HEALTH TOPICS A TO Z

Health-care activities - for instance, immunizations, diagnostic tests, medical treatments, and laboratory examinations - protect and restore health and save lives. But what about the wastes and by-products they generate?

From the total of wastes generated by health-care activities, almost 80% are general waste comparable to domestic waste. The remaining approximate 20% of wastes are considered hazardous materials that may be infectious, toxic or radioactive. The wastes and by-products cover a diverse range of materials, as the following list illustrates (percentages are approximate values):

• Infectious wastes -- cultures and stocks of infectious agents, wastes from infected patients, wastes contaminated with blood and its derivatives, discarded diagnostic samples, infected animals from laboratories, and contaminated materials (swabs, bandages) and equipment (disposable medical devices etc.); and
• Anatomic - recognizable body parts and animal carcasses.

Infectious and anatomic wastes together represent the majority of the hazardous waste, up to 15% of the total waste from health-care activities.

• Sharps -- syringes, disposable scalpels and blades etc.

Sharps represent about 1% of the total waste from health-care activities.

• Chemicals -- for example solvents and disinfectants; and
• Pharmaceuticals -- expired, unused, and contaminated; whether the drugs themselves (sometimes toxic and powerful chemicals) or their metabolites, vaccines and sera .

Chemicals and pharmaceuticals amount to about 3% of waste from health-care activities.

• Genotoxic waste -- highly hazardous, mutagenic, teratogenic1 or carcinogenic, such as cytotoxic drugs used in cancer treatment and their metabolites; and
• Radioactive matter, such as glassware contaminated with radioactive diagnostic material or radiotherapeutic materials;
• Wastes with high heavy metal content, such as broken mercury thermometers.

Genotoxic waste, radioactive matter and heavy metal content represent about 1% of the total waste from health-care activities.

The major sources of health-care waste are hospitals and other health-care establishments, laboratories and research centres, mortuary and autopsy centres, animal research and testing laboratories, blood banks and collection services, and nursing homes for the elderly.

High-income countries can generate up to 6 kg of hazardous waste per person per year. In the majority of low-income countries, health-care waste is usually not separated into hazardous or non-hazardous waste. In these countries, the total health-care waste per person per year is anywhere from 0.5 to 3 kg.

Health impacts

Health-care waste is a reservoir of potentially harmful micro-organisms which can infect hospital patients, health-care workers and the general public. Other potential infectious risks include the spread of, sometimes resistant, micro-organisms from health-care establishments into the environment. These risks have so far been only poorly investigated. Wastes and by-products can also cause injuries, for example radiation burns or sharps-inflicted injuries; poisoning and pollution, whether through the release of pharmaceutical products, in particular, antibiotics and cytotoxic drugs, through the waste water or by toxic elements or compounds such as mercury or dioxins.

Sharps

Throughout the world every year an estimated 12 000 million injections are administered. And not all needles and syringes are properly disposed of, generating a considerable risk for injury and infection and opportunities for re-use.

• Worldwide, 8-16 million hepatitis B, 2.3 to 4.7 million hepatitis C and 80 000 to 160 000 HIV infections are estimated to occur yearly from re-use of  syringe needles without sterilization2.  Many of these infections could be avoided if syringes were disposed of safely. The re-use of disposable syringes and needles for injections is particularly common in certain African, Asian and Central and Eastern European countries.
• Regarding injection practices, public health authorities in West Bengal, India, have recommended a shift to re-usable glass syringes, as the disposal requirements for disposable syringes could not be enforced.
• In developing countries, additional hazards occur from scavenging on waste disposal sites and manual sorting of the waste recuperated at the back doors of health-care establishments. These practices are common in many regions of the world. The waste handlers are at immediate risk of needle-stick injuries and other exposures to toxic or infectious materials.

Vaccine waste

In June 2000, six children were diagnosed with a mild form of smallpox (vaccinia virus) after having played with glass ampoules containing expired smallpox vaccine at a garbage dump in Vladivostok (Russia). Although the infections were not life-threatening, the vaccine ampoules should have been treated before being discarded.

