## Breadcrumb

-  Publications 
-  Articles 

#           The response of soil and stream chemistry to decreases in acid deposition in the Catskill Mountains, New York, USA      

      November 1, 2017    

The Catskill Mountains have been adversely impacted by decades of acid deposition, however, since the early 1990s, levels have decreased sharply as a result of decreases in emissions of sulfur dioxide and nitrogen oxides. This study examines trends in acid deposition, stream-water chemistry, and soil chemistry in the southeastern Catskill Mountains. We measured significant reductions in acid deposition and improvement in stream-water quality in 5 streams included in this study from 1992 to 2014. The largest, most significant trends were for sulfate (SO42−) concentrations (mean trend of −2.5 μeq L−1 yr−1); hydrogen ion (H+) and inorganic monomeric aluminum (Alim) also decreased significantly (mean trends of −0.3 μeq L−1 yr−1 for H+ and −0.1 μeq L−1 yr−1 for Alim for the 3 most acidic sites). Acid neutralizing capacity (ANC) increased by a mean of 0.65 μeq L−1 yr−1 for all 5 sites, which was 4 fold less than the decrease in SO42−concentrations. These upward trends in ANC were limited by coincident decreases in base cations (−1.3 μeq L−1 yr−1 for calcium + magnesium). No significant trends were detected in stream-water nitrate (NO3−) concentrations despite significant decreasing trends in NO3− wet deposition. We measured no recovery in soil chemistry which we attributed to an initially low soil buffering capacity that has been further depleted by decades of acid deposition. Tightly coupled decreasing trends in stream-water silicon (Si) (−0.2 μeq L−1 yr−1) and base cations suggest a decrease in the soil mineral weathering rate. We hypothesize that a decrease in the ionic strength of soil water and shallow groundwater may be the principal driver of this apparent decrease in the weathering rate. A decreasing weathering rate would help to explain the slow recovery of stream pH and ANC as well as that of soil base cations.

## Citation Information

## Related Content

                  -              Connect           

#### Michael R. McHale

##### Supervisory Research Hydrologist (RGE)

New York Water Science Center

mmchale@usgs.gov

518-285-5675

####             Douglas A Burns (Former Employee)          

##### Coordinator, Delaware River Basin Next Generation Water Observing System (NGWOS)

New York Water Science Center

#### Jason Siemion

##### Hydrologist

New York Water Science Center

jsiemion@usgs.gov

518-285-5623

#### Mike Antidormi

##### Hydrologist

New York Water Science Center

mantidormi@usgs.gov

518-285-5638

## Related Content

#### Michael R. McHale

##### Supervisory Research Hydrologist (RGE)

New York Water Science Center

mmchale@usgs.gov

518-285-5675

####             Douglas A Burns (Former Employee)          

##### Coordinator, Delaware River Basin Next Generation Water Observing System (NGWOS)

New York Water Science Center

#### Jason Siemion

##### Hydrologist

New York Water Science Center

jsiemion@usgs.gov

518-285-5623

#### Mike Antidormi

##### Hydrologist

New York Water Science Center

mantidormi@usgs.gov

518-285-5638

### Study Area

### Contact

####               New York Water Science Center          

425 Jordan RoadTroy, NY12180-8349United States

dc_ny@usgs.gov

(518) 285-5695 

(518) 285-5601

### Explore Search

                  - United States
                  - catskill mountains
                  - New York

View All **