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Microbial Versus Chemical Degradation of Atrazine in Soils
Author(s) -
Skipper H. D.,
Gilmour C. M.,
Furtick W. R.
Publication year - 1967
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1967.03615995003100050014x
Subject(s) - atrazine , incubation , soil water , microbial biodegradation , chemistry , environmental chemistry , population , biodegradation , bioassay , pesticide , bacteria , biology , agronomy , microorganism , ecology , biochemistry , genetics , demography , organic chemistry , sociology
Significance of microbial vs. chemical degradation of atrazine was determined using 14 C‐labeled atrazine and greenhouse incubation studies. Bacterial isolates evolved 0.4–0.7% of the input ethylamino chain‐labeled atrazine as 14 CO 2 in 2 weeks, whereas, Aspergillus fumigatus respired 4.0% in sterile soil. No detectable 14 CO 2 was evolved from ring‐labeled atrazine by any of the cultures tested. In nonsterile soils degradation of the hydroxyatrazine ring was 3‐fold greater than for chloroatrazine in 2 weeks (1.5% vs. 0.5%). The native soil population respired 2.2–2.6% of chain‐labeled atrazine in 4 weeks. Hydroxyatrazine accounted for approximately 20% of the extracted 14 C‐activity after 2–4 weeks incubation of 14 C‐atrazine in nonsterile or sterile soils. Greenhouse bioassay data showed a 73% loss of atrazine toxicity after 3–4 weeks incubation at 30C in nonsterile soil. These results support chemical hydrolysis of chloroatrazine to hydroxyatrazine as the major pathway of degradation in soils with microbial attack being of minor importance.