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Subacute dietary toxicities of dicrotophos and dieldrin in time-replicated trials with young ring-necked pheasants and mallards

By:
Edited by:
D.W. Lamb, E.E. Kenaga
DOI: 10.1520/STP28376S

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Abstract

The dietary toxicities of (E)-phosphoric acid 3-(dimethylamino)-1-methyl-3-oxo-1-propenyl dimethyl ester (dicrotophos) and 3,4,5,6,9,9-hexachloro-1a,2,2a,3,6,6a,7,7a-octahydro-2,7:3,6-dimethanonaphth[2,3-b]oxirene (dieldrin) to 10-day-old ring-necked pheasants (Phasianus colchicus) and 5-day-old mallards (Anas platyrhynchos) were compared in five time-replicated trials. Toxicities were calculated as median lethal concentrations (LC50s) based on 5 days of ad libitum feeding on geometrically spaced concentrations of toxicant. The LC50s were more uniform for dieldrin than for dicrotophos with both species and more uniform for pheasants than for mallards with both compounds. The LC50s of dieldrin and dicrotophos averaged 59 [standard deviation (SD) = 4.4] and 45 ppm (SD = 5.0) for pheasants, and 156 (SD = 24.9) and 102 ppm (SD = 24.9) for mallards. Changes in LC50s between successive trials, although possibly haphazard, were nearly always in the same direction for both compounds with both species. Feeding rates at various concentrations of equivalent potency gave meaningful insight into the sensitivity and vulnerability of both species to these insecticides. Comparisons of 5 and 10-day-old mallards demonstrated the importance of age differences to interpretation of short-term subacute toxicity data. For example, at 5 days dicrotophos was 1.5 times more toxic than dieldrin, but at 10 days dieldrin was 2.6 times more toxic. These differences are explained.

Additional Publication Details

Publication type:
Book chapter
Publication Subtype:
Book Chapter
Title:
Subacute dietary toxicities of dicrotophos and dieldrin in time-replicated trials with young ring-necked pheasants and mallards
Series number:
757
DOI:
10.1520/STP28376S
Year Published:
1982
Language:
English
Publisher:
American Society for Testing and Materials
Publisher location:
Philadelphia, Pennsylvania
Contributing office(s):
Patuxent Wildlife Research Center
Description:
164
Larger Work Type:
Book
Larger Work Subtype:
Other Government Series
Larger Work Title:
Avian and Mammalian Wildlife Toxicology: Second Conference
First page:
105
Last page:
120
Number of Pages:
164