NATURE PODCAST

The sanitation crisis making rural America ill

The lack of adequate sanitation in parts of the rural US, and physicists reassess muons’ magnetism.

Listen to the latest science news, with Nick Petrić Howe and Shamini Bundell.

In this episode:

00:45 How failing sanitation infrastructure is causing a US public health crisis

In the US, huge numbers of people live without access to adequate sanitation. Environmental-health advocate Catherine Coleman Flowers tells us about her new book looking at the roots and consequences of this crisis, focusing on Lowndes County, Alabama, an area inhabited largely by poor Black people, where an estimated 90% of households have failing or inadequate waste-water systems.

Book review: Toilets – what will it take to fix them?

07:56 Research Highlights

Why adding new members to the team can spark ideas, and how manta rays remember the best spots for pampering.

Research Highlight: Want fresh results? Analysis of thousands of papers suggests trying new teammates

Research Highlight: What manta rays remember: the best spots to get spruced up

10:13 Reassessing muons’ magnetic moment

A decade ago, physicists measured the ‘magnetic moment’ of the subatomic muon, and found their value did not match what theory suggested. This puzzled researchers, and hinted at the existence of new physics. Now, a team has used a different method to recalculate the theoretical result and see if this discrepancy remains.

Research Article: Fodor et al.

News: Is the standard model broken? Physicists cheer major muon result

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Transcript

Listen to the latest science news, with Nick Petrić Howe and Shamini Bundell.

Host: Shamini Bundell

Welcome back to the Nature Podcast. This week, the battle for better sanitation in the US…

Host: Nick Petrić Howe

And a new measure of the muon’s magnetism. I’m Nick Petrić Howe.

Host: Shamini Bundell

And I’m Shamini Bundell.

[Jingle]

Host: Shamini Bundell

First up on the show, flushing a toilet is something most of us probably do without thinking twice. But for many people, living without basic sanitation is something they have to deal with every day. For some, what goes into toilets doesn’t get whisked away underground with the pull of a lever. Instead, it flows directly from their houses to the ground outside, oozing into back gardens and cesspools, and when it rains, that raw sewage can back up into their homes. It’s a horrifying thought and yet for decades this has been the situation faced by millions of people, including in rural communities living in the United States of America, the richest nation in the world. Catherine Coleman Flowers is the author of the new book Waste, which is about her fight against America’s dirty secret. She told our reporter Anand Jagatia more about the book and her story.

Interviewee: Catherine Coleman Flowers

The type of conditions that people face are, one, there are people that are living in homes where the sewage is ‘straight piped’, as it’s described, onto the ground. When they flush the toilet, it comes out of the house. It means you see everything that was in the toilet out on top of the ground. And a lot of the people that are in those conditions are poor and they generally live in mobile homes, but we’ve also found people that live in houses where the septic tank that they had put in place or cess pool no longer work and they disconnected them. The second problem that we found are those people that had paid for waste water treatment and put in place these septic systems and they have failed. The sewage, the gravity pushes the sewage back into the homes and it usually comes in through the bathtubs or whatever, and we’ve had situations where people have come back home and their homes have been flooded with raw sewage. The third problem that we found are people that are paying waste water treatment fees that are part of small municipalities, and they have these lagoon systems in these rural communities, which is essentially a big pond where all of the sewage from the town goes there, and they build it next to a residential community, and every time it rains or when there’s a failure, it ends up in their houses or in their yards.

Interviewer: Anand Jagatia

The book largely focuses on the situation that’s faced by people living in Lowndes County, which is where you grew up in Alabama. Access to clean water and sanitation is one of the United Nations’ sustainable development goals, and clearly the United States of America isn’t a developing country, right? It’s the richest nation on Earth, and yet there are people who don’t have access to this kind of basic human right.

