Lead poisoning
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Lead Poisoning. We Regulate Lead Paint, And Outlaw Leaded Fuel But, We Hunt with Lead Ammunition and Fish with Lead Sinkers and Lures. Lead Toxicity. Known since 2 nd Century BC Damages cell membranes Disrupts enzyme production Interfere with Vitamin D and heme production

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Lead Poisoning

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Lead Poisoning

We Regulate Lead Paint,

And Outlaw Leaded Fuel

But, We Hunt with Lead Ammunition and Fish with Lead Sinkers and Lures


Lead Toxicity

  • Known since 2nd Century BC

  • Damages cell membranes

  • Disrupts enzyme production

    • Interfere with Vitamin D and heme production

  • Blocks NMDA receptors which bind glutamate in neurons

  • Effects organs

    • Kidneys, heart, gonads


Some Exposure in Hunters

  • Hunters that eat more venison have more lead in blood, but very low levels typically

CDC and North Dakota Dept of Health, 2008 Study of hunters


Some Steps Taken

  • Lead shot banded from waterfowl hunting

    • US, 1991

    • Canada, 1997

  • Lead in fishing lures/weights banned selectively

    • 13 Loon lakes in WA, May 2011

  • National ban on lead denied 2010 by EPA

    • Petition to amend Toxic Substances Control Act of 1976 by CBD, ABC, led by Michael Fry claimed

      • 20 million birds / year killed

      • 3,000 tons of lead on hunting grounds / year

      • 4,000 tons in fresh water


Loons, Lead, Stones


Loon Deaths


Swans in the Northwest

  • Since 1999, 2300 swans (mostly Trumpeter and some Tundra) died from ingesting lead shot in BC and Whatcom County, WA

www.swansociety.org


California Condorand other Scavengers

Photo by Sue Haig

(Lambertucci et al. 2011)


Lead Shot Ban Does Not Protect Bald and Golden Eagles

Kramer and Redig 1997


Eagles in Pacific Northwest Get Lead from Scavenging, (e.g. coyote)

Stauber et al. 2010


Exposure Particularly Bad in Winter, not during Autumn Hunting


In Wyoming, Ravens Exposed to Lead in Autumn

(Craighead and Bedrosian 2008)


Raven Exposure is Related to Hunting Season


California Condor: A Rare Species

Figure from Wallace et al. 2007 California Condor Master Plan

  • Captive breeding and release has brought the condor from 22 birds and extirpation from the wild to 300+ birds and 150+ wild birds in two decades

    • 4 breeding facilities

    • Releases southern and central California, Arizona, Baja in Mexico

  • Condors survive in the wild only through constant and costly human assistance and intervention


(Walters et al. 2010)


Lead is Major Problem for Condors

During Hunting Season


Chelation

Molecules with negative charge bind positively charged lead, form non-toxic chelate that is excreted

Example from Snapping Turtle

(Borkowski 1997)


Banning Lead Ammunition in the Range of the California Condor in California (2008)

Kelly et al. 2011


Less Lead in Scavengers After Ban

Not Fully Protecting Condors:

2010 first chick born in Pinnacles in 100 years has to be chelated (Audubon California)


In Arizona, when Condors scavenge on North Kaibab, they encounter and ingest lots of lead

3 Birds Died in 2008

Green et al. 2008


Condors Go North During Hunting Season


Movements into high lead, north Kaibab, is expected to kill Condors


HUMANSHunting Good, Lead Bad

Photo by Anna Fuentes

Conclusion: condors suffer lead poisoning from ingestion of spent ammunition sufficiently frequently to raise mortality rates well above those required for sustainability

Conclusion: Hunters are the dominant predators within condor’s range and are important source of food for condors

Recommendation: Eliminating lead threat should not be accomplished by reduction in hunting, but by replacement of lead ammunition with non-lead alternatives. Hunters should be made aware of their importance to condors

(Walters et al. 2010)


Lead Is Not the Only Problem

  • Recommendation: Continue to clean up trash, conduct experiments with aversive training

  • Conclusions: Successful nesting in southern California is contingent upon intensive nest monitoring because of the microtrash problem

  • Most promising approaches to problem are cleaning up trash, returning offending adults to captivity for aversive training, promoting more natural foraging patterns

    • Latter may not reduce feeding of microtrash by breeders with tradition of such behavior

Photo courtesy of USFWS


References

  • Pokras, M., Kneeland, M., Ludii, A., Golden, E, Major, A., Miconi, R., and R. H. Poppenga. 2009. Lead objects ingested by common loons in New England. Northeastern Naturalist 16:177-182.

  • Green, R. E., Hunt, W. G., Parish, C. N., and I. Newton. 2008. Effetiveness of action to reduce exposure of free-ranging California Condors in Arizona and Utah to lead from spent ammunition. PLOS One 3:e4022.

  • Craighead, D. and B. Bedrosian. 2008. Blood lead levels of common ravens with access to big-game offal. J. Wildlife Management 72:240-245.

  • Kramer, J. L. and P. T. Redig. 1997. Sixteen years of lead poisoning in eagles, 1980-95: an epizootiologic view. J. Raptor Research 31:327-332.

  • Borkowski, R. 1997. Lead poisoning and intestinal perforations in a snapping turtle due to fishing gear ingestion. J. Zoo and Wildlife Medicine 28:109-113.

  • Lambertucci, S. A., Donazar, J. A., Huertas, A. D., Jimenez, B., Saez, M., Sanchez-Zapata, J. A., and Hiraldo, F. 2011. Widening the problem of lead poisoning to a South-American top scavenger: lead concentrations in feathers of wild Andean condors. Biological Conservation 144:1464-1471.

  • Kelly, T. R., Bloom, P. H., Torres, S. G., Hernandez, Y. Z., Poppenga, R. H., Boyce, W. M., and C. K. Johnson. 2011. Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures. PLOS One 6:e17656.

  • Walters, J. R., Derrickson, S. R., Fry, D. M., Haig, S. M., Marzluff, J. M., and J. M. Wunderle. 2010. Status of the California Condor and efforts to achieve its recovery. Auk 127:969-1001.

  • Stauber, E., Finch, N., Talcott, P. A., and J. M. Gay. 2010. Lead poisoning of bald and golden eagels in the US inland Pacific northwest region—an 18-year retrospective study: 1991-2008. J. Avian Medicine and Surgery 24:279-287.


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