-BY LORETTA OKONKWO

Introduction:


The disposal and management of municipal solid waste is a globally challenging issue especially in developing countries due to its adverse environmental effects.

Mankind depends on the environment to sustain their lives and that solid waste is one of the three major environmental problems, other major environmental issues include flooding and desertification in Nigeria and many other developing and even developed countries are threatened by this. In the current world economic paradigms, sustainable socio-economic development of every community depends much on the sustainability of the environment. The contamination of the environment by anthropogenic (influence of human being on nature) practices is globally known to impacts negatively on the environment.

What is solid waste?
The term solid waste means materials such as: household garbage, food wastes, yard wastes, and demolition or construction debris. It also includes discarded items like household appliances, furniture, scrap metal, machinery, car parts and abandoned or junk vehicles.

Household solid waste is one of the most difficult sources of solid waste to manage because of its diverse range of composite materials. A substantial portion is made up of garbage, a term for the waste matter that arises from the preparation, and consumption of food and consists of waste food, vegetable peelings and other organic matter. Other components of household solid waste include plastics, paper, glass, textiles, cellophane, metals and some hazardous waste from household products such as paint, garden pesticides, pharmaceuticals, fluorescent tubes, personal care products, batteries containing heavy metals and discarded wood treated with dangerous substances such as anti-fungal and anti-termite chemicals.

Since the beginning, mankind has been generating waste, be it the bones and other parts of animals they slaughter for their food or the wood they cut to make their carts. With the progress of civilization, the waste generated became of a more complex nature. At the end of the 19th century the industrial revolution saw the rise of the world of consumers. Not only did the air get more and more polluted but the earth itself became more polluted with the generation of non-biodegradable solid waste. The increase in population and urbanization was also largely responsible for the increase in solid waste. In Nigeria, rapid urbanization, rural-urban migration, little or no town planning efforts coupled with attitudinal irresponsibility, lack of political will, ineptitude and graft have independently and collectively created environmental challenge in Nigeria resulting to human or solid waste decorating streets and public space everywhere in Nigeria.

In view of the above, it is a known fact that every household generates garbage or waste day in and day out. Items that we no longer need or do not have any further use for fall in the category of waste. There are different types of solid waste depending on their source.

Types of Solid Waste
Solid waste can be classified into three different types depending on their source, which include:
a)Household waste,  generally classified as municipal waste,
b)Industrial waste, as hazardous waste, and
c)Biomedical waste or hospital waste, as infectious waste.

Municipal Solid Waste (Household Waste):
Municipal solid wastes consist of day-to-day consumed and discarded items such as household waste (food wastes), containers, product packaging and other miscellaneous like residential, commercial, electronic wastes, institutional and industries sources, construction and demolition debris, sanitation residue, and waste from streets.
This garbage is generated mainly from residential and commercial complexes. With rising urbanization and change in lifestyle and food habits, the amount of municipal solid waste has been increasing rapidly and its composition changing. More than 25% of the municipal solid waste is not collected at all; 70% of the Nigerian cities lack adequate capacity to transport it and there are no sanitary landfills to dispose of the waste. The existing landfills are neither well equipped nor well managed and are not lined properly to protect against contamination of soil and groundwater.

Hazardous Waste (Industrial Waste):
Industrial and hospital wastes are considered hazardous as they contain toxic substances. Certain types of household wastes are also hazardous. Hazardous wastes could be highly toxic to humans, animals, and plants; corrosive, highly inflammable, or explosive; and could react when exposed to certain things e.g. gases. Household wastes that can be categorized as hazardous waste include old batteries, shoe polish, paint tins, old medicines, and medicine bottles.
Hospital wastes contaminated by chemicals used in hospitals are considered hazardous. These chemicals include formaldehyde and phenols, which are used as disinfectants, and mercury, which is used in thermometers or equipment that measure blood pressure. Most hospitals in Nigeria do not have proper disposal facilities for these hazardous wastes.

In the industrial sector, the major generators of hazardous waste are the metal, chemical, paper, pesticide, dye, refining, and rubber goods industries. Direct exposure to chemicals in hazardous waste such as mercury and cyanide can be fatal.

