Impacts of Lead Ammunition on Wildlife, Humans, and the Environment
Molly Tranel
MNDNR
MACP Contaminants and Natural Resource Management Workshop
History of Lead Ammunition in USA
1870s: Large waterfowl die-offs; Discovered
pheasant mortality from lead shot ingestion
1940’s: Reports >16,000 ducks die
1980’s: Bald eagles in MN poisoned from
lead shot , MN bans use of lead shot for
waterfowl hunting
1991: Federal ban on lead shot for
waterfowl hunting
1999: Ban on lead shot for any hunting on
federal Waterfowl Production Areas
Literature Review Findings
Considerable research exists on the
impacts of lead ammunition- >500 scientific articles
Lead ammunition negatively affects wildlife- >130 species reported worldwide
Lead ammunition can impact human health- Elevated lead blood levels from game consumption
Nontoxic alternatives are now available- Gun Digest Book of Green Shooting
Number of Species Affected by Lead
Ammunition
Passerines
8
Reptiles
2
Mammals
6
Upland
Gamebirds
16
Other Waterbirds
18
Raptors &
Scavengers
31
Waterfowl
51
132 Species
(Tranel & Kimmel, 2009)
Ways Wildlife Ingest Lead
1. Mistake Lead Shot
for Grit.
2. Incidentally Ingest
Lead While Feeding
3. Secondarily Ingest
Lead Through Prey
How are birds affected by lead?
Decreased survival
-Poor body condition
-Weakened muscles
-Reduced weight & starvation
Reduced immune systems
More vulnerable to disease
& parasites
Impaired reproduction
Behavioral changes
How many birds are affected?
Depends on how heavily
hunted an area is.
Numbers may be
underestimated because
birds expel shot
Sick or dead birds are hard to find
They hide when dying
Predators eat them
Species % >10 μg/g bone lead Year Sampled
Hungarian
Partridge 11 (19/169) 2001
Sharp-tailed
Grouse 5 (4/79) 2001
Mallard *8 (17/214) 1989/90
*This level was high enough to prompt a ban on
lead shot for waterfowl hunting.
Percent of upland game birds & ducks
from Canada, with elevated
(>10 μg/g) bone lead.
Percent of upland game birds that
ingested shot.
Species % ingesting shot Year Sampled
Northern Bobwhite 1.3 2002
Ruffed Grouse 1.2 2005
Pheasant 3 (G. Britain) 2005
34 (Canada) 2007
Chukar 8 2007
Doves Ingesting Shot
Acute toxicosis hypothesis: Evidence
suggests doves purposefully ingest
Pb pellets, and succumb to acute
effects of Pb on the circulatory/
central nervous systems.
Conducted two experiments to test hypothesis:
(1) force-fed doves Pb pellets, and monitored survival
and physiological characteristics, and
(2) provided Pb and steel pellets ad lib. and monitored
relationship between pellet availability and selection.
Doves Ingesting Shot Results show doves
purposefully ingest Pb pellets,
and succumb to the acute
effects of Pb.
Survival rates (0.57–0.08) with
≤2–19 ingested Pb pellets show
that even at low doses birds are
dying rapidly.
Although some survived the
post-treatment period, those
individuals would have likely
died in the wild due to
secondary causes of mortality
(Schulz et al. 2006a). 11
treatment
control
Background
Example: J.A. Reed Area September 2005
1,425 hunters reported ~40,000 rounds fired
185 acres of managed sunflower/wheat
2,500 lbs. of lead 13.5 lbs. of lead / acre
75,000 pellets / acre ~2 Pb pellets per ft2
Tennessee:
1.2% hunter-killed doves ingested Pb pellets; some
w/ 24 Pb pellets.
New Mexico:
3.5% hunter-killed doves ingested Pb pellets
USGS 8 state survey
2.5% hunter-killed doves ingested Pb pellets
Pellets per dove ranged 1–43; 3.8% of doves
ingesting ≥15 pellets
Doves Ingesting Shot
Pellet ingestion rate (5.1%)
was within the range
previously reported from
hunter-killed doves (2.0% –
6.5%)
Data also show that when
pellets are available, some
proportion of mourning
doves will ingest pellets,
and those doves ingesting
pellets will eventually die.
Discussion THE FOLLOWING EXAMPLE IS ONLY
FOR DEMONSTRATION PURPOSES TO SHOW THE POTENTIAL MAGNITUDE OF THE PROBLEM.
