It’s about time this effect was well documented see: Center for Limnology Salt Study
What would we expect? Adding a highly soluble, conservative pollutant will runoff into and accumulate in lakes.
This is not new news. My studies of metro lakes in the 1980s also documented this. It got no traction (excuse the pun) as safety trumped contaminating lakes (and streams and groundwater …).
I published a blog, copied below, called Salt and Mirrors following a plea to use less slat in the Twin Cities several years ago.
[From December 2014]
Salt is bad for our lakes. Chloride, the offending element in salt, has been accumulating in metro lakes for the past half century, corresponding to the use of de-icing road salt. This is an insidious kind of pollution because its impacts are gradual. Yet, increases in chlorides affects the entire lake food chain, favors undesirable, even toxic, algae species and gives aquatic invasive species an additional edge over native species.
So, when public agencies and other environmental organizations call for individuals to use less salt on our sidewalks and driveways, that is good, right?
Of course it is.
But we are looking at this the wrong way. If we want to stop the increasing chloride pollution to our lakes, moderating individuals’ salty behavior will not accomplish this.
Metro road salt use is 700 million pounds per season. Seventy percent – 70% – of this ends up in our water. This is the elephant in the room and until we recognize this, urging changes in individuals’ behavior deflects the issue.
The real issue is we have made a choice – dry winter roads in exchange for polluting our lakes. Our transportation agencies are on a mission to reduce deicing salt use, but using less just means we are polluting our lakes more slowly.
A main theme in A Lake Manager’s Notebook (discontinued), is our lack of attention to quantifiable objectives. Agencies’ salt reduction goals are stated in terms of less, but not in terms of exactly how much less. Lacking specific targets, how do we know if our lakes are really being protected?
Our lake management institutions have adopted a self-empowerment ethic for protecting our lakes. In this context, I often see reference to the old Pogo cartoon with the caption, “We have met the enemy and he is us.” This makes me cringe because it implies individuals (us) are the enemy of lakes while at the same time distancing our institutions from addressing the underlying systemic problems.
Chloride pollution to lakes (also groundwater, wetlands, rivers and streams) is a bona fide, pervasive problem and its overwhelming source is road salt. Mitigating road salt use will not be easy, because convenient, cheap alternatives do not exist. However, deflecting the onus to citizens and away from agencies is wrong-minded.
So what do we do?
I think we need to shift our attitude and approach to something that more realistically recognizes our societal choices so we can live with and best manage their consequences. I don’t see that we will significantly change road salt use any time soon. Of course, citizens should reduce their use of de-icing salt, mostly because we can. More importantly however, citizens, through our institutions should address these concerns more comprehensively and as a matter of public policy. An involved citizenry can make good public policy choices when given accurate information. I don’t see the benefit of delusion.