Effects of Acid Rain. Harmful to fish Increase mercury concentration Increase inorganic aluminum exposure Fatal in high concentrations

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2 Acid Rain Cycle Source: Acid Rain Revisited, advances in scientific understanding since the passage of the 1970 and 1990 Clear Air Act amendments. Hubbard Brook Research Foundation. Science Links TM Publication, Vol. 1, no. 1.

3 Effects of Acid Rain Harmful to fish Increase mercury concentration Increase inorganic aluminum exposure Fatal in high concentrations Reduces tree health Red spruce & sugar maple Growth decline Winter injury Alters soil Leaches base cations (e.g. calcium) Mobilizes inorganic aluminum Sulfur and nitrogen accumulation

4 But now for some good news! Clean Air Act (1970) Amended 1977 & Sets standards for SO2 & other pollutants and requires implementation plans to ensure standards are met 2. Directs EPA and States to establish air quality programs which set enforceable emissions limits on large pollutantemitting facilities 3. Authorizes EPA to set emission standards for motor vehicles and fuels 4. Set forth provisions to reduce acid rain CAIR/CSAPR (2005) Cap and trade to reduce power plant SO 2 and NO x emissions NH Air Toxics Control Program (1987) Regulate hazardous air pollutant emissions

5 In 2011, a scrubber aimed to reduce mercury emissions when online at PSNH (Eversource) Merrimack Power Station It is also effective at reducing SO2 emissions

6 Trend in US Sulfur Dioxide Emissions 35,000 30,000 25,000 Thousand Tons 20,000 15,000 10,000 5,000 0

7 80 Sulfur Dioxide Emissions in New Hampshire 70 Thousand Tons

8 NHDES Acid Rain Monitoring Programs Rooftop Rain Initiated in 1972 ph, Sulfate, Nitrate Remote Pond Initiated in 1981 Samples collected spring with NH Fish & Game ph, ANC, Specific conductance, Sulfate, Nitrate Acid Outlet Initiated in 1983 Samples collected spring & fall (associated with turnover) ph, ANC, Specific conductance, Sulfate, Nitrate

9 NHDES Acid Rain Monitoring Programs Individual parameters of individual waterbodies Non-parametric Mann-Kendall trend tests Significance declared a p 0.05 Nitrate: Detection limit 0.05 mg/l. Non detectable results assigned values of mg/l to conduct trend analysis

10 6.5 ph Trends in Rooftop Rain at DES ph (Units) Significant increase Average ph Median ph

11 Sulfate Concentration of Rooftop Rain at DES mg/ L Significant decrease Mean Median

12 2.5 Nitrate Concentration of Rooftop Rain at DES ppm Significant decrease Mean Median

13 Are these precipitation trends reflected by our state waterbodies?

14 ph (units) 6.5 REMOTE POND ph & ANC Example ANC (mg/l) No significant trend ph Acid Neutralizing Capacity (ANC)

15 SO₄² (mg/l) 7 REMOTE POND Sulfate & Nitrate Example NO 3- (mg/l) Significant decrease Sulfate (SO₄² ) Nitrate(NO3-) Not detectable

16 25 20 REMOTE POND Specific Conductance Example Significant decrease umho/cm Specific Conductance

17 Remote Pond Trend Direction 100% % of Waterbodies 90% 80% 70% 60% 50% Increasing Trend Stable 40% 30% 20% 10% Decreasing Trend 0% ph ANC Specific conductance Sulfate Nitrate

18 7.2 ACID OUTLET ph Example ph (units) No significant trend 5.4 Fall Sampling Spring Sampling

19 7 ACID OUTLET ANC Example 6 5 Significant increase mg/l Fall Sampling Spring Sampling

20 6 ACID OUTLET Sulfate Example 5 4 mg/l Significant decrease 0 Fall Sampling Spring Sampling

21 Fall Acid Outlet Trend Direction Spring % of Waterbodies 100% 80% 60% 40% Increasing Trend Stable Decreasing Trend 20% 0%

22 Summary Rooftop rain ph increase Sulfate & nitrate decrease Remote pond Majority of ph & ANC stable 100% decrease in sulfate & specific conductance Majority decrease in nitrate Acid outlet Majority of ph & ANC increasing or stable Greater improvements in Fall 80% decrease in sulfate & nitrate Specific conductance results scattered

23 Take home messages Recovery is occurring but incomplete Sulfate concentration in waterbodies has drastically decreased, following reductions in sulfur dioxide emissions Long term datasets valuable for trend monitoring

24 Thanks! Dave Neils Walt Henderson Scott Ashley Dave Healy Jeff Underhill Questions?