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Science

Plastic Pipes Are Polluting Drinking Water Systems After Wildfires (theconversation.com) 72

An anonymous reader quotes a report from The Conversation: 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.

To determine if plastic pipes could be responsible for drinking water contamination after wildfires, we exposed commonly available plastic pipes to heat. The temperatures were similar to the heat from a wildfire that radiates toward buildings but isn't enough to cause the pipes to catch fire. We tested several popular plastic drinking water pipes, including high-density polyethylene (HDPE), crosslinked polyethylene (PEX), polyvinyl chloride (PVC) and chlorinated polyvinylchloride (CPVC). Benzene and other chemicals were generated inside the plastic pipes just by heating. After the plastics cooled, these chemicals then leached into the water. It happened at temperatures as low as 392 degrees Fahrenheit. Fires can exceed 1,400 degrees. While researchers previously discovered that plastics could release benzene and other chemicals into the air during heating, this new study shows heat-damaged plastics can directly leach dozens of toxic chemicals into water.
What can be done about the contamination? The report says a community can stop water contamination if they can quickly isolate the damaged pipes. Rinsing heat-damaged pipes can also work, but some plastic pipes require more than 100 days of nonstop water rinsing to be safe to use. If that's the case, the pipes may need to be replaced instead.

"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," the report adds. "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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Plastic Pipes Are Polluting Drinking Water Systems After Wildfires

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  • by ccham ( 162985 ) on Tuesday December 15, 2020 @07:53PM (#60835654)

    So how much chemical damage does one house fire or brush fire do to a community? I have often wondered about sun exposure as mains pipes will sit outside in stacks for months at project sites and in distribution before being installed. CPVC and similar pipes do degrade under sunlight.

    • If they're stored outside, go elsewhere. Especially PEX. 2 weeks is the limit.
    • by jsrjsr ( 658966 ) on Tuesday December 15, 2020 @08:24PM (#60835754)

      You are correct that PVC and CPVC degrade under sunlight (due to UV). However, the penetration of UV is very shallow. I doubt it compares to the chemical changes caused by heat that affects the entire pipe, but I can't really answer that question for certain.
      https://www.usplastic.com/know... [usplastic.com]

      Other pipes used include acrylonitrile butadiene styrene (ABS), polybutylene (PB), high-density polyethylene (PE), and cross-linked polyethylene (PEX). There are probably others. Each has its own set of advantages and disadvantages.

      How all of these plastics behave when exposed to UV or heat is an interesting question that may not have an answer available. Given the discovery of chemical leaching after wildfires in California, I expect how heat affects these pipes will see more investigation soon.

    • by Joce640k ( 829181 ) on Wednesday December 16, 2020 @07:32AM (#60836838) Homepage

      I grew up with real lead pipes, never had any of these problems.

    • So how much chemical damage does one house fire or brush fire do to a community?

      Community, not so much. Chemical releases from house fires are normally highly localised which is why people are generally advised to stay away and part of why surrounding homes are evacuated.

      The bigger issue is for the fire fighters. Firefighters have a significant and measurably higher cancer rate than the general population, and even they use breathing air support when they enter a building.

    • I expect the amount of damage varies. Most mains are burred underground. As Hot air normally rises and what gets underground is from radiant heat, which moves much slower, a normal brush fire may be too quick to heat up those pipes. However a larger and more prolonged fire, could do much more damage.

      America has been getting lazy with water quality. With Lead, PFOA and other pollutants seeping in without much oversight until people start getting sick.

  • by zenlessyank ( 748553 ) on Tuesday December 15, 2020 @07:55PM (#60835662)

    Sometimes the damages are hard to measure. Who would have thought plastic pipes would melt underground.

    Go back to brass.

    • by kenai_alpenglow ( 2709587 ) on Tuesday December 15, 2020 @08:01PM (#60835686)
      if the pipes have gotten that hot, they're probably shot. Just replace the things, your walls are probably opened up with the damage so the cost is not that high. Brass? Are you kidding?! Look at the price! Copper won't last long with certain water (acid eats them quickly, experience speaking). Galvanized? no better. Might as well go with lead. Or cored tree logs. I wouldn't have a house with metal pipes unless I can get at and replace every single one easily. Plastic (Pex/(C)PVC) lasts almost forever. At least in the houses I've owned.
      • Re:Fire Is Hell (Score:4, Interesting)

        by jenningsthecat ( 1525947 ) on Tuesday December 15, 2020 @09:38PM (#60835944)

        Copper won't last long with certain water (acid eats them quickly, experience speaking)... I wouldn't have a house with metal pipes unless I can get at and replace every single one easily.

