USGS research study exposes a concerning boost in groundwater salinity across the U.S., linked to roadway salt and irrigation. This postures threats to marine life, facilities, and human health through aspects like radium.
For over thirty years, U.S. Geological Survey (USGS) scientists have actually been tracking the quality of groundwater in wells throughout the country. Their focus has been on discovering potentially damaging chemicals or substances that might adversely affect ecosystems or human health. In all, they have actually measured up to 500 chemical constituents, consisting of major ions, metals, pesticides, volatile natural substances, fertilizers, and radionuclides.
Findings on Increased Salinity
Of these constituents, there have actually been substantial increases of Na and Cl ions and dissolved solids– all related to salinity. Details and patterns found in the multidecadal study were just recently provided at the Geological Society of Americas GSA Connects 2023 conference.
The research study is presently part of the National Water Quality Network, continuing work that began in 1992 as part of the National Water Quality Assessment Project. “The initial goal was to assess the status of water quality in the country, consisting of groundwater, surface water, and eco-friendly health,” says Bruce Lindsey, a hydrologist with USGS. Gradually, they focused on specific constituents that might have remaining harmful effects.
USGS Decadal Change in Groundwater Quality program map revealing how concentrations of pesticides, nutrients, metals, and natural pollutants in groundwater are changing throughout decadal periods across the United States. Credit: U.S. Geological Survey
Sampling Wells and Methodology
The scientists tested wells within three different network types: domestic areas, urban areas, and farming locations. Domestic wells, or personal wells that are not regulated by the Environmental Protection Agency or a regional municipality, represented medium depth aquifers and drinking water. Urban and agricultural wells were shallower, generally around 30 to 50 ft deep.
The group identified 82 networks, each with 20 to 30 wells, and identified 28 constituents to track that had levels of concern. Water was tested every 10 years to track changes in chemical concentrations. These constituents and tasting outcomes can be seen on the USGSs interactive groundwater map, which reveals decadal modifications.
Salinity Increases and Implications
” If we take a look at all 28 constituents across all 82 networks, dissolved solids, chloride, and salt had statistically significant boosts more frequently than any other constituents that we have on our list,” states Lindsey. “If you take a look at the map, youll see patterns right away that jump out.”
One of these spots is the Northeastern and Upper Midwest areas, “particularly around metropolitan areas where theres cold weather and a lot of roadway salt,” states Lindsey. “We got information on road salt application and discovered connections between these boosts in chloride and sodium and liquified solids with the roadway salt application rates.”
A picture of a USGS researcher gathering information. Credit: U.S. Geological Survey
Another area likewise had elevated levels of Cl, Na, and dissolved solids: the arid regions of the nation, especially in the southwest. These regions naturally have high salinity in the soil to begin with, however watering complicates the concern.
” When watering agriculture in dry regions, you get a lot of evaporation,” Lindsey discusses.
Environmental and Health Impacts
These rising levels of Na, Cl, and liquified solids can cause numerous issues, starting with the environment. Lots of streams are fed by groundwater, and greater concentrations of chloride in the water can knock out the natural balance that marine life is utilized to.” [Rising levels] is something that can take 20, 30, 40 years to develop … which implies that it can likewise take that long to recuperate if management of the sources of salinity changes,” states Lindsey.
Liquified salt ions can also position problems for facilities. As the salinity of groundwater boosts, corrosivity can end up being a concern. Corrosive groundwater, if neglected, can liquify lead and other metals from pipelines and other parts present in household pipes.
Lindsey and his colleagues have also found a special concern related to increasing salinity with implications for human health. In a sandy aquifer in southern New Jersey, they found that a mixture of low pH water and high salinity groundwater has actually set in motion the radium– a radioactive element that is damaging to human beings.
” It returns to road salt,” he says. “Road salt is increasing, triggering salt and chloride to increase, which is causing radium to increase.”
Lindsey keeps in mind that there appears to be increased awareness of the ecological results of roadway salt, with trucks spreading less salt or municipalities changing to a lower-concentration salt water. And while dead grass near salted highways is a clear hint at an oversalting problem, Lindsey hopes that research like this will highlight other cascading effects of increasing salinity in groundwater.
Reference: “Increasing Salinization of Groundwater in the United States” by Bruce Lindsey, 18 October 2023, GSA Connects 2023. DOI: 10.1130/ abs/2023AM -391692.
For over thirty years, U.S. Geological Survey (USGS) scientists have actually been tracking the quality of groundwater in wells throughout the nation. “The original objective was to evaluate the status of water quality in the country, consisting of groundwater, surface water, and eco-friendly health,” says Bruce Lindsey, a hydrologist with USGS. As the salinity of groundwater boosts, corrosivity can end up being an issue. Lindsey keeps in mind that there seems to be increased awareness of the ecological impacts of road salt, with trucks spreading out less salt or towns changing to a lower-concentration salt water. And while dead grass near salted roads is a clear hint at an oversalting issue, Lindsey hopes that research study like this will highlight other cascading impacts of increasing salinity in groundwater.