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Studies on the effects of the insecticides phorate and malathion on soil microorganisms
Author(s) -
GonzalezLopez J.,
MartinezToledo M. V.,
Rodelas B.,
Salmeron V.
Publication year - 1993
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.5620120709
Subject(s) - malathion , denitrifying bacteria , bacteria , phorate , nitrifying bacteria , microorganism , chemistry , organophosphate , biology , microbiology and biotechnology , pesticide , environmental chemistry , toxicology , food science , agronomy , nitrification , nitrogen , denitrification , organic chemistry , genetics
A study was made of the effects of two selected organophosphorus insecticides, phorate and malathion, at concentrations of 10, 50, 100, 200, and 300 μg/g of an agricultural soil on total bacteria populations, fungi, aerobic dinitrogen‐fixing bacteria, denitrifying bacteria, nitrifying bacteria, and nitrogenase activity (acetylene‐reduction assay). The presence of phorate at a concentration of 300 μg/g or malathion at concentrations of 100 to 300 μg/g significantly decreased dinitrogen fixation. Dinitrogen‐fixing bacteria significantly decreased at concentrations of 100 to 300 μg/g of malathion. The presence of 10 to 300 μg/g of malathion significantly reduced the total number of bacteria. However, denitrifying bacteria were significantly increased at concentrations of 50 to 300 μg/g of malathion. Nitrifying bacteria and fungal populations were not affected as a consequence of the addition of the organophosphorus insecticides, showing that these microorganisms can tolerate high amounts of those substances.