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the process of photosynthesis

Figure 8.7  The crippled hand of a Minamata disease victim (W. Eugene Smith).

(Adapted from Cunningham and Cunningham, 2011)

What can we learn from the Minamata story? Although the source was suspected, it still took 12 years before it was recognised. The government and the company denied responsibility and we may suspect a political and economic motive for their refusal to recognise the problem for more than ten years, despite the evidence. We can also see that pollutants can enter the human body through complex routes. The mercury changed its form after it was released into the bay, making it harder to trace. It was not put straight into human food but entered it by bioaccumulation through the food chain from micro-organisms, through small fish to bigger fish.

Another important point from this example is whether the generator of waste is responsible for the waste that they produce, the pollution that they cause in the environment and for the harm caused by that pollution. In this example, the pollution was traced back to the polluter and compensatory payment was made. However, it took a long time and some think that payment was not adequate for the damage caused.

 Human exposure to pollution

Exposure is the state of being unprotected. It is a set of conditions that allows a pollutant or contaminant to enter the human body. The presence of pollution, the medium that the pollutant is in and the human subject or host that will be affected by the pollutant are the set of conditions used to describe the exposure. In the Minamata example, the source was the Chisso factory, the medium was the water and the subjects were the people who consumed contaminated fish.

There are three main routes by which people are exposed to pollution. These are:

  • Ingestion: in the Minamata example people ingested contaminated fish.
  • Inhalation: repeatedly breathing in air pollutants can cause respiratory diseases.
  • Skin contact (also called dermal exposure): direct contact, usually with the hand, in which chemicals penetrate the skin and enter the circulatory system.

Figure 8.8 indicates the possible exposure routes for pollutants and links from source to recipient.

View larger imageFigure 8.8  Exposure routes of pollutants.

 Preventing and controlling polon

In this final section we look at some important principles that should be applied when attempting to prevent or control pollution. Pollution prevention means avoiding or minimising the generation of wastes that produce pollutants, thereby restricting their release into the environment. Pollution control focuses on measures taken after wastes have been produced to limit the damage they may cause. It is often more difficult and expensive to control pollution after it has been released into the environment.