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CHEMICAL COMPOSITION OF SOFTWATER FLORIDA LAKES AND THEIR SENSITIVITY TO ACID PRECIPITATION 1
Author(s) -
Hendry Charles D.,
Brezonik Patrick L.
Publication year - 1984
Publication title -
jawra journal of the american water resources association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.957
H-Index - 105
eISSN - 1752-1688
pISSN - 1093-474X
DOI - 10.1111/j.1752-1688.1984.tb04644.x
Subject(s) - alkalinity , environmental science , nutrient , weathering , environmental chemistry , watershed , hydrology (agriculture) , chemistry , geology , ecology , biology , geochemistry , geotechnical engineering , organic chemistry , machine learning , computer science
Based on alkalinity data for 596 lakes, 31 percent of Florida's 7300 lakes have < 100 μeq/l alkalinity and are sensitive to acid depostion. More than two‐thirds of the lakes in 12 northern Florida counties fit this criterion. Increasing aluminum and decreasing nutrient and chlorophyll a concentrations were observed with decressing pH in a survery of 20 softwater lakes. Maximum measured aluminum values (100‐150 μg/L) are below levels asociated with fish toxicity. Factor analysis showed that lake chemistry was related to three principal factors, representing three major processes: watershed weathering, acidification, and nutrient inputs. An acidification index defined as the difference between excess SO 4 2‐ and excess (Ca 2+ +Mg 2+ ) accounted for 74 percent of the variance in lake pH. Comparison of historical (late 1950a) and present data for pH, alkalinity, and excess SO 4 2‐ indicated loss of alkalinity (>25 μeq/L) and increase in excess SO 4 2‐ (16‐34 μeq/L) in several softwater lakes.