Stream quality is strongly correlated with human health

In a new study from Virginia Tech, experts have identified a clear connection between stream quality and human health. Streams represent a critical interface between human beings and the environment. They serve as a major source of drinking water, as well as a place where we often go to enjoy nature.

To explore the relationship between the quality of streams and human well-being, experts in the College of Natural Resources and Environment and the Department of Biological Systems Engineering analyzed data on local demographics, indicators of human well-being, and indicators of stream health.

The study revealed that health statistics such as cancer rates and food insecurity are strongly correlated with water quality across the Commonwealth of Virginia. The team also identified a link between stream quality and demographics such as race and population density.

Paul Angermeier is a professor in the Department of Fish and Wildlife Conservation and assistant unit leader of the Virginia Cooperative Fish and Wildlife Research Unit for the U.S. Geological Survey.

“We started off wanting to explore the general, intuitive relationship between human well-being and ecosystem health,” explained Angermeier. “Many of us intuit that healthy ecosystems produce benefits that accrue to people, but that outcome isn’t well documented in a quantitative way.”

Environmental quality management processes often separate the natural world from human experiences, and the researchers needed a new approach.

“When we consider natural resources, we tend to think about whether we’re managing an environment for nonhuman considerations or human ones,” said Professor Leigh-Anne Krometis. “For instance, at the state level we have a department of environmental quality and a department of health, which both deal with the subject of water quality, but in different ways. What we wanted to see was how those two perspectives converge.”

The study authors used water quality measurements provided by the Virginia Department of Environmental Quality and county-level demographics data from the U.S. Census Bureau. 

“We had large data sets that we had to organize and process,” explained Professor Marc Stern. “Our expectations on finding meaningful relationships between stream health and human factors weren’t that high. The fact that they showed up so distinctly was a surprise.”

The researchers discovered that there is a strong correlation between ecosystem health and human demographics. For example, more polluted streams were associated with higher degrees of overall mortality.

“We still don’t have hard data on how people are interacting with nature,” said Angermeier. “For instance, we found that mortality rates for people are correlated with contamination levels in fish. What does that mean? Are people eating contaminated fish, are they merely sharing a polluted water source, or is it something else?” 

“A better understanding of the mechanisms by which people are interacting with water will help us draw clearer conclusions about health outcomes.”

The study is published in the journal Ecological Indicators.

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By Chrissy Sexton, Earth.com Staff Writer