Solid waste includes solids or semisolids, non-soluble materials (including gases and liquids in containers) such as agricultural refuse, demolition waste, industrial waste, mining residues, municipal garbage, and sewage sludge. The most common types of solid waste are municipal solid waste, industrial waste, agricultural waste and hazardous. The solid waste composition varies from region to region and time to time. There are following different types of waste. Biodegradable waste i.e. could be decomposed naturally such as food and kitchen waste, green waste, paper, etc. Recyclable material i.e. could be recycled again and again; such as paper, glass, bottles, cans, metals, certain plastics, fabrics, clothes, batteries.
Inert waste not liable to decompose such as construction and demolition waste, dirt, rocks and debris, electrical and electronic waste (WEEE); such as electrical appliances, TVs, computers and screens. Composite wastes; such as waste clothing, Tetra Packs, waste plastic. Domestic hazardous waste and toxic waste medication; such as paints, chemicals, light bulbs, fluorescent tubes, spray cans, fertilizer and pesticide containers and shoe polish. Solid waste generation in Pakistan ranges between 0.283 to 0.612 kg/capita/day and the waste generation growth rate is 2.4 per cent per year.
Solid domestic waste is typically dumped on low-lying land. This land could be used for more productive purposes and potentially valuable recyclable materials are lost. The following are the main problems regarding solid waste management in Pakistan. There is no proper waste collection system. Waste is dumped on the streets. Different types of waste are not collected separately. There are no controlled sanitary landfill sites.
Citizens are not aware of the relationship between ways of disposing of waste and the resulting environmental and public health problems. The unavailability of proper disposal methods and resources for solid waste managing results in various environmental and human health hazard effects. Problems can spread over a wide area. Skin and eye infections are common. Dust in the air at dumpsites can cause breathing problems in children and adults. Flies breed on uncovered piles of rotting garbage and spread diseases like diarrhea, dysentery, typhoid, hepatitis, and cholera. Mosquitoes transmit many types of diseases like malaria and yellow fever. Dogs, cats and rats living around refuse to carry a variety of diseases including plague and flea born fever. Intestinal, parasitic and skin diseases are found in workers engaged in collecting refuse.
The most serious problem is groundwater contamination. As water filters through any material, chemicals in the material may dissolve in the water, a process called leaching. The resulting mixture is called leachate. As water percolates through municipal solid waste, it makes a leachate that consists of decomposing organic matter combined with iron, mercury, lead, zinc, and other metals from rusting cans, discarded batteries and appliances. It may also contain paints, pesticides, cleaning fluids, newspaper inks, and other chemicals.
Contaminated water can have a serious impact on all living creatures, including humans, in an ecosystem. When waste is burnt heavy metals like lead, toxic gases and smoke spreads over residential areas. The wind also carries waste, dust and gases caused by decomposition. Putrefaction of waste in sunlight during daytime results in bad smells and reduced visibility. Karachi is the industrial and corporate centre of Pakistan. This one city alone contributes. About 20 per cent to the countrys GDP accounts for half of the governments revenue.
At the same time, its port handles majority of the countrys sea-borne trade. However, all this come at a certain price. The sea water of the metropolitan is considered to be the worst affected part of the countrybecause of the discharge of industrial waste from Korangi, Landhi, and Karachi ExportProcessing Zone. In the Korangi industrial area; 2,500 industrial units including 170 tanneries dispose untreated waste into the sea. A continuous flow of water with animal dung from Bhains Colony is another source of pollution. Added to this are the oil spills from shipsand fishing trawlers transiting the port. Interestingly, City District Government Karachi is among the biggest cause of polluting the sea by throwing three tons of waste in it on a daily basis.
The resulting situation is a harbinger of many ills. It is disrupting fishing activities, paralyzing economic activities and eventually impacting the local fishing communities. Besides depriving the fishermen from their livelihood, the growing pollution levels are also destroying the marine life. Some of the marine life is contaminated with lead, which if consumed by humans through seafood, can lead to anemia, kidney failure, and braindamage. Even the mangrove forests, protecting the feeder creeks from sea erosion as wellas a source of sustenance for fishermen, are threatened by this pollution. Unfortunately, this ever worsening situation has failed to draw the attention of both thepublic as well as private sector. Till date no serious initiatives have been taken in this regardand even now the attitude of concerned authorities is marked with a lack of commitment.
The first writer is M.Sc. (Hons). Environmental Sciences, while the second one is Lecturer Zoology, University of Agriculture, Faisalabad, Pakistan.