Several incidents concerning medical waste being spotted on public and private beaches have drawn a lot of public attention on the issue of management of medical waste. One such incident happened back in June 1987, when in Indiana polis, twelve children were found playing with blood vials that they had picked from a bin placed outside an HMO medical office.
Two of these vials were infected with the AIDS virus (10). These issues and others raise concerns on how medical waste is handled, treated and disposed.
Medical waste can be defined as all the waste that is generated by health facilities and other sources such as funeral homes, research laboratories, doctor’s clinic funeral homes, nursing homes and veterinary facilities.
These wastes consists the hazardous (radioactive materials), infectious also referred to as red bag waste and any other waste generated within the facility (4). Medical waste although not voluminous, is infectious and toxic and leads to serious environmental pollution (1).
According to Environmental protection Agency (EPA), hospitals generate around 3.2 million tons of medical wastes per annum. (10). 10 to 15 0percent of this medical waste generated is infectious. In most hospitals, the non infectious waste is land filled while the infectious one is incinerated.
Medical waste requires proper handling, disposal and treatment to minimize the environmental and health risks associated with it. Illegal or careless disposal of medical waste not only creates an aesthetic and health problem, but also increases public apprehension on the existing medical waste management methods.
Due to the liabilities and the safety related concerns, some municipals refuse or ban any medical waste from their incinerators and landfills. Various states have prohibited all un-sterilized infectious waste from the municipal landfills.
The states have also banned construction of commercial incinerators handling medical waste. These afro mentioned bans, have made it increasingly difficult for medical facilities and hospitals in the country to properly manage medical waste (3).
This situation is further complicated by the lack of clear and concise regulatory climate. These inconsistencies are present in the Federal guidelines laid down by the States with regards to the definition of medical waste and the management options available for handling, transporting, treating and disposing medical waste (5).
The current situation can only change if the Congress adopts bills relating to medical waste management. In the meantime, most states have been mandated to devise their own plans and programs of managing the medical waste generated. This means that there are a lot of variations between different states and local requirements.
This paper aims at looking at the disposal problems posed by medical waste for both the local government and hospitals, the methods used in disposing medical waste, the long term implications medical waste has on the environment and the conclusions drawn from the discussion (2).
Classification of Medical Wastes
Medical waste is heterogeneous in nature as it comprises a variety of materials ranging from general waste such as food, office waste and non-infectious waste from patients. It also includes infectious waste e.g. contaminated sharps and blood products, hazardous waste generated from pharmaceuticals, cytotoxic chemicals from chemotherapy, mercury as well as radioactive wastes.
Classifying infectious waste has proved difficult due to the variations resulting from different State regulations (10). These different classifications lead to inconsistency in storage, disposal and treatment practices across different states. The variations also influence the preferred treatment methods, cost of management and eventually, the possible environment and health hazards created by these wastes.
Around 10 to 15 percent of all medical waste is infectious but this percentage can differ from 3 to 90 percent, depending on the definition and procedure adopted (10). The state entities, EPA and Centers for Disease Control (CDC) have all tried to find the proper definition of infectious waste based on the characteristics of the waste.
According to EPA, infectious waste is any waste with the possibility of causing an infectious disease. EPA has broadened its category of infectious waste compared to CDC. This has led to the adoption of EPA instead of CDC guidelines, in hospitals and other areas that generate medical waste, helping in minimizing potential environmental and health risks (4).
Another concern is whether to classify infectious waste as hazardous which will increase the cost of managing it due the construction of special facilities. Such a move would improve the management of medical waste, but lead strict regulations and prosecution of illegal dumpers.
Some of the wastes recommended to be included in the infectious category are waste from dialysis, stocks and cultures with infectious agents, blood products and human blood, contaminated sharps, soiled dressings, surgical gloves sponges and other surgical waste (6).
Varied definition of infectious and hazardous medical waste has led to the public being exposed to this hazardous waste that poses a health risk. For example, the public was barred from accessing beaches in the East coast after bloody bandages, sutures and needles were found in the shores.
Infectious waste is sent to the incinerators, thus if the category was broadened as discussed above, such waste would not have ended up in the beaches (10).
Handling of Medical Waste
There are various occupational hazards associated with handling medical waste. Waste handlers and health workers are primarily exposed to this type of risk as they more than often handle this waste. Handling hospital waste include packing, storing and transporting it properly to avoid any contamination and littering as discussed below;
1. Packaging- before packaging any medical waste, it must be sorted into different categories and packed accordingly. This is a time consuming activity and quite risky to the handler.