        I've never known copper to corrode significantly unless it's carrying water that most would consider unpotable. I wouldn't have a house with anything other than copper - preferably installed and soldered by me.

        I don't like plastic at all for drinking water. I've even thought about replacing the fancy fixtures with plain old utility-grade brass to minimize the amount of plastic - I can often taste the crap that water leaches out of even the priciest fixtures.

        • Re:Fire Is Hell (Score:4, Insightful)

          by Anonymous Coward on Tuesday December 15, 2020 @10:33PM (#60836062)

          Be careful with that brass fixation. Brass is ass. It is usually laced with an unknown amount of lead in it, because mixing lead in makes it easier to machine. And since everything is made in China at the lowest possible cost these days, you can bet they've got some lead in there.

        • A friend had to have his whole house re-plumbed after major leaks from copper - 20 years old.
          • by jbengt ( 874751 )
            Then the installation was bad. Copper piping should last 50 years, at least. But you can't use steel supports and you have to isolate it wherever it might come in contact with other metals.
            • by gweihir ( 88907 )

              Then the installation was bad. Copper piping should last 50 years, at least. But you can't use steel supports and you have to isolate it wherever it might come in contact with other metals.

              Depends on the water. In some conditions it does not. But you can find that out easily before you put in the pipes. If you bother to do so. Also, in some conditions you have to hard-solder it, because soft solder will get eaten through. If you do it on the cheap under those conditions, things will get very expensive later on. Again, something you can easily find out before.

        • A big problem with copper and the big advantage with PEX (After cost) is freeze resistance. However, most people are doing PEX wrong for that. You have to use an all-plastic system like Flair-it to gain the maximum advantage, and even Flair-it used to be better (when it was made out of nylon.) The rates of expansion and contraction vary between the plastic pipe and the copper rings (Sharkbite) or the stainless crimp clamps typically used to connect PEX. If you use push-fit connectors or Flair-it then the ma

      • Rodents will chew through pex and other plastic pipes to get at the water. Other than that they are great. Even had a long section freeze because the house wasn’t properly insulated (about 90 years old) and it didn’t have a single problem.
    • by gweihir ( 88907 )

      My take is somebody did this on the cheap and either knew they were not burying them deeply enough or did not even bother to find out.

  • Generally, if you can afford the luxury, use the considered safe municipal water supply for things like shitting, showering, laundry, and irrigation. Every place we've ever lived has endured multiple yearly incidences of higher than allowed levels of chemicals deemed counterproductive to longevity.

    Consume your plastic particulates in microdoses, the old fashioned way, drinking and cooking straight from the plastic bottle.

    • by raymorris ( 2726007 ) on Tuesday December 15, 2020 @08:57PM (#60835830) Journal

      A friend if mine works at the bottling plants which bottles a dozen brands of water. The source labeled on the bottle the name of a spring and of a lake, because those are the sources of the tap water they bottle. The bottled water is very literally tap water put into plastic bottles.

      There are two brands that are an exception to this. Walmart / Sam's brand is the same tap water with the hardness adjusted by adding calcium chloride as needed for consistent and better taste. Fiji water is in fact from Fiji, rather than being tap water from whichever bottling plant is closest to you. So those are the two exceptions, as far as widely available bottled water.

      Fiji is dirtier water than you'll find in a municipal water supply, particularly containing high levels of arsenic. That's because the EPA regulates tap water and requires extensive testing. The FDA is responsible for food and drink, including bottled water, and doesn't require the same regular testing, instead acting more reactively when problems come up.

      • by rmdingler ( 1955220 ) on Tuesday December 15, 2020 @09:35PM (#60835922) Journal

        You're genuinely best off filtering your own water source, despite the problematic likely source of your incoming water supply. Yet, most people are adverse to maintaining filtration systems, to the point of ignoring replenishing salt in softener systems and replacing filters in reverse osmosis systems.

        Bottled waters from companies like Coke and Pepsi are significantly more likely to be litigation free of harmful contaminants.

        • Re: (Score:2, Interesting)

          by Anonymous Coward

          Yet, most people are adverse to maintaining filtration systems, to the point of ignoring replenishing salt in softener systems and replacing filters in reverse osmosis systems.

          You typically don't need to replace filters in a reverse osmosis system. Sure, the manual says to do it regularly, but they're really just trying to sell you more filters.

          I've tested my water before and after replacing the filters, and believe it or not, the water is measurably cleaner using old filters than when I've got new filters.

          Why? As dirt and crap gets lodged into the filters, the filter pores become constricted. The more constricted it becomes, the less stuff can pass through. Thus, the water on th

          • by Bengie ( 1121981 )
            Same issue with HEPA filters. They get better at filtering as they get used, but their flow rate drops.
    • by narcc ( 412956 )

      Our local municipal water is fantastic. They update us regularly on testing and the quality is always adequate. (Yes, we have confirmed ourselves with independent testing.)

