Streams and rivers in the United States (U.S.) have experienced an increase of alkaline over the last half century, leading to saltier water bodies, and may pose a risk to drinking water, damaging pipelines as well as other infrastructure, according to a recent study published in the Proceedings of the National Academy of Sciences.
The study, which examined data taken from 232 U.S. Geological Survey monitoring sites in depth, found that it could be traced to farmers fertilising their fields and municipal workers spreading salt over roads to fight against ice over a number of decades. But the runoff has only served to make waterways in the U.S. saltier.
However, according to Reuters, those two factors are not the only two events that led to a higher salt content in water bodies; salt can be released by several other ways as well, including floods that reach sewage systems and carry contaminants into waterways, and fracking operations at oil and gas sites.
Moreover, this increased salinity makes water more alkaline as it slowly breaks concrete and rocks in rivers down, as well as minerals found in soil and water. The contaminants then released have the potential to leach zinc and copper from the rocks and soil found in streams, and erode pipelines and allow lead to seep into drinking water much like the Flint water crisis – where the elevated levels of salt in the water led to lead poisoning. And as the study also found, a combination of salts is capable of causing more damage that one salt alone.
But while alkaline water can drive scaling inside water pipes – something desirable as it keeps metals from seeping from the pipe – too much scaling can constrict, or even block, pipes.
“Until now, we didn’t fully appreciate the role that different salts play in altering the pH of streams and rivers of our country,” lead scientist of the study and University of Maryland geologist, Sujay Kaushal, said.
The study also found that 66 per cent of streams and rivers have become more alkaline over the past half century – but water treatment facilities are not able to filter out salts, instead using chemicals to treat them. According to Kaushal, however, the issue, is not the chemicals used, but how much to use. Because floods and storms are intermittent and unpredictable, it is difficult for utilities to correctly determine the right amount of chemicals to use.
Source: Reuters
