(6) Pollution

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A hypothetical contaminated lake

Assume that tiny amounts of 20 different synthetic chemicals have been detected in a local lake. Each is present in an amount so tiny that it alone is highly unlikely to cause a problem, certainly not in the short run. Many of these chemicals are also found, likewise in tiny amounts in our bodies. Should we be concerned?

Possibilities that could increase your concern

1. Among the 20 contaminants are chemicals that are very similar to one another. Similar chemicals may exert toxic effects in similar ways and the levels of each, if added together, could potentially pose a problem. Organophosphate pesticides are one example.

There are many different organophosphates, but each exerts toxicity in a similar way. So, if several of the contaminants are organophosphates, the total concentrations added together may cause concern.

2. Even if none of the chemicals act similarly in the body, perhaps some combination of them could exert a synergistic effect, that is, one chemical could magnify the effect of another chemical out of all proportion to its concentration. Testing for synergistic effects among 20 chemicals is almost impossible because we could not reasonably test them in all possible combinations.

3. Species differ widely in their sensitivity to toxicants. One species may be many times more sensitive than another. And within any individual species, including humans, there is also a range of sensitivity.

Possibilities that could decrease your concern

1. Two chemicals may be antagonists, i.e., one may inhibit the toxicity of another, lessening the chance of an adverse effect. Basically, one chemical acts as an antidote to the other.

2. Hundreds or thousands of chemicals are naturally present in the water; some or many may be similar chemically to the synthetic contaminants.

3. Animal and human bodies deal with contaminants using biochemical pathways that evolved over millions of years to break down natural poisons in the environment. Our bodies have no way of knowing if a given chemical is natural or synthetic.

4. A quarter century ago, chemists probably couldn’t even have detected many of these chemicals. Only now with sophisticated analytical methods can we even know if there are chemicals that might be of concern.


1. (a) Possibilities that might increase your concern. Did any of these points increase your concern? Explain. (b) Possibilities that could decrease your concern. Did any of these points lessen your concern? Explain.

2. Even testing a few chemicals in mixtures for possible toxicity is complicated and expensive. However, it is possible to examine the effect of the contaminated water itself on aquatic life. This is called whole effluent toxicity.24 Does whole effluent toxicity reassure you as a logical way to test toxicity? Why?

3. With which of the following conclusions do you most tend to agree and why? (a) It is alarming that many synthetic chemicals are detected. Our health, our children’s health, and wildlife are likely affected. Let’s find the sources of the chemicals and stop further emissions. (b) We cannot worry about every low-level contaminant. We cannot reduce emissions to zero and it would be prohibitively expensive to even reduce them to near zero. And, quite often a synthetic chemical also occurs in nature as a natural chemical. Animals and plants have evolved protective means over eons of dealing with natural poisons, and most probably can manage the chemicals in this lake too. Taking a chemical off the market could pose other problems – the chemical that replaces it in an industrial process may also pose problems that are now unknown. Let’s devote our limited resources to higher-risk problems.

4. Think about air pollution in an agricultural setting and ponder a situation that occurs with increasing frequency as people move into areas previously devoted to farming. New residents may complain about farm odors when farmers spread sewage sludge on their fields as a fertilizer or soil amendment. Both State and US environmental agencies support spreading carefully treated sludge. But one complaining resident said, “The human body knows when something is not good for you. Sludge must be bad. It smells so bad, it can make you nauseous.” (a) Does the fact that sludge smells bad mean that airborne substances are present at a harmful level? Explain. (b) Before you can decide whether concerns are legitimate, what questions would you want answers to?

5. Another resident said, “When someone spreads sludge, you get flies in your house . . . It’s awful.” Do flies present a potential danger? Explain.

6. If you were thinking of moving into a rural area: (a) What questions would you want to ask? (b) Should sellers be required to provide you with information on sludge-spreading or similar operations around their homes?

7. Consider that you already live in a rural setting. (a) How would you react if a large industrial farm (one with thousands of pigs, cattle, or poultry crowded into a limited space) moved into your rural neighborhood? What would your environmental and health concerns be?

Degradation of global environmental health

At the Earth Summit held in Rio de Janeiro, Brazil, in 1992, the heads of 120 governments met together. Their mission was to decide how to deal with Earth’s environmental problems including climate change, air and water pollution, deforestation, and loss of biodiversity (extinction of species). One result was Agenda 21, a strategy for sustainable development or, as one participant phrased it, “a blueprint for how humankind must operate in order to avoid environmental devastation.”

In 1997, 158 governments gathered for an Earth Summit+5 to discuss progress, but they found that environmental conditions were worse. A Malaysian delegate exclaimed, “Five years from Rio we face a major recession . . . a recession in spirit. We continue to consume resources, pollute, and spread and entrench poverty as though we are the last generation on Earth.”

Yet again in 2002, governments gathered for a World Summit on Sustainable Development. Despite a continuing grim environmental picture, participants took a different approach: they recognized that environmental sustainability is not possible when great numbers of people lacked even basic amenities such as safe drinking water and sanitary facilities. One major outcome was that all 191 UN member states pledged to meet eight Millennium Development Goals by 2015. One goal was to cut extreme poverty in half while “ensuring” environmental sustainability.

Gross pollution often goes hand in hand with gross poverty.

Pollution in less-developed countries

Environmental degradation in impoverished countries, often called less-developed countries is, according to the Asia Development Bank, “pervasive, accelerating, and unabated”. In an Atlantic Monthly article, William Langewiesche describes one city, New Delhi, India, where “. . . the pollution . . . seemed apocalyptic.

The streams were dead channels trickling with sewage and bright chemicals, and the air on the street barely breathable.”Rivers in some cities are described as “open stinking sewers.”

The World Health Organization (WHO) tells us that 2.6 billion people have no access to hygienic toilets. They use buckets, bushes, ditches, or rivers; if lucky, they have latrines. More than a billion lack safe drinking water. The WHO estimates that at least 1.6 million lives are lost each year through lack of access to sanitation and clean drinking water. Millions more are left chronically ill from the water they must drink.

Millions of deaths result yearly from infections caused by eating contaminated food.

Just by breathing the air, children in a heavily polluted city such as New Delhi inhale the equivalent of two packs of cigarettes each day.

Living in rural areas may be worse: up to 3 million deaths result worldwide each year from air pollution; about half of these arise from intolerable indoor air pollution. This occurs because almost 90% of impoverished households burn straw, wood, or dried manure inside their homes for cooking and often for heating, with very poor ventilation. Women and children are most affected.

 The effects of pollution go beyond deaths to impacting people’s ability to live healthy lives. One illustration: almost half the world’s population, especially small children, may suffer from waterborne diseases.


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