OSU study raises concerns about elevated lead levels from old telephone cables

Before telephone wires were coated in plastic, they were originally protected by a layer of lead. Lead-sheathed cables were largely phased out in the 1950s, but in Portland’s oldest neighborhoods, some of them still hang from utility poles. A recent study from Oregon State University tested lead levels in moss in some neighborhoods and found that lead levels are up to 600 times higher in places where the cables were once used than in other nearby areas. The findings raise concerns about whether the cables could lead to increased risk of lead exposure for residents of older neighborhoods.

Alyssa Shiel is an associate professor in the College of Earth, Ocean and Atmospheric sciences at OSU and the study’s lead author. She joins us with more details.

This transcript was created by a computer and edited by a volunteer.

Dave Miller: From the Gert Boyle Studio at OPB, this is Think Out Loud. I’m Dave Miller. Before telephone wires were coated in plastic, they were protected by a layer of lead. These lead-covered cables were largely phased out in the 1950s, but in Portland’s oldest neighborhood, some of them still hang from utility poles. A recent study from Oregon State University, using moss that grows on trees, found that lead levels are up to 600 times higher in places near these cables than in other places.

Alyssa Shiel is an associate professor in the college of earth, ocean and atmospheric sciences at OSU. She is the study’s lead author, and she joins us now. It’s great to have you on Think Out Loud.

Alyssa Shiel: Thanks, Dave, for having me on the show.

Miller: Some longtime listeners may remember the story of the Portland-based Bullseye Glass Company and the heavy metals that were being released there that we learned about because of samples of moss. Can you give us a refresher on how it is that moss can be used to measure pollution?

Shiel: The moss that are used in these studies grow on trees. And they’re acting as air monitors. They have high surface areas. And metals, like lead or cadmium from the air, settle onto their surfaces, and the moss take them up. What that study that you’re referring to by the US Forest Service did is they looked at moss samples from across the city, and they identified high levels of cadmium near those glass manufacturers. And we’ve kind of gone back to do something similar in this case with lead.

Miller: And what did you learn about lead levels from moss, citywide in Portland, when you first started to do this work?

Shiel: So when I first started to do this work, I connected with folks at the U.S. Forest Service, mainly a research ecologist, Sarah Jovan, who was involved in that work on cadmium. And what we wanted to do is look at lead across the city, see how variable lead levels were across the city, what people might be exposed to in different parts of the city. And this work using moss allows us to do that kind of high-resolution work, in contrast to studies that use one or two air monitors.

So we started looking across the city. And what we saw was significant lead levels across all of Portland, about 12 times higher than rural areas. And then when we separated out older neighborhoods from newer neighborhoods, we saw that those older neighborhoods had higher levels, about 20 times higher than rural or “background” areas. And when we were looking at this, what we realized is most of this lead was coming from legacy leaded gasoline emissions. And this was pretty surprising, because leaded gasoline was banned in the U.S. almost 30 years ago. So that means that that lead is sticking around, mainly in soils and dust. The fact that we’re seeing it in our moss means that it’s being mobilized by wind, by traffic, by landscaping. And it just hasn’t gone away.

Miller: If I can just stop you there … I mean, because obviously we’ll talk about the findings from the most recent study. But this was startling to me. What does it say that even after phasing out lead from gasoline 30 years ago or more, that it’s still so present in our environment that it could be aerated and sucked up by moss?

Shiel: One of the takeaways from this part of the study for me is really that we want to be conscious of what we’re putting into the environment because it may be with us for a long time. We see that with the leaded gasoline. Any metals, like lead, that we’re putting into the environment, the amount that’s gonna be there is also cumulative. So if you’re just putting a little in from one source and a little in for another, that’s adding up.

Miller: Back to one of those original findings that you got, which was that older Portland neighborhoods had 20 times higher rates of lead in general than rural areas, as opposed to newer Portland neighborhoods which were “just” 12 times higher. At the time, a couple of years ago, did you have an adequate explanation for that difference?

Shiel: We realized pretty quickly that it was likely to be those legacy leaded gasoline emissions. To verify that, one of the things we did is we worked with John Christy at the Portland State University to get archival samples – basically samples that were collected during the period of time leaded gasoline was in use. We got samples and we measured those, along with ours, to verify that leaded gasoline was in fact the source of the majority of that lead.

Miller: So let’s turn to the lead-covered telephone cables. How much did you know about those when you started this work?

Shiel: The answer to that, Dave, is absolutely nothing. So when we were looking at this big picture, we saw this trend between newer neighborhoods and older neighborhoods, where older neighborhoods were somewhat higher. And that made sense with the historical use of leaded gasoline. It would have been used more in older parts of the city, so we would see these higher levels.

But there were some places in our study that had extremely high levels, in one case as much as 600 times the rural background. That’s huge. And when we went to these neighborhoods where those levels were found, it wasn’t obvious what the source was. We went and we expected to see some sort of industry source, something really big, and it was just quiet neighborhoods. We were trying to come up with an explanation, really pulling our hair a bit. And then last summer, the Wall Street Journal did a big investigative report that identified these old lead-sheathed telephone cables as a source of lead. And we realized that that could be it for us. And then sure enough, when we went back to those same neighborhoods and we just looked up, there they were.

Miller: Can you describe what you saw when you looked up?

