of the available separators have been subjected to rigorous testing and have met ISO 11143 standards. Be sure to confirm that the amalgam separator meets these ISO 11143 standards at the time of installation.
If the dental office has a septic system, do we need an amalgam separator?
Yes, if you have a septic system, installation of an amalgam separator is important, and you need to be particularly careful, since most of your wastewater has chemical residues (not just mercury and silver), and could potentially contaminate the drain field and the groundwater, which may be also used for drinking water. Unlike sewer treatment plants run by the city, which process the solids within a matter of days, septic tanks have a holding time of years, and thereby create a situation of low pH anaerobic conditions at the bottom of a septic tank where the amalgam waste is likely to collect. Such conditions have been shown, in the natural environment, to be very conducive to mercury methylation through common bacteria. Once methylated, mercury becomes mobile and would exit the tank to the drainfield along with other supernatant. Silver, at low pH (at the bottom of the septic tank), also have a higher solubility. For more detail on how to manage septic systems to avoid contamination click this link:
http://www.govlink.org/hazwaste/publications/IRAC_septic1.pdf
What are ISO standards and what does ISO 11143 Standard Mean?
ISO standards are developed by the International Standards Organization. The ISO is a worldwide federation of national standards bodies. The work of preparing International Standards is normally carried out through ISO technical committees. There are ISO standards developed specifically for dental amalgam separators. These standards are designed to ensure that the separator removes at least 95% of waste mercury from the dental wastewater before discharge to sewer.
The official ISO 11143 standard for amalgam separators was published on 12/1/99. Be sure that the separator you purchase was tested using the official ISO 11143 standards in place after 12/1/99. Your separator manufacturer should provide you with a copy of the one-page test report annex upon request. Don’t be fooled, some may claim that their amalgam separator is compliant with this standard and may not actually be ISO 11143 certified. Others may claim that they had their amalgam separator ISO 11143 tested before December 1, 1999. This poses a problem because their separator was only tested against the draft ISO 11143 standard and there are significant changes between the draft and the official standard.
How do I choose the right separator for my office?
Amalgam separators are increasingly being used and required in many areas of the United States. Choosing the right separator for your office depends upon a number of factors, including: number of operatories, compatibility with your vacuum system, ease of operation, maintenance and replacement frequency, and whether or not waste disposal is included in the contract with the vendor. Cost is also a prime consideration and may range from $300 to over $2000, depending on whether installation and maintenance are included and whether the equipment is leased or owned, and if waste disposal fees are included. Be prepared to shop around for the machine that works best for you. These separators vary widely in sophistication and effectiveness. The following criteria should help you select the right system:
For more information in choosing a separator please see the articles from the JADA and King County Metro.
What about the amalgam sludge waste from the separator?
The most important consideration is whether your separator vendor will be handling this waste as part of your contract or whether you will be responsible for this waste yourself. If your dental office will be managing this waste stream yourselves, you should follow these practices:
How do I handle wastes from chair-side traps?
Chair-side traps are either disposable or reusable. Disposable amalgam traps are preferable to reusable traps because it is difficult to effectively remove amalgam particles from the reusable trap without spilling them into the drain or garbage. Consider replacing size 40 mesh traps with size 100 mesh traps if your suction system can function adequately with the smaller mesh. These finer screens may be more effective at trapping amalgam particles, however, they may require cleaning and changing more often. Change or clean chair-side traps as often as necessary per the manufacturers directions. Use universal precautions when handling the chair-side trap.
Reusable chair-side traps:
Disposable chair-side amalgam traps:
How do I properly manage amalgam from vacuum pump filters?
(located by the central suction pump)
How do I recycle contact and non-contact amalgam?
Salvage and store all contact and non-contact scrap amalgam in separate, appropriately labeled, tightly closed containers. Recycle scrap amalgam through an amalgam recycler or hazardous waste hauler. Follow the requirements of your amalgam recycler for the storage, disinfection and shipping of scrap amalgam.
What should I NOT do with scrap amalgam?
When removing an existing amalgam, remove it in chunks so that it is more likely to be caught in the chair-side trap.
How should I dispose of waste amalgam capsules?
After mixing, amalgam capsules may still contain small amounts of mercury. All capsule waste, including any defective capsules, should be placed in a marked container with other non-contact scrap amalgam and then be recycled. Be sure to check with your amalgam recycler to see if they will take capsules with your scrap amalgam.
Do not dispose of amalgam capsules in the garbage, the red biomedical bag or through incineration. The capsules are hazardous waste and must be properly recycled or disposed through a hazardous waste hauler. Some Washington counties may take amalgam wastes at their hazardous waste collection facility. Contact your county solid waste department to find out if they accept this type of waste. Some companies also take amalgam waste shipped via mail-away containers.
How should I manage elemental mercury?
(also referred to as free, bulk, or raw mercury)
In the event that elemental mercury is present in your dental office:
What questions should dentists ask their amalgam waste service providers?
Should I consider replacing mercury contaminated plumbing?
After your office adopts its new mercury and amalgam management practices, it may be a good time to clean or replace sink traps. Mercury from past practices often settles at low points such as sink traps and sumps. The slow dissolution of the mercury in a sink trap or sump can release mercury into the wastewater for years after past disposal practices have been corrected.
