Studies on the survival of coliform bacteria from human and animal wastes

Abstract

The problem of pollution is as old as our civilized society. Its effects began to show when man changed from hunting to utilizing land for agricultural and animal husbandry practice. This change in the way of life forced human beings to stay in one area for long periods of time, and hence the accumulation of waste products of different types was inevitable.

The problem increases with population growth and the rapid rate of industrialisation. The more industrialised a society is, the greater is the amount of waste derived from the consumption of various products (food, water, goods) and the more advanced the technology is, the more numerous are the numbers of types of waste products rejected into the environment (i.e. isotope materials, pesticides, detergents etc...).

All of these waste products, if not treated and disposed of correctly, will cause pollution water, soil and air.

All of these waste products, if not treated and disposed of correctly, will cause pollution to waters, soil and air.

In the early days, when many epidemic disease (water borne in particular) were prevalent and uncontrolled, the pollution caused by microbial pathogens in water, so called microbial pollution, greatly affected public health.

At the moment, this microbial pollution is still a problem in developing and under-developed countries because there are still epidemics of many water-borne diseases which are not yet controlled by sewage treatment facilities and medical care. (Sommuck Unakul and McQuary, 1967).

In the case of developed countries, advanced technology leads to the increased consumption of various natural resources and food products etc. This results in the production of huge amounts of waste products of various types which can create different forms of pollution in water, soil and the air. However, with good medical and good sewage treatment facilities, the so-called microbial pollution is not such a problem, and other forms of pollution, namely inorganic, and organic pollution have become more obvious.

Today there is increasing evidence of accumulation of pesticides in natural food chains and also evidence of problems caused by detergents which cause foaming of rivers and sewage treatment plants and contribute a substantial amount of phosphorous to streams to cause eutrophication of lakes.

Inorganic pollutants can render water alkaline or acidic or too high in salt content so as to make it unsuitable for irrigation purposes and industrial usage.

The organic pollutants can create eutrophication of lakes which may lead to algal blooms, some of which can make water poisonous to livestock. Also eutrophication of lakes often leads to a depletion of oxygen and hence, can affect the fishing industry. Various authors such as Culp and Culp (1970) have pointed out that many recreation activities can be affected by high densities of aquatic plant s growing in the water. In an eutrified lake, the mass of weed will eventually die-off , and if washed up on shore in large quantities, the odour it produces can change a holiday resort into an undesirable place. It is quite obvious that the price of land in the area may be greatly affected as a result.

For these reasons, it is obvious that pollution, no matter in what form it is, can affect people in society. This explains why many people of different occupations and interests are concerned with pollution problems; and there is no doubt that it will continue to arouse public attention; especially with the present trend of increasing population and urbanisation in the world.