Calc, in the context of water, refers to calcium, a major positive ion found naturally in fresh water. It's derived from the many minerals containing calcium that are prevalent on Earth.
The Prevalence of Calcium in Water
Calcium is not just a trace element; it’s a significant component of our environment:
- Earth's Surface: Calcium constitutes 4.9% of the Earth's surface.
- Soil: It makes up 0.07% to 1.7% of soil composition.
- Rivers: Calcium concentrations in rivers average about 15 mg/L.
- Groundwater: Groundwater contains varying levels, ranging from 1 mg/L to less than 500 mg/L of calcium.
Practical Implications
The presence of calcium in water can lead to:
- Hard Water: High levels of calcium and magnesium ions make water 'hard,' leading to scale buildup in pipes and appliances.
- Water Quality: The concentration of calcium is a significant factor in determining water quality for various purposes, including drinking, agriculture, and industrial use.
Understanding Calcium Sources in Water
Calcium enters water bodies through:
- Mineral Dissolution: Water dissolves calcium-containing minerals in rocks and soil.
- Runoff: Surface runoff carries calcium from the land into rivers and groundwater.
Table of Calcium Concentrations in Water
| Source | Typical Calcium Concentration |
|---|---|
| Rivers | 15 mg/L |
| Groundwater | 1-500 mg/L (variable) |
