14 DAY TRIAL // According to new measurements conducted by the United States Geological Survey (USGS), it would appear that salt and other materials used for deicing the streets during the winter season have negative repercussions on streams in the urban environment.
The investigators found that aquatic life is severely affected by salt contamination. Fish have a difficult time surviving in small streams around cities and major metropolises.
The effects of so-called winter runoff were analyzed in areas of eastern Wisconsin and Milwaukee, although measurements were collected from other locations as well.
“While winter driving and walking safety are the priority in treating pavements, this study suggests the need for advancements that will reduce salt loads to surface waters without compromising safety,” explains Matthew C. Larsen, who is the Associate Director for Water at the USGS.
“We expected to see elevated chloride levels in streams near northern cities during the winter months,” adds USGS Wisconsin Water Science Center expert Steve Corsi.
“The surprise was the number of streams exceeding toxic levels and how high the concentrations were,” adds Corsi. The expert was also the leader of the new study.
“This study shows that chloride contamination of urban streams is a problem in many places; it’s not just a Milwaukee problem,” Corsi goes on to say.
He explains that, in addition to city authorities, private individuals, companies and small businesses use salt on their own as well, which contributes to overall pollution levels.
In the investigation, the USGS team discovered that half of the Milwaukee streams they analyzed became toxic for life during the winter months.
It was additionally determined that, in the northern parts of the United States, more than 55 percent of all streams are contaminated. The data was derived from studies of streams in 15 northern cities.
“Other major sources of salt to US waters include wastewater treatment, septic systems, farming operations, and natural sources from geologic deposits,” USGS experts say in a press release.
“These sources may contribute to chloride levels at individual streams in this study, but the geographic, land-use, and seasonal patterns observed in this study suggest deicing activities as the dominant source,” they conclude.