Introduction
Biomedical waste can be elucidated as any waste generated throughout diagnosis, treatment or immunization of humans or animals, or in research works pertaining thereto, or in the production or testing.1 This incorporates waste products like plastic, latex, glass, metallic foils, sharps, cotton, gauze, extracted teeth and delicate tissues, and dental substances which can be contaminated with body fluids.1 Generated waste can be potentially hazardous and may be a serious threat to human wellbeing if waste handling is indiscriminate. Proper control of dental waste is undoubtedly an important aspect of environmental health safety and must become an integral part of dental services with prevention and minimization of waste being the most practical solution.
History
It is reported that the issue of BMW was first discussed at an assembly convened via the World Health Organization regional office for Europe at Bergen, Norway in 1983. The earnestness of this issue was highlighted all through the “beach wash- ups” of summer 1988. Investigations performed by the Environment Protection Agency (EPA) of USA culminated in the passing of Medical Waste Tracking Act (MWTA), November 1988. Over the years, the problem has taken rounds to be known as a worldwide humanitarian concern.2
In our country, this matter has attracted the heed of the Honorable Supreme Court of India and certain recommendations have been issued. The Bio-medical waste (Management and Handling) Rules 1998 lay down modus operandi for scrapping of BMW. Pollution control boards of each state have been given the responsibility of authorizing and imposing the regulations.2
Categories of Biomedical Waste
There are a total of ten categories mentioned in The Government of India, “Biomedical Waste (Management and Handling) rules” 1998, which have been listed in Table 1 along with their treatment and disposal methods.3
Table 1
Categories of biomedical waste, their segregation and disposal
*There will be no chemical pretreatment before incineration; Chlorinated plastics shall not be incinerated; †Deep burial shall be an option available only in towns with population less than five lakh (5,00,000) and in rural areas; ‡Chemical treatment using at least 1% hypochlorite solution or any other equivalent chemical reagent; It must be ensured that chemical treatment ensures disinfection; §Mutilation/shredding must be such so as to prevent unauthorized reuse
Biomedical waste generated in dental office can be classified as:4
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Dental amalgam wastes
Other scrap heavy metals such as lead foils
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X-Ray processing wastes
Chemicals, dsinfectants and sterilizing agents
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Medical waste
Non hazardous waste
These waste materials can lead to various perils encompassing health and occupational hazards, environmental hazards such as water, air and soil pollution, along with social, economic and political problems. Dental waste also can prove to be critical owing to the presence of dangerous, toxic as well as pathogenic agents, comprising pathological, chemical, pharmaceutical, radioactive, infectious and sharp and cutting waste.
Hazards of Dental Waste
As BMW produced in the dental practice consists of infectious agents, toxic chemicals or pharmaceuticals and sharps, it is all the more risky for people who are exposed to the same. There are health risks to populations, i.e. dentists, dental auxiliaries, patients, waste handling and treatment workers, and overall population as a whole.
Pathogens present in infectious waste can enter the body through a puncture or cut in the skin, with the aid of inhalation or ingestion via mucous membranes. There is a concern about Human Immunodeficiency Virus as well as Hepatitis Virus, for which a robust evidence of transmission via healthcare waste is available. Bacteria that are resistant to antibiotics and disinfectants may also play their part towards hazards created by inappropriately managed waste.3
A good deal of chemical substances is toxic, genotoxic, corrosive, flammable, reactive, explosive or shock sensitive. They may lead to intoxication even in smaller quantities, due to both acute or chronic exposure and injuries, including burns. Disinfectants are utilized in great numbers and can be corrosive. Reactive chemicals may perhaps lead to the formation of highly toxic secondary compounds.3
Radioactive waste is genotoxic and thus may affect genetic material. The effects of exposure range from headache, dizziness, and vomiting to even malignancies.3
Besides health hazards, the overall population is very thoughtful of the visual impression of health‑care waste. There can be esthetic degradation of the surroundings from the careless disposal. There can be several adverse environmental impacts from inappropriate handling of waste. It may lead to changes in microbial ecology and microbial resistance to several anti‑microbial agents. If waste accumulates, it can be a potential health hazard. The reason is that it decomposes and facilitates fly breeding, draws attention of rodents, which when present in the waste may be transported back to man’s meals through flies and dust. There is also a likelihood of water and soil pollution and heaps of waste represents an unsightly appearance and nuisance that occurs from bad odor.3
Biomedical Waste of Concern in Dental Office
Dental waste constitutes a subdivision of hazardous BMW. With an increase in the burden of oral health and the expansion of dental practice, dentistry has made a huge contribution to the production of hazardous BMW in the form of lead foil in X-ray film, chemicals, and dental mercury etc.5 The most common BMW materials of dental concern include:
Mercury (Hg)
It has been several years in the dental profession that mercury as amalgam is being employed as a dental filling material. Mercury is known to be a toxic and bioaccumulative metal. Mercury usually exists in nature in the form of sulfide and various minerals. It is present in elemental, inorganic and organic forms. The dental industry uses approximately 6% of the total annual domestic consumption of mercury, which is estimated to contribute significantly to mercury emissions to wastewater streams (14% in one study). It is also known that mercury has toxic effects on plants, animals and humans.6
Silver
Silver is another heavy metal that can set foot in our water system through improper disposal of dental office waste. The radiographic fixer solution used (commonly used in dental radiograph processing) contains silver. The concentration of silver in the used fixing agent solution is usually 8 to 12 g/L. Another common source of waste in dental clinics is unused films which should not be placed in ordinary garbage. Unused film contains unreacted silver, which may be toxic to the environment.6
Lead
Another by-product of traditional radiography is the protective lead layer contained in each film packet. Although the lead shield itself is small, the accumulated waste generated can be large. Lead is a harmful metal and, if it is thrown away and sent to landfills, it can contaminate soil and groundwater.6
Management of Dental Waste
Medical waste must be managed according to its type and characteristics. For waste management to be effective, waste must be managed at every step, from acquisition to disposal.7 The waste sorting system can ensure that the waste is processed according to the hazard of the waste, and that the correct method of disposal is adopted and the correct transportation equipment is used.
