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A Research Compendium of Rehabilitation Strategies for Damaged Urban Areas
Introduction
Urban areas are characterized by their high concentration of population and intensive human activities in a relatively small land area, particularly in big towns and cities. The urban ecosystem has very high economic, political and social importance. Urban areas play a major role in transforming resources into useful goods and services that contribute to national economic production. They affect both local and regional environments because of the concentration of consumption of goods and generation of wastes in one area. Urbanization invariably results in high per capita consumption rates that, in turn, cause higher demand for natural resources and more environmental risks.
In the process of development, urban areas are the first to be industrialized. As factories and manufacturing firms are established, more people are attracted to converge in these areas for employment and to improve their socio-economic status.
In the 20th century the ever-increasing population of major cities in the Philippines, particularly Metro Manila, placed greater pressures on the environment. Metropolitan Cebu is another crowded city which has more than 18,000 registered business establishments (DENR 1990). Today, there are about 15,000 industrial firms in the country and 69% of these are situated in Metro Manila. The transport and industrial sectors both contribute approximately 40% to 60% of pollution load.
The build up of transportation facilities in urban areas grows rapidly through the years. Metro Manila has almost a million motor vehicles which spew tons of carbon monoxide and carbon dioxide into the air daily, aside from the noise polluti on produced by engines and horns. The eight (8) million commuters who use up space and litter the streets aggravate the stressed environment.
Inefficient sewage collecti on and water polluti on aggravate the environmental problems as huge discharge of untreated wastewater from domestic and industries have rendered major rivers in the metropolis biologically dead. At present, an average Filipino generates 35-70g of sewage and 640-1,600g of solid waste per day. In Metro Manila alone, 6,169 tons of wastes are generated daily (Reyes 2007) which is enough to fill 1,500 dump truck trips per day. From the total volume of trash generated, 1,500 tons daily are illegally dumped on private lands, rivers, creeks, and in Manila Bay, while other wastes are openly burned. In Rodriguez and Payatas waste sites, 76kg of arsenic are released annually into water bodies surrounding Metro Manila.
A major problem besetting the inland waters is the infiltration of the leachate or “garbage juice” brought about by open and controlled dumping. Leachate emanates from bacterial decomposition of garbage eventually contaminating bodies of water used for fishing, bathing, drinking, agriculture, industrial and other domestic needs.
Likewise, groundwater can also pose serious threats in terms of quality and quanti ty. Since 1995, the groundwater table in Metro Manila was estimated to recede at an accelerating rate of 5-12m/year which has led to saltwater intrusion in a two-kilometer coastal strip extending from Cavite to Navotas-Malabon (DENR-MEIP 1992 as cited by World Bank 2000).
Flooding also affects about 1.9 million people and inflicts losses of about PhP900 million per year. Almost 7% of Metro Manila (about 44km2) is prone to flooding. Mostly affected are the medium and highly dense residential districts. Flooding occurs as a result of poor drainage system. In river systems, easement of encroachment is a common problem. This is aggravated by the presence of informal settlers and business establishments along riverbanks.
The air quality in Metro Manila and its vicinities are alarming. Fine particulate emissions result in about 2,000 premature deaths and 9,000 cases of chronic bronchitis in the country’s four largest urban areas annually. Emissions of pollutants were largely blamed on public buses, jeepneys, utility vehicles, trucks, and motorcycles; 70% of air pollutants are attributed to motor vehicles Reyes 2007) and 30% to stationary sources (e.g., industries).
Likewise, persistent organic pollutants (POPs) pose a risk on human beings and the environment. Pesticides, industrial chemicals, and unintentional by-products from the emissions of incinerators from hospital wastes, municipal wastes and from dioxins as by-products of processes used by metal smelters, refineries and cement kilns were found to cause cancer and tumor. Pesticides have been demonstrated to cause a variety of serious health effects on the human immune, reproductive, nervous and endocrine systems.
The influx of people and overcrowding into the metropolis aggravates an already stressed situation in sidewalks, canals, and estuarines. Urban areas suffer from pollution coming from various sources. Before anyone realizes it, people from urban centers have already been choked up by pollutants from factories, fumes, and toxic gases into the air, and chemical pollutants into the waterways. All these pose immediate health hazards to the population.
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