In the first of this two-part series in our Cleaning Up The Mess space, DR AZAD MOHAMMED, Eco-toxicologist and UWI lecturer tells us how successive governments lack of environmental policing and enforcement of laws have slowly poisoned our air, land, and water, and created a toxic landscape, leading to a dramatic rise in the average number of cancer-related deaths in T&T.
It is often been said that our quest for wealth has time and again generated much of the pollution that plagues our society and contributes to general degradation of our natural environment. Living in a way that is less damaging to the Earth is not easy, but it is vital, because pollution is pervasive and often life-threatening. About 70,000 chemicals are on the market, with around 1,500 new ones appearing annually. At least 30,000 are thought never to have been comprehensively tested for their possible risks to people. But the snag is that modern society demands many of them and some are essential for survival.
What then really is pollution? Pollution occurs when substances resulting from human activities are added to the environment, causing a detrimental alteration to its physical, chemical, biological or aesthetic characteristics. There are many ways of classifying pollutants; (1) physical state, (2) based on chemical structure, (3) disease causing agents, or (4) toxicity. Most polluting substances occur as solids, liquids or gases or combination of these in land, air and aquatic environments. The harm created by pollution may be direct, through the toxic effect of a substance, or indirect, through the modification of the environment in which organisms live.
For example, pesticide or oil spilled into rivers may result in immediate mass fish kills. However, nitrogen and phosphorus released from households and sewage treatment plants may stimulate plant growth. However, excessive plant growth can be harmful in water systems. High levels of nitrates and phosphates in surface waters can stimulate excessive algal growth causing green mats on the water body. Over time as the algae die and decay it reduces the oxygen available in the water, harming fish and other aquatic life.Some man-made chemicals, endocrine disruptors like phthalates and nonylphenol-a breakdown product of spermicides, cosmetics and detergents-are blamed for causing sex changes in some animals.
Waste water discharge from industries also contains high levels of organic chemicals, oily waste, toxic chemicals and salts, such as sodium and potassium. These salts are especially important when these wastewater streams are discharged into freshwater systems as it can alter the ionic composition of water bodies and intern the ability of organisms to maintain their own internal ionic balance. Some pollutants can also cause chronic problems which may only manifest over prolonged exposure to low concentrations of pollutants. Studies have shown that seven-20 per cent of cancers may be attributed to poor air and pollution in homes and workplaces.
In Trinidad and Tobago it has been reported that during the period 2000 and 2002 there was an 11 per cent increase in new cancer cases and a 35 per cent increase in the average number of cancer related deaths annually, when compared to a similar period from 1995-1999. The specific effect of pollution is often related to the type of pollutant and the levels of specific chemicals in the environment. The World Health Organisation estimates that people die worldwide annually as a result of exposure to outdoor air pollutants resulting from vehicles and industrial emissions. Chemical contaminants on land and water systems resulting from industries, domestic and agricultural activities also contribute to deterioration of eco-system health which ultimately impacts on human health.
Water-borne diseases are responsible for 80 per cent of illnesses and deaths in developing countries, killing a child every eight seconds. Each year 2.1 million people die from diarrheal diseases associated with poor water quality. Can we really accept that we live in a way that is enormously damaging to the environment and ourselves?
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