Geology topics

M. R. Smith

Publications and source records attributed to M. R. Smith.

10 recordsLinked to original sources

USGS2006

Lead poisoning in captive Andean condors (Vultur gryphus)

Elevated lead in the tissues of raptors, especially those that scavenge, is a common occurrence, and lead poisoning appears to be a significant problem in the ongoing recovery effort for California condors (Gymnogyps californianus). Elevated blood lead levels have been found in released birds, and a number of birds have died of lead poisoning. In earlier work, we dosed turkey vultures (Cathartes aura) with lead shot but found them to be a poor model for lead poisoning. In this study, we dosed four Andean condors (Vultur gryphus) with lead shot and found them to be quite sensitive, as two of the birds died and the other two exhibit signs of lead poisoning within 50 days. All lead-responsive parameters were affected, and regurgitation of dosed shot occurred only once. The response of the Andean condors appeared to mimic California condors, suggesting that once exposed to lead, the possibility of survival is poor. This is consistent with observations in the wild, where otherwise healthy birds exposed to metallic lead quickly succumb. At the very least, the release program has to maintain constant surveillance and an active lead monitoring program.

Journal of Wildlife Diseases↗

USGS2003

Experimental lead poisoning in Turkey Vultures, Cathartes aura

Lead-induced mortality appears to have been a major factor in the decline of the California condor ( Gymnogyps californianus ). We orally dosed turkey vultures ( Cathartes aura ) with BB-sized lead shot from January 1988 through July 1988 to determine physiologic response (delta-aminolevulinic acid dehydratase inhibition, erythrocyte protoporphyrin levels, anemia), diagnostic tissue lead concentrations (blood, liver, and kidney), and comparative sensitivity of this species. Two turkey vultures died and two became so intoxicated they were euthanized. Overall, responses of measured parameters were comparable to other species exposed to lead although there was considerable individual variation. Survival time (143–211 days), even with the large numbers of shot and constant redosing, was much longer than reported for other species of birds, suggesting considerable tolerance by turkey vultures to the deleterious effects of lead ingestion. Based on these observations, turkey vultures appear to be poor models for assessing the risk of lead poisoning to California condors or predicting their physiologic response.

Journal of Wildlife Diseases↗

USGS2001

Lead poisoning of waterfowl by contaminated sediment in the Coeur D'Alene River

The Coeur d'Alene River basin in Idaho has been contaminated by mine tailings that have impaired the health of wildlife since the early 1900s. In other parts of the world, virtually all lead poisoning of waterfowl is caused by the ingestion of manmade lead artifacts, primarily spent lead shotshell pellets or, occasionally, fishing sinkers. However, in the Coeur d'Alene River basin in Idaho, nonartifactual lead poisoning was the ultimate cause of death of most of 219 (77%) of 285 waterfowl carcasses that had been found sick or dead from 1992 through 1997. The majority of these 219 waterfowl (172 tundra swans [Cygnus columbianus], 33 Canada geese [Branta canadensis], and 14 other species) were poisoned by ingesting river sediment that was contaminated with lead. The next most common cause of death (20 instances, 7%) was lead poisoning accompanied by ingested shotshell pellets. The remaining 46 waterfowl succumbed to trauma, infectious diseases (aspergillosis, avian cholera, tuberculosis), or miscellaneous problems, or the cause of death was not determined.

Idaho↗

USGS1998

Necrotizing enteritis as a cause of mortality in Laysan albatross, Diomedea immutabilis, chicks on Midway Atoll, Hawaii

A necropsy survey of Laysan albatross, Diomedea immutabilis , chicks on Midway Atoll in June 1993, 1994, and 1995 revealed 54% (21/39), 67% (49/71), and 93% (15/16), respectively, to have enteritis as the most severe pathologic finding. The lesion was limited to the ileum, ceca, and large intestine. We were unable to attribute a single infectious etiology to this lesion. Many birds with enteritis also exhibited renal lesions similar to those encountered in chickens experimentally deprived of water. We propose that enteritis is a significant cause of mortality in Laysan albatross chicks on Midway and that it may be a sequela to dehydration. It is likely that the pathology of dehydration in Laysan albatross differs from that in chickens largely because of diet.

