- The Effect of Water Chemistry on the Solubility and Properties of Freshly Precipitated Copper Solids
- Pitting Corrosion of Copper in High-pH and Low-Alkalinity Waters
Copper is a common, malleable metal that occurs naturally in rock, soil, water, sediment, and air. It is used to make products such as coins, electrical wiring, and water pipes for household plumbing.
Copper Exposure and Human Health
Though a small amount of copper is required by the human body as an essential nutrient, long-term exposure to high levels of copper may cause serious health problems. Research has shown that short periods of exposure to high levels of copper can cause gastrointestinal disturbance, including nausea and vomiting. Using water with elevated levels of copper over many years may cause liver or kidney damage.
Copper Corrosion in Household Piping Systems
The primary sources of copper in drinking water are corroding pipes and brass components of household piping systems. Signs of high levels of copper in drinking water include a metallic taste or blue to blue-green stains around sinks and plumbing fixtures. The solubility of these by-products ultimately determines the level of copper at our taps. The only way to accurately determine the level of copper in drinking water is to have the water tested by a state-certified laboratory.
There are two types of copper corrosion:
Both types are caused by certain characteristics of water chemistry, including:
- low pH,
- high alkalinity, and
- the presence of sulfates or nitrates.
Uniform corrosion is identified by the presence of a relatively uniform layer of copper corrosion by-products across the inner surface of a pipe wall. It is typically associated with elevated copper levels at our taps.
Nonuniform corrosion, or pitting, is the isolated development of corrosion cells across the inner surface of a pipe wall. Pitting corrosion is seldom associated with elevated levels of copper at our taps. However, excessive pitting corrosion can lead to “pinhole” leaks in the pipe. This can result in water damage and mold growth.