Whenever plumbing parts are removed or cleaned, caution should be taken to avoid spilling the contents in case amalgam or mercury are present. Pour and brush out the sludge and handle it as you would handle contact amalgam. The plumbing parts can then be put back in place or recycled.
What should I do in the case of a mercury spill?
Mercury spill kits are available from a number of sources, including: companies that specialize in Occupational Safety and Health Administration (OSHA) compliance supplies and equipment; amalgam recyclers; and dental product suppliers. Before purchasing a kit, make sure it comes with complete instructions on how to perform a spill clean-up. Train several staff members in proper spill clean-up procedures.
The following steps should be followed in the event of a mercury spill:
What concerns are there with office renovations and mercury spills?
Alert renovators to the possibility of historical mercury spills that may have resulted in the presence of mercury in carpets, floor cracks, behind moldings and other areas where elemental mercury may have been used, or where amalgam capsules may have been spilled.
What should I do with used fixer?
Used fixer from X-ray processing is defined as a dangerous waste because it contains high concentrations of silver – 3,000 to 8,000 parts per million (anything over 5 ppm is dangerous waste). Because of these high silver levels, it’s illegal to put used fixer down the drain, into a septic system or into the garbage.
Which is more cost-effective, on-site or off-site treatment of used fixer?
Using silver recovery units for the management of used fixer only makes economic and practical sense if the flow of used fixer is at least 2-3 gallons per week. Most dental offices generate a gallon or less of used fixer per month; not enough flow to make on site silver recovery cost-effective, due to the cost of buying and periodic replacement of two such units (two are required). Such minimal flow also allows the steel wool in the recovery units to rust between uses, making the units ineffective in as little as 6 months after first use.
What should I do with used developer?
UNUSED developer contains hydroquinone which is a toxic substance, so unused developer cannot go down the drain. Because hydroquinone is used up in the developing process, USED developer is non-hazardous and is safe to be disposed to SEWER.
How should I handle used x-ray film?
Used x-ray film contains silver. If the silver concentration is high enough, the used film would be a dangerous waste. Although most film does not contain enough silver to make it a dangerous waste, the best management practice is to collect it for silver recycling.
What should I do with lead foil?
Lead is a dangerous waste and should not be put in the garbage or in with red bag biomedical waste or sharps.
Are lead lined boxes a concern?
Yes! Dentists who use certain old-fashioned dental boxes to store X-ray film may be unwittingly exposing themselves and patients to dangerous levels of lead, according to an Associated Press story. Dental inspectors in Washington and Wisconsin stumbled onto the bizarre risk after noticing that X-ray film stored in certain boxes had a dusting of white powder.
Laboratory analysis found that the powder was almost 80% lead. Wiping off the powder didn't get rid of the lead, says Food and Drug Administration (FDA) engineer Dave Daly. To keep X-ray film fresh before placing it into patients' mouths, dentists usually store it either a safe distance from X-ray machines or in lead-lined radiation-proof containers specially treated to keep lead from leaching. That's important because lead poisoning can cause serious neurological damage, particularly in children.
But it turns out that some dentists use old-fashioned boxes--often made of wood, shoebox-sized--with an untreated lead lining to store X-ray film. Washington and Wisconsin alerted the FDA that hundreds of such boxes may be in use, Daly says. One dentist told a state inspector that he used his for nostalgic reasons: his dentist father had passed it down.
The FDA issued a nationwide alert telling dentists to throw away X-ray film stored in such boxes. While no illnesses have been reported, "in may cases there are highly dangerous levels of lead on the films, enough to potentially cause serious adverse health effects in patients and health care professionals," the alert warns.
The FDA cautions that the boxes need to be disposed according to each state's safe-lead regulations. The boxes cannot be converted for other use.
How should I handle worn out lead aprons?
When aprons are no longer usable, they must be disposed of as dangerous waste due to their lead content. Keep them out of the landfill and the biomedical waste red bag.
BMPs for Cleaning/disinfecting solutions
How should waste disinfecting solutions be handled?
Disinfectants, cleaning solutions, chemiclave solutions and cold sterilants may designate as dangerous waste depending on their ingredients and concentrations.
What are safe cleansers for flushing the vacuum system?
Flush the vacuum system with disinfecting line solution before changing the chair-side trap. Note: Recent research has suggested that some types of line cleansers, such as those that contain bleach, may solubilize mercury from amalgam particles. This would increase the release of mercury into the dental wastewater. According to the Naval Dental Research Institute, the following line cleansers do not appear to dissolve mercury from amalgam and are alternative disinfectants to bleach:
The best method is to flush the line with an appropriate line cleanser at the end of the day, and then change the trap the next morning before the suction is used. This method will allow the particles in the trap to dry.
An alternative method is to flush the system with a cleaning solution according to the product’s directions; then remove the lid from the trap and allow air to pass through the trap until the contents are dry (usually not more than five minutes).
Copyright © Washington State Department of Ecology. See http://www.ecy.wa.gov/copyright.html.
