title: Decreased acid deposition and the chemical recovery of Killarney, Ontario, lakes.
abstract: Lakes in Killarney Park near Sudbury, Ontario, Canada, have shown dramatic water quality changes including general increases in pH and alkalinity, and decreases in SO4(2-), base cations and metals. While some lakes have recovered to pH > 6.0, many are still highly acidic despite decades of improvement. Very high historical S deposition related to emissions from the Sudbury metal smelters dominated the acidification process in this region. However, since the implementation of substantial S emission controls (90%) at the smelters, the Sudbury emissions are no longer the major source of S deposition in the Sudbury area. Wet deposition of SO4(2-) and SO4(2-) concentrations in lakewaters at Killarney now approach values in the Dorset, Ontario, area, about 200 km from Sudbury. This suggests that the S deposition to the Killarney area is now primarily from long-range transport, not from local sources. Studies of Killarney lakes are revealing the complex nature of the chemical recovery process. As lake acidity decreases, other changes including decreased Ca2+ concentrations, increased transparency, and altered thermal regimes may potentially affect some of these ecosystems. It is clear that continuing assessments of the recovery of Killarney lakes, within a multiple-stressor framework, are needed.
authors.affiliation: Ontario Ministry of the Environment, Department of Biology, Laurentian University, Sudbury, Canada. bkeller@vianet.on.ca
authors.forename: Wendel
authors.initials: W
authors.lastname: Keller
authors.forename: Jocelyne H
authors.initials: JH
authors.lastname: Heneberry
authors.forename: Sushil S
authors.initials: SS
authors.lastname: Dixit
mesh_terms: D015258:Acid Rain; D000397:Air Pollution / Q000517:prevention & control*; D002118:Calcium / Q000032:analysis; D004784:Environmental Monitoring; D006863:Hydrogen-Ion Concentration; D007477:Ions; D009864:Ontario; D013455:Sulfur / Q000032:analysis* / Q000737:chemistry; D014867:Water / Q000737:chemistry; D014881:Water Supply
chemical_list: D015258:Acid Rain; D007477:Ions; D014867:Water; D013455:Sulfur; D002118:Calcium