Midway Atoll↗

USGS1996

Lead exposure in Laysan albatross adults and chicks in Hawaii: Prevalence, risk factors, and biochemical effects

Prevalence of lead exposure and elevated tissue lead was determined in Laysan albatross ( Diomedea immutabilis ) in Hawaii. The relationship between lead exposure and proximity to buildings, between elevated blood lead and droopwing status, and elevated liver lead and presence of lead-containing paint chips in the proventriculus in albatross chicks was also examined. Finally, the effects of lead on the enzyme δ-amino-levulinic acid dehydratase (ALAD) was determined. There was a significant association between lead exposure or elevated tissue lead and proximity to buildings in albatross chicks and presence of lead paint chips in the proventriculus and elevated liver lead in carcasses. Although there was a significant association between elevated blood lead and droopwing chicks, there were notable exceptions. Prevalence of elevated tissue lead in albatross chicks was highest on Sand Island Midway and much less so on Kauai and virtually nonexistent in other areas. Prevalence of lead exposure decreased as numbers of buildings to which chicks were exposed on a given island decreased. Laysan albatross adults had minimal to no lead exposure. There was a significant negative correlation between blood lead concentration and ALAD activity in chicks. Based on ALAD activity, 0.03–0.05 μg/ml was the no effect range for blood lead in albatross chicks.

Hawai'i↗

USGS1996

The efficacy of protoporphyrin as a predictive biomarker for lead exposure in canvasback ducks: effect of sample storage time

We used 363 blood samples collected from wild canvasback dueks ( Aythya valisineria ) at Catahoula Lake, Louisiana, U.S.A. to evaluate the effect of sample storage time on the efficacy of erythrocytic protoporphyrin as an indicator of lead exposure. The protoporphyrin concentration of each sample was determined by hematofluorometry within 5 min of blood collection and after refrigeration at 4 °C for 24 and 48 h. All samples were analyzed for lead by atomic absorption spectrophotometry. Based on a blood lead concentration of ≥0.2 ppm wet weight as positive evidence for lead exposure, the protoporphyrin technique resulted in overall error rates of 29%, 20%, and 19% and false negative error rates of 47%, 29% and 25% when hematofluorometric determinations were made on blood at 5 min, 24 h, and 48 h, respectively. False positive error rates were less than 10% for all three measurement times. The accuracy of the 24-h erythrocytic protoporphyrin classification of blood samples as positive or negative for lead exposure was significantly greater than the 5-min classification, but no improvement in accuracy was gained when samples were tested at 48 h. The false negative errors were probably due, at least in part, to the lag time between lead exposure and the increase of blood protoporphyrin concentrations. False negatives resulted in an underestimation of the true number of canvasbacks exposed to lead, indicating that hematofluorometry provides a conservative estimate of lead exposure.

Louisiana↗

USGS1995

Application of brain cholinesterase reactivation to differentiate between organophosphorus and carbamate pesticide exposure in wild birds

Brain cholinesterase activity was measured to evaluate pesticide exposure in wild birds. Thermal reactivation of brain cholinesterase was used to differentiate between carbamate and organophosphorus pesticide exposure. Brain cholinesterase activity was compared with gas chromatography and mass spectrometry of stomach contents. Pesticides were identified and confirmed in 86 of 102 incidents of mortality from 29 states within the USA from 1986 through 1991. Thermal reactivation of cholinesterase activity was used to correctly predict carbamates in 22 incidents and organophosphates in 59 incidents. Agreement ( P < 0.001) between predictions based on cholinesterase activities and GC/MS results was significant.

Journal of Wildlife Diseases↗

USGS1991

Lead poisoning of a marbled godwit

A thin adult female marbled godwit ( Limosa fedoa ) found dead at Benton Lake National Wildlife Refuge, Montana, was found to have 17 ingested lead shot in its gizzard. Its liver contained 51.7 ppm lead (wet weight). Based on these necropsy findings a diagnosis of lead poisoning was made.

Montana↗

USGS1990

Lead hazards within the range of the California condor

The prevalence of lead in Golden Eagles (Aquila chrysaetos) occurring within the recent historical range of the California Condor (Gymnogyps californianus) was determined by analyzing blood samples from 162 Golden Eagles captured between June 1985 and December 1986 at three sites. We found no significant differences between sex and age classes in blood lead levels nor were there differences between residents and migrants. Significant differences were found between months with the highest blood lead levels occurring during the fall/winter period. Approximately one-third (35.8%) of the Golden Eagle population sampled had elevated blood lead levels, values similar to those reported for free-flying California Condors. Given this rate of exposure, if the proposed releases of California Condors back to the wild are to succeed, whether in their former range or elsewhere, any potential for lead poisoning must be reduced. It is essential that we identify the sources of the lead, the seasonal and geographic distribution of these sources, and develop management strategies to reduce or eliminate the hazard.

California↗

USGS1989

Lead contamination of golden eagles Aquila chrysaetos within the range of the California condor Gymnogyps californianus

Blood samples were taken from 66 golden eagles from June 1985 to January 1986 and analyzed for their lead content. Thirty-nine percent had blood lead levels greater than 0.2 ppm, indicating exposure to environmental lead. Within the exposed group, 3 had blood levels exceeding 0.6 ppm and one exceeded 1.0 ppm. These data suggest that lead, probably in the form of shot, bullets, or bullet fragments, poses a hazard to scavenging birds within the range of the California condor.

Book chapter↗