Is the use of rock salt for snow and ice control on roads directly linked to increased zinc in storm water flows?
asked 6 April 2017 asked by Carrie (510 points)
I can't say if it is related but from what I checked in 2003, the USEPA added this compound to its list of toxic pollutants under section 307(a) of the Clean Water Act. It seems that other potential components and impurities of road salt can include calcium, potassium, iron, magnesium, aluminum, lead, phosphorus, manganese, copper, zinc, nickel, chromium, and cadmium. You can read on the subject and from what the study is saying the ratio of zinc to chloride steadily increased by about an order of magnitude (from 0.3 x 10 -4 to 2.7 x 10-4) during the storm as chloride concentrations decreased from 960 to 360 mg/L. https://webdmamrl.er.usgs.gov/g1/ggranato/trb1533.pdf