The impacts of TXB Pollution on acid sensitive lake -.Julian Aherne
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The impacts of TXB Pollution on acid sensitive lake -.Julian Aherne

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The impacts of TXB Pollution on acid sensitive lake -.Julian Aherne The impacts of TXB Pollution on acid sensitive lake -.Julian Aherne Presentation Transcript

  • the impacts of transboundary air pollution on acid sensitive lakesjulian aherne, heidi scott, andrew burton, colin whitfield, kevin adkinson, thomas cummins, and others… Ireland’s Environment 2012: EPA-STRIVE Research Conference Trinity College Dublin [28 June 2012]
  • overview | atmospheric pollution can adversely affect the naturalenvironment leading to significant impacts on ecosystem services.sulphur and nitrate dioxide cause acidification.excess nitrogen causes decreased ecosystem biodiversity.heavy metals and persistent organic pollutants may accumulate in soiland water and cause damage to the environment and human health.as a consequence, during the last two decades international policies havefocused on reducing emissions of transboundary air pollutants. source: www.apis.ac.uk
  • objective | the principal objective was to assess the impacts of major transboundary air pollutants on acid-sensitive lakes and soils, their response to reductions in emissions of sulphur and nitrogen oxides, and to address knowledge gaps in relation to the levels of heavy metals and persistent organic pollutants in semi-natural ecosystems. • assess response of rainfall chemistry to emissions reductions • evaluate response of surface waters (predominantly small upland headwater lakes) to changes in atmospheric deposition • evaluate the levels and controls on trace metals in acid-sensitive lakes • evaluate the influence on sea-salt on acidification of lakes • evaluate the drivers of long-term patterns in surface waters • evaluate the controls on green house gases… • characterise the physico-chemical characteristics of acid sensitive soils • evaluate total and methylmercury in the soil and water • evaluate the presence of POPs in the soil and water of selected headwater lake catchmentsemission reductions | western | marine | semi-natural ecosystems | climate
  • (a) assess response of rainfall chemistry to emissions reductions location of monitoring stations contributing precipitation chemistry to the co-operative programme for monitoring and evaluation of the long range transmission of air pollutants in Europe (EMEP [Chemical Co- ordinating Centre]).
  • one-day back-trajectory wind-rose plots showing the proportion (%) of air bydirection and source during the period 1989–2009 for sites in west (Mayo) andeast (Wicklow)
  • –1 –1 –1 Non-marine sulphate (mg L ) Nitrate (mg L ) Ammonium (mg L )0.6 0.40 0.6 Valentia Observatory Turlough Hill0.5 The Burren 0.5 Ridge of Capard 0.30 Oak Park Glenveagh0.4 0.4 Johnstown Castle Lough Navar Median concentration0.3 0.20 0.30.2 0.2 0.100.1 0.10.0 0.00 0.0 1990 1995 2000 2005 2010 1990 1995 2000 2005 2010 1990 1995 2000 2005 2010 long-term annual trend (1991–2009) in non-marine sulphate, nitrate and ammonium concentration in precipitation (mg L–1) at EMEP stations
  • (b) evaluate response of headwater lakes to changes in atmospheric deposition sensitivity of surface waters to survey lakes sampled during spring acidification based on soil and geology 1997 and 2007 (n = 77)
  • significant decreases in SO42–, nmSO42– and non-marine base cations, and significantincreases in alkalinity between the 1997 and 2007 lake surveys, suggesting that lakes haveresponded to reductions in long-range transboundary air pollution. However, there were nosignificant changes in surface water pH and AlT. It is likely that inter-annual variations in seasalt inputs and DOC concentrations (organic acidity) may have contributed to the delay inrecovery of pH.
  • (c) evaluate the levels and controls on trace metals in acid-sensitive lakes sensitivity of surface waters to trace metal survey lakes sampled acidification based on soil and geology during spring 2008 (n = 122)
  • order of total trace metal concentrations (µg L–1) was (highest to lowest) : Fe >Al > Mn > Sr > B > Zn > Ba > Ti > Mo > Se > V = As > Bi > Cr > Ni = Cu > Cd > Pb >Tl > Co > U > Hg. The study lakes were strongly dominated by Fe, Al and Mn,measurements BDL were common for certain elements such as Be (100% BDL),Cd (79%), Se (40%), Co (39%) and Pb (29%).fractions: trace metals (i.e., Al, Mn, Fe, Ni, Cu, Zn, Sr, Ba, V and B) werepredominantly in dissolved form; although elevated particulate fractions wereobserved for Mn (20%), Al (25%) and Fe (33%). The dissolved labile phase wasthe dominant form for Sr (98%), Ba (90%), Mn (78%) and Zn (75%). In contrast,the dissolved non-labile phase was dominant for Cu (78%), Ni (67%), Fe (58%),V (58%) and Al (48%).