Hospital Waste (Infectious Waste):
Hospital waste is generated during the diagnosis, treatment, or immunization of human beings or animals or in research activities in these fields or in the production or testing of biologicals. It may include wastes like sharps, soiled waste, disposables, anatomical waste, cultures, discarded medicines, chemical wastes, etc. These are in the form of disposable syringes, swabs, bandages, body fluids, human excreta, etc.
This waste is highly infectious and can be a serious threat to human health if not managed in a scientific and discriminate manner. It has been roughly estimated that of the 4 kg of waste generated in a hospital at least 1 kg would be infected.
Surveys carried out by various agencies show that the health care establishments in the developing countries are not giving due attention to their waste management. After the notification of the Bio-medical Waste (Handling and Management) Rules, many of the larger hospitals have either installed the treatment facilities or are in the process of doing so.

The Implication of Solid Waste on Human Health and Environment
Modernization with progress has had its share of disadvantages and one of the main aspects of concern is the pollution it is causing to the earth – be it land, air, and water. With increase in the global population and the rising demand for food and other essentials, there has been a rise in the amount of waste being generated daily by each household. This waste is ultimately thrown into municipal waste collection centres from where it is collected by the area municipalities to be further thrown into the landfills and dumps. However, either due to resource crunch or inefficient infrastructure, not all of this waste gets collected and transported to the final dumpsites. If at this stage the management and disposal is improperly done, it can cause serious impacts on human health and problems to the surrounding environment.
Wastes that are not properly managed, especially excreta and other liquid and solid waste from households and the community, are a serious health hazard and lead to the spread of infectious diseases. Unattended waste lying around attracts flies, rats, and other creatures that in turn spread disease.  This leads to unhygienic conditions and a rise in the health problems.

Electronic waste is another cause responsible for ill health (e-waste) and other hazardous left over. Electronic waste refers to end of-life electronic products including computers, printers, photocopy machines, television sets, mobile phones and toys which are made of sophisticated blend of plastics, metals, among other materials. UNEP (2005) observed that the number of electronic devices used per capita at the global scale is growing at a rate of about 4% and will continue to increase as it is becoming the fastest waste stream worldwide.

The ever-increasing consumption of resources results in huge amounts of solid wastes from industrial and domestic activities, posed significant threats to human health. However, the ills of inappropriately disposed municipal solid wastes are quite numerous to be mentioned. Health deterioration, accidents, flood occurrences, and environmental pressures are just a few of the negative effects.

In many developing countries, solid waste disposal sites are found on the outskirts of urban areas. These areas become children’s sources of contamination due to the incubation and proliferation of flies, mosquitoes, and rodents. They, in turn, are disease transmitters that affect population’s health, which has its organic defenses in a formative and creative state. The said situation produces gastrointestinal, dermatological, respiratory, genetic, and several other kinds of diseases.

Certain chemicals if released untreated, e.g. cyanides, mercury, and polychlorinated biphenyls are highly toxic and exposure can lead to disease or death. Some studies have detected high incidence of cancer in residents exposed to hazardous waste. Many studies have been carried out in various parts of the world to establish a connection between health and hazardous waste.

Prevention, Recommendation and Conclusion
In today’s polluted world, learning the correct methods of handling the waste generated has become essential. Proper methods of waste disposal have to be undertaken to ensure that it does not affect the immediate environment or cause health hazards to the people living there. At the household-level proper segregation of waste has to be done and it should be ensured that all organic matter is kept aside for composting, which is undoubtedly the best method for the correct disposal of this segment of the waste. In fact, the organic part of the waste that is generated decomposes more easily, attracts insects and causes disease. Organic waste can be composted and then used as a fertilizer.

Poor waste handling practices and inadequate provision of solid waste management facilities in cities of developing countries result in indiscriminate disposal and unsanitary environments that pose a threat to the health of urban residents.
Improper handling, storage and disposal of wastes are major causes of environmental pollution, which provides breeding grounds for pathogenic organisms and encourages the spread of infectious diseases. For instance the presence of houseflies in the kitchen during cooking correlates with the incidence of childhood diarrhoea. In addition, an association was found between waste burning and the incidence of respiratory health symptoms among adults and children.

Ensuring that waste generated in the home is properly stored and promptly picked up for proper disposal will help in reducing the incidence of infectious diseases in our urban areas. Identifying areas of deficiency and planning strategies at addressing these deficiencies will help achieve sound environmental health.

Most developing nations including Nigeria are fast becoming an e–waste destination because most second hand electronics, substandard and recycled electronics from several parts of the world find fertile grounds in these countries and are patronized mostly by the low income population. As a result of these ugly practices most municipal solid wastes contain high quantities of these e–wastes.
There is therefore the need for urgent and strict control measures by Nigeria government to regulate the importations of substandard electronics which have short life span.

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