LEAD PIPES

Pitt researchers reveal hidden impacts of drinking-water treatment on urban streams

University of Pittsburgh

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Image showing flow of water and treated water.

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Credit: PLOS Water, et. al.

Aging lead-pipe drinking water systems, along with the public health measures implemented to reduce their risks, are reshaping the chemistry and health of nearby urban streams. New research from University of Pittsburgh biogeochemists, hydrologists, and environmental engineers uncovered previously overlooked environmental impacts of a common water treatment practice: adding orthophosphate to drinking water systems to prevent lead pipe corrosion. Published in PLOS Water, the study reveals that phosphate used in drinking water treatment can leak into urban streams, altering their chemistry and potentially accelerating eutrophication, the process where such nutrients lead to excessive growth of algae and aquatic plants..

And such lead-pipe networks are widespread throughout the Northeast, Great Lakes region and Midwest — meaning as many as 20 million Americans and their nearby streams may face similar challenges.

In collaboration with local water authorities, the scientists studied five urban streams to look for changes in the pre- and post-implementation of orthophosphate-based corrosion control on stream chemistry. Their findings show statistically significant increases in phosphorus and metal concentrations in streamwater following the treatment, indicating that subsurface infrastructure is not a closed system. Phosphorus concentrations in urban streams increased by over 600% following orthophosphate dosing, while trace metals such as copper, iron, and manganese also rose by nearly 3,500%, suggesting co-transport of corrosion byproducts.  

“We were surprised by how clearly the effects of drinking water treatment appeared in stream chemistry. This finding suggests that our underground infrastructure isn’t as sealed off from the environment as we often assume,” said first author Dr. Anusha Balangoda, Assistant Teaching Professor in Geology and Environmental Science in the Kenneth P. Dietrich School of Arts & Sciences. “Our study is the first to examine urban stream chemistry and the influence of drinking-water additives.”

"We absolutely need to protect people from lead in drinking water," said co-author Dr. Emily Elliott, co-founder and chair of the Pittsburgh Water Collaboratory and professor in Geology and Environmental Science. "But we also need to understand how these treatments affect our rivers and ecosystems." Elliott collaborated with co-authors Sarah-Jane-Haig, an associate professor, and Isaiah Spencer-Williams, a doctoral student, both also in Civil and Environmental Engineering. Their paper, titled "From Pipes to Streams: The Hidden Influence of Orthophosphate Additions on Urban Waterways," was published November 13 in PLOS Water.

Public-health emergencies arising from corroded, lead-water pipes are nothing new— contaminations have made the news in the past decade in Flint, Michigan, Washington, D.C., and more recently in the study area of Pittsburgh. Phosphate corrosion inhibitors are used in water systems across North America, the United Kingdom, and parts of Europe. The researchers noted that the potential ecological consequences of this dosing of drinking-water system pipes does to streams, rivers, and groundwater remain “largely unexplored, particularly in the U.S.”

The study examined a pathway of phosphorus pollution that has received little attention: leakage from drinking water pipes rather than traditional sources like wastewater discharge or industrial runoff. The researchers monitored five above-ground urban stream reaches, selecting these because most Pittsburgh streams are buried in an underground pipe network, and collected detailed water chemistry samples monthly over a two-year period spanning before, during, and after orthophosphate treatment implementation (February 2019 to June 2020). They also conducted nutrient addition bioassays at three key time points, using both streamwater and tap water controls, to assess the ecological impacts on algal growth.

The scientists offer four corrective actions to address phosphate leakage from buried water infrastructure systems: 

1. Repair Aging Infrastructure. Urgently address the issue of drinking water pipe networks losing 40-50% of treated water through leaks and breaks, thereby preventing phosphate-enriched water from reaching urban streams and groundwater.

2. Upgrade Wastewater Treatment. Implement tertiary treatment processes at wastewater treatment plants to remove excess phosphorus. The study shows effluent phosphorus increased 26% after dosing began, yet many plants lack phosphorus removal capabilities that can achieve an 80-99% reduction.