  • toxicity: trace metal concentrations were low, within the range of pristineglobal surface water concentrations; however, dissolved zinc, cadmium,inorganic labile aluminum and manganese may potentially reach levels harmfulto aquatic organisms in some lakes (~20%).sources: redundancy analysis indicated that metals were predominantly derivedfrom geochemical weathering. However, a number of trace metals (e.g., lead,zinc) were correlated with anthropogenic atmospheric deposition (non-marinesulphate), suggesting atmospheric sources or elevated leaching owing to acidicdeposition. Dissolved organic carbon (DOC) was a major driver associated withhigher concentrations of dissolved metal fractions.
  • (d) evaluate the levels and controls on green house gases ghg: the majority of lakes were supersaturated with CO2, N2O and CH4. principal components analysis indicated that higher levels of CH4 and N2O supersaturation were exhibited under different land-cover conditions. Methane supersaturation was highest in lower elevation catchments with an evaporative hydrologic character and high organic carbon concentration. In contrast, lakes characteristic of N2O supersaturation were low in carbon and located in more rapidly flushed higher elevation catchments.
  • (e) evaluate the influence on sea-salt on acidification of lakes –1 Daily chloride (mg L ) 250“Lowest March pressure on record for Valentia ObservatoryIreland on 10th” Met Eireann, Glenveagh ParkMonthly Weather Bulletin, March 200 –1 March 10: Valentia Observatory 1967.0 (mg L )2008.“Deep depressions passing close to or 150over Ireland brought very unsettledconditions, with strong winds and 100spells or rain or showers each day. Allareas received heavy rain betweenthe 9th and 11th… The same period 50produced very strong winds…” 0 0 50 100 150 200 250 300 350 Julian day (2008)
  • sodium:chloride ratio in lake water during 2007 (left) and 2008 (right) surveys
  • –1 –1 –1 Chloride (mg L ) Dissolved organic carbon (mg L ) Calcium (mg L ) 100 20 4.0 75 15 3.0 50 10 2.0 25 5 1.0 0 0 0.0 2007 2008 2007 2008 2007 2008 pH –1 –1 8.0 Total aluminium (µg L ) Manganese (µg L ) 200 100 7.0 150 75 6.0 100 50 5.0 50 25 4.0 3.0 0 0 2007 2008 2007 2008 Y2007 Y2008Box-plot comparison of paired lake chemistry (n ~ 50) observations from the2007 and 2008 surveys, before and after the 10 March 2008 sea-salt event.
  • (f) & (g) POPs and Hg in headwater catchments: intensive study catchments
  • (e) evaluate the presence of POPs in the soil and water of lake catchments Concentrations of POPs in Water at Study Lakes (n=5) 600 60 CUM ADA MUL 500 50 SGI CLE 400 40 pg/L pg/L 300 30 200 20 100 10 0 0 s an -a -b T Ps s AH CH ulf es es DD OC CB lP talH os ien ien tal er lP T ota To en d lod lod To oth T ota tal cyc cyc tal To tal tal To To To POPswater: mean ± S.D. (n=3) lake concentrations of POPs estimated from SPMDsdeployed during the period from July, 2009 to January, 2010 at the five studysites. Other OCPs include OCS, HCB, Methoxyxhlor, and Pentachloranisole.
  • 2 Concentrations of POPs in Soil at Study Sites (n=5) Concentration of POPs per m of Soil at Study Sites (n=5) 40 2500 60 1500 CUM CUM ADA ADA 50 MUL 500 20 2000 MUL SGI SGI CLE CLE 40 400 15 1500 2 2 30 300 g/mng/g ng/g g/m µ µ 10 1000 200 20 5 500 100 10 0 0 0 0 To To To To To To tal To tal tal tal To tal tal PA tal DDTo PC PA tal D PC Hs PB T ta Bs PB To DT DE lo Hs DE tal Bs s the s oth e POPs r O CP POPs r OC s P s soil: concentrations (left) and pool (right) of POPs measured in soils at the five study sites ( ng/g and µg/m2), sampled during October 2010. Other OCPs include HCHs, Cyclodienes-a and b, Endosulfan, OCS, HCB, Methoxyxhlor, and Pentachloranisole.
  • POPs summary• physical, meteorological, and chemical parameters exhibited correlations with POPs in SPMDs and soil samples, e.g., lake:catchment ratio, rainfall, DOC, and source air (e.g., Endosulfan and % overland air).• the role of media partitioning for many of the compounds is apparent. Even in highly organic soils, HCHs, HCB, Endosulfan, and less-chlorinated PCBs have a tendency to revolatilize or washout more readily and are more likely to be captured in SPMDs. Whereas, ‘heavier’ compounds, e.g., PAHs, PBDEs, and the more-chlorinated PCBs bind to soil and sediments.• observed concentrations were well within, or below, the range of ‘background’ values from continental Europe and internationally.
