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 Mercury in Buildings and Equipment
Overview
Mercury is one of the most widespread, persistent and toxic contaminants in our environment. Its incorporation into many products and its emission from combustion processes has resulted in well documented instances of watercourse poisonings, high level occupational exposures, and worldwide, chronic, low-level environmental exposures. In order to prevent the continued release and build-up of mercury in the environment, many organizations and state and federal agencies are currently working towards eliminating major sources of mercury releases.
Veterinary facilities have traditionally been significant users of mercury-containing devices, although that trend has been reversed in recent years as many facilities have implemented mercury pollution prevention (P2) programs.
As veterinary facilities eliminate mercury-containing devices, it is important to consider where the devices will go. If not properly disposed of, mercury can enter the environment via a number of paths:
- If a mercury-containing item is thrown into the trash and the trash goes to a landfill, the mercury may be released into the atmosphere from landfill vapors or leachate. If the trash is incinerated, mercury vapor will be released into the air.
- If mercury is flushed through a wastewater system, the mercury will probably adhere to the wastewater sludge. It may then be spread on farmland, or may evaporate and be deposited elsewhere.
This section of the web site focuses on facility-related mercury devices, namely batteries, fluorescent light bulbs, and electrical devices. The most common of these items are identified and recommendations are provided for recovery or safe disposal. This section also covers mercury found in pipes and traps.
You can find additional information on mercury in these other areas of the web site:
Much of the information contained in the section is taken from the Wisconsin Mercury Sourcebook. This SourceBook is a compilation of the best mercury reduction work to date. It was designed as a working document to help guide communities through the process of writing comprehensive community mercury reduction plans. The SourceBook provides a seven step outline for drafting a reduction plan, and contains source identification materials for nineteen sectors, including:
- Dentists
- Hospitals and Clinics
- Laboratories
- Nursing Homes
- Veterinary Clinics
Mercury Sources
Facility personnel may encounter mercury-containing devices during routine maintenance or overhaul activities. The following is a list of mercury containing devices that are common to veterinary facilities.
- Fluorescent lamps mercury vapor, metal halide, and high pressure sodium lamps all potentially contain some mercury.
- Mercuric oxide batteries offer a reliable and constant rate of discharge. The larger mercuric oxide batteries (which look like 9-volt or fat AA batteries) are often used in healthcare facilities. Some of the medical devices that require mercuric oxide batteries include cardiac monitors, pH meters, oxygen analyzers and monitors, and telemetry instruments.
- Mechanical tilt switches are activated by a change from a vertical to a horizontal position. These are used in products like thermostats and silent switches. Mercury containing tilt-switches may also be present in or under the lids of clothes washers and chest freezers - they stop the spin cycle or turn on a light. Mercury tilt switches are also found in motion sensitive and position sensitive safety switches in clothes irons or space heaters. If a mechanical switch is not visible in these items, a mercury switch is probably being used.
- Float control switches may be used in septic tank and sump pumps to turn the equipment on and off when water is at a certain level.
- Plunger or displacement relays are used in high current, high voltage applications that could include lighting, resistance heating, or power supply switching.
- Mercury-containing thermostat probes or flame sensors may be found in several types of gas-fired appliances that have pilot lights such as ranges, ovens, clothes dryers, water heaters, furnaces, or space heaters.
- Gauges found in manometers or vacuum gauges may contain mercury.
Recovery and Disposal Options
Important Note: All veterinary employees who handle or manage mercury-containing products should be trained on the proper handling and emergency procedures for these products and for mercury.
All intact mercury devices can be recycled, however, broken devices and mercury cleanup debris must be disposed of as hazardous waste. Recycling is a much less expensive option and should be always considered first. If a device is accidentally broken in the veterinary facility, contact your hazardous waste coordinator and store all of the debris in a sealed plastic container and transfer it to a closed compatible container labeled "Hazardous Waste" (with a description of the contents) and manage it as a hazardous waste (more information on cleanup and disposal).
There should be several convenient collection points for spent lamps within the healthcare facility. Lamps from the collection points should be taken by the hazardous waste management coordinator to the healthcare facility's designated hazardous waste collection point. The lamps can be sorted for recycling or disposal at the collection point. Do not break or crush lamps, unless using a commercial lamp crusher that captures mercury vapor.
For other devices, remove any mercury-containing parts from the equipment. Store the parts in a tightly covered container labeled as to its contents. Parts from switches, thermostats, relays and thermostat probes can be stored in the same container. The container could be located in the supply area of the facility where replacement parts are stored until it is full and ready for transport to the healthcare facility's designated hazardous waste collection point.
The recycling options depend mainly on the type of device, but may also vary by location. Many mercury-containing devices are classified as "universal waste," a special category of hazardous waste. State laws for universal wastes vary and may affect recycling options (use the State Universal Waste Locator to find out the rules in your state). The following recycling options are available to most veterinary facilities:
- Lamps. Fluorescent, mercury vapor, metal halide, and high pressure sodium lamps are all recyclable. Many resources are available for locating a lamp recycling facility in your area. LampRecycle.org is a good place to start looking. It is sponsored by the National Electrical Manufacturers Association (NEMA). Also, see the Waste Reduction – Fluorescent Lamps section of this web site.
- Mercuric oxide batteries. Some battery manufacturers offer recycling programs for mercuric oxide batteries. Check with your battery suppliers to learn if they have collection plans and if they will coordinate packaging and transportation to their facilities. Also, see the Waste Reduction – Batteries section of this web site.
- Mechanical tilt switches present in thermostats. Check with the Thermostat Recycling Corporation. TRC is a private corporation established by thermostat manufacturers Honeywell, General Electric, and White Rodgers. It is a voluntary, industry program that provides a mechanism for the proper disposal of mercury switch thermostats, regardless of brand. This program is active in the 48 contiguous states.
- All other mechanical or float switches, relays, probes, gauges or sensors. Recyclers are available that accept these equipment components. The best options include manufacturer "take-back" programs and commercial mercury recyclers. Also, check with your local and state agencies.
Mercury in Pipes and Traps
Mercury is often found in the plumbing at dentists' offices in the form of amalgam, a compound containing about 50% mercury, which is used in dental fillings. Other healthcare buildings such as hospitals, laboratories and veterinary centers should also be inspected for mercury in the drain pipes. Some tips for inspecting drainage pipes include:
- Mercury tends to sink and deposit at the bottom of pipes.
- Mercury is most likely to form in low spots along piping or tilage.
- Mercury can collect in u-bends below sinks.
- When cutting pipes, be careful not to cut the bottom half of the pipe or lower sections of pipe. This will cause the mercury in the amalgam to vaporize and be dangerous to workers.
When working in a building where significant mercury contamination of pipes and traps is likely, either assume that the sludge is hazardous waste, or get the waste tested by an environmental testing lab or environmental consultant using the Toxicity Characteristic Leaching Procedure.
More Resources
Alternatives to Mercury-containing Light Sources. National Electric Manufacturer's Association (NEMA) presents a brief review of mercury-containing and mercury-free electric lamps that are in current use and those which may be available in future.
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