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Year and age effects on residues of dieldrin and heptachlor in dead gray bats, Franklin County, Missouri--1976, 1977, and 1978

Environmental Toxicology and Chemistry

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Abstract

Dead gray bats (Myotis grisescens) containing lethal concentrations of dieldrin were found beneath a maternity roost in Bat Cave Nos. 2 and 3, Franklin County, Missouri, in 1976, 1977 and 1978. Whereas residues of dieldrin, DDE [I, I --dichloro-2,2-bis(p-chlorophenyl)ethylene] and PCB polychlorinated biphenyls in bats appeared not to change significantly over the 3 years, residues of heptachlor-related chemicals increased in 1977 to potentially dangerous concentrations and remained elevated in 1978. Lethal brain levels of dieldrin in adult bats (geometric mean = 12.1 ?g/g), compared with juvenile bats (geometric mean = 6.5 ?g/g), indicated that juveniles are nearly twice as sensitive. The estimated population of gray bats (as maximum number of nonflying young) at Bat Cave Nos. 2 and 3 in 1976 and 1978 was 1,800 bats, but in 1979 no bats were present. Dieldrin, perhaps in conjunction with heptachlor, may have caused the decline and disappearance of this colony. However, dieldrin was banned in 1974 and Missouri's authorization to use heptachlor on corn expired in 1981. Furthermore, three organophosphate insecticides (chlorpyrifos, dyfonate and mocap) are to be substituted. We hope that the gray bats remaining in this area of Missouri survive the residues of dieldrin and heptachlor still in their food chains and prove to be unaffected by the new organophosphates

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Year and age effects on residues of dieldrin and heptachlor in dead gray bats, Franklin County, Missouri--1976, 1977, and 1978
Series title:
Environmental Toxicology and Chemistry
Volume
2
Issue:
4
Year Published:
1983
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
387-393
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Environmental Toxicology and Chemistry
First page:
387
Last page:
393