To appreciate the chemistry involved in environmental science, we must begin with the fundamentals. Matter may be transformed from one type of substance into others, but it cannot be created or destroyed. This principle is referred to as the law of conservation of matter. In environmental science, this principle helps us understand that the amount of matter stays constant as it is recycled in ecosystems and nutrient cycles.
The law of conservation of matter also makes it clear that we cannot simply wish away “undesirable” matter, such as nuclear waste and toxic pollutants. Because harmful substances can’t be destroyed, we must take steps to minimize their impacts on the environment. The nuclear reactors at Fukushima Daiichi used the element uranium to power its reactors. An element is a fundamental type of matter, a chemical substance with a given set of properties that cannot be broken down into substances with other properties. Chemists currently recognize 92 elements occurring in nature, as well as more than 20 others that they have created in the lab.
Elements especially abundant on our planet include oxygen, hydrogen, silicon, nitrogen, and carbon. Each element is assigned an abbreviation, or chemical symbol (for instance, H for hydrogen and O for oxygen). The periodic table of the elements organizes the elements according to their chemical properties and behavior.