Interviewee: Catherine Coleman Flowers

Yes, I think when I take people to see it they are very shocked because they don’t expect to see what they see because against the backdrop of all of this wealth is this type of inequality and it tends to exist in rural communities, poor communities and especially in communities of colour.

Interviewer: Anand Jagatia

Right at the beginning you say that you can’t really begin to understand the situation in Lowndes County without looking at the wider context and specifically looking at the history of slavery in the United States and also the soil in this part of the world. Can you sort of unpack that a bit for us?

Interviewee: Catherine Coleman Flowers

In terms of the history, after the United States constitution ended the importation of slaves from Africa, they started robust slave trading markets here in the South, and one of those places was Montgomery, Alabama, which is the capital city of Alabama. And from there, a lot of slaves were sold into areas like Lowndes County. Lowndes County now is at least 80% Black. The soil was the reason that people were brought there in the first place, so that they could farm the cotton that was grown there. But the soil is also the reason that we can’t treat waste water. The soils in our communities, especially in the Black Belt region of Alabama, holds water and water can really impact the way these onsite septic systems work. The other problem is that underneath the soils, we have high water tables, and that’s another problem that impacts, and the more we have climate change, the more the water tables, which were high normally, are getting even higher and makes it harder to use onsite septics for treatment, and that’s what creates a lot of the problems. And I think the way it has been addressed has been largely because of the history and legacy of slavery.

Interviewer: Anand Jagatia

As someone who’s been an activist in this area for many years, trying to give people a voice and trying to get the story of this place told, you’ve actually had to learn a lot of science along the way and work with scientists and kind of just figure stuff out. Can you tell us a little bit about what that journey was like and what kind of scientists you had to work with?

Interviewee: Catherine Coleman Flowers

Well, basically, in the beginning, I started working with people that were associated with the health department, but I started to learn that what they were telling me was only part of the story. It was to support the narrative and the laws that they had written. A part of what we had to do was listening to the local people in the community. A lot of the science that I was taught was actually taught by them. They were the scientists because they were living with the failures, so they were able to tell us, for an example, when it rained, they had more problems. One of the things that happened as a result of listening to local people, they started talking about illnesses, and I had my own personal experience that led to me partnering with Baylor’s National School of Tropical Medicine and Dr Peter Hotez, and he said, ‘I’m going to send my parasitologist there. We need to look for hookworm.’ And he also talked about what he termed ‘neglected diseases of poverty’. We did this parasite study, and as a result we found that at least 30% of the population, based on our study, were infected with some intestinal parasites, generally hookworm. Hookworm, at least in children, it can cause them to be anaemic, it can also slow their development, and hookworm was thought to be wiped out in the United States in the early part of the 1900s, but we proved that that was not the case.

Interviewer: Anand Jagatia

I mentioned earlier the UN’s sustainable development goals and when people think of those things, they’re going to have an image of their head of the kinds of places that those goals need to be targeted at. In your experience, is poverty in rural communities something that isn’t really given enough attention?

Interviewee: Catherine Coleman Flowers

I believe that poverty in rural communities is a problem, and a lot of rural communities are dying because of lack of investment, and they don’t have the tax base to maintain the infrastructure that was put in place and the state has put nothing there to support them. We give a lot of tax breaks and give a lot of money and incentives to industry, but we don’t do the same thing when it comes to people, and I think that if we reverse that paradigm and start investing in communities that we would see the results of that in a positive way, including sanitation equality and the human right to water and sanitation.

Host: Shamini Bundell

That was Catherine Coleman Flowers talking to Anand Jagatia about her new book Waste: One Woman’s Fight Against America’s Dirty Secret. You can find a review of the book in the show notes.

Host: Nick Petrić Howe

Coming up, we’ll be hearing how a new measurement of the subatomic muon may mean the standard model lives to fight another day. Right now, though, it’s time for this week’s Research Highlights, read by Dan Fox.

