Wet and Dry Deposition of Excess Chloride near a Hardrock Salt Mine

Jeremy Dietrich1, Tom Butler2, Francoise Vermeylen3 and John Dennis4

A preliminary study was undertaken to assess both wet and dry deposition of chloride in the vicinity of an active salt mine in Lansing, NY.  Multi-day sampling of 3 wet events and 3 dry events were undertaken using triplicate NADP sampling buckets over a 5 station transect from 244 m to 600 m from the salt pile storage facilities at the mine.  A 6th, control site was located 4100 m from the salt piles. Overall wet and dry deposition rates were estimated for each site using a random effects model. Similar analyses were performed on the conductivity of the wet samples, and dry samples with a standard addition of deionized water added to the dry sample buckets after collection. The transect was arranged north of the mine and deployments were attempted when forecasts predicted that the transect area was going to be downwind of the mine, at least some of the time.

Summary results show the control site having an average daily wet deposition of 3.2 ±22.3 (s.e.) mg Cl-/m2 and a daily dry deposition of 3.1 ±22.5 mg Cl-/m2. Stations 1 through 4, located 250 to 550 m from the salt piles, show a 40 to 75-fold increase in wet deposition and a 19 to 41-fold increase in the mean daily dry Cl- deposition, compared to the control site.

Combining wet + dry deposition on an annual basis, Cl- deposition was 25 to 48 times greater than the control site for stations #1 through #4. Annual NaCl total deposition in kilograms per hectare were: Station #1, 904; #2, 837; #3, 725; #4, 470; and #5, 342, with a standard error of ~ ±20%. Our control location yields an annual deposition rate of only 19 kg NaCl/ha.  There is an excess of NaCl deposition of 61 metric tons/yr for the 235 hectare area within a 500 m radius of the salt piles.  Within a 1 km radius of the salt piles, the excess NaCl deposition is 99 metric tons per year. These data suggest substantial excess chloride deposition to the surrounding landscape, especially within ½  km of the salt piles. Visible damage to local vegetation and excess corrosion of metal nearby most likely from excess salt deposition, corroborates these findings.


1Ichthyological Associates, jeremy.a.dietrich@gmail.com
2Cornell University & The Cary Institute of Ecosystem Studies, tjb2@cornell.edu
3Cornell Statistical Consulting Unit, fmv1@cornell.edu
4Chris Dennis Environment Fund, johnvdennis@gmail.com