Mercury in the Lab, What can you do?

Mercury, a potent and persistent bioaccumultive neurotoxin is on the Environmental Protection Agency’s (EPA) list of the most dangerous chemicals on the planet. Because of this, the EPA and the AmericanHospital Association (AHA) are working to reduce or eliminate mercury waste from the healthcare sector. In light of these efforts, the CAP has issued the following recommendations on mercury reduction in medical laboratories.

Recommendations to the CAP Membership on Mercury Reduction

The College recommends that laboratories evaluate moving toward reducing or eliminating mercury. The CAP Laboratory Accreditation Program currently includes a checklist question pertaining to mercury as follows:

Checklist questions pertaining to adherence to local regulations and handling of hazardous materials are already well established.

Background

In medical laboratories, mercury has long been considered the standard for use as an oxidizer, mordant and preservative. This was the case before viable alternatives existed that yield high quality, accurate results. Mercury is a potent neurotoxin, a persistent bioaccumultive toxin and on the Environmental Protection Agency (EPA) list of the most dangerous chemicals on the planet. Mercury is persistent in the environment and in living organisms, bioaccumulates over time and is extremely toxic even in small doses.

The EPA and the American Hospital Association (AHA) are working to reduce or eliminate mercury waste from the healthcare sector. Hospitals for a Healthy Environment (H2E), www.sustainablehospitals.org is an organization created to provide advice, resources and a communication network for the community in support of the EPA/AHA initiative. Industry is moving rapidly toward mercury free alternatives for the many products affected. The medical laboratory is also being challenged to find alternatives to the mercury containing fixatives commonly used in histopathology laboratories.

The CAP recommends a phased-in approach to mercury reduction. Understanding your current practices, including disposal, and doing an inventory of mercury-containing items is the first phase.

Phase 1

Policy

• Develop a policy that states a preference for non-mercury containing items when available, prioritize elimination of items for which there is a ready and reliable substitute, (e.g. thermometers, sphygmomanometers, barometers and batteries), and require proper management of mercury-containing items including waste collection, spill control and training.

Inventory

• Identify, inventory and label those items and reagents containing mercury.

Regulations

• Ensure that all mercury-containing items and reagents are managed properly when disposed of. Mercury is prohibited from general trash, and may be considered hazardous waste and prohibited from sewer disposal. Check with your local regulatory authority on disposal methods for mercury-containing items and reagents. It must be recognized that state and local regulations vary, and what may be voluntary at the federal level, may be mandatory at the state or local level. The CAP suggests you contact your local authorities to determine the specific compliance requirements pertaining to your facility. In many states, discharging mercury-containing wastes down the drain may be a serious violation and the disposal and purchase of mercury is increasingly being regulated at the federal, state and local levels.

Phase 2

Comparability

The number one concern for pathologists is the comparability of results with mercury-free alternatives.

• Set up and run parallel blind testing for procedures that will require your approval for change.
• Plan and/or replace equipment that uses mercury-containing reagents or parts with mercury-free alternatives.

Cost

If a facility is managing their mercury-containing wastes as hazardous chemical wastes according to EPA’s Resource Conservation and Recovery Act (RCRA) standard, switching to a mercury-free alternative may introduce a significant cost savings.

Phase 3

Conversion

Following successful parallel testing, immediate conversion to an alternative solution is recommended. Alternatives for the following have been used effectively:

• B-5 fixative
• Harris Hematoxylin
• Zenker's Solution
• Schaudinn's fixative

Note:

Test kits that use horseradish peroxidase as the enzyme probably use thimerosal, a mercury-containing preservative. Use the package insert to determine if a kit uses mercury. If this information is not readily available in the insert, contact the manufacturer.

