3 Factors influencing waste generation, environmental and health hazards

Dr. Yogalakshmi K. N

Objectives:

1.      To analyze the various factors influencing waste generation

2.      To understand the various environmental effects caused by waste generation and disposal

3.      To gain knowledge about the health hazards associated with waste generation and waste disposal

Solid waste

Waste is defined as any unwanted or unusable substance that is discarded after primary use. Wastes are normally generated as a result of human and animal activities. Urbanization and rapid advancements in industrialization has led to an increase in the production and consumption processes resulting in the generation of wastes from various sectors that include agricultural, commercial, domestic, industrial, institutional, social and from community activities. Over time, these waste accumulate and can have real impacts on the health and the environment. Waste management is intended to reduce adverse effects of waste on health, the environment or aesthetics.

Solid wastes are any discarded or abandoned materials that is of no use. that can be solid, liquid, semi-solid or containerized gaseous material discarded by the human society. According to the source of generation and type they are classified as urban wastes, agricultural wastes, biomedical wastes, bulky waste, open area waste, radioactive wastes, e wastes and many more. The term refuse is also used for solid wastes. Examples of solid wastes include waste tires, septage, scrap metal, latex paints, furniture and toys, garbage, appliances and vehicles, oil and anti-freeze, empty aerosol cans, paint cans and compressed gas cylinders, construction and demolition debris, asbestos, plastics, styrofoam containers, bottles etc. A number of factors influence the generation of waste. They include geographical location, topography, seasons, climate, population density, lifestyle and many more.

The waste management involves various steps namely waste collection, segregation, transport, processing, treatment and disposal. Disposal is the final step in the waste management. Ultimately all solid waste ends in disposal site either directly or after some processing and treatment it ends in disposal sites. Most of the developing and under developed countries, dispose or dump the solid waste in an open land without any protection or environmental control. Such dumping is not safe and is called as open dumps or open dumping. Solid waste is also disposed off in water bodies eg. Sea, ocean, lake, river etc. Sometimes they are also burned in open areas, the phenomenon termed as open burning. The solid waste must be properly managed to avoid environmental and health hazards.

Factors influencing waste generation

The rate of change of quantity of solid waste generation with respect to stipulated time is termed as waste generation. The waste generation rate is governed by various factors (i.e) it depends mainly upon the geographical location, customs, climate, living conditions and economic standard of the area. The characteristics, quantities, volume and composition of solid waste generated may differ from one country to another and between urban and rural areas. The factors influencing waste generation is discussed below.

Population: Population is one of the major factor governing waste generation. Increasing population will always increase the rate of waste generation. Highly populated countries show high per capita waste generation. Population density influences the quantity of waste generation. Higher the population density more is the quantum of waste generation. More developed countries are known to produce more waste, because abundance of goods results in higher waste generation. Age also is one another factor that influences waste generation.

Urban and rural area: People migrate from rural areas to urban areas in search of employment and education opportunities. Urbanization and industrialization is the main reason for the migration of people. In India, it is estimated that about 100,000 people migrate every day from rural areas to urban areas. The rate of migration is around 3.6 per cent per year. Thus, waste generation is high in urban areas when compared to rural areas. For example urban areas generate all type of waste namely: paper, plastics, food waste, packaging materials, electronic waste and many more. In rural areas, the type and amount of waste generation is very minimum. Mostly it would be farm waste, agricultural waste and biodegradable waste.

Economic status and lifestyle: Economic status influences the waste generation to a great extent. Waste generation is high among high income groups and high-income countries. Higher the income rate and rate of urbanization greater is the solid waste generation. With increase in income the consumption of goods also increases resulting in increased waste generation. More packaging materials, papers, clothes, electronic gadgets, furniture etc. are generated in high income society.

Geographical location: Geographical location mainly plays a role in the generation of yard waste, agricultural waste etc. Locations where the autumn season is predominant can generate huge amount of yard waste. In northern parts of India during the months of February and march, yard waste generation is high. Agricultural waste generation is also high during the harvest season. Geographical location can also be interlinked to collection frequency. A place located at higher altitudes might show waste accumulation due to reduced collection frequency. Likewise, places of tourist importance accounts for high waste generation.