The National Accreditation Board for Hospitals and Healthcare Providers (NABH) recommends certain principles for waste management which are as under:8
Develop a waste management plan, which is based on an assessment of the current situation and minimizes the amount of waste generated.
Separate clinical (infectious) waste from non-clinical waste in a special container.
Use special carts for transportation of waste.
Store waste in specific areas with restricted access.
Sharps should be collected and stored in a sharps container. The sharps container should be made of plastic or metal and have a closable lid. Mark storage areas with biohazard sign.
Make sure that trolleys or carts used for the transport of separate waste collection are not used for any other purpose: they must be cleaned regularly.
Determine the storage area of the waste before disposal or before sending it to the final disposal area.
As per the updated color coding for Biomedical Waste Management (2016), waste should be disposed off in respective color bags as listed below:9
Yellow: Collected in yellow non – chlorinated plastic bags or containers
Human anatomical waste: Human tissues, body parts and organs.
Soiled waste: Blood defiled items, plaster casts, cotton swabs, bag with remaining or discarded blood.
Expired as well as discarded medications: Pharmaceutical waste comprising of ampules along with vials.
Chemical liquid waste: X-ray developing liquid, disposed formalin, contaminated secretions, aspirated fluids, liquid released from laboratories and floor washings.
Microbiology, Biotechnology & laboratory waste: Culture media, specimens of microorganisms, live/attenuated vaccines.
Disposal of mercury containing waste
Management of waste containing vaporous mercury includes:10
Storage of unused mercury in leak-proof containers.
Communication with a certified biomedical waste carrier (CWC) with regard to disposal and recycling..
Use a “mercury spill kit” in case of a spillage incident.
Not disposing off elemental mercury in the garbage.
Avoid washing elemental mercury in the drain.
Using disposable amalgam separators on dental suction devices in order to prevent amalgam accumulation.
Required amalgam amount only mixed or use premeasured amalgam capsules.
Use mercury containers to store all scrap/old amalgam.
Disposal of sharps
Sharp objects are considered highly hazardous medical waste because they can cause injuries and stab wounds. Due to exposure to contaminated sharp objects, there is always a risk of transmission of blood-borne pathogens (such as HIV, Hepatitis B, and Hepatitis C).
The needle should be destroyed with a needle destroyer or a syringe melting and disposing system. Crushed sharp tools should be placed in a puncture-proof sharps container, which should contain 1% NaOCl for disinfection. After the container is three-quarters full, it must be sent to the common treatment facility for shredding, packaging, and disposal in a landfill.11
Green Dentistry
Green or Eco-friendly dentistry is an upcoming and emerging trend in the dental profession. It aims at diminishing the overall environmental impact of dental practice in shifting towards an ecologically sustainable health care system by incorporating a high-tech perspective. Reducing the generation of BMW in the dental office is one of the components of green dentistry. Green dentistry is a whole - earth initiative to tooth care that lessens the pessimistic environmental viewpoint of dentistry and builds a caring environment for humans. It is based on the model of four R’s – Rethink, Reduce, Reuse and Recycle.9
Conclusion
As healthcare practitioners, we as dentists should be concerned about promoting not just human health along with well-being, but also that of the environment. Biomedical Waste management programs cannot be a success in the absence of the required devotion, self-motivation, willingness, cooperation and participation of all the employees of health care sectors. Dental practitioners need to be educated via educational programs regarding the correct waste disposal methods to improve their practical abilities in the dental office. A holistic approach will definitely help our profession to triumph in today’s world of increased public environmental concern and protective litigation.
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