Materials for Water Systems: Health & Toxicity

Systems serving 6 million people have shown harmful levels of lead in drinking water

Flint, Michigan may be the first city that comes to mind when you think of the crises that can occur in cities where lead service lines are still prevalent in their water systems. However, Flint is hardly alone in this category. Other cities, such as Newark, New Jersey; Washington, DC; and most recently Benton Harbor, Michigan have faced similar public health emergencies, making the risk associated with lead piping all too real.

In 2016, USA Today conducted a review of data from the U.S. Environmental Protection Agency (EPA) regarding water systems with lead levels that exceeded EPA standards. This data showed that nearly ‎2,000 drinking water systems, which were serving 6 million people in all 50 states, have experienced excessive or ‎harmful levels of lead, with 373 of these systems failing repeatedly.

‎As more cities and municipalities begin the important process of replacing their lead pipes, it is equally important to seriously consider the best options for replacement materials. The goal should not be a short-term fix, but to install a well-designed system that is non-toxic, resilient, and sustainable. Key areas to consider regarding health and toxicity are permeation, absorption, and leaching.

Permeation

Porous piping materials are more susceptible to incidence of permeation. More permeable materials will allow increased amounts of environmental contaminants to go through the pipe wall and enter water supplies. Copper, iron, and steel pipes do not allow for permeation.

Absorption

Porous piping materials also “adsorb” chemicals more easily, sponging up a toxins and creating an ongoing contamination source that can spread from area to area inside a structure, around a block or across a town. Reactive surface structures can also increase adsorption in plastic piping when compared to copper, iron, and steel pipes, which have a significantly lower rate of absorption.

Leaching

Plastic pipes have complex chemical constructions with additives to abate UV degradation, reduce corrosion, and improve ductility. This makes it hard to anticipate what substances can get leached into a water system during normal operation or when the pipes are stressed (from wildfires or otherwise). By contrast, common metal pipes have simple chemistries. They have low leaching characteristics and require no additives to meet the needs of most piping applications.

Be on the lookout for the next post in our series on using proven materials for water systems.