Urban solid waste (USW), formerly known as municipal solid waste (MSW), is defined as "waste generated in households, resulting from the disposal of materials used in domestic activities, derived from products consumed and their containers, wrapping or packaging; waste from any other activity in commercial facilities or public places the characteristics of which resemble household waste; and waste resulting from cleaning of roads and public places, provided these are not considered by regulations under a different waste category” in the General Law on Waste Prevention and Integrated Management (DOF, 2003 and 2007).
Latin America and the Caribbean is the most urbanized region worldwide, with a urban population that grew from 61 to over 78% between 1975 and 2001. Increased urbanization, economic growth and higher consumption rates lead to higher waste generation. Recent studies conducted by the World Bank predict that waste generation will increase from 131 to 179 million tonnes from 2005 to 2030 in this region (Hoornweg and Giannelli, 2007).
In the past thirty years, the per capita waste generation in Latin America has doubled, and its composition has changed from mostly organic to non-biodegradable, making its management more difficult. Although some progress has been made in landfills, these mainly occur in large cities (OPS, 2005). In rural areas, solid waste disposal is largely uncontrolled, with wastes commonly disposed of in open dumps, on roadsides, in ravines and water bodies (OPD, 2005). Despite not having received sufficient attention and lacking sufficient information, waste disposal by discharge into water bodies and the sea remains a problem as it increases eutrophication and pollution with organic compounds, chemicals, metals and pathogens (MEA, 2005).
Impacts to human health due to physical, chemical and biological agents contained in USW are the main effect of poor waste management practices. Typical agents related to USW that affect the health of workers and people exposed to them are basically the foul odors and dust, which can cause headache, nausea and stress. Furthermore, the presence of pests such as rats, cockroaches and insects increases the risk of disease transmission (e. g. cholera or dysentery). Waste accumulation in drains limits the flow of either rainwater during the rainy season or standing water during the dry season, fostering the proliferation of these pests. Dengue incidence in tropical countries is associated with improper disposal of abandoned vehicles, tires and discarded containers where rainwater accumulates, allowing the proliferation of disease vectors (OPS, 2005). The presence of pathogenic microorganisms is also favoured by the continuous disposal of toilet paper, gauzes and diapers, among others; these pathogens are, however, poorly resistant to unfavorable environmental conditions and their survival is limited in outdoor places. There are scarce morbidity data derived from epidemiological studies on the association between diseases and MSW. Some pathogens present in MSW are known to cause gastrointestinal disorders (Ascaris lumbricoides and Entamoeba coli, for example), viral diseases (such as hepatitis B) and dermatitis (OPS, 2005; IBAM, 2006).
On the other hand, the presence of USW in water bodies has several consequences; for instance, USW disposed of in surface water alters the habitat physical structure and impairs water quality (Fatta et al., 2000; Fetter, 2001; MEA, 2005), while aquifers may be contaminated by leachate infiltration (for details, see the section on Quality in the Water chapter). This issue is aggravated by the presence of industrial waste or chemicals, such as those released from batteries, as they containing toxic materials (Semarnap-INE, 1999; Semarnat-INE, 2004; IBAM, 2006).
Open dumps release foul odors, smoke, gases and suspended particulate matter due to the induced or spontaneous burning of garbage and wind transport. Air pollution resulting from burning in open dumps and incinerators lacking pollution-control systems imposes serious health risks for the presence of organochlorinated compounds and highly hazardous chemicals (MEA, 2005; OPS, 2005; IBAM, 2006).
In Mexico, the growing volume of solid waste produced, the difficulty of collection, the rapid saturation of landfills and the waste of valued materials, have made it necessary establishing mechanisms to promote recycling and share the responsibility for waste management across the sectors directly or indirectly involved in waste generation. An example of this is the General Law on Waste Prevention and Integrated Management, which addresses the prevention of waste generation and the valuation of materials contained in waste (Cortinas de Nava, 2004; IBAM, 2006).
Cortinas de Nava, Cristina. Legislación Mexicana sobre Planes de Manejo de Residuos y de Productos de Consumo que al Desecharse se Convierten en Residuos. Ponencia en el Taller de Trabajo Orientado a la Formulación de una Propuesta a Nivel Técnico de “Política Centroamericana sobre Residuos y Desechos Sólidos y de una Propuesta Regional Sobre Depósitos y Retornos”. 2004.
DOF. Ley General para la Prevención y Gestión Integral de los Residuos. México. 2003 (8 de octubre).
DOF. Reforma a Ley General para la Prevención y Gestión Integral de los Residuos. 2007 (19-Octubre).
Fatta, D. C., P. Naoum, P. Karlis y M. Loizidou. Numerical simulation of flow and contaminant migration at a municipal landfill. Journal of Environmental Hidrology. 8:1-11. 2000.
Fetter, C. W. Applied Hidrogeology. Prentice Hall. Nueva Jersey. 2001.
Hoornweg D., and N. Giannelli. Managing municipal solid waste in Latin America and the Caribbean. Integrated the private sector. Harnessing incentives. Grid Lines. Note No. 28-Oct. 2007. Washington, D.C. 20433. USA.
IBAM. Manual de gestión Integrada de residuos sólidos municipales. En: Ciudades de América Latina y el Caribe. 1ª. Edición 2006. Brasil. 2006. Documento en PDF. Disponible en: http://www.gentein.com.mx/images/publicaciones/girs_esp.pdf.
Fecha de consulta:26-03-2012.
MEA. Ecosystems and Human Well-being: Current state and trends. Waste processing and detoxification. USA. 2005.
OPS. Informe Regional sobre la Evaluación de los Servicios de Manejo de Residuos Sólidos Municipales en la Región de América Latina y el Caribe. Washington, DC. 2005.
Semarnat-INE. Contaminación por pilas y baterías en México. México. 2004.
Semarnap-INE. Minimización y Manejo Ambiental de los Residuos Sólidos en México. México. 1999.