Until fairly recently, medical waste management was not generally considered an issue. In the 1980s and 1990s, concerns about exposure to human immunodeficiency virus (HIV) and hepatitis B virus (HBV) led to questions about potential risks inherent in medical waste. Thus hospital waste generation has become a prime concern due to its multidimensional ramifications as a risk factor to the health of patients, hospital staff and extending beyond the boundaries of the medical establishment to the general population.
Hospital waste refers to all waste, biologic or non biologic that is discarded and not intended for further use. Medical waste is a subset of hospital waste; it refers to the material generated as a result of diagnosis, treatment or immunization of patients and associated biomedical research. Biomedical waste (BMW) is generated in hospitals, research institutions, health care teaching institutes, clinics, laboratories, blood banks, animal houses and veterinary institutes.
Although very little disease transmission from medical waste has been documented, both the American Dental Association (ADA) and Center for Disease Control recommend that medical waste disposal must be carried out in accordance with regulation.
Hospital waste management has been brought into focus in India recently, particularly with the notification of the BMW (Management and Handling) Rules, 1998. The rule makes it mandatory for the health care establishments to segregate, disinfect and dispose their waste in an eco-friendly manner.
POTENTIAL IMPLICATIONS OF BIOMEDICAL WASTE
Risk to healthcare workers and waste handlers
Improperly contained contaminated sharps pose greatest infectious risk associated with hospital waste. There is also theoretical health risk to medical waste handlers from pathogens that may be aerosolized during the compacting, grinding or shredding process that is associated with certain medical waste management or treatment practices. Physical (injury) and health hazards are also associated with the high operating temperatures of incinerators and steam sterilizers and with toxic gases vented into the atmosphere after waste treatment.
Risk to the public
Public impacts are confined to esthetic degradation of the environment from careless disposal and the environmental impact of improperly operated incinerators or other medical waste treatment equipment.
There may be increased risk of nosocomial infections in patients due to poor waste management. Improper waste management can lead to change in microbial ecology and spread of antibiotic resistance.
This constitutes about 85% of the waste generated in most healthcare set-ups. This includes waste comprising of food remnants, fruit peels, wash water, paper cartons, packaging material etc.
A) Potentially infectious waste
Over the years different terms for infectious waste have been used in the scientific literature, in regulation and in the guidance manuals and standards. These include infectious, infective, medical, biomedical, hazardous, red bag, contaminated, medical infectious, regulated and regulated medical waste. All these terms indicate basically the same type of waste, although the terms used in regulations are usually defined more specifically. It constitutes 10% of the total waste which includes:
- Dressings and swabs contaminated with blood, pus and body fluids.
- Laboratory waste including laboratory culture stocks of infectious agents
- Potentially infected material: Excised tumours and organs, placenta removed during surgery, extracted teeth etc.
- Potentially infected animals used in diagnostic and research studies.
- Sharps, which include needle, syringes, blades etc.
- Blood and blood products.
B) Potentially toxic waste
- Radioactive waste: It includes waste contaminated with radionuclide; it may be solid, liquid or gaseous waste. These are generated from in vitro analysis of body fluids and tissue, in vitro imaging and therapeutic procedures.
- Chemical waste: It includes disinfectants (hypochlorite, gluteraldehyde, iodophors, phenolic derivatives and alcohol based preparations), X-ray processing solutions, monomers and associated reagents, base metal debris (dental amalgam in extracted teeth).
- Pharmaceutical waste: It includes anesthetics, sedatives, antibiotics, analgesics etc.
STEPS IN WASTE MANAGEMENT
Medical waste should be managed according to its type and characteristics. For waste management to be effective, the waste should be managed at every step, from acquisition to disposal. The following are the elements of a comprehensive waste management system: waste survey, segregation, accumulation and storage, transportation, treatment, disposal and also waste minimization.
The survey should differentiate and quantify the waste generated. It should determine the points of generation, the type of waste at each point and the level of generation and disinfection within the hospital. This helps to determine the method of disposal.
This consists of placing different kinds of wastes in different containers or coded bags at the point of generation [Table 1]. It helps to reduce the bulk of infectious waste as well as treatment costs. Segregation also helps to contain the spread of infection and reduces the chances of infecting other health care workers.
Waste accumulation and storage
Waste accumulation and storage occurs between the point of waste generation and site of waste treatment and disposal. While accumulation refers to the temporary holding of small quantities of waste near the point of generation, storage of waste is characterized by longer holding periods and large waste quantity. Storage areas are usually located near where the waste is treated. Any offsite holding of waste is also considered storage.