Bulk waste is put in polythene bags and colors used in differentiating different categories of wastes. Infectious waste is placed in red bags and all the waste is securely closed in readiness for storage or transportation. Sharps are put in puncture proof containers due to their infectious capability and also due to their prick injuries (7).
2. Storage- hospitals must designate special areas for storing the waste before it is transported or disposed. The area must be regularly disinfected and kept at the right temperature. According to EPA, storage areas must have the bio-hazard symbol and sufficient packaging to prevent vermin’s and rodents from accessing the area.
The waste must also be stored for the shortest period possible, although EPA does not give the stipulated period, leading to a State disparity in specified temperatures and times. Lack of uniformity in regulating storage temperature and time can sometimes lead to increased rates of putrefaction and microbial growth (8).
EPA guidelines address the movement of infectious of waste on-site briefly, and provide limited information on how to move this waste off-site. Such recommendations involve using leak proof and rigid containers to move the waste and not using mechanical loading devices that can rapture packed waste.
There are no guidelines on how to handle and transfer medical waste off-site. Although EPA, recommends that hazard labels be put on all medical waste in accordance to Federal, State and municipal regulations, the energy and transport department limit the use of this label, confusing commercial waste handlers (10).
Varied definition of infectious waste across different states complicates the matters and increases the likelihood of improper disposal and potential exposure to the public.
For example, if a state does not classify bloodied sutures and bandages as infectious waste, it can dispose this waste from another state in the municipal landfill. However, such waste can be washed by storm water to the beaches and pose a health risk (9).
Methods Used In Disposing Medical Waste
As hospitals generate a lot of waste, both non-infectious and infectious wastes are incinerated together. There is no data on the exact waste incinerated in hospitals or information on the number of current medical incinerators available.
Municipal incinerators burn a large volume of waste compared to hospital ones. However, hospital incinerators are situated in highly populated regions, leading to a greater probability of public exposure to toxic fumes and air pollutants.
These small incinerators emit higher levels of pollutants, although few risk assessments are carried out, making it impossible to evaluate the risks emanating from these incinerators in comparison to other sources e.g. the municipal incinerators (10).
Moreover, the short stacks in hospital incinerators might permit emissions from the incinerators to go into the hospitals via windows and air-conditioning ducts. Hospitals in US use three types of incinerators namely: rotary kiln models, multiple chamber air and controlled air.
Most medical waste incinerators are closed air, since they are associated with lower costs and lesser pollution. The advantage associated incinerators is that they can reduce large volumes of waste, sterilize it, and make it possible for it to be disposed traditionally through landfills. Secondly, modern incinerators harness the heat created during the process and use it to power generators within the facility (8).
Autoclaving uses steam sterilization in treating wastes before they are sent off to the landfills. Autoclaving is done in closed compartments, where pressure and heat are applied generating steam, within a given length of time so as to sterilize medical apparatus.
All microorganisms found in the medical waste are destroyed by the steam generated and then disposed off disposed in landfills. After autoclaving medical waste, it undergoes compaction through shredding so that it is not used for any other purposes and then later on disposed in the landfills.
However, autoclaving is not recommended for pathological waste due to the presence of low levels of radiation. The advantage of this method is that it can be used in processing 90 percent of medical waste and compaction reduces the volume of waste after (7).
Long term Environmental Implications of Medical Waste
Improper disposal of medical waste have far reaching environment impacts. Disposal of medical waste in oceans or other water bodies can lead to contamination of water by the pathogens found in this waste. Medical wastes such as soiled bandages or plastic gloves destroy the aesthetic appearance of the environment when they litter the beach or other places.
On the other hand, the disposal methods used in getting rid of the medical waste causes serious air pollution. According to a JAMA study carried out in 2009, the health sector accounts for 8 percent carbon emission (8). Most of the medical waste is plastic that produces furans and dioxins during combustion.
Most old medical incinerators have no equipment for controlling pollution. The incinerator ash generated from combusting contaminated waste may contain potentially toxic chemicals that will end up in the landfill and cause environmental pollution.
When autoclaving is used in disposal, the waste might not completely sterilized since the density and volume of material being sterilized determine the effectiveness of the process (7). There is a possibility of incomplete sterilization if the autoclave is overloaded and these pathogens will end up in the landfill, polluting the environment and posing a health risk to the public.
From the discussion above, it is clear that poor regulatory framework has hindered proper management of medical waste disposal. Medical waste is disposed through incineration and autoclaving, but both methods cause environmental pollution and pose a risk to the public health.
Incineration releases toxic gases, while in autoclaving there is the risk of incomplete sterilization, transferring pathogens to the landfills. It is important for medical facilities to adopt new technology in waste disposal to reduce the environmental pollution.
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