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Dan Fox

Want fresh results? Well, it might be time to find some new colleagues. At least, that’s what a group of researchers investigating the effectiveness of newly formed teams may have found. Teamwork is vital to science, but little is known about the differences in effectiveness between established teams and newly created ones. To get a better understanding, a group of researchers analysed hundreds of thousands of physical science articles. They found that teams of co-authors that had worked together the least produced the smallest number of research papers, but their work had the greatest originality. Their papers also had significantly more impact in several research areas than papers from teams whose members had worked together before. According to the authors, large and fresh teams had the most original and impactful work, but they also stress it’s not clear whether this is a cause and effect relationship. Assemble your team and read that paper in full at Nature Human Behaviour.

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Dan Fox

Even sea creatures need a little pampering from time to time, with giant manta rays making regular visits to ‘cleaning stations’, where small fish rid the rays of skin parasites at the coral-reef equivalent of a day spa. Now it seems that the rays are more discerning members than previously realised, able to identify and remember spots where they have received quality cleaning. A group of researchers tracked 34 reef manta rays off the coast of eastern Australia, to try and understand how cleaning stations influenced their movements. They found the highest density of rays are places where cleaning fish called blue-streak cleaner wrasses were most abundant, with the rays typically visiting during the day, when cleaner wrasses are most active. The rays’ behaviour suggests they have a mental map of spots that offer both high-quality cleaning and proximity to foraging grounds. Use your mental map to find that paper at Ecology and Evolution.

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Host: Nick Petrić Howe

Next up this week, reporter Ali Jennings has been finding out how a strange discrepancy between a theoretical result and one measured experimentally has got physicists redoing their sums to see if they’ve stumbled into a whole new world of physics.

Interviewer: Ali Jennings

The standard model describes the elementary subatomic particles and most of the fundamental forces that make up the Universe. It is currently scientists’ best accepted theoretical description of the quantum world and how these particles and forces interact with each other. So, when there’s an experimental result that the standard model can’t explain, quantum physicists get excited because that could mean that there’s new physics out there to discover. Step forward the muon. A muon is a subatomic particle similar to the electron, and both generate a magnetic field. One aspect of the muon’s magnetic field – the ‘magnetic moment’ – was measured experimentally back in 2001, and here is where it gets interesting. The experimental result was not what previous theoretical calculations based on the standard model predicted, and physicists have been trying to find out why.

Interviewee: Zoltan Fodor

So, the previous calculations, people have been doing for many, many decades.

Interviewer: Ali Jennings

This is Zoltan Fodor from Penn State University in the US. He and his colleagues had a paper out in Nature last week where they recalculated the muon’s magnetic moment using a different theoretical approach, and they concentrated on improving one area of calculations that physicists had previously found difficult to accurately ascertain.

Interviewee: Zoltan Fodor

So, if you look at the calculation for the magnetic moment of the muon and you look at the error, essentially all of the errors are coming from the strong interaction.

Interviewer: Ali Jennings

The strong interaction is the fundamental force that holds together subatomic particles called hadrons. Hadrons can momentarily pop in and out of existence near a muon, and their strong interaction can affect the muon’s magnetic moment. Up until now, the most precise theoretical calculations of this effect have been based on data taken from other experiments, but Zoltan has a different approach. He and his collaborators designed a computer model to simulate how hadrons interact with muons, but the model is based entirely on theory and to build it, they had to work out how the world functions at a subatomic level.

Interviewee: Zoltan Fodor

So, what we do, we put the world on a mesh, on a space-time grid, we call it lattice, and we solved the underlying equations on these space-time lattices, and you can solve it for these hadronic contributions to the muons magnetic moment, and that’s what we did.

Interviewer: Ali Jennings

Zoltan compares it to weather forecasting, and to help predict the weather, aircraft fly around measuring variables like temperature, pressure and windspeed at specific points on a grid. Those measurements are put into a computer and can be used to calculate the coming weather. But instead of temperature and pressure, Zoltan’s variables are in the subatomic particles and forces interacting with the muon, and there are a lot of them.

