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In Situ Manipulation of Water Chemistry Using Crushed Limestone and Observed Effects on Fish
Author(s) -
Gunn J. M.,
Keller W.
Publication year - 1984
Publication title -
fisheries
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 79
eISSN - 1548-8446
pISSN - 0363-2415
DOI - 10.1577/1548-8446(1984)009<0019:ismowc>2.0.co;2
Subject(s) - alkalinity , substrate (aquarium) , acid neutralizing capacity , environmental chemistry , chemistry , soft water , neutralization , environmental science , mineralogy , ecology , soil science , biology , acid deposition , soil water , organic chemistry , antibody , immunology
In acidic lakes near Sudbury, Ontario, limestone additions were used to create favorable microenvironments for early life stages of salmonids. Under acutely toxic conditions (eg. pH 4.6, total Al > 400 μg/L), substrate baskets, containing as little as 15 kg of crushed limestone, neutralized interstitial water, permitting high survival of incubating eggs and fry. Such small‐scale, site‐specific neutralization reduced mortality and/or increased growth of fry under a variety of ambient chemical conditions. Flow‐through filter tanks and stream bed additions were used to neutralize flowing water. Effects on fish were similar to those with the substrate baskets. Both treatment procedures produced significant changes in water chemistry, including elevations in pH, alkalinity, conductivity, and Ca. A 345 tonne stream bed addition was largely ineffective at controlling springtime pH depressions but produced substantial annual increases (70–145%; 6000–9000 kg as CaCO 3 ) in the downstream discharge of alkalinity. Neutralization was primarily used to provide on‐site controls to assess acidification effects, but our findings also suggest that small‐scale treatments such as limestone covered spawning sites could be of remedial value in acidic systems. The detrimental effects of precipitating Al during neutralization deserve further attention.