To contain spills, storage areas should not have floor drains and should be recessed to hold liquids. Floor and walls should be impervious to liquid and easy to clean. They should be disinfected regularly. Refrigeration may be required for prolonged storage of putrifiable and other wastes. Storage area should be posted with 'EXPLICIT' signs.
When medical waste is not treated on site, untreated waste must be transported from the generation facility to another site for treatment and disposal.
The term 'treatment' refers to the process that modifies the waste in some way before it is taken to its final resting place. Treatment is mainly required to disinfect or decontaminate the waste, right at source so that it is no longer the source of pathogenic organisms. After such treatment, the residue can be handled safely, transported and stored.
- Needles and syringe nozzle - shredded in needle destroyer and syringe cutters
- Scalpel blades/ Lancet/ Broken glass should be put in separate containers with bleach, transferred to plastic/ cardboard boxes; sealed to prevent spillage and transported to incubators
- Glassware should be disinfected, cleaned and sterilized
- Culture plates with viable culture should be autoclaved; media are placed in appropriate bags and disposed off. The plates can be reused after sterilization
- Gloves should be shredded / cut / mutilated before disposal.
- Swabs should be chemically disinfected followed by incineration. If they contain only a small amount of blood that does not drip, they can be placed in the garbage.
- Disposable items are often recycled and have the risk of being used illegally. Dipping in freshly prepared 1% sodium hypochlorite for 30 min. - one hour, followed by mutilation before disposal should be the policy adopted for such items.
- Under no circumstances, should heat be used for disposal of amalgam. The heat will cause mercury to volatize and be released to the environment. So teeth with amalgam restoration should be treated by immersion in high-level disinfectant (e.g. Gluteraldehyde) for 30 min. Treated teeth can then be rinsed.
- Liquid waste generated by the laboratory is either pathological or chemical in nature. Non-infectious waste should be neutralized with reagents.
- Liquid infectious waste should be treated with a chemical disinfectant for contamination and then neutralized.
The waste disposal methods vary in their capabilities, cost, availability to generation and impacts on the environment. The various disposal methods include incineration, autoclaving, chemical methods, thermal methods (low and high), ionizing radiation process, deep burial and microwaving [Table 2].
Incineration and autoclaving are considered traditional methods. Chitnis et al . have devised a solar heating system for disinfecting infectious waste in economically less developed countries. They obtained a considerable reduction in the amount of viable bacteria by this method. However, 'considerable reduction in viable number of bacteria' seems to be misleading term. The medical waste should be completely free of pathogenic bacteria before disposal. This would ensure maximum public hygiene quality.
Untreated medical waste can be disposed off in sanitary landfills. Disposal without treatment is not recommended for human tissues, sharps and culture from clinical laboratories.
Whereas ordinary solid or liquid waste requires no treatment before disposal, practically all infectious waste must first be treated. The cost for disposal of infectious waste may be ten times the cost for disposal of ordinary solid waste. Any measures that decrease the amount of infectious waste generated will simultaneously decrease the cost of infectious waste disposal.
Cost of biomedical waste management
The cost of construction, operation and maintenance of system for managing waste represents a significant part of overall budget of a hospital if the BMW handling rules have to be implemented in their true spirit. Self-contained on-site treatment methods may be desirable and feasible for large healthcare facilities. They will not be practical or economical for smaller institutes. An acceptable common system should be in place which will provide regular supply of color coded bags, daily collection of infectious waste, safe transportation of waste to off site treatment facility and final disposal with suitable technology.
DENTAL WASTES OF ENVIRONMENTAL CONCERN
Dental Amalgam particles are a source of mercury, which is known to be neurotoxic and nephrotoxic. Fetuses and newborn babies are more sensitive to mercury than adults and there seems to be a great difference in sensitivity among individuals.
Management includes disposal of amalgam scrap as hazardous waste or more aptly sent to a recycler. Waste mercury is disposed similarly. Empty amalgam capsules are to be disposed off in the garbage. Since amalgam decomposes on heating; amalgam scrap should not be disposed in the waste that could eventually be incinerated.
To minimize the amount of mercury vapour emitted from waste amalgam, ADA recommends that it be stored under a small amount of photographic fixer in a closed container. It should be labeled as 'scrap amalgam'.
- X-ray fixer solution: It is considered a hazardous waste because of its high silver content. In the environment, free ionic silver acts as an enzyme inhibitor by interfering with the metabolic processes of organisms. These have to be disposed off as a hazardous waste or sent to a silver recovery system.