Interviewee: Zoltan Fodor

So, it’s about a couple of billion variables, and you calculate how these variables interact with each other. The complexity is enormous, and if you want to reach an error of uncertainty which is comparable with the uncertainty of the experiment then it’s really a tremendous work.

Interviewer: Ali Jennings

So, Zoltan and his collaborators simulated a tiny slice of the subatomic world based entirely on the underlying quantum theory. They then used this to predict the magnetic moment of the muon. This is the first time that this kind of calculation has been done to such a fine margin of error, and if their new theoretical prediction was different from the experimental measurements, then new kinds of physics could be on the horizon. But that’s not what they found.

Interviewee: Zoltan Fodor

Our result was surprisingly much, much closer to the experimental result. So, our result suggests that there is probably nothing beyond the standard model.

Interviewer: Ali Jennings

I asked Zoltan how he felt about that.

Interviewee: Zoltan Fodor

If you ask me then, yes, it’s a little bit of a pity that it is not a new force or a new interaction that we have found. But if nature decided that there is nothing new in the muon’s magnetic moment, then let it be.

Interviewee: Davide Castelvecchi

When I first heard about it, I thought it was a huge bummer.

Interviewer: Ali Jennings

This is Nature’s senior reporter for the physical sciences, Davide Castelvecchi.

Interviewee: Davide Castelvecchi

The standard model always wins. There’s no hope for new physics. But of course it’s a bit more complicated than that.

Interviewer: Ali Jennings

In fact, last week there was excitement over a new experimental measurement of the muon’s magnetic moment. That new result would have reinforced the difference between the experimental and theoretical measurements were it not for Zoltan’s new calculations. So, how does the physics community feel about Zoltan’s findings?

Interviewee: Davide Castelvecchi

I think that people are taking a ‘wait and see’ attitude because it’s only the first time that this calculation with lattice has been done with sufficient precision, and there’s a lot of other teams that are working on cross-checking it. But they also say that it’s very puzzling that the result would be so much more different from the conventional way of calculating it.

Interviewer: Ali Jennings

In other words, how could the previous theoretical calculations of the muon’s magnetic be so different from Zoltan’s new calculations given that they’re both based on the standard model. One possible explanation could stem from the way experimental data is used in the previous calculations.

Interviewee: Davide Castelvecchi

If there are new kind of physics laws that affect the experimental data, then you may not be interpreting it correctly. When people take experimental data and plug it into the calculations, they do it based on the standard model. But if there’s something wrong with the standard model then all bets are off.

Interviewer: Ali Jennings

So, Zoltan’s result doesn’t shut the door on new physics. There may well be other subatomic particles waiting to be found. And of course, the standard model still has a number of problems. For example, it cannot explain gravity or dark energy or dark matter.

Interviewee: Davide Castelvecchi

So, there’s a lot of reasons why physicists expect the standard model ultimately to either fail or need some expansion. People know that there has to be something else there.

Interviewer: Ali Jennings

So, don’t give up on that brand new physics just yet.

Host: Nick Petrić Howe

That was Ali Jennings speaking to Zoltan Fodor from Penn State University and Davide Castelvecchi of Nature. You can find a link to Zoltan’s paper and Davide’s news article on all that’s going on in the world of muons in the show notes.

Host: Shamini Bundell

And that is all for this edition of the Nature Podcast. Before we go, there’s just time to give a shoutout to a new film that’s up on the Nature Video YouTube channel. We have a new animation all about coronavirus variants and the science behind them. We’ll put a link to that in the show notes so do check it out.

Host: Nick Petrić Howe

And as always you can reach out to us on Twitter – we’re @NaturePodcast. Or you can send us an email – we’re podcast@nature.com. I’m Nick Petrić Howe.

Host: Shamini Bundell

And I’m Shamini Bundell. Thanks for listening.

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