3. Optimize Dosing Concentrations. Determine the minimum effective orthophosphate concentration that protects human health from lead exposure while minimizing ecological harm to receiving waters.

4. Develop Innovative Approaches to Monitor Infrastructure-Ecosystem Interactions. Create new monitoring and assessment methods to understand how additives in drinking water systems reach and affect urban streams through subsurface connections. 

"Pittsburgh isn't unique—millions of Americans are served by water systems with lead pipes and aging infrastructure," Elliott said. "Our findings suggest this issue extends far beyond one city, particularly in the Midwest and Northeast where both lead pipes and phosphate treatment are common. We need a national conversation about infrastructure and water quality."

This research was supported by the National Science Foundation RAPID funding program (grant NSF No. 1929843), as well as the Pittsburgh Water Collaboratory. The Pittsburgh Water and Sewer Authority contributed drinking water sample collection, chemical analysis and water treatment information.

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Journal

PLOS Water

Method of Research

Data/statistical analysis

Subject of Research

Not applicable

Article Title

From Pipes to Streams: The Hidden Influence of 2 Orthophosphate Additions on Urban Waterways

Article Publication Date

13-Nov-2025

Paleogenomics: humans and dogs spread across Eurasia together

A genomic study shows that over the last 10,000 years, diverse Eurasian cultures kept and spread genetically distinct dog populations.

Ludwig-Maximilians-Universität München

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Dogs have been part of human societies across Eurasia for at least 20,000 years, accompanying us through many social and cultural upheavals. A new study by an international team, published in the journal Science, and led by Laurent Frantz, paleogeneticist at the Ludwig Maximilian University of Munich (LMU) and Queen Mary University of London (QMUL) shows that the spread of new cultures across Eurasia, with different lifeways, was often associated with the spread of specific dog populations.

Scientists from LMU, QMUL, the Kunming Institute of Zoology and Lanzhou University in China, and the University of Oxford, sequenced and analyzed the genomes of 17 ancient dogs from Siberia, East Asia, and the Central Asian Steppe – including, for the first time, specimens from China. Important cultural changes occurred in these regions over the past 10,000 years, driven by the dispersal of hunter-gatherers, farmers, and pastoralists. The specimens came from archaeological sites between 9,700 and 870 years old. In addition, the researchers included publicly available genomes from 57 ancient and 160 modern dogs in their analyses.

Dogs followed metalworkers across the Eurasian Steppe over 4,000 years ago

A comparison of ancient dog and human genomes reveals a striking concordance between genetic shifts in both species across time and space, most notably during periods of population turnover. This link is especially evident during China's transformative Early Bronze Age (~4,000 years ago), which saw the introduction of metalworking. The research shows that the expansion of people from the Eurasian Steppe, who first introduced this transformative technology to Western China, also brought their dogs with them.

This pattern of human-dog co-movement extends back far beyond the Bronze Age. The research traces signals of co-disperal back at least 11,000 years, when hunter-gatherers in northern Eurasia were exchanging dogs closely related to today's Siberian Huskies.

“Traces of these major cultural shifts can be teased out of the genomes of ancient dogs,” says Dr. Lachie Scarsbrook (LMU/Oxford), one of the lead authors of the study. “Our results highlight the deeply rooted cultural importance of dogs. Instead of just adopting local populations, people have maintained a distinct sense of ownership towards their own dogs for at least the past 11,000 years.”

“This tight link between human and dog genetics shows that dogs were an integral part of society, whether you were a hunter-gatherer in the Arctic Circle 10,000 years ago or a metalworker in an early Chinese city,” says Prof. Laurent Frantz. “It’s an amazing, enduring partnership and shows the sheer flexibility of the role dogs can play in our societies, far more than with any other domestic species.”

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Journal

Science

DOI

10.1126/science.adu2836 

Article Title

Genomic evidence for the Holocene co-dispersal of dogs and humans across Eastern Eurasia

Article Publication Date

13-Nov-2025

Extensive dog diversity millennia before modern breeding practices

University of Exeter

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Photograph of an archaeological canid skull used for the photogrammetric reconstruction of 3D models in the study. 