      It is possible to live somewhere with safe water. Though it probably helps to have the people responsible also depend on the water they manage for their own use. I don't know, get out of the city I guess.

      I can't imagine living in a place for any significant length of time without safe-to-drink water on tap, let alone multiple places!

      B

    • I prefer to filter water. Right now we are drinking out of a Berkey travel unit, but in the past we've used an RO filter. However, we were on a well then. The waste of an RO system, albeit much reduced from back when I was using RO (when I installed ours, 11:1 waste was considered good!) is a problem on a muni water system. Our RO waste went into the septic, and then into the leachfield in the front yard, where it fed trees.

      These days I would suggest a UV+Carbon block filtration regime. You never know what'

  • You know, it's horrible that California doesn't have affordable housing... We should do something about those damn developers jacking up prices!

    Also, I have to go send letters to the legislature demanding they adjust the building code to require all metal fixtures and pipes installed by union labor.

    When you get to Texas and your instinct scratches at you, saying "don't mention how backwards they are having PEX piping, gas cans that work, etc." listen to it.
    • by teg ( 97890 )

      You know, it's horrible that California doesn't have affordable housing... We should do something about those damn developers jacking up prices! Also, I have to go send letters to the legislature demanding they adjust the building code to require all metal fixtures and pipes installed by union labor. When you get to Texas and your instinct scratches at you, saying "don't mention how backwards they are having PEX piping, gas cans that work, etc." listen to it.

      In most areas of the developed world where housing costs are considered an issue, the problem is not the cost of the houses itself but the lack of available cheap property to build on. The final cost of the house is the most that the target audience is capable of paying. Deduct the cost of construction, and you have the price of the property. Tougher construction requirements will reduce the value of the property, but not increase the final price - in these areas.

  • thin out the forests and clear some brush instead of throwing away money on the downstream consequences of poor forest management. It's also probably a goid plan to not require dense multifamily housing so that a kitchen fire upstairs doesn't screw up the water downstairs.
    • by bussdriver ( 620565 ) on Tuesday December 15, 2020 @11:59PM (#60836204)

      Simply put in a chemical or coat the piping (PEX) with something that changes color at 300F or so and that will indicate what needs replacement.

      • Not included: xray glasses to see through whatever the pex is hidden behind (ground, drywall, the floor, the ceiling...)
        • After you tear down the fire damaged wall coverings (;apparently, not obvious,) you can then see if the pipes were damaged.

          Xray fires? burn the wall from the inside out so then we won't ever see the pipes? and we'll not open up the wall because it'll look perfectly fine.

          Concrete spalling? you may have bigger problems but maybe that is indication enough of likely pipe problems.

  • Copper can tolerate relatively high heat, and is naturally anti-bacterial. Sure it costs more, and requires some skill, but let's just see where that cheap plastic is condition wise after 50 years. Probably worse than copper pinholes and full of bacteria (or no bacteria, sorry living on well water I almost forgot about all that chlorine and fluoride city dwellers consume in a day).

    As for plastic, what building is put back into service after it was at such a temperature to toxify that plastic? Wouldn't it
    • by brunes69 ( 86786 ) <slashdot@nOSpam.keirstead.org> on Tuesday December 15, 2020 @08:55PM (#60835826)

      For the most part you are not going to have bacteria growth in pressurized PEX pipes simply because there is no oxygen nor growth medium in the water. The water could sit in the pipes for 50 years and is still not going to have any significant amount of bacteria. Copper on the other hand, it will slowly corrode. PEX is also much more environmentally friendly to manufacture than copper pipes, and far far simpler to install.

      • Legonella has a different view point. Water regulations here in the UK prohibit "dead legs" in the pipe work for that reason. Though copper does have an anti microbial action. Personally never seen any copper pipe attacked by acid in the UK, presumably because such water would not meet required standards for drinking water.

      • by jbengt ( 874751 )

        For the most part you are not going to have bacteria growth in pressurized PEX pipes simply because there is no oxygen nor growth medium in the water.>/blockquote> PEX is not an oxygen barrier, and even if it were, there are anaerobic bacteria that live in pipes all the time. But that doesn't even matter for potable water, since it's an open loop and the water is always carrying sufficient oxygen for microbes.

      • Somebody should tell the water treatment authorities 'cause all this time they've been adding extra chlorine (or other anti-microbials) to their water in order to keep it safe in transit to your tap. If only the stupid engineers had consulted you they could have saved TONs of money. You would have been awarded the Disrupter of the Year award, but you didn't include any gig workers or data harvesting.
    • Every kid I know that lives on well water takes supplemental fluoride or has rotten teeth.