- X-ray developer solution: Developer solution can typically go into the wastewater drain. Developer and fixer solutions should not be mixed with fixer solutions. If mixed, they should be separated and treated independently as required.
- X-ray cleaner solution: Many cleaners for X-ray developer system contain chromium. If the cleaner solution used contains chromium, it should be disposed as a hazardous waste or switch to a non-chrome cleaner.
- X-ray lead foil / lead shields: The lead foils and lead shields contain pure lead. Lead is a heavy metal that affects neurological development and functions and can potentially leach from landfills into the environment. These are hazardous waste unless they are recycled for their scrap metal content or disposed off as hazardous waste.
PLASTIC IN HEALTH CARE
Disposable syringes, bottles, blood and uro bags, catheters, surgical gloves, etc are some of the examples of plastic usage in health care. Plastic has been associated with decline in sperm count, genital abnormalities and a rise in the incidence of breast cancer. Burning of plastics releases carcinogens like dioxin and furan. Once hailed as a 'wonder material', plastic is now a serious environmental and health concern, essentially due to its non-biodegradable nature. The options for plastic waste disposal are environmentally compatible long-term land filling or recycling. All disposable plastic should be subjected to shredding before disposing off to vendor. Designing eco-friendly, biodegradable plastics are the need of the hour. Minimizing the generation of plastic waste is also very important.
Safe and effective management of waste is not only a legal necessity but also a social responsibility. Lack of concern, motivation, awareness and cost factor are some of the problems faced in the proper hospital waste management. Proper surveys of waste management procedures in dental practices are needed. Clearly there is a need for education as to the hazards associated with improper waste disposal. Lack of apathy to the concept of waste management is a major stymie to the practice of waste disposal. An effective communication strategy is imperative keeping in view the low awareness level among different category of staff in the health care establishments regarding biomedical waste management.
Proper collection and segregation of biomedical waste are important. At the same time, the quantity of waste generated is equally important. A lesser amount of biomedical waste means a lesser burden on waste disposal work, cost-saving and a more efficient waste disposal system. Hence, health care providers should always try to reduce the waste generation in day-to-day work in the clinic or at the hospital.
1. Gordon JG, Rein Hardt PA, Denys GAMayhall CG. Medical waste management Hospital epidemiology and infection control. 20043rd Lippincott Williams and Wilkins publication:1773–85
2. Rao SK, Ranyal RK, Bhatia SS, Sharma VR. Biomedical waste management: An infrastructural survey of hospitals MJAFI. 2004;60(4)
3. Rutala WA, Weber DJ. Disinfection, sterilization and control of hospital waste Mandell, Douglas and Bennett's Principles and practice of infectious diseases. 20056th Elsevier Churchill Livingstone Publication:3331–47
4. Sharma M Hospital waste management and its monitoring. 20021st Jaypee Brothers Medical Publication
5. Harrison B. States act to regulate medical waste JADA. 1991;122:118–20
6. . Environment management for control of hospital infections: Proceedings of 7th
conference of hospital infection society - India CME. 9 January 2003 Vellore CMC
7. Manual for control of hospital associated infection: Standard operative procedures. 1999 Delhi National AIDS control organization:50–66
8. Laboratory diagnosis, biosafety and quality control. Delhi National institute of communicable diseases and national AIDS control organization:26–41
9. Seymour Block S Disinfection, sterilization and preservation. 20015th Lippincott Williams and Wilkins publication
10. Wilson HF, Edward Bellinger G, Mjor A. Dental practice and the environment Int Dent J. 1998;48:161–6
11. Cocchiarella L, Scott Deitchman D, Young D. Biohazardous waste management: What the physicians need to know Arch Fam Med. 2000;9:26–9
13. Preben Horsted - Bindslev. . Amalgam toxicity - environmental and occupational hazards J Dentist. 2004;32:359–65
14. Available from: http://www.p2pays.org/ret/01/00020htm
for more information
15. Available from: http.//www.cdphe.state.co.us/hw/photopdf
. for more information
16. Drummond L, Michael Cailas D, Croke K. Mercury generation potential from dental waste amalgam J Dentist. 2003;31:493–501
18. Fan PL, Bindslev DA, Schmalz G, Halbach S, Berendsen H. Environmental issues in dentistry - mercury Int Dental J. 1997;47:105–9
19. Available from: http.//www.plasticsresource.com
. for more information
20. Chitnis V, Chitnis S, Patil S, Chitnis D. Solar disinfection of infectious biomedical waste: A new approach for developing countries Lancet. 2003;362:1285–6