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Credit: C. Ameen (University of Exeter)

A groundbreaking archaeological study has revealed when domestic dogs first began to show the remarkable diversity that characterises them today. 

By applying cutting-edge shape analysis to hundreds of archaeological specimens spanning tens of thousands of years, researchers have traced the emergence of distinct dog forms deep into prehistory, pinpointing the moment dogs began to diversify in size and shape - at least 11,000 years ago.

These findings challenge long-standing assumptions that canine diversity is largely a recent phenomenon shaped by selective breeding, which started with the Victorian Kennel Clubs. Instead, the study demonstrates that significant variation in skull shape and size among domestic dogs was already present thousands of years ago, soon after their divergence from wolves.

Published today in Science and led by the University of Exeter and the French CNRS, the study is the most comprehensive of its kind in terms of both geographic reach and timespan, with specimens ranging from the Pleistocene to the present day. The research, which began in 2014, analysed 643 modern and archaeological canid skulls - including recognised breeds, street dogs, and wolves - spanning the last 50,000 years.

The international team of archaeologists, curators and biologists from more than 40 institutions collaborated to create 3D models of the skulls to study their size and shape using a method known as geometric morphometrics. Results show that by the Mesolithic and Neolithic periods, dogs already exhibited a wide range of shapes and sizes. This variation likely reflected their diverse roles in early human societies, from hunting and herding to companionship.

“These results highlight the deep history of our relationship with dogs,” said co-lead author Dr Carly Ameen of Exeter's Department of Archaeology and History. “Diversity among dogs isn’t just a product of Victorian breeders, but instead a legacy of thousands of years of coevolution with human societies.”

The earliest specimen identified as a domestic dog came from the Russian Mesolithic site of Veretye (dating to ~11,000 years ago). The team also identified early dogs from America (~8,500 years ago) and Asia (~7,500 years ago) with domestic skull shapes. After that, the study shows a lot of variation emerging relatively quickly.

Dr Allowen Evin, co-lead author from the CNRS based at the Institut of Evolutionary Science-Montpellier, France, explained: “A reduction in skull size for dogs is first detectable between 9,700–8,700 years ago, while an increase in size variance appears from 7,700 years ago. Greater variability in skull shape begins to emerge from around 8,200 years ago onwards.

“Modern dogs exhibit more extreme morphologies, such as short-faced bulldogs and long-faced borzois, which are absent in early archaeological specimens. However, there is a large amount of diversity among dogs even as early as the Neolithic; it was double that of Pleistocene specimens and already half the range seen in dogs today.”

The study also underscores the challenges of tracing the earliest dogs. None of the Late Pleistocene specimens - some previously proposed as “proto-dogs” - had skull shapes consistent with domestication, suggesting that the very first stages of the process remain difficult to capture in the archaeological record.

Professor Greger Larson, senior author of the study from the University of Oxford, said: “The earliest phases of dog domestication are still hidden from view, and the first dogs continue to elude us. But what we can now show with confidence is that once dogs emerged, they diversified rapidly. Their early variation reflects both natural ecological pressures and the profound impact of living alongside humans.”

By demonstrating that dog diversity emerged millennia earlier than assumed, the study opens new avenues for exploring how human cultural and ecological shifts shaped the evolutionary history of our closest animal companions.

The article, The emergence and diversification of dog morphology, is published today (Thursday) in Science. The research was supported by funding from national and international agencies, including the Natural Environment Research Council (UK), the Arts and Humanities Research Council (UK), the European Research Council, the Social Sciences and Humanities Research Council of Canada, the Russian Academy of Sciences, and the Fyssen Foundation. 
 

Photograph of a modern dog skull used for the photogrammetric reconstruction of 3D models in the study.

Credit

C. Ameen (University of Exeter

Static visualisation of skull shape differences between modern dogs (pink) and modern wolves (green), shown relative to an average morphology.

Credit

C. Brassard (VetAgro Sup/Mecadev)

Journal

Science

DOI

10.1126/science.adt0995 

Method of Research

Imaging analysis

Subject of Research

Animals

Article Title

The emergence and diversification of dog morphology

Article Publication Date

13-Nov-2025