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Effects of application rate on avian risk from granular pesticides
Author(s) -
Stafford Tamara R.,
Best Louis B.
Publication year - 1998
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.5620170325
Subject(s) - pesticide , granule (geology) , toxicology , linear correlation , biology , ecotoxicology , zoology , environmental science , chemistry , environmental chemistry , ecology , mathematics , paleontology , statistics
Fensulfothion was formulated on silica granules to evaluate the relationship between avian risk of adverse effects from granular pesticides and granule availability. Captive house sparrows ( Passer domesticus ) were offered the granular pesticide in bands on soil surfaces at application rates of 50, 100, 200, 400, 800, 1,200, 1,600, or 2,000 LD50/ft 2 . Individual pesticide granules were formulated with ½ the LD50 for house sparrows (0.3 mg/kg). Bird behavior, survival, and brain cholinesterase activity were used to assess pesticide exposure. A significant negative correlation between brain ChE activity and the natural logarithm of application rate indicated that the relationship between avian risk and granule availability was asymptotic rather than linear. Thus, the assumption, implicit in the LD50/ft 2 risk index, that the potential exposure of birds to granular pesticides increases as granule availability increases may result in overestimates of risk to birds from granular pesticides, particularly at higher granule application rates.