Monitoring Great Horned Owls for Pesticide Exposure in Southcentral Iowa

Buck, Jeremy A.; Brewer, Larry W.; Hooper, Michael J.; Cobb, George P.; Kendall, Ronald J.

doi:10.2307/3802231

Cited by 10 publications

(7 citation statements)

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“…The nocturnal lifestyle does not seem to be a criterion for a high level of ChE activity because Buck et al (1996) found 2.4-4.8 times lower activities in great horned owl (Bubo virginianus) than in nocturnal species in our study. However, this American species is larger and shows a greater AChE:BChE ratio (near one) than the Strigidae species of the present study.…”

Section: Discussionmentioning

confidence: 59%

Plasma B-Esterase Activities in European Raptors

Roy

Grolleau

Chamoulaud

et al. 2005

Journal of Wildlife Diseases

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B-esterases are serine hydrolases composed of cholinesterases, including acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and carboxylesterase (CbE). These esterases, found in blood plasma, are inhibited by organophosphorus (OP) and carbamate (CB) insecticides and can be used as nondestructive biomarkers of exposure to anticholinesterase insecticides. Furthermore, B-esterases are involved in detoxification of these insecticides. In order to establish the level of these enzymes and to have reference values for their normal activities, total plasma cholinesterase (ChE), AChE and BChE activities, and plasma CbE activity were determined in 729 European raptors representing 20 species, four families, and two orders. The diurnal families of the Falconiforme order were represented by Accipitridae and Falconidae and the nocturnal families of the Strigiforme order by Tytonidae and Strigidae. Intraspecies differences in cholinesterase activities according to sex and/or age were investigated in buzzards (Buteo buteo), sparrowhawks (Accipiter nisus), kestrels (Falco tinnunculus), barn owls (Tyto alba), and tawny owls (Strix aluco). Sex-related differences affecting ChE and AChE activities were observed in young kestrels (2-3-mo-old) and age-related differences in kestrels (ChE and AChE), sparrowhawks (AChE), and tawny owls (ChE, AChE, and BChE). The interspecies analysis yielded a negative correlation between ChE activity and body mass taking into account the relative contribution of AChE and BChE to ChE activity, with the exception of the honey buzzard (Pernis apivorus). The lowest ChE activities were found in the two largest species, Bonelli's eagle (Hieraaëtus fasciatus) and Egyptian vulture (Neophron percnopterus) belonging to the Accipitridae family. The highest ChE activities were found in the relatively small species belonging to the Tytonidae and Strigidae families and in honey buzzard of the Accipitridae family. Species of the Accipitridae, Tytonidae, and Strigidae families were characterized by a BChE contribution that dominated the total ChE activity, while in the species of the Falconidae family, AChE activity dominated. With the exception of the barn owl, CbE activity (eserine-insensitive ␣-naphthyl acetate esterase [␣-⌵〈⌭] activity) in all species was almost absent or very low. The values obtained in this study for ChE, AChE, and BChE activities and the AChE:BChE ratios for buzzard, kestrel, barn owl, and tawny owl provide a good estimate of the normal values in free-living individuals of these European species. They can be used as a baseline to evaluate the effect of anticholinesterase insecticides in the field.

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Section: Discussionmentioning

confidence: 59%

Plasma B-Esterase Activities in European Raptors

Roy

Grolleau

Chamoulaud

et al. 2005

Journal of Wildlife Diseases

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“…There are several possible explanations for this apparent discrepancy between measured pathways of exposure (air and diet) and the biomarker (TCPy) of exposure. One possibility is that dermal and/or soil ingestion plays a far greater role in exposures than was predicted by the modeling exercise of Buck et al (1996). However, this seems highly unlikely, since the exposure assumptions were somewhat conservative, and it is unlikely that the estimates would be off by several orders of magnitude (which would be required for these pathways to account for >90% of the "excess" TCPy found in urine).…”