      • by G00F ( 241765 )

        I grew up on well water and do not have rotten teeth. Infact no cavities. My siblings who love junk food and soda a lot more than me have less cavities than most.

        Brushing your teeth with fluoride is much better than swallowing water down fluoride.

    • As for plastic, what building is put back into service after it was at such a temperature to toxify that plastic?

      The building itself doesn't have to be involved in the fire, it just needs to be part of the water system that had melted plastic pipes in another building.

  • ..."Insurance companies can use pricing to encourage property owners and cities to install fire-resistant metal pipes instead of plastic."

    *NO ONE* uses copper in new construction, it was phased out a long time ago. PEX is much more environmentally friendly and also much, much, much less labour intensive.

    • by PPH ( 736903 )

      PEX is much more environmentally friendly

      Benzene. It appears not to be.

      and also much, much, much less labour intensive.

      That's what it boils down to (sorry). Cheap ass developers.

    • by Necron69 ( 35644 )

      PEX is also highly used because it has no resale value, unlike copper. Nobody bothers to steal PEX tubing.

      Nobody is switching back to copper, fires or not.

      - Necron69

    • by jbengt ( 874751 )

      *NO ONE* uses copper in new construction, it was phased out a long time ago.

      That is demonstrably untrue. Most of the new construction projects I work on have copper piping for potable water.

  • Always thought it was weird that Acetal (https://en.wikipedia.org/wiki/Polyoxymethylene) gets used to make pipe fittings - when it burns, it gives off formaldehyde, as i discovered that one time in an injection molding failure..

    • Yeah, and also wire is jacketed with PVC by code, and that gives off dioxin when it burns. Lots of irrigation lines are still PVC as well. Manufactured wood products also put out a lot of goodies when they combust, and most houses are now made out of just them and framing, at least as far as structure goes. Foam board insulation is common, and often toxic when burnt. Cheap windows and siding are made from vinyl. Framing aside, the entire modern home is one big toxic mess.

  • by Strider- ( 39683 ) on Tuesday December 15, 2020 @09:58PM (#60835986)

    It all depends on how deep the pipe is buried. In northern regions, where pipe is buried below the frost line (say 3' or more down), there's no way it's going to get hot enough to matter. I've been through a major wildfire, and the fire only impacted the top 8 to 12" of soil. Everything under that was unaffected.

    • by jbengt ( 874751 )
      Around where I live, water piping is required to be buried at least 5 feet underground, though the frost line is 3' 6". Sewers are allowed to be buried 3'6" to the top of pipe, because they are not full of water and so won't burst if they freeze.
      I don't see how a forest fire could get the buried piping up to the 200C, 300C, 400C in TFA.
      Also, plastic water pipes will be damaged if they get up to even 100C and are rated only for temperatures much below that (about 80C for CPVC and 60C for PVC ).
  • I thought PVC was only good for irrigation, NOT for drinking.

    Wasn't there a thing about PVC and Agent Orange? The issue is the chloride. In theory, Agent Orange might have been safe except the gov wanted so much of the stuff back in the days of the war and they had to increase production. When they did, the temperatures were too high and it created dangerous chlorides. Same with PVC. High temp makes bad cancer causing stuff!

    The more recent example (not a chloride) is Zantac. At the right temp it is saf
  • Where were those plastic pipes?
    As it appears they were nut (properly) buried.
    So someone chose the 'cheap' route but the result is expensive.
  • by burtosis ( 1124179 ) on Wednesday December 16, 2020 @07:48AM (#60836880)
    Drinking water systems are under a reasonable amount of pressure if they are operable. Water boils at 212F/100C or thereabouts, it takes quite a bit of heat to cause the phase change to steam, to the point “a watched pot never boils”. This is why they dry tested the pipes instead of testing them in the condition they would have in the field. You can boil water in a large leaf over a fire because the leaf will be kept at roughly the water temperature it’s in contact with. You won’t be able to raise the temperature of the interior surface of the pipe above boiling until the additional pressure from steam generation ruptures it and all the water comes out of that section at which point it’s probably obvious it needs replacement anyway. Like others have said, if it was properly buried, there is no way the temperature would significantly change even during a forest fire (or even during winter for that matter).
  • From the summary: "Rinsing heat-damaged pipes can also work, but some plastic pipes require more than 100 days of nonstop water rinsing to be safe to use. If that's the case, the pipes may need to be replaced instead."
    If flushing pipes is effective then a relatively inexpensive home carbon filtration system could easily treat the water for period of time to bridge the gap the water is at safe levels again.

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