Ion concentrations refer to the amount of charged particles, or ions, present in a solution. Ions can be positively charged, known as cations, or negatively charged, called anions. These concentrations are crucial in various fields, including biology, chemistry, and environmental science, as they influence chemical reactions and biological processes. In biological systems, such as in the human body, ion concentrations are vital for functions like nerve signaling and muscle contraction. For example, the balance of sodium and potassium ions across cell membranes is essential for maintaining proper cell function and overall homeostasis.