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 buildings such as schools, hospitals and laboratories should also be inspected for mercury in the drainpipes. Below are some tips for inspecting drainage pipes.

• Mercury tends to sink and deposit at the bottom of pipes. (See Figure 1)
• Mercury is most likely to form in low spots along piping or tilage. (See Figure 2)
• 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.

Hospitals have experience with cleaning mercury out of pipes and traps. Detailed information about appropriate procedures is available in an Infrastructure Report by Beth Israel Hospital to the Massachusetts Water Resources Authority and the Medical Academic and Scientific Community Organization (MASCO), available on the web at http://www.masco.org/mercury/infra/pp.html

Mercury Thermometers

Description: Fever thermometers for home and medical use, laboratory thermometers, and industrial thermometers.

How to Identify: Most industrial thermometers contain mercury. The bulbs of thermometers containing mercury are usually silver in color. Types of mercury thermometers include:

• ASTM and laboratory
• cup case
• industrial thermometers
• incubator/water bath
• minimum/maximum
• sling psychrometer
• tapered bulb
• weather thermometers

Amount of Mercury: Typical fever thermometers contain about 0.5 grams of mercury each, while larger laboratory thermometers contain up to 3 grams of mercury. Industrial thermometers can be even larger.

Alternative Devices: Mercury-free alternatives are digital, aneroid, and alcohol thermometers, and for most applications they are as accurate as mercury thermometers. Digital thermometers tend to last longer, however, because they are less likely to break.

Safe Handling: Mercury thermometers are easily broken when not handled carefully. If a break occurs, use two pieces of paper or two razor blades to scoop it up from a smooth surface. An eyedropper can also be used. Mercury spill kits are available from safety equipment supply companies for larger mercury spills.

Safe Disposal: Homeowners can use local household hazardous waste collection programs for disposal, if available. For businesses:

• Store mercury devices in a suitable leak proof, airtight container, labeled "Mercury Devices for Recycling."
• Be careful to keep the devices from breaking and releasing mercury into the environment.
• If breakage occurs, immediately contain and clean up the spill.

Either:

• Send or take devices to a mercury recycler. Discuss proper shipping methods with the recycler. Or
• Take advantage of subsidized mercury collection/drop-off services for small businesses if your city, county or state environmental or solid waste program offers them.
• Find out whether you must follow any record keeping and other regulatory requirements, depending on the amount of hazardous waste your business generates.

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