Liming of a final cut acid lake


Action: Add lime or similar chemicals

A before-and-after study in 1982–1985 in Missouri, USA (Knauer 1986) reported that after adding lime to an acidic lake (along with other interventions in the watershed to reduce acidic runoff), phytoplankton became more abundant. Two years before intervention, the acidified lake (pH 2.8) contained <0.005 mg chl a/m3. Around one year after intervention began, the lake (pH now 6.8) contained 3.3 mg chl a/m3. Methods: Between June and December 1984, a total of 109 tonnes of hydrated lime were added to Cross-Mitchell Lake: a 4-ha, 315,000 m3 lake in an abandoned mining area. Some lime was sprayed into the lake, and some was mixed in with boat propellers. Additional interventions in the watershed reduced runoff of acidic water into the lake (details not clearly reported). The study does not distinguish between the effects of these interventions and liming. Water samples were taken before (September 1982) and after (August 1985) intervention to quantify the chlorophyll a concentration and pH.

Output references
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