IMPACT OF MEDICAL WASTE DISPOSAL
HEALTH-CARE activities protect and restore health and save lives. But what about the waste and by-products they generate?
Of the total amount of waste generated by health-care activities, about 85 percent is general, non-hazardous waste comparable to domestic waste.
According to the World Health Organisation, ( WHO), the remaining 15 percent is considered hazardous material that may be infectious, chemical or radioactive.
Types of waste
Waste and by-products cover a diverse range of materials, as the following list illustrates:
• Infectious waste: waste contaminated with blood and other bodily fluids (e.g. from discarded diagnostic samples), cultures and stocks of infectious agents from laboratory work (e.g. waste from autopsies and infected animals from laboratories), or waste from patients with infections (e.g. swabs, bandages and disposable medical devices);
• Pathological waste: human tissues, organs or fluids, body parts and contaminated animal carcasses;
• Sharps waste: syringes, needles, disposable scalpels and blades, etc.;
• Chemical waste: for example solvents and reagents used for laboratory preparations, disinfectants, sterilants and heavy metals contained in medical devices (e.g. mercury in broken thermometers) and batteries;
• Pharmaceutical waste: expired, unused and contaminated drugs and vaccines;
• Cytotoxic waste: waste containing substances with genotoxic properties (i.e. highly hazardous substances that are, mutagenic, teratogenic or carcinogenic), such as cytotoxic drugs used in cancer treatment and their metabolites;
• Radioactive waste: such as products contaminated by radionuclides including radioactive diagnostic material or radiotherapeutic materials; and
• Non-hazardous or general waste: waste that does not pose any particular biological, chemical, radioactive or physical hazard.
The major sources of health-care waste are:
• hospitals and other health fa
cilities
• laboratories and research centres
• mortuary and autopsy centres
• animal research and testing laboratories
• blood banks and collection services
• nursing homes for the elderly
High-income countries generate on average up to 0.5 kg of hazardous waste per hospital bed per day; while low-income countries generate on average 0.2 kg.
However, health-care waste is often not separated into hazardous or non-hazardous wastes in low-income countries making the real quantity of hazardous waste much higher.
Health risks
Health-care waste contains potentially harmful microorganisms that can infect hospital patients, health workers and the general public. Other potential hazards may include drug-resistant microorganisms which spread from health facilities into the environment.
Adverse health outcomes associated with health care waste and by-products also include:
• sharps-inflicted injuries;
• toxic exposure to pharmaceutical products, in particular, antibiotics and cytotoxic drugs released into the surrounding environment, and to substances such as mercury or dioxins, during the handling or incineration of health care wastes; • chemical burns arising in the context of disinfection, sterilization or waste treatment activities;
• air pollution arising as a result of the release of particulate matter during medical waste incineration;
• thermal injuries occurring in conjunction with open burning and the operation of medical waste incinerators; and
• radiation burns.
Sharps-related
Worldwide, an estimated 16 billion injections are administered every year. Not all needles and syringes are disposed of safely, creating a risk of injury and infection and opportunities for reuse.
Injections with contaminated needles and syringes in low- and middle-income countries have reduced substantially in recent years, partly due to efforts to reduce reuse of injection devices.
Despite this progress, in 2010, unsafe injections were still responsible for as many as 33, 800 new HIV infections, 1.7 million hepatitis B infections and 315, 000 hepatitis C infections.
A person who experiences one needle stick injury from a needle used on an infected source patient has risks of 30%, 1.8 percent, and 0.3 percent respectively of becoming infected with HBV, HCV and HIV.
Additional hazards occur from scavenging at waste disposal sites and during the handling and manual sorting of hazardous waste from health-care facilities.
These practices are common in many regions of the world, especially in low- and middle-income countries.
The waste handlers are at immediate risk of needle-stick injuries and exposure to toxic or infectious materials.
In 2015, a joint WHO/UNICEF assessment found that just over half (58 percent) of sampled facilities from 24 countries had adequate systems in place for the safe disposal of health care waste.
Environmental Impact
Treatment and disposal of healthcare waste may pose health risks indirectly through the release of pathogens and toxic pollutants into the environment.
• The disposal of untreated health care wastes in landfills can lead to the contamination of drinking, surface, and ground waters if those landfills are not properly constructed.
• The treatment of health care wastes with chemical disinfectants can result in the release of chemical substances into the environment if those substances are not handled, stored and disposed in an environmentally sound manner.
• Incineration of waste has been widely practised, but inadequate incineration or the incineration of unsuitable materials results in the release of pollutants into the air and in the generation of ash residue. Incinerated materials containing or treated with chlorine can generate dioxins and furans, which are human carcinogens and have been associated with a range of adverse health effects. Incineration of heavy metals or materials with high metal content (in particular lead, mercury and cadmium) can lead to the spread of toxic metals in the environment.
• Only modern incinerators operating at 850-1100 °C and fitted with special gas-cleaning equipment are able to comply with the international emission standards for dioxins and furans.
• Alternatives to incineration such as autoclaving, microwaving, steam treatment integrated with internal mixing, which minimise the formation and release of chemicals or hazardous emissions should be given consideration in settings where there are sufficient resources to operate and maintain such systems and dispose of the treated waste.
Waste management: reasons for failure
Lack of awareness about the health hazards related to health-care waste, inadequate training in proper waste management, absence of waste management and disposal systems, insufficient financial and human resources and the low priority given to the topic are the most common problems connected with health-care waste. Many countries either do not have appropriate regulations, or do not enforce them.
The way forward
The management of health-care waste requires increased attention and diligence to avoid adverse health outcomes associated with poor practice, including exposure to infectious agents and toxic substances.
( The author is a communication expert specialised in Agriculture, Environment and Public Health Journalism) Comment: +260977694310