published on 1 November 2007 in ecosystems

The environment and health

Two faces of the same coin
The topic of the relationship between the environment and health is very transversal, i.e. it involves biologists, naturalists, doctors, chemists, physicists and engineers, and also sociologists, philosophers, economists and politicians at the same time. Therefore it is evident that the complex nature of the topic makes it very difficult to provide an exhaustive description in a small amount of space. For this reason we want to start discussing the topic in general, and in its global expressions.
In order to understand the repercussions the problem has, however, it must first of all be clear that the progressive deterioration of the environment – from the physical and chemical point of view and also in biological terms – is creating a considerable challenge to the civilization of the new millennium. This is proved by the fact that one of the main worries of the most important Institutions for public health in the world, the World Health Organization (WHO) stems from the awareness that a growing part of humanity now lives in extremely bad environmental conditions. It is feared, that without adequate resolutions, to be implemented on an international scale, the future of our species will have to face problems deriving from an environment that is less and less compatible with man’s health.

Due to unhealthy environmental conditions man is exposed to a number of different dangers, that range from acute diseases, such as intoxications, irritations and other syndromes with a short course, which also include some infectious diseases that are associated with various forms of environmental degradation, to chronic diseases, such as cancer, cardiovascular pathologies and other degenerative diseases, that are stimulated, for example, by air pollution, whose onset however is caused also by other factors of risk.
The number of subjects worldwide who are at risk of being affected by one of these diseases – specially in the urban areas and in poorer areas in the developing countries – cannot be calculated precisely. However it can be stated, without fearing any retractions, that the problem now concerns hundreds of millions of individuals, who are totally unaware of being exposed to very dangerous forms of environmental pollution. The degradation in the conditions of life in fact is not necessarily a visible fact.
Therefore it is quite clear why  protection of the environment is  taking on an increasingly decisive role in agreements that are signed in international political venues. And this is not only to preserve the natural resources of the planet from their constant impoverishment and deterioration, but mainly because it is starting to be understood that the prevention of environmental unbalance is the only way to guarantee a recovery of those conditions that are fundamental to our well-being.

Human and environmental health
In order to understand that the crisis of human well-being coincides with the crisis of the environment, firstly it must be clarified that the concept of good health must be regarded on a  very general scale. This concept in fact must be extended to all biological systems, therefore not only to the human organism, but also to other animal and vegetable organisms. In practice,  in order to speak of man’s good health, we must be able to speak of the good health of the entire ecosystem in which man lives, breathes and feeds. If this fundamental condition is not respected, the concept of good health, remains an abstract concept that is therefore void of any practical significance.
Contrary to the general opinion, in fact, the environment is not only outside our body but also inside. Very consistent parts of the environment continuously enter the organism, at least in the form of air, water and food. It is evident that if these components are contaminated physically, chemically or biologically, the organism will be contaminated in turn. And sooner or later, there will be signs of malaise or of the real disease. In practice, no animal can avoid introducing “parts of the environment” continually into its system, for the simple reason that no animal can survive without carrying out its minimum functions, that in fact are those of breathing, eating and drinking.
This simple description of the close bond that exists between the environment and life should already indicate how important it is to  establish a respectful relation with everything that surrounds us. In fact human history is very rich with examples that confirm these concepts. Notwithstanding the infinity of events that have marked the past history of Homo sapiens, if we tread its evolutionary history backwards, it is possible to identify events that have taken place and have occurred repeatedly, very frequently,  so that today it is possible for us to calculate with a good level of approximation, the trend of the state of health of ancestral populations. Whenever, in the past there have been significant changes in the health of a human population this has always depended on equally significant changes in the ecological equilibriums. These changes, in some cases were triggered by natural events, but more often they were the result of human activities which already at that time were able to significantly alter the environment,   physically and chemically and also biologically. It is known, for example, that many remote civilizations, like those in the Middle East or North Africa, or in South East Asia or Latin America, after having experienced periods of great splendour and prosperity , were later characterized by ruinous epilogues. Many factors today indicate that the fall of these historical civilizations was characterized by veritable ecological catastrophes (caused by wars or other events) that in turn provoked a worsening in the state of health of the human populations. Archaeologists have discovered for example that between the Fifth and Sixth century B.C.,  the Mesopotamian civilization experienced a severe degradation  of  its natural heritage, particularly with regard to the water resources and the forests, which automatically led to a drop in the conditions of health and of the average life span of the population. The impact of these devastations, of anthropic origin, however, was not so severe  as to jeopardize the regeneration of the deteriorated natural resources , i.e. the ecological damages provoked by man did not have such a widespread effect as to  irreversibly jeopardized the capacity of the natural systems to recover in relatively short times, on a geological scale.