Below is a partial list of tests which may be affected:

• Fertility markers test kits (FSH, LH, HCG, prolactin)
• Tumor marker test kits (PSA, AFP, ferritin, CEA)
• Human growth hormone test kits
• Allergy test kits (IgE, IgG)
• Cardiac marker test kits (troponin, CRP, myoglobin, homosysteine)

Ongoing Efforts to Identify Suitable Substitutions

The following substances/procedures for which more research and development may need to be done to identify suitable substitutions:

• Cajal's stain
• Carnoy-Lebrun method
• Channing's solution
• Formal sublimate fixative
• Hayem’s blood counting fluid for red cells
• Helly’s fixative
• Millon's reagent
• Muir’s capsule stain mordant
• Nessler reagent
• Mallory's Phosphotungstic Acid - Hematoxylin Stain (modified) PTAH
• Stabilur tablets
• Stieve's fixative
• Susa fixative
• Ziehl-Neilson method

References

Included with these recommendations is a list of mercury-free alternatives. The CAP has not verified or validated the specific information regarding these alternatives.

Alternatives for B-5 Mercury Based Fixatives

AZF Fixative
Newcomer Supply
800-383-7799 - http://www.newcomersupply.com/home.html

• AZF (Acetic Zinc Formalin) Working Solution is a replacement for B-5 mercury based fixatives.

B-Plus Fixative(TM)
BBC Biochemical
800-635-4477 - http://www.bbcus.com

• Replacement for B-5 fixative, contains formaldehyde and zinc -- may be disposal considerations.
• B-Plus is designed to fix lymphoid and hematopoietic tissues without the use of mercury

B-5 Fixative Modified
Newcomer Supply
800-383-7799 - http://www.newcomersupply.com/home.html

• B-5 Fixative Modified is a Zinc Chloride-Stock Solution used as an alternative to mercury based fixatives.

Histo-Fix
Trend Scientific, Inc (Division of Richard-Allan)
800-522-7270

• Formalin-free fixative; aqueous mixture of pyrrolid-2-one, polyol, urea, and a zinc salt

Z-5
Anatech Ltd.
800-ANATECH - http://www.anatechltdusa.com

• Replacement product for B-5, contains formaldehyde and zinc -- may be disposal considerations

Zenkers Fixative Modified
Newcomer Supply
800-383-7799 - http://www.newcomersupply.com/home.html

• Zenker's Fixative Modified with zinc chloride contains no mercury

Zinc Formal-Fixx
Shandon, Inc.
800-245-6212 - http://www.shandon.com

• Formaldehyde fixative, contains zinc - may be disposal considerations

Alternative Stains

Harris Hematoxylin
Anatech Ltd.
800-ANATECH - http://www.anatechltdusa.com

• Hematoxylin stain with alcohol, acetic acid, Al-ammonium sulfate, sodium iodate

Thimerisol Alternatives

Methyl paraben, Propyl paraben, Thymol
No direct substitutes are available for thimerisol. However the replacement of thimerisol can be effected by knowing the properties of the solution containing thimerisol and matching those properties with a suitable substitute preservative. For many solutions, methyl and propyl paraben have been used successfully, as has thymol. Thymol has been used for many years to inhibit microbial growth in stain solutions.

Parasitology Fixatives

Alpha-Tec Systems PROTO-Fix Parasitology Fixative
Alpha-Tec Systems
360-260-2779, http://www.alphatecsystems.com

• Single vial fixative for concentration, permanent stain, EIA, IFA and PCR procedures
• Contains no mercury, zinc, copper or other heavy metals
• Proto-fix has no controlled hazardous chemicals regulated for disposal or transport

SAF Fixative
Medical Chemical Corporation
(800) 424-9394 - http://www.med-chem.com/

• SAF (Sodium Acetate Acetic Acid Formalin) is a mercury-free alternative to PVA for Parasitology.

Zinc-PVA - paracytology transport vials
Medical Chemical Corporation
Carol Santaloci, Account Representative
800-252-1125 - http://www.med-chem.com

• Z-PVA mercury-free fixative is a replacement for mercuric chloride PVA
• For permanent staining