Issue

Lead is a heavy, soft, and malleable metal found in natural deposits, such as ores containing other elements. It has no characteristic taste or smell. In drinking water systems, lead has been used to produce:

• service lines (banned since 1988),
• solder (banned since 1988), and
• a variety of brass pipes and plumbing devices.

Effects of Lead on Human Health and How It Enters Drinking Water

Lead poses a significant health concern. For infants and children, exposure to high levels of lead in drinking water can result in delays in physical or mental development. For adults, it can result in high blood pressure, kidney problems, or even cancer. Although the main avenues of exposure to lead are ingesting paint chips and inhaling dust, EPA estimates that 10-20% of human exposure to lead may come from lead in drinking water.

Most lead enters our drinking water through the interaction of the water and plumbing materials containing lead. The most important factors contributing to lead leaching into our drinking water are:

• water chemistry,
• the age of the piping, and
• amount of exposed lead at the surface of the material in contact with the water.

Plus, trace amounts of certain soluble contaminants, that include lead, can stick to corrosion deposits within distribution systems. Changes in water chemistry or physical changes within the system can later rerelease concentrated amounts of these contaminants into the water supply.

Lead is rarely found in source water. Lead mining and smelting operations may contribute to the contamination of source water in certain areas.

To prevent lead from entering our drinking water, there are three categories of control:

• Physical control is the removal of lead-containing materials or the limiting of lead content in materials.
• Point-of-use control is the use of devices attached to water taps or in lines near water outlets. These devices include:
•  filter units,
• ion exchangers,
• reverse osmosis units, and
• adsorber cartridges.
• Chemical treatment control occurs during water treatment. Chemical approaches used to reduce lead levels in water are:
• pH and alkalinity adjustment,
• phosphate addition, and
• silicate addition

Action

Regulations require sampling at entry points to the distribution system to ensure compliance. Increased levels of lead in drinking water are primarily due to the corrosion of distribution and household plumbing materials. Water utilities must collect water samples at kitchen or bathroom taps of residences and other buildings. This requirement significantly complicates sample collection and requires that water utilities coordinate with consumers to ensure that proper sampling and compliance is achieved.

Results and Impact

If the levels of lead in your drinking water are found to be consistently above the action level, your water supplier must take steps to reduce the amount of lead so that it is consistently below that level. Additional actions, such as providing alternative drinking water supplies, may be required to prevent serious risks to public health.

Technical Contact

Darren Lytle
513-569-7432

Michael Schock
513-569-7412