| |
|
Toxic chemicals: the legacy of a chemical society
We are a "chemical" society, using hundreds of chemicals in our normal daily activities: washing, eating, house-cleaning, tending the lawn and garden, driving. Of the almost 10 million chemicals known today, approximately 100 000 chemicals are used commercially.
Most toxic chemicals are discharged directly into our waterways as waste, but many also enter the water after everyday use in the home, agriculture and industry. They constantly change the chemical composition of our waters. One way is seepage: the chemicals soak through the earth into the groundwater from waste disposal sites and agricultural lands, for example. Another way is runoff: the chemicals are washed into bodies of water from the land where they were used or spilled, or from the air into which they were emitted.
The chemicals can cause problems with the taste, odour and colour in water. Fish and wildlife can experience reduced fertility, generic deformities, immune system damage, increased incidence of tumours, and death.
Many of the chemicals that enter the water are, even in minute amounts, toxic to human, plant and animal life. Pesticides, PCBs, and PCPs (polychlorinated phenols) are typical examples. Pesticides are used in agriculture, forestry and homes. PCBs although no longer used in new installations, are still found as insulators in older electrical transformers, and PCPs can be found in wood preservatives. The very qualities which make them desirable for use – toxicity and persistence, for instance – make them so harmful to the environment.
|
Water Pollution Menu
Previous