Radioactive wastes

The use of radiation sources in medical and other applications is widespread throughout the world. Occasionally, the public is exposed to radioactive waste, usually originating from radiotherapy treatments, that has not been properly disposed of. Serious accidents have been documented in Goiânia, Brazil in 1988 in which four people died from acute radiation syndrome and 28 suffered serious radiation burns. Similar accidents happened in Mexico City in 1962, Algeria in 1978, Morocco in 1983 and Ciudad Juárez in Mexico in 1983.

Risks associated with other fractions of health-care wastes, in particular blood waste and chemicals, have been relatively poorly assessed, and need to be strengthened. In the meantime, precautionary measures need to be taken.

Risks associated with waste disposal

Although treatment and disposal of health-care wastes aim at reducing risks, indirect health risks may occur through the release of toxic pollutants into the environment through treatment or disposal.

• Landfilling can potentially result in contamination of drinking water. Occupational risks may be associated with the operation of certain disposal facilities. Inadequate incineration, or incineration of materials unsuitable for incineration can result in the release of pollutants into the air. The incineration of materials containing chlorine can generate dioxins and furans3, which are classified as possible human carcinogens and have been associated with a range of adverse effects. Incineration of heavy metals or materials with high metal contents (in particular lead, mercury and cadmium) can lead to the spread of heavy metals in the environment. Dioxins, furans and metals are persistent and accumulate in the environment. Materials containing chlorine or metal should therefore not be incinerated.
• Only modern incinerators are able to work at 800-1000 °C, with special emission-cleaning equipment, can ensure that no dioxins and furans (or only insignificant amounts) are produced. Smaller devices built with local materials and capable of operating at these high temperatures are currently being field-tested and implemented in a number of countries.
• At present, there are practically no environmentally-friendly, low-cost options for safe disposal of infectious wastes. Incineration of wastes has been widely practised, but alternatives are becoming available, such as autoclaving, chemical treatment and microwaving, and may be preferable under certain circumstances. Landfilling may also be a viable solution for parts of the waste stream if practised safely. However, action is necessary to prevent the important disease burden currently created by these wastes.

In addition, perceived risks related to health-care waste management may be significant. In most cultures, disposal of health-care wastes is a sensitive issue and also has ethical dimensions.

Waste management -- reasons for failure

The absence of waste management, lack of awareness about the health hazards, insufficient financial and human resources and poor control of waste disposal are the most common problems connected with health-care wastes. Many countries do not have appropriate regulations, or do not enforce them. An essential issue is the clear attribution of responsibility of appropriate handling and disposal of waste. According to the 'polluter pays' principle, this responsibility lies with the waste producer, usually being the health-care provider, or the establishment involved in related activities.

Steps towards improvement

Improvements in health-care waste management rely on the following key elements:

• The build-up of a comprehensive system, addressing responsibilities, resource allocation, handling and disposal. This is a long-term process, sustained by gradual improvements;
• Awareness raising and training about risks related to health-care waste, and safe and sound practices;
• Selection of safe and environmentally-friendly management options, to protect people from hazards when collecting, handling, storing, transporting, treating or disposing of waste.

Government commitment and support is needed to reach an overall and long-term improvement of the situation, although immediate action can be taken locally.

Health-care waste management is an integral part of health-care, and creating harm through inadequate waste management reduces the overall benefits of health-care.

WHO's response

The first global and comprehensive guidance document, Safe Management of Wastes from Health-Care Activities, released by WHO in 1999, addresses aspects such as regulatory framework, planning issues, waste minimization and recycling, handling, storage and transportation, treatment and disposal options, and training.

It is aimed at managers of hospitals and other health-care establishments, policy makers, public health professionals and managers involved in waste management. It is accompanied by a Teacher's Guide, which contains material for a three-day workshop aimed at the same audience.

The Interagency Guidelines for the Safe Disposal of Unwanted Pharmaceuticals in and after Emergencies provide practical guidance on the disposal of drugs in difficult situations in or after emergencies are also available.

The full text of these publications is available on the WHO water, sanitation and health web site

Planned WHO products and activities include:

• The publication of a decision-maker's guide for health-care waste management in primary health care centres;
• The implementation of health-care waste systems at country level;
• The development of a database on practical options for health-care waste management, mainly targeted at developing country situations;
• Testing of low-cost options for health-care waste management;
• The development of guidance for the disposal of blood and blood bags;
• An approach for promoting the use of products in health-care activities leading to reduced production of wastes or less harmful wastes.