Human activities make the Earth’s air, soil and freshwater saltier ( salinization) and this continued salt accumulation poses an “existential threat” to the environment if current patterns persist, said a recent scientific review.
IMPACT OF HUMAN ACTIVITIES
While geologic and hydrologic processes naturally bring salts to the Earth’s surface over time, human activities, such as mining, land development, agriculture, construction, and industrial operations, has accelerated the natural “salt cycle.” This has far-reaching implications, including the disruption of ecosystems and the potential contamination of drinking water, said the research led by University of Maryland Geology Professor Sujay Kaushal.
SALT’S PERVASIVE ROLE
The researchers identify the prevalence of various salt ions in underground and surface water, extending beyond common sodium chloride. Salts like calcium, magnesium, potassium, and sulphate ions play crucial roles. When these ions are displaced in large quantities, they can lead to environmental issues.
GLOBAL IMPACT
The study reveals that human-caused salinization has affected approximately 2.5 billion acres of soil worldwide, equivalent to the size of the United States. It has also led to increased salt ion concentrations in streams and rivers, coinciding with the global rise in salt use and production.
SALT IN THE AIR
In some regions, lakes drying up release saline dust into the atmosphere. Additionally, road salts in snowy areas can become aerosolized, contributing to particulate matter containing sodium and chloride.
CASCADING EFFECTS
Salinization has cascading effects. For instance, saline dust can accelerate snowmelt, impacting communities reliant on snow for their water supply. Salt ions can also bind to contaminants in soils and sediments, forming harmful “chemical cocktails” that circulate in the environment.
URGENT NEED FOR ACTION
Road salts, which are widely used in the U.S., present a significant concern. The study recommends policies to limit road salt usage or promote alternatives, such as beet juice for de-icing roads. Striking a balance between public safety and water quality is crucial, with the short- and long-term risks of road salts needing careful consideration.
PLANETARY BOUNDARY FOR SALT USE
The study’s authors call for the establishment of a “planetary boundary for safe and sustainable salt use,” similar to the concept of carbon dioxide levels being associated with a planetary boundary to mitigate climate change. Regulating salt levels, although challenging, is vital to prevent its harmful accumulation in the environment.
Sujay Kaushal, the lead author, emphasizes the increasing levels of salt in the environment and the importance of finding the right balance to address the risks associated with excessive salt in our water.
This study serves as a stark reminder of the need to manage salt-induced environmental changes and their implications for both ecosystems and human well-being.
