Health and environmental impacts

Health and environmental impacts

The generation of wastes may present threats to the environment and public health, but this depends on the type of waste management option and the way it is controlled. Waste is a complex mixture of different substances, only some of which are intrinsically hazardous to health.

4.1 Potential health impacts

Disease or injury may result from inappropriate exposure to:

·                     infectious agents

·                     sharps

·                     toxic or hazardous chemicals or pharmaceuticals

·                     radioactive substances

For further information on specific clinical wastes, refer to Health impacts of health-care waste (World Health Organisation, 1999).

4.1.1 Infectious Agents

WA Health facility waste may contain any of a great variety of pathogenic micro-organisms that can enter the human body by a number of routes. The primary routes of infection include:

·                     through a puncture, abrasion, or cut in the skin

·                     through the mucous membranes’

·                     by inhalation

·                     by ingestion.

With the exception of waste containing pathogenic cultures or excreta of infected patients, the microbial load of health-care wastes is generally not very high. Furthermore, health care wastes do not seem to provide favourable media for the survival of pathogens. This may be due to the presence of antiseptics and the environmental conditions.

Pathogenic microorganisms have limited ability to survive in the environment as they have little resistance to conditions such as temperature variances, humidity, ultraviolet irradiation and the availability of necessary organic substrate materials. However, pathogenic microorganisms in WA Health facility waste streams that are of concern include blood-borne viruses, bacteria resistant to antibiotics and chemical disinfectants (that may be transferred to indigenous bacteria via the waste disposal system – especially from laboratory strains), pathogenic bacteria, prions and agents of degenerative neurological diseases.

Certain blood-borne viruses are a concern in WA Health facility wastes. The Hepatitis B virus is very persistent in dry air and can survive for several weeks on a surface, brief exposure to boiling water and to some antiseptics, including 70% ethanol. An infective dose of hepatitis B or C virus can survive for up to a week in a blood droplet trapped inside a hypodermic needle10. It should be recognised that survival times and the risk of transmission taking place is affected by a range of factors including viral load, exposure of the needle to the elements, humidity, and the amount of blood involved.

Also the role of vectors such as rodents and insects should be considered when evaluating the survival or spread of pathogens in WA Health facility wastes. This applies to management of health-care wastes both within and outside health-care establishments. Vectors such as rats, flies and cockroaches, which feed or breed on organic waste, are well known passive carriers of microbial pathogens and should be included in any waste management plan.

4.1.2 Sharps

Concentrated cultures of pathogens and contaminated sharps (particularly hypodermic needles) are the waste items that represent the most acute potential hazards to health and are considered as a very hazardous waste class. Sharps may not only cause cuts and punctures but also infect wounds through pathogen contamination.

4.1.3 Pharmaceutical and cytotoxic wastes

Pharmaceutical and cytotoxic wastes can present hazards to members of the public, waste management workers and the environment. Inappropriate storage of medicines in the home can be a source of poisonings of children and confusion for other consumers, particularly the elderly.

Disposal of pharmaceutical waste at landfill sites may result in medicines being available for both misuse and abuse by consumers.

Pharmaceutical substances do not readily break down and can remain biologically active for years: contamination of wastewater with pharmaceuticals in levels exceeding predicted no-effect concentrations has been documented. Leaching of pharmaceutical substances from landfill has also occurred.

Potential environmental risks associated the inappropriate disposal of pharmaceutical and cytotoxic wastes include direct toxicity, hormonal disorders and mutations.

Incineration at high temperatures eliminates the risks from these substances.

4.1.4 Radioactive substances

Radioactive wastes may present a range of external radiation hazards depending on their activities and emissions and may, if ingested or inhaled, present a variety of internal radiation hazards to the human body dependent upon the nuclide and its chemical and physical forms.

4.2 Groups potentially at risk

Exposure to hazardous clinical and related wastes may occur at any stage from generation to final disposal and could affect those living near a waste disposal site or influence the occupational health of the workforce involved in waste management. The groups potentially at risk include:

                medical and other health care sector personnel, including maintenance and other staff at facilities

                patients in health-care facilities or receiving home care;

                visitors to health-care establishments;

                workers in support services allied to WA Health facility, such as laundries, waste handling, and transportation;

                workers in waste disposal facilities (such as landfill or incinerators), including scavengers11.

Other health-related activities such as home-based health care (e.g. dialysis) and that generated by illicit drug use (usually intravenous) can also generate hazardous wastes. The handling of used needle and syringes in waste facilities from illicit drug use is covered in Appendix 3.