Shiel: Do you want me to describe sort of how these cables look?

Miller: Please. It’s a key point here. I got to say, yesterday when I was looking at this, I immediately after looked at the OSU website that you put up, and then I went to my backyard where there are cables directly over a vegetable garden, because I was intensely curious. And this is something I’d never thought about. I think this is the definition of “news you can use” if you’re listening right now.

Shiel: So these lines are only going to be found in older neighborhoods. In a lot of cases, they’ll have already been removed from neighborhoods. But where they remain, what you’ll see is kind of this matte metallic appearance. They look like metal cables, almost like thin lead pipes. The easiest way to identify them is often, they’re hung from this support wire – a thin metal wire – with these cable rings. And then you end up with this kind of two-stranded appearance. And that two-stranded appearance is a really fast way to identify these cables. I often see these now because I’m looking all of the time when I’m driving around. If they don’t have that support wire and those cable rings, it is a little bit harder to identify them. Sometimes I will walk along a street a bit to make sure that I really think it’s those cables by that matte metallic appearance.

But I guess what I would do if folks are concerned about these cables and they do live in older neighborhoods, we’ve put up some pictures and created some graphics to try to help people identify them.

Miller: We have a link to that website on our website as well.

I’m just curious, what goes through your mind when you’re walking around in Portland or Corvallis or wherever, and you see these lead-lined cables above you that you know when it rains, little, tiny bits of lead are raining down on the dirt or the pavement?

Shiel: Well one of the things that it’s kind of brought to the front of my mind is that we’re just not always aware of these sources. And so I guess I’m trying to be more mindful overall, looking for potential sources of lead and other metals that could be in our cities or other places where we live. One thing I would say is that people should think about is these cables have been up in a lot of cases for like 100 years. So I don’t actually think that the lead is dripping down quickly, I think this has been a very slow leach, a little bit over time, but it’s had 100 years to accumulate in that soil.

As with any older infrastructure that’s lead, looking at the possibility of removing these cables seems important. But I would also encourage people to think about the soil underneath if they find these cables, and whether or not they’re likely to be exposed. We try to give some information on this on the website. If folks are living in places where they have these cables and there’s ground cover, like grass or cement or bushes, you’re not nearly as likely to have an exposure as if it’s bare soil. And also, if it’s an area where people don’t go, maybe you walk through it very occasionally, you’re not likely to have an exposure. But like you’re saying, if you found these cables over a garden that you’re using, well then that might be more alarming. That would be a place where you could take some action to reduce possible exposure.

Miller: And what kinds of actions would you recommend?

Shiel: If folks are living in older neighborhoods and have these cables or are concerned the cables were there in the past, if you have children especially, you can look at getting a blood lead level test. That’s the best way to find out if you’ve been exposed. And certainly, because children are at greater risk for lead exposure, talking to their pediatrician would be important.

In terms of just reducing exposure overall, if there is not something covering the ground, you could look at adding some sort of cover to the ground in those areas. We kind of want to caution people about working in those areas without wetting the soil, so that you avoid the possibility of exposure to dust. For folks that really have these lead cables on their property or near their property, you can get soil lead tests. We link to that on our website as well. If people have these cables near their property and they want to test their soil, you can submit your soil for lead testing.

Miller: How might the levels of lead from these overhead cables compare to what people might have in peeling paint chips from an old house? I’m just wondering about the relative likely dangers, likely levels of different sources of household lead.

Shiel: Part of this is how likely you are to be exposed to these things. If you have lead paint in your home that’s chipping, peeling, creating a dust that children might inhale or get on their hands, ingest, the risk for large exposures is pretty big. This soil, this outdoor exposure, in most cases we’re gonna be talking about a pretty limited area that’s impacted, potentially, near your home. It may be an area that’s not being used already, or if it is an area that is being used, it’d be pretty easy to avoid.

So I think it’s important that people know if you are concerned about this as a lead source, you can get your blood lead levels tested. But it may not indicate that you’re getting lead from the cables. It is possible that there are other lead sources to consider, and talking to your pediatrician about that would be a good idea.

Miller: Let’s say that somebody does go to your website, then looks above their yard or their neighborhood, and indeed sees some of these lead-covered telephone wire covers. Is there any recourse for them? Can they call their telephone provider, internet provider, the city or Oregon DEQ, and say, “hey, take these down”?

Shiel: That’s gonna be a tough one for me to answer. What I can say is I’ve been partnering with folks at Oregon Health Authority, the Multnomah County Health Department and the Department of Environmental Quality (DEQ). They are aware that these cables are present, they are aware of this research, and they’ve been helping to develop the materials that you’ll find on our website.

In terms of actually getting the cables taken down, they belong to the telephone companies. So taking them down, the path to that is not clear to me at this point.

Miller: What do you hope to study next?

Shiel: This has been kind of the first phase of research. We’ve been looking at moss and air quality. And what we wanna do next is look at soil in these same areas, because it’s that soil where we’re actually worried about people being exposed through things like ingestion and inhalation.

Miller: Alyssa Shiel, thanks very much.

Shiel: Thank you, Dave.

Miller: Alyssa Shiel is an associate professor in the college of earth, ocean and atmospheric sciences at Oregon State University. She is the lead author of this new study that found higher levels of lead in older Portland neighborhoods because they’re more likely to have had, or still have lead-covered telephone lines.

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