Introduction

Medical waste is broadly defined as any solid or liquid waste that is generated in the diagnosis, treatment of immunization of human beings or animals in research pertaining thereto, or in the production or testing of biological material. According to World Health Organisation (WHO) estimates 85% of hospital waste is actually non-hazardous and around 10% is infectious while the remaining 5% is non-infectious but consists of hazardous chemicals like  methylchloride and formaldehyde. Here., the main concern of infectious hospital waste is the transmission of HIV and Hepatitis B or C viruses. In this context, syringes and needles have the highest disease transmission potential. Hospital waste, till recently was not being managed but it was simply ‘disposed off’. The disposal of hospital waste can be very hazardous particularly when it gets mixed with municipal solid waste and is dumped in uncontrolled or illegal landfills such as vacant lots in neighboring residential areas and slums. This can lead to a higher degree of environmental pollution, apart from posing serious public health risks such as AIDS, Hepatitis, plague, cholera, etc.

In the total amount of municipal waste a city generates, only 1 to 1.5% is hospital waste, of which 10-15% is considered infectious. It is estimated, a city like New Delhi with about 40,000 beds generates about 60 metric tons of hospital waste per day. But whatever the amount of hospital waste there be, it proves to be harmful to the community. This needs immediate treatment and effective disposal. Discarded blood and blood products serve as significant foci of hazardous diseases. The waste stream from X-ray units has chemical contamination of silver bromide  (Fixon),  glutaraldehyde,  hydroquinone and potassium hydroxide. The waste stream from the sterilization of syringes usually has infectious materials and methanol. The usual infective waste consists of bandages,  gauzes, cotton waste, amputated human parts, placenta and used dialysis kits containing plastic andaluminum. The sterilization of dialysis units, operation theatres and private wards contributes formaldehyde. The waste from laboratory contains infectious materials as well as reagents and solvents used for analytical purposes. Further, unhygienic conditions in general ward toilets, coupled with frequent strikes by Class IV staff create what are virtually secondary foci of infectious diseases within the hospital premises. Such areas are often stockpiles of heterogeneous infectious material and contribute greatly to the incidence of  nosocomial infections. The persistence of these organisms in the environment at 20-30ºC is shown to vary from 2 weeks to a month. This aggravates health hazards when associated with the biomedical wastes generated in the hospitals.