Section: Vc5 Limitations Of Use Of Tcpy As a Biomarker For Chlor-mentioning

confidence: 99%

“…When adjusted for age and body weight, partial aggregate daily intake rates were 0.012 µg/kg-day, of which approximately 94% was derived from diet and 6% was from inhalation exposures. Earlier modeling exercises that incorporated surface loading and hand wash data along with numerous assumptions about exposures via the dermal and inhalation pathways (Buck et al, 1996) yielded an estimate of a median exposure of 0.09 µg/kg-day (∼8 times greater than the measured exposures of Clayton et al, 2003), from which 81% was estimated to be due to inhalation exposure, and 19% from diet (Buck et al, 1996). The modeling exercise of Buck et al suggested that soil ingestion and the dermal pathways were relatively insignificant pathways for exposure (each contributing less than 0.1% of total estimated exposure).…”

Section: Vc5 Limitations Of Use Of Tcpy As a Biomarker For Chlor-mentioning

confidence: 99%

Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment

Eaton¹,

Daroff²,

Autrup³

et al. 2008

Critical Reviews in Toxicology

553

392

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“…Though one of the birds, an American robin, contained no chlorpyrifos, there were no further analyses for other organophosphorus insecticides. As documented in studies with great-horned owls in similar Iowa habitat (Buck et al 1996) and raptor species in California's Central Valley (Gallagher et al 1994), chlorpyrifos treatments often coincide with applications of other anti-AChE pesticides in adjacent farmland where wildlife can travel, dividing their time over multiple exposure scenarios. Comparisons of chlorpyrifos-treated fields are made with nontreated reference sites and the number of mortalities on reference sites establishes the anticipated background casualty frequency for the treatment sites.…”

Section: Terrestrial Risk Assessment For Chlorpyrifos In Corn Agroecomentioning

confidence: 95%

“…A study using radio-tagged great horned owls, which consume small mammals that could contain insecticide residues, demonstrated anti-AChE exposure, but no effects, following insecticidal treatment of corn fields (Buck et al 1996). Seven owls were monitored in 1988 and 15 in 1989, both before and after treatment of corn fields in south central Iowa with terbufos granules (as Counter ® 15G Insecticide) or chlorpyrifos granules (as Lorsban ® 15G).…”

Section: Terrestrial Risk Assessment For Chlorpyrifos In Corn Agroecomentioning

confidence: 99%

Chlorpyrifos: Ecotoxicological Risk Assessment for Birds and Mammals in Corn Agroecosystems

Solomon

Giesy

Kendall

et al. 2001

Human and Ecological Risk Assessment: An International Journal

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A tiered risk assessment was conducted for the use of granular and liquid formulations of chlorpyrifos in corn agroecosystems in the U.S. The initial screening Tier I assessment suggested that under high-exposure scenarios the granular and some spray formulations present potential hazards to birds. Higher tiered probabilistic risk assessments were conducted separately for the granular and liquid formulations. The probabilistic assessment indicated that risk to birds from exposure to granular formulation is small and that this route of exposure would not be a significant source of mortality. Similarly, the assessment of potential exposure of birds to food items contaminated with chlorpyrifos showed that the risk from exposure via food was small, even if it was assumed that birds feed only on the treated fields. Although they have potentially greater sensitivity to chlorpyrifos, effects in nestling birds consuming food items from fields treated with granular chlorpyrifos were negligible. However, risks to young birds may be greater where the major source of food is from fields treated with liquid formulations of chlorpyrifos. A review of field studies showed that wildlife mortality incidents associated with use of either granular or liquid formulations of chlorpyrifos are not widely apparent in agroecosystems. Based on the multiple lines of evidence, we conclude that the presumption that chlorpyrifos use in corn agroecosystems will result in extensive Solomon et al. mortality of terrestrial wildlife, particularly birds and mammals, is not supported by the scientific evidence.

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Monitoring Great Horned Owls for Pesticide Exposure in Southcentral Iowa

Cited by 10 publications

References 0 publications

Plasma B-Esterase Activities in European Raptors

Plasma B-Esterase Activities in European Raptors

Review of the Toxicology of Chlorpyrifos With an Emphasis on Human Exposure and Neurodevelopment

Chlorpyrifos: Ecotoxicological Risk Assessment for Birds and Mammals in Corn Agroecosystems

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