Globalization of a problem
Nowadays, however, the situation is very different, because the power of technologies and the speed of the globalization processes greatly amplify the environmental problems and public health, so much so that the risk, for humans, of being affected by a disease of environmental origin, both infectious and non infectious, can rapidly move form one end of the globe to the other. This often implies that with the very first significant environmental symptoms, a critical level has already been reached, and at this stage, controlling the situation becomes much more difficult. For example, in case of a severe accident with an environmental impact that produces toxic components, all the necessary countermeasures should be taken immediately to prevent or limit any gaseous contaminations that are harmful for the environment and for health. In case of the contrary, the emissions could spread in the atmosphere and move rapidly, covering enormous distances compared to the point of origin, exploiting the air currents, thus provoking dangerous situations also in very far off areas. It is evident that to reduce human exposure to a polluting  agent that  has a limited diffusion in the environment is much easier than decreasing the same after the diffusion has spread to much vaster geographical areas. It is exactly on these aspects that environmental prevention must concentrate, undoubtedly without forgetting that in some cases the precautionary measures  are preferable to those of pure prevention. For example deciding that  it is more convenient to totally remove a source of danger rather than reduce the probable negative effects that it may cause.
We can take an example from the recent news: the avian flu epidemic that hit the headlines of newspapers all over the world for some months, reaffirms the above statement. From a small “accident” an unpredictable outfall may originate on a global scale, in other words a hazard for the health of the entire population of the earth (avian flu still is not known to have spread from one species to another, though this is much feared). The real cause of this viral syndrome among chickens, is in the total inattention to the most elementary measures of environmental hygiene that characterize poultry animal breeding farms in some countries in the Far East. And yet this is not enough to explain the global diffusion of the disease. As it is known in fact, its spreading is favoured by migratory birds that are receptive to the virus, that greatly increase the geographic area of risk for the animals, and theoretically also for humans. As it can be seen, the  ways in which a simple environmental alteration can grow gigantically, to a risk of  planetary proportions, are unpredictable and this is the very first principle that must be borne in mind in environmental and health risk management.

On a global scale, one of the factors that contribute the most to the intensity of the sanitary impact in environmental deterioration, is the urbanization process. Today there is still a migratory phenomenon, from the more  disadvantaged rural areas to the urbanized areas that are considered more “liveable”. This phenomenon mainly involves developing countries. This massive movement from the countryside to the cities is often motivated by the mirage of a job, an escape from insecurity (also alimentary), in search of a better life-style, or , more simply in the hope of finding more stimulating social relations. It must be said that those who are involved in these mass movements have perfectly comprehensible motivations to encourage their choice; now who would not be attracted by the possibility of better living conditions? However, it must also be said that in many cases what these people are confronted with a reality that is not much like what they hoped to find.
Cities, in fact, are increasingly chaotic and crowded, and as such, in many circumstances they become places in which exposure to environmental (or other types of) risks increases impressively. Many of the world’s megalopolises now have millions and millions of inhabitants, and if we think of the problems of polluted air and water they have to deal with, it is easier to understand the reason why in many cases urbanization seems to produce many more troubles than those it solves, specially for newcomers.
The example of Mexico city is emblematic. The Mesoamerican capital city has a population of over 20 million people, and approximately 5 million vehicles circulating on the roads, which generates the most clamorous case of urban pollution in the world. Here there is an enormous concentration of atmospheric emissions, besides remarkable problems of disposal of waste waters and solid urban waste. The consequences can be seen in terms of the impact of these types of pollution on the health of the population and in particular on the poorer people who do not have many resources  to  take care of their health (living in healthier homes, eating more nutritious foods, availing of the necessary medical care, etc.). And here, naturally, we see another topic of great importance for the relationship between the environment and health. Experts believe that lastly, the cause of the progressive degradation of the environment and its impact on human health today is to be attributed to excessive poverty – in the large cities, but also in other areas that are not necessarily urbanized, in the developed and in the less developed parts of the world. In practice, often a perverse mechanism sets off, due to which human crowding leads to an exponential increase in environmental pollution, specially in those areas in which  knowledge, technologies and services that could reduce the phenomenon are lacking – just think of the large urban  conglomerations  in the Third world,  where sewage systems are absent.
Thus, there is an increase in the pollution, waste products, a senseless use  of water and combustible energetic products, and as a consequence there is also an increase in the exposure to diseases, specially among the poorer classes of the population. The specific reasons of these deceitful dynamics   that affect the weaker groups  of persons,  vary from country to country. However the larger health organizations (such as the WHO) have widely documented that poverty always  entails a long list of woes, among which the risk of illness and premature death due to a degraded environment is undoubtedly, together with the drama of hunger, the first humanitarian emergency of the planet.

Written by Carlo Modonesi

With the sponsorship of the Italian Ministry of Education, Universities and Research
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