subybaja
E. Spengler
Yeah, I mistook this for a rusty truck site instead of an environmental science site.
Here, let me google that for you.
Upper limits for road salt pollution in lakes
Christopher T. Solomon, Hilary A. Dugan, William D. Hintz, Stuart E. Jones
First published: 25 July 2023
https://doi.org/10.1002/lol2.10339
Citations: 1
Abstract
Widespread and increasing use of road deicing salt is a major driver of increasing lake chloride concentrations, which can negatively impact aquatic organisms and ecosystems. We used a simple model to explore the controls on road salt concentrations and predict equilibrium concentrations in lakes across the contiguous United States. The model suggests that equilibrium salt concentration depends on three quantities: salt application rate, road density, and runoff (precipitation minus evapotranspiration). High application combined with high road density leads to high equilibrium salt concentrations regardless of runoff. Yet if application can be held at current rates or reduced, concentrations in many lakes situated in lightly to moderately urbanized watersheds should equilibrate at levels below currently recommended thresholds. In particular, our model predicts that, given 2010–2015 road salt application rates, equilibrium chloride concentrations in the contiguous United States will exceed the current regulatory chronic exposure threshold of 230 mg L−1 in over 2000 lakes; will exceed 120 mg L−1 in over 9000 lakes; and will be below 120 mg L−1 in hundreds of thousands of lakes. Our analysis helps to contextualize current trends in road salt pollution of lakes, and suggests that stabilization of equilibrium chloride concentrations below thresholds designed to protect aquatic organisms should be an achievable goal.
...
Most of the lakes and reservoirs (“lakes”) larger than 1 ha in the contiguous United States for which the model predicts high equilibrium road salt chloride concentrations, given reported 2010–2015 salt application rates, are in the Northeast and Midwest (Fig. 3). The road network is densely developed in many places within this region, and salt application rates are often high. Lakes larger than 1 ha with predicted equilibrium chloride concentrations in excess of the 230 mg Cl− L−1 threshold were most abundant in Illinois and Ohio, where they represented 9–10% of all lakes larger than 1 ha (Fig. 3b). Lakes with predicted concentrations above this threshold were also present in Indiana, Iowa, Kansas, Michigan, Minnesota, New York, Pennsylvania, and Wisconsin, where they represented < 0.1% to 1% of lakes larger than 1 ha, and in the District of Columbia, where they represented 17% of 12 lakes. Lakes with predicted equilibrium road salt chloride concentrations above the 120 mg Cl− L−1 threshold used as a water quality guideline in Canada were much more abundant: in Illinois and Ohio 23–28% of lakes had predicted concentrations above this threshold, and in several other states 1–7% of lakes were above this threshold (Fig. 3b). Across the contiguous United States, more than 9000 lakes (2%) were predicted to have equilibrium road salt chloride concentrations in excess of 120 mg Cl− L−1.
MgCl− L−1 is a unit of concentration for chloride ions in a solution
Explanation
Magnesium chloride (MgCl2) is a soluble ionic compound that produces two moles of chloride anions for every mole of salt that dissolves in water. For example, if the concentration of MgCl2(aq) is 0.25 mol⋅L−1, then [Cl−] = 0.50 mol⋅L−1.
Units
Concentration units are often presented as mass per volume, such as milligrams per liter (mg/L) or mg. L-1.
Magnesium chloride is an inorganic compound that is highly soluble in water. It has many practical uses, and is the primary precursor to magnesium metal. Hydrated magnesium chloride is the most readily available form.
Too bad the Germans don't make any real pickups though.