Seasons: The rate of waste generation and its composition varies with seasons. Harvest seasons result in high quantity of waste generation. Generally, waste generation is high in summer seasons than winter. High temperature might lead to faster decomposition of eatables and vegetables. This might be one of the reason for increased waste generation. Seasons that favor tourism will also act as a factor to increase waste generation.

Public attitude: The attitude of the public to change their habits and lifestyle might lead to reduced waste generation. Buying clothes more than required, wasting food, frequent replacement of household items, mobile phones and electronic gadgets might be few of the reasons for waste generation. Change in public attitude might reduce the waste generation.

Legislation: Strict legislation might reduce the quantity of waste generation. Existence of local and state regulations at least for the use and disposal of specific items might reduce the waste generation. For example, Indian rules control the generation of packaging materials and plastics.

Environmental effects of waste generation and disposal:

Waste generation, its improper disposal has resulted in a number of environmental effects. It affects water, air, land, soil and noise pollution. The various environmental effects are listed below.

Water pollution: Improper waste management (i.e) open dumping of waste results in surface and ground water pollution. Waste generates a watery liquid termed ‘leachate’ oozes out due to the field capacity. This watery liquid slowly infiltrates through the soil into the ground water and affects them. Precipitation over the waste leads to the leaching of pollutants into the surface run off. Also, leachate gets mixed with the surface run off and is carried to surface water bodies like rivers, streams, lakes etc. Eutrophication and loss in water quality of the water body might be the consequences.

Likewise, the entry of leachate alters the pH of the groundwater. Changes in pH favours dissociation of minerals in the aquifers into the water. This might cause increased loss in water quality. Moreover, the contamination can spread depending on the characteristics of the aquifer especially sand and gravel. Soil also plays a great role in restricting the movement of ions into the groundwater. Clay soil might restrict the movement of ion by capturing them in the soil matrix.

Soil Pollution: Open dumping of waste without any liners or other protection causes the entry of pollutants into the soil. As mentioned earlier, the pollutants bind to the soil and its minerals thereby increasing the pollutant level in the soil. The accumulation of metals in the soil reduces its productivity and microbial diversity. The microbial diversity gets altered due the pollutants in the soil. Metals like Cd, Cu, Ni, Pb and Zn alters the soil chemistry. The pH of the soil is too disturbed by the waste. This results in the loss of various minerals thereby affecting the overall nature of the soil.

Vegetation is also affected by the waste dumping. The pollutants and heavy metals in the soil gets absorbed through the root system into the plants. The pollutants hinder the normal metabolism in plants thereby leading to invisible injuries that might on a later stage lead to plant death. Poor vegetation is observed in those places where the waste has been dumped for many years. Sometimes the waste dumping affects and destroys the entire ecosystem.

Air pollution: The surrounding air is affected by the emission of methane, carbon dioxide, oxides of Sulphur and nitrogen and other volatile organic compounds during the waste decomposition. Their emissions alter the air quality initially on local level which might extend to regional level depending on the rate of emissions and meteorological conditions. Likewise burning of waste in open areas leads to the emission of particulate matter (ash) and various gaseous emissions. Open burning also results in the emissions of many carcinogens namely the dioxins and furans. Polychlorinated dibenzofurans (PCDFs) commonly called as dioxins and furans are released during the burning of plastics. They are of more significance because their carcinogenic and mutagenic property. Incinerators without air pollution control devices also result in the release of particulate matter (ash) and gases. Hydrogen chloride, carbon monoxide, lead, mercury, arsenic, cadmium and selenium are other pollutants released during burning.

Noise pollution: Noise pollution is generally generated during the transport of waste in vehicles. Vehicles and machinery used in waste processing are the main source of noise pollution. The impacts of noise pollution can be reduced by proper maintenance of machinery and vehicles. Workers can be saved from occupational hazard by using ear plugs, muffs etc. Green belts can also minimize noise by acting as barrier.

