Dr. Shyam P Lohani

Usually a by-product of healthcare activities, hospital waste includes sharps, non-sharp blood-contaminated items, blood, body parts and tissues, chemicals, pharmaceuticals, and radioactive materials. Adequate management of healthcare waste reduces the chances of exposure to healthcare workers, waste handlers, patients and their families, and the community of preventable infections, toxic effects, and injuries.
Safe and sound management of healthcare waste involves three key principles which include reduction of generation of wastes, segregation of general trash from hazardous wastes, and waste treatment that lowers risks to health workers and the community. Healthcare activities produce about 80 per cent of general waste. Of the total waste, the remaining 20 per cent is considered hazardous that may be infectious, toxic, genotoxic, and radioactive.

Waste generation
Healthcare waste is generated owing to different activities in different departments. These wastes can be categorised as per their nature. Infectious wastes are those contaminated with blood and their by-products, cultures, and stocks of infectious agents. These wastes are generated from patients in general wards, discarded diagnostic samples containing blood and body fluids, and contaminated materials such as swabs, bandages and equipment such as disposable medical devices.
Infectious wastes are potential to cause diseases to a likely host as they contain sufficient concentration of pathogens. Liquid waste such as faeces, urine, blood, or other bodily secretions like sputum or lung secretions are included in infectious waste. Chemicals used in the diagnostic laboratory, cultures and clinical specimens, slide, culture dish, needle, syringes, as well as radioactive waste such as Iodine-125, iodine -131 are also infectious. Even healthy body parts should be considered infectious waste for precautionary reasons.
Another important category of waste is pharmaceutical waste that includes expired, unused, and contaminated drugs; vaccines, and sera. Bottles, vials used in the handling of pharmaceuticals and drugs and equipment used for the mixing and administration of cytotoxic drugs are also included in this category. Cytotoxic drugs or genotoxic drugs are drugs that have the ability to reduce/stop the growth of certain living cells and are used in chemotherapy for cancer.
Genotoxic waste is highly hazardous, mutagenic, teratogenic, or carcinogenic. Cytotoxic drugs and their metabolites used in cancer treatment are highly harmful. Drugs used in oncology or radiotherapy units that have a high hazardous mutagenic or cytotoxic effects produce genotoxic waste. Faeces, vomit, or urine resulting from patients treated with cytotoxic drugs or chemicals should also be considered as genotoxic.
Radioactive waste includes glassware contaminated with radioactive diagnostic material or radiotherapeutic materials. Liquids, gas, and solids contaminated with radionuclides having ionizing radiations with genotoxic effects are considered as radioactive waste.
Every year an estimated 16,000 million injections are used worldwide. However, the needles and syringes are not properly disposed of after their intended use. Infectious and anatomic wastes comprise of about 15 per cent of the total waste from healthcare activities. Representing only one per cent of the hazardous waste, sharps are a major source of disease transmission if not properly managed. About three per cent of wastes from healthcare activities are generated from pharmaceuticals and chemicals while only one per cent is genotoxic waste, radioactive matter, and heavy metal.
Injections with contaminated syringes caused 21 million hepatitis B virus (HBV) infections, two million hepatitis C virus infections, and 260,000 HIV infections worldwide (WHO, 2000). Those infections were avoidable provided injections were disposed of safely. It is advisable to use disposable syringes and needles for injections that reduce the transmission of infections. Additional hazards occur from scavenging at waste disposal sites and the manual sorting of hazardous waste from healthcare establishments in many developing countries. The immediate risk of needle-stick injuries and exposure to toxic or infectious materials is mainly to those who handle the waste.
The amount of waste generated per bed per day is different for high and low-income countries as it is estimated that high-income countries generate up to 0.5 kg of hazardous waste on average per bed per day in comparison to low-income countries which generate on average 0.2 kg of hazardous waste per hospital bed per day (WHO, 2000).

Proper management
Separation of waste as hazardous and non-hazardous is important for appropriate treatment and disposal of hospital waste. However, such practice is poor in low-income countries that grossly underestimate the real quantity of hazardous waste. Appropriate treatment and safe disposal of healthcare waste reduce risks. However, indirect health risks may occur through the release of toxic pollutants into the environment if that waste is not treated and disposed of safely. Improperly constructed landfills may contaminate drinking water. Occupational risks may occur at disposal facilities that are not well designed, used, and maintained.
The most common methods of management of hospital waste include incineration that has widely been practised throughout the world. However, inadequate incineration or the incineration of unsuitable materials results in the release of pollutants into the air and of ash remained. Known human carcinogens such as dioxine and furans that may cause adverse health effects are generated following incineration of waste containing chlorine compound.
Incineration of waste containing heavy metals or materials with high metal content such as lead, mercury, and cadmium can lead to the spread of toxic metals to the environment. Dioxins, furans, and heavy metals are persistent chemicals and have the potential to bio-accumulate in the environment. Materials containing chlorine or metal should never be incinerated.
The government has recently developed standard operating procedures (SOP) for Nepali healthcare industries (MoHP, 2020). It is urged that all healthcare establishments follow the SOP strictly so as to minimise the risk associated with healthcare waste.

(A Professor, Lohani is the founder and academic director of Nobel College. lohanis@gmail.com)