The Rocky Road to a Healthier River:

We investigated how concentrations of salts play a role in mobilizing metals and other pollutants into our rivers and streams. Our research is intended to improve our understanding of chemical cocktails in our waterways and to better manage our water quality. 

Our research focused on five cities, sampling along different rivers and streams to analyze the presence of specific salts and chemical cocktails. This approach helped us to understand how salt and chemical concentrations in the waterways shifted downstream as they moved through developed land and/or green spaces.

Depending on how land is being used, various salts, nutrients, metals, and organic matter end up being "mixed together" to create unique "chemical cocktails". These cocktails enter our waterways and build up over time, combining and compounding upon one another.

• Are salt concentrations elevated in cities across the U.S.?
• Do distinct mixtures of salts and metals relate to different kinds of land use and human activities?
• Can green space (such as stream restoration, parks, and conservation areas) reduce salt concentrations?

Sampling occurred along nine rivers and streams, spanning five different U.S. metropolitan areas, including:

1. Baltimore, Maryland: Scotts Level Branch and Gwynns Falls
2. Washington, D.C.: Northwest Branch - Anacostia River, Watts Branch, and Bull Run
3. Cincinnati, Ohio: Licking River
4. Denver, Colorado: Boulder Creek and the South Platte River
5. Portland, Oregon: Willamette River

In waterways that flow through increasingly urbanized areas (Boulder Creek, South Platte River, Licking River, Bull Run, Watts Branch, and Willamette River) the salty chemical cocktails increased in concentration alongside increasing degrees of urbanization.

These elevated salt concentrations suggest that freshwater salinization can occur in urbanized streams in different parts of the U.S.

Although we generally observed increasing salinity and chemical cocktails in cities , there were three streams with decreasing or stable trends as they flowed through parks and restoration areas (Scotts Level Branch, Northwest Branch - Anacostia River, and Gwynns Falls).

These findings suggest that parks, conservation areas, forest cover and other natural features may protect waterways from the urban impacts of salinization and reduce pollutant mobilization observed in other sampling locations.   

Our research showed that we can anticipate increasing concentrations of salty chemical cocktails in rivers as they flow through more urban areas. The elevated concentration of salty chemical cocktails in urbanized areas suggests that this is a common attribute of waterways that move through our cities and suburbs. Conservation areas, forest cover, and other natural features or practices that manage stormwater flow may prevent the impacts of salinization and pollutant mobilization observed in more urbanized areas.

These results showcase how land use plays a role in the movement of salts and chemical cocktails into our waterways, and of the potential for point and nonpoint source pollution management in addressing salinization and freshwater quality in our communities.

The full details of this research are available in the peer-reviewed paper " Salty chemical cocktails as water quality signatures: Longitudinal trends and breakpoints along different U.S. streams "  _{EXIT}  available in the journal, Science of the Total Environment.

Increasingly salty waterways – and those with increased concentrations of chemical cocktails – pose a risk to the health of our freshwater systems, to our drinking water infrastructure, and to our public health.

To better manage the health of our waterways, studies like these point to potential solutions that address freshwater salinization and manage concentrations in our waterways. As this research suggests, green spaces – parks, conservation areas, forested zones – and other stormwater management practices can prove to be valuable tools in support of salinization management.

Once salt enters our environment it becomes challenging to remove it in an effective way. In order to address the risks freshwater salinization poses to the environment, our human health, and the built infrastructure, a multi-faceted approach involving community, municipal, and private partners is required. Our response to these risks need be based on sound science and effective management techniques, with a focus on a holistic approach to decrease salt use and minimize its pathways into our waterways.

There are a number of ways that you can play a part in this:

• Shovel walkways and driveways regularly and when possible, before snow turns to ice
• Use just enough salt required to melt the snow or ice, and only in the right conditions
• Use alternatives, like sand, for traction and to reduce salt use
•  Learn more about smart salt application practices   _{EXIT} 

• Keep kids (and yourselves) from ingesting snow – especially any that may have had contact with road salts, deicers, or other potentially harmful applications
• Keep your pets' paws secure on winter walks, and minimize any potential ingestion of contaminated water or soil

• Learn what steps your local government may be taking towards more responsible salt management policies
• Explore whether salt watch programs and pledges exist for your community to develop best practices through
•  Connect with your elected officials  _{EXIT} 

•  Learn about Winter Salt Application Trainings and Resources like SaltWise   _{EXIT}  to see if similar resources are right for your community
• Consider alternatives to rock salt application: brines, beet juices, and sands can help to minimize freshwater salinization
• Educate colleagues and community members; develop salt watch programs and pledges to foster responsible salt practices
•  Explore additional resources on salt guidance and tools available