US Drinking Water at Risk As Nitrogen Pollution in River Basins Increases

Drinking water in the United States is at risk, scientists have said, as nitrogen pollution seems to be increasing.

In a new study, scientists found that a third of the world's drinking water could be polluted with nitrogen by 2025.

Researchers of the study are also concerned that water will not just be polluted, but there will be a severe lack of it at this time. And this could affect up to 3 billion people, the paper published in Nature Communications reports.

"We are surprised that water pollution by nitrogen aggravates water scarcity in more than one-fifth of the sub-basins worldwide," Mengru Wang, an assistant professor at Wageningen University & Research in the Netherlands, told Newsweek.

"This means that not only water quantity matters, but water quality is also important and should be urgently addressed in future water resource management."

Nitrogen is a chemical compound that is produced in abundance due to the burning of fossil fuels. When there is too much nitrogen in the atmosphere it can produce ammonia and ozone, which are harmful pollutants. This can drastically affect the health of waterways, as well as forests and soils.

Areas of the U.S., as well as South China, Central Europe and Africa, are all projected to become hotspots of water scarcity, the study reported, largely due to an excess of nitrogen in the area.

Water pollution was of particular concern in the south of North America, the study reported.

"We found that water pollution aggravates water scarcity in 2,000 sub-basins worldwide," the authors write in the study. "The number of sub-basins with water scarcity triples due to future nitrogen pollution worldwide.

"In 2010, 984 sub-basins are classified as water scarce when considering only quantity-induced scarcity, while 2,517 sub-basins are affected by quantity- and quality-induced scarcity. This number even increases to 3,061 sub-basins in the worst-case scenario in 2050."

To reach these findings Wang and colleagues took a close look at river basins around the world. They discovered that when levels of nitrogen pollution is considered, it drastically increases the amount of basins that can be considered water scarce.

This is because their overall water quality is poor. Sub-basins, which are smaller units of larger river basins, are a source of drinking water for many communities. The problem is that they are also in areas where urban activities are underway, meaning they are at risk of pollution.

In 2010, they found that 2,517 sub-basins lacked water, and also had poor water quality.

The authors estimate that by 2050, 3,061 sub-basins will be "water quantity-quality scarce." These basins provide water for 3 billion people.

For this reason, researchers are calling for policymakers to consider water quality as a matter of urgency when they are implementing water-management policies.

Real-time examples of water scarcity is occurring in the U.S. now. For example, the Southwest is facing a water crisis as the Colorado River is seeing some of the lowest flows in a century. This means that important reservoirs like Lake Mead, which provides water for 25 million people, have also seen low water levels.

Many put the problem down to climate change causing drought due to a lack of precipitation. However, the study notes that while climate change is a factor in water scarcity, agriculture and urbanization are also affecting water pollution as well as demand.

While the researchers assessed nitrogen as a "water quality indicator" in their study, there are many other threats that can be considered.

"There are other pollutants that may cause water pollution worldwide. We do not know how that will change the picture of clean-water scarcity," Wang said.

"With our model, we are looking forward to adding other emerging pollutants such as plastics, pesticides, pathogens, antibiotics in such an assessment in this article to better understand the future changes in clean-water scarcity worldwide.

"Research is thus needed to identify the impacts of these indicators or pollutants on future water scarcity among sectors as a joint effort of the water quality community."

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