A clean environment is essential for human health and well-being. Exposure to environmental pollution remains a major source of health risk throughout the world.
It is extremely difficult to assess the complex interactions between the environment and human health; this makes the use of the precautionary principle particularly useful. The best-known health impacts range from ambient air pollution, poor water quality, to toxic chemical exposures, climate change, and degraded urban environments. The resulting impact is estimated to cause over 25% of deaths and diseases globally, reaching nearly 35% in regions such as sub-Saharan Africa.
Outdoor or ambient air pollution is a major environmental health threat affecting everyone in both developed and developing countries. According to the World Health Organization (WHO), around 80% of outdoor air pollution-related premature deaths were due to ischaemic heart disease and strokes, while 14% of deaths were due to chronic obstructive pulmonary disease or acute lower respiratory infections; 6% of deaths were due to lung cancer.
There are six common air pollutants. These are particle pollution (often referred to as particulate matter), ground-level ozone, carbon monoxide, sulfur oxides, nitrogen oxides, and lead. Of the six pollutants, particle pollution and ground-level ozone are the most widespread health threats. Exposure to these pollutants is associated with numerous effects on human health, including increased respiratory symptoms, hospitalization for heart or lung diseases, and even premature death.
Most air pollution is man-made and includes both “mobile” sources—cars—and “stationary” sources—smoke stacks. Moreover, in those cities where residential use of coal and wood for cooking and heating is permitted, the emissions from households using these fuels can make an important contribution to the level of urban outdoor air pollution.
People living in low- and middle-income countries disproportionately experience the burden of outdoor air pollution with 88% of the 3.7 million premature deaths occurring in low- and middle-income countries, and the greatest burden in the WHO Western Pacific and South-East Asia regions.
On the other hand, water pollution, defined as any contamination of water with chemicals or other foreign substances that are detrimental to human, plant, or animal health, is also one of the greatest dangers to human health. These pollutants include fertilizers and pesticides from agricultural runoff; sewage and food processing waste; lead, mercury, and other heavy metals; chemical wastes from industrial discharges; and chemical contamination from hazardous waste sites.
Worldwide, nearly two billion people drink contaminated water that could be harmful to their health. Even our clearest streams, rivers, and lakes can contain chemical pollutants. Heavy metals such as lead and mercury can produce severe organ damage. Some chemicals can interfere with the development of organs and tissues, causing birth defects; others can cause normal cells to become cancerous.
Some chemical pollutants enter water sources as runoff from agricultural fields—pesticides; or as drain water—from kitchens and bathrooms—from human homes and businesses. These pollutants also seep into groundwater reservoirs from landfills and underground sewage containers; after they enter groundwater sources, they contaminate freshwater drinking supplies and are difficult to clean up. Moreover, some of our waterways also contain human and animal wastes.
The bacteria in these wastes can cause high fever, cramps, vomiting, and diarrhoea. These illnesses are particularly dangerous for young children; in fact, they account for almost 60% of early childhood deaths worldwide. Although sewage treatment plants have reduced the occurrence of water-related illnesses in some nations, less developed nations still struggle to find safe, fresh water. In some regions of the world—parts of India, China, and Africa, for example—water-related illnesses are still a leading cause of death.
In recent decades, a wide range of modern pollutants have emerged. For instance, roughly 40 million metric tons of electronic waste—e-waste—are produced globally each year, and about 13% of that weight is recycled mostly in developing countries. Developing countries with rapidly growing economies handle e-waste from developed countries, and from their own internal consumers. About 9 million tons of this waste—discarded televisions, computers, cell phones, and other electronics—are produced by the European Union.
Air pollution in Beijing, 2013. Credit: Feng Li/Getty Images. Source: CNN.
Exposure routes can vary dependent on the substance and recycling process. Generally, exposure to the hazardous components of e-waste is most likely to arise through inhalation, ingestion, and skin contact. In addition to direct occupational—formal or informal—exposure, people can come into contact with e-waste materials, and associated pollutants, through contact with contaminated soil, dust, air, water, and through food sources, including meat. The Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal bans the exchange of hazardous waste, including e-waste, between developed and developing countries.
The process of climate change has important implications for human health. Scientific research has shown that the temperature of the Earth has risen to an alarming figure during the past few years. It will most probably rise further if we do not stop polluting the environment.
In recent years, not only many forests have been burnt because of the extremely hot weather, but also human health has been severely affected. In fact, the health of human populations is sensitive to shifts in weather patterns and other aspects of climate change.
These effects occur directly, due to changes in temperature and precipitation and occurrence of heat waves, floods, droughts, and fires. Indirectly, health may be damaged by ecological disruptions brought on by climate change—crop failures, shifting patterns of disease vectors—or social responses to climate change—such as displacement of populations following prolonged drought.
In recent years, however, it has become apparent that promoting human health sometimes undermines environmental protection. Some actions, policies, or technologies that reduce human morbidity, mortality, and disease can have detrimental effects on the environment. For example, food is necessary to sustain human life.
Malnutrition can weaken the human immune system and exacerbate many health problems. Each year six million children under the age of five die from starvation, and hundreds of millions of people are malnourished. The production of food, however, can have a variety of adverse environmental impacts, including deforestation, habitat destruction, loss of biodiversity, and air and water pollution.
Although different modes of food production—industrial vs. non-industrial—have different environmental impacts, no method of producing food leaves the environment unscathed. Mosquito-borne illnesses, such as malaria, are a major public health problem in the developing world. Some of the methods applied to prevent mosquito-borne illnesses, such as draining swamps and spraying pesticides (especially DDT), can have adverse environmental impacts, such as destruction of habitats and species.
Finally, medical care itself creates a great deal of waste and pollution that can harm the environment. Hospitals use large amounts of electricity, oil, coal and natural gas, and produce tons of hazardous medical waste, such as used syringes, bandages, and gloves, and leftover tissue and blood which contribute to environmental pollution.
In conclusion, it is important to understand the various forms of pollution and how it is created to identify the best way to stop it. Most sources of outdoor air pollution are well beyond the control of individuals and demand action by cities, as well as national and international policymakers in sector as transport, energy waste management, buildings and agriculture.
Although e-waste management has made great progress in the past decade, and many laws and regulations have been implemented in different parts of the world, the informal e-waste recycling processes still exist. How to effectively and universally implement these policies and measures is still a key point.
Averting the onset of pollution in any area could be the start and the simplest preventive solution to the problem. This calls for a conscientious effort to adopt good practices or habits by the people, the passage and the proper implementation of appropriate government laws, and the strict compliance especially by potential industrial pollutants.
References
http://www.eea.europa.eu/themes/human
http://www.epa.gov/air/urbanair/
http://www.niehs.nih.gov/health/topics/exposure/water-poll/
http://www.dummies.com/
http://hubpages.com/hub/reduce-pollution
The article was first published in print in SCIplanet, Summer 2014.
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