Final answer:
Pollution is the introduction of harmful chemicals or wastes into the environment, which can affect air, water, and soil and lead to adverse changes in ecosystems and human health. This can result from various human activities or natural occurrences, and the spread of new contaminants since the Industrial Revolution has introduced numerous unforeseen hazards.
Step-by-step explanation:
The introduction of harmful levels of chemicals or wastes into the environment is called pollution. Pollution occurs when contaminants, which can be chemicals, wastes, or other harmful substances, are introduced into the natural environment, leading to adverse changes. These contaminants can be introduced through various sources, such as industrial, residential, and commercial activities, and even through natural occurrences like volcanic eruptions or wildfires.
Contaminants are often present in different parts of the environment like water, air, and soil, and they can have detrimental effects on ecosystems, wildlife, and human health. The presence of contaminants at levels higher than what would be naturally occurring can lead to their concentration along trophic levels in ecosystems, a process known as bioaccumulation, which can have severe implications for biodiversity and food security.
Since the beginning of the Industrial Revolution, over 80,000 new chemicals have entered commerce, many of which have spread globally and are found in remote regions. These substances include pollutants such as heavy metals, pesticides, and persistent organic pollutants (POPs), which have no evolutionary history in biological systems and hence no natural resistance, making their impact on the environment and health especially concerning.