Odour and aesthetics: Uncontrolled dumping might affect the aesthetics of the site. It creates visual hindrance to the trespassers and individuals living in nearby locality. The beauty of the city or town is lost due to open dumping of waste. Likewise, dumping or temporary storage of waste leads to odour problem due to decomposition of waste. The odour problem can be minimized by increasing the collection frequency from storage sites. Containment of waste in controlled landfill can also minimize the odour problem.

Health effects of waste generation and disposal:

Waste disposal in open dumps, long period of storage in the collection site or processing site (transfer station), improper handling and management might lead to numerous health effects in human beings and animals. Occupational health hazards are also caused during accidents, waste transport and processing. Some of the health effects are discussed below.

• Waste dumps acts as a store house of infective microorganisms and pathogens. They provide suitable environment and food for their growth. So workers when they come in contact with the waste are affected with various diseases.
• The flies, mosquitoes, stray animals such as rats, cats, dogs, cows, pigs act as carrier to bring the infection to the residential area and population living the towns and cities.
• Epidemics can also be caused by the carriers that transport the vectors to the human beings
• Typhoid, salmonellosis, gastro-enteritis, dysentery, malaria, filaria and dengue are the popular diseases caused by flies and mosquitoes. Life cycle of the insect plays an important role in creating infection. The flies generally lay eggs in the warm, moist environment of decomposing food wastes. The organic content in the waste acts as feed for the larva. Once they get matured they migrate from waste to soil before transforming to pupae. The pupae remain dormant in soil and then migrates to the other area after it becomes and adult fly. Thus, the life cycle of fly occurs in the waste pile. Proper cleaning of storage bins, frequent collection and dumping waste in controlled environment might avoid the infections associated with flies.
• Proper covering of the waste material can avoid the breeding of flies in the waste
• Accumulation of water in broken furniture, tyres, broken vessel, tins and cans might act as breeding grounds for mosquitoes. Proper sanitary practices and cleanliness can eliminate the mosquito problems.
• Roaches: Typhoid, cholera and amoebiasis are the infections caused by roaches. Poor management of solid waste can result in these infections.
• Rats and other rodents causes the spread of diseases such as plague, murine typhus, leptospirosis, histoplasmosis, rat bite fever, dalmonelosis, trichinosis and many more. Waste dumps act as a source of food and shelter for the rodents.
• Pigs are involved in the spread of diseases like trichinosis, cysticerosis and toxoplasmosis, which are generally transmitted through infected pork, eaten either in raw state or improperly cooked. Solid wastes, when fed to pigs, should be properly treated otherwise it might cause infections.
• Occupational health hazards: Occupational health hazards are popular among workers handling waste and operating machineries. Accidents might also occur and can be considered as occupational hazard.
• Sharps, syringes, broken glass, blades in the waste causes cut to the workers involved in collecting and transporting the waste.
• Storage containers with sharp edges might cause injury and henceforth result in occupational hazard
• Infections of skin and blood results from direct contact with waste and previously infected area and wounds.
• dust from the waste materials affects eyes on exposure. o diseases can also spread through animal bites
• Inhalation of gases while burning wastes can lead to chronic respiratory diseases and cancer
• Accidents due to waste handling: Loading, unloading and carrying of waste containers might lead to muscle wear and tear, bone and muscle disorders. Dust in roads and smoke arising from burning of waste might reduce visibility and might cause accidents. Chemical burns can occur when workers are exposed to small amount of hazardous material such as pesticides, cleaning solutions and solvents in households and commercial establishments. Methane explosion in landfill sites is again a major threat of accident. Careless dumping of lead-acid, nickel-cadmium and mercuric oxide batteries might affect the children and adults.

Summary

• To summarize, at the end of this module we have factors influencing waste generation
• Environmental effects associated with waste disposal and improper management health hazards associated with waste disposal and improper management

References

• TV Ramachandran (2009), ‘Management of Municipal Solid Waste’. Centre for Ecological Sciences, IISc Karnataka research foundation.
• Tchnobanglous G and Frank Kreith (2002), Handbook of solid waste management, Mc Graw hill handbook publications.
• www.nptel/Municipal solid waste management.com