  • (e) evaluate total and methylmercury in the soil and water 5 0.18 0.15 4 Plot 1 0.12 MeHg (ng/L)THg (ng/L) 3 0.09 2 0.06 1 0.03 0 0.00 CUM ADA MUL SGI CLE CUM ADA MUL SGI CLE Site Site water: averages concentrations of THg (n= 6) and MeHg (n= 4) in study lakes between 2010 and 2011.
  • relationships between THg (and MeHg) in water and lake chemistry 4.5 0.14 4.0 0.12 3.5Predicted THg (ng/L) 0.10 3.0 2.5 0.08 2.0 0.06 1.5 Predicted MeHg(ng/L) 0.04 1.0 0.5 0.02 0 1 2 3 4 5 0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.16 0.18 THg (ng/L) MeHg (ng/L) THg = –2.458 + (0.327 * TOC) + MeHg = –0.0602 + (0.0023 * (0.261 * Na+) – (1.178 * SiO2) – Conductivity) + (0.0215 * Gran (0.606 * d18O) Adj R2 = 0.56 Alkalinity) + (0.0501 * SiO2) + (0.0031 * Turbidity) Adj R2 = 0.48
  • 400 500 400 300THg (ng/g) THg ( g/m ) 2 300 µ 200 200 100 100 0 0 CUM ADA MUL SGI CLE CUM ADA MUL SGI CLE Site Site soil: averages concentrations (left) and pools (right) of THg in soil at the five study catchments, October 2010.
  • Age Chronology of MUL Peat Core Fluxes of THg in MUL Peat Core 0 2 2010 1994 ± 1 Hg summary 0 2 2010 1994 ± 1 4 6 1973 ± 2 1961 ± 2 • various physical and chemical 4 6 1973 ± 2 1961 ± 2 8 10 1953 ± 3 1946 ± 3 8 10 parameters exhibited 1953 ± 3 1946 ± 3 12 1940 ± 3 12 correlations with Hg in water and 1940 ± 3 soil samples; notably THg is 14 1931 ± 3 14 1931 ± 3 16 1921 ± 3 16 Year 1921 ± 3 Year 18 1905 ± 4 18 strongly influenced by the level of 1905 ± 4Depth (cm) Depth (cm) 20 1880 ± 5 20 1880 ± 5 22 24 1811 ± 17 1787 ± 25 22 24 organic matter in soil and water 1811 ± 17 1787 ± 25 26 28 1753 ± 45 • lake concentrations of Hg in this 26 28 1753 ± 45 30 30study were similar to levels measured inTHg (µg/m ) and soils water 50 100 150 200 250 300 350 0 10 20 30 40 50 60 70 2 THg (ng/g) elsewhere. Age Chronology of SGI Peat Core • peat core records Peat Core there Fluxes of THg in SGI indicate 0 2010 0have been significant decreases 2010 since the highest peaks (1950– 2 2001 ± 2 2 2001 ± 2 4 1988 ± 2 4 1988 ± 2 6 8 1980 ± 3 1970 ± 3 6 8 1980s), indicative of regulation 1980 ± 3 1970 ± 3 10 1959 ± 4 10and enforcement of Hg 1959 ± 4 emissions. 12 1949 ± 4 12 1949 ± 4 14 1937 ± 4 14 1937 ± 4 • northwestern sites appear to 16 1927 ± 5 16 1927 ± 5 Year Year 18 1914 ± 5 18 1914 ± 5Depth (cm) Depth (cm) 20 22 1896 ± 6 1872 ± 7 20 22have highest levels of THg and 1896 ± 6 1872 ± 7 24 26 24 26 MeHg in lake water and soils. 28 28 30 30 0 100 200 300 400 500 600 0 20 40 60 80 THg (ng/g) 2 THg (µg/m )
  • overall conclusions3. precipitation chemistry shows a significant response to emission reductions of sulphur dioxide (and tentative for nitrogen oxides)4. in concert, lake chemistry has responded to reduced anthropogenic sulphur deposition, but pH has not changed owing to increases in dissolved organic carbon5. trace metal concentrations were low, dominated by iron, aluminium and manganese; however, dissolved zinc, cadmium, inorganic labile aluminum and manganese may potentially reach levels harmful to aquatic organisms6. lakes were supersaturated with GHGs; however, effluxes contributed little to national emissions. Methane and nitrous oxide are strongly related to landscape characteristics7. Sea-salt events can have significant and widespread impacts on lake chemistry (albeit temporary)8. levels of POPs and Hg were low, consistent with background regions and strongly associated with organic carbonclimate: potential future changes to biogeochemical cycling of carbon (soil organic matter / dissolved organic carbon) and climate variability (storminess) will influence acid status, trace metals and mercury, and POPs in semi-natural ecosystems…