Monday, December 14, 2020

Plastic pipes are polluting drinking water systems after wildfires - it's a risk in urban fires, too


https://news.yahoo.com/plastic-pipes-polluting-drinking-water-192745370.html

The Conversation

Andrew J. Whelton, Associate Professor of Civil, Environmental & Ecological Engineering, Purdue University, Amisha Shah, Assistant Professor of Civil Engineering and Environmental and Ecological Engineering, Purdue University, and Kristofer P. Isaacson, Ph.D. Student, Purdue University
Mon, December 14, 2020, 2:27 PM EST


When wildfires swept through the hills near Santa Cruz, California, in 2020, they released toxic chemicals into the water supplies of at least two communities. One sample found benzene, a carcinogen, at 40 times the state’s drinking water standard.

Our testing has now confirmed a source of these chemicals, and it’s clear that wildfires aren’t the only blazes that put drinking water systems at risk.

In a new study, we heated plastic water pipes commonly used in buildings and water systems to test how they would respond to nearby fires.

The results, released Dec. 14, show how easily wildfires could trigger widespread drinking water contamination. They also show the risks when only part of a building catches fire and the rest remains in use. In some of our tests, heat exposure caused more than 100 chemicals to leach from the damaged plastics.

As environmental engineers, we advise communities on drinking water safety and disaster recovery. The western U.S.’s extreme wildfire seasons are putting more communities at risk in ways they might not realize. Just this year, more than 52,000 fires destroyed more than 17,000 structures – many of them homes connected to water systems. Heat-damaged plastic pipes can continue to leach chemicals into water over time, and ridding a water system of the contamination can take months and millions of dollars.


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Andrew J. Whelton, Associate Professor of Civil, Environmental & Ecological Engineering, Purdue University, Amisha Shah, Assistant Professor of Civil Engineering and Environmental and Ecological Engineering, Purdue University, and Kristofer P. Isaacson, Ph.D. Student, Purdue University
Mon, December 14, 2020, 2:27 PM EST
<span class="caption">Heat-damaged plastic pipes can continue to leach chemicals into water over time.</span> <span class="attribution"><a class="link rapid-noclick-resp" href="https://www.gettyimages.com/detail/news-photo/debris-of-a-burnt-house-are-seen-on-january-04-2020-in-news-photo/1197404614" rel="nofollow noopener" target="_blank" data-ylk="slk:Darrian Traynor/Getty Images">Darrian Traynor/Getty Images</a></span>
Heat-damaged plastic pipes can continue to leach chemicals into water over time. Darrian Traynor/Getty Images

When wildfires swept through the hills near Santa Cruz, California, in 2020, they released toxic chemicals into the water supplies of at least two communities. One sample found benzene, a carcinogen, at 40 times the state’s drinking water standard.

Our testing has now confirmed a source of these chemicals, and it’s clear that wildfires aren’t the only blazes that put drinking water systems at risk.

In a new study, we heated plastic water pipes commonly used in buildings and water systems to test how they would respond to nearby fires.

The results, released Dec. 14, show how easily wildfires could trigger widespread drinking water contamination. They also show the risks when only part of a building catches fire and the rest remains in use. In some of our tests, heat exposure caused more than 100 chemicals to leach from the damaged plastics.

As environmental engineers, we advise communities on drinking water safety and disaster recovery. The western U.S.’s extreme wildfire seasons are putting more communities at risk in ways they might not realize. Just this year, more than 52,000 fires destroyed more than 17,000 structures – many of them homes connected to water systems. Heat-damaged plastic pipes can continue to leach chemicals into water over time, and ridding a water system of the contamination can take months and millions of dollars.
A baffling source of contamination

The cause of drinking water contamination after wildfires has baffled authorities since it was discovered in 2017.

After the 2017 Tubbs Fire and 2018 Camp Fire, chemicals were found in buried water distribution networks, some at levels comparable to hazardous waste. Contamination was not in the water treatment plants or drinking water sources. Some homeowners found drinking water contamination in their plumbing.

Tests revealed volatile organic compounds had reached levels that posed immediate health risks in some areas, including benzene levels that exceeded the EPA hazardous waste threshold of 500 parts per billion. Benzene was found at a level 8,000 times the federal drinking water limit and 200 times the level that causes immediate health effects. Those effects can include dizziness, headaches, skin and throat irritation and even unconsciousness, among other risks.

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Rinsing heat-damaged pipes won’t always remove the contamination. While helping Paradise, California, recover from the 2018 Camp Fire disaster, we and the U.S. Environmental Protection Agency estimated that some plastic pipes would have required more than 100 days of nonstop water rinsing to be safe for use. Instead, officials decided to replace the pipes.

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Some plastics can slowly leach chemicals like benzene over time, and this could go on for months to years, depending on the scale of contamination and water use. Boiling the water doesn’t help and can release benzene into the air.

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Communities can take steps to avoid contaminated drinking water in the event of a fire. Water companies can install network isolation valves and backflow prevention devices, to prevent contaminated water moving from a damaged building into the utility pipe network.

Insurance companies can use pricing to encourage property owners and cities to install fire-resistant metal pipes instead of plastic. Rules for keeping vegetation away from meter boxes and buildings can also lessen the chance heat reaches plastic water system components.

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