Given a 350–475 million fall population (Dunks et al. 1982, Otis et al. 2008), we can “roughly” estimate that 18–24 milliondoves may be dying annually in North America from Pb toxicosis.
(ingestion rate x population = dead doves)
(0.05 x 350 million = 17.50 million)
(0.05 x 475 million = 23.75 million)
(Note that the 2006 HIP dove harvest was estimated to be 18.3 – 20.2 million).
Other Pb Research:
Crippling Rates & Nontoxic Shot
Debate will likely include speculation about nontoxic shot resulting in increased crippling loss of mourning doves.
Evaluated waterfowl crippling rates prior to, during, and after nontoxic regulations implementation, and made inferences about mourning dove crippling rates if further nontoxic shot regulations are enacted.
These data suggest long-term mourning dove crippling rates might not increase as evidenced from historical waterfowl data.
16
Pre-nontoxic shot Phase-in Nontoxic shot
Period
0.130
0.140
0.150
0.160
0.170
0.180
0.190
0.200
95
% C
I of
Mo
vin
g A
vera
ge C
rip
pli
ng
Rate
s
Ducks
Pre-nontoxic shot Phase-in Nontoxic shot
Period
0.110
0.120
0.130
0.140
0.150
95%
CI
Movin
g A
vera
ge C
rippli
ng R
ate
s
Geese
Human Health Impacts
Consumption of game birds linked to
elevated blood lead levels in adults, children,
and newborns Greenland1, Russia2, Canada3
Lead fragments from bullets found in
venison. MN4
Food sources can become contaminated in
heavily hunted areas.
1Johansen et al. 2004, 2006; 2 Odland et al. 1999; 3 Dewaily
et al. 2000, 2001; 4Grund et al. 2009
Impacts of Lead on Humans
Children absorb lead at a faster
rate and are more sensitive to it.
Pregnant women can transfer
lead to the fetus.
Low level lead exposure linked to:
- Lower IQ – cognitive function
- Behavioral problems – aggression,
depression, ADD, and ADHD
- High blood pressure, memory loss
later in life
Canfield R, et al. 2004. NEJM 348: 1517-1526.
IQ and Blood Lead
2009 US CDC
level for
intervention in
children
Slide courtesy of
Michael Kosnett,
CDC Childhood
Lead Prevention
Committee
(Image courtesy of the Minnesota Dept of Natural Resources)
Radiograph of
the chest of a
deer-sized
animal
illustrating
lead
fragmentation
of a ballistic
tip rifle bullet.
The North Dakota CDC study[Iqbal, 2008]
Participants consumed game in the form of
venison, other game, and birds.
Consumption of wild game was significantly
associated with lead blood levels.
Participants who consumed wild game had
higher lead levels than those who did not
consume wild game.
All participants were below the CDC level of
concern (10mg/dL).
Reducing your risk of lead exposure
If you hunt with lead, there’s some lead
in the meat
The only way to completely eliminate lead is
to use nontoxic shot / bullets
Avoid using rapid expansion bullets
Choose wise shots
Cut liberally around wound channel
Do not consume internal organs
Conclusion: Certainties
Pb is a well established ecological
poison, and there no “safe” level
of ingestion.
Hunters deposit large amounts of
Pb shot on popular dove feeding
sites, a certain proportion of
doves feed on these sites and
ingest pellets, and die.
Any animal shot with Pb-based
ammunition likely will contain
some amount of Pb residue in the
meat.
Conclusion: Uncertainties
Relationship between pellet ingestion
and pellet availability on areas with
different levels of hunter and bird use.
Proportion of the population impacted
by Pb poisoning, and whether that
proportion is significant.
Population impacts to other species of
surface-feeding seed-eating songbirds
and upland game-birds.
Impacts of nontoxic ammunition
regulations on hunter recruitment and
retention, and impacts on ammunition
industry
“Hunters have a reputation as being
good conservationists, if we don‟t do
something about the lead issue we
could lose that reputation.”
- Board Member of the New Ulm Chapter
Isaac Walton League
Hunter Education the next step?
Several states (CA, AZ, IA,
WY) are including lead ammo
in hunter education and safety
courses.
Providing information on types,
where to buy non-toxic ammo,
and even free ammo.
Getting the word
out when new
non-toxic ammo
or tackle is
available.
AZ Game and Fish Hunter Survey
Only 23% of the hunters were aware
that lead poisoning was a problem
faced by condors
83-97% were willing to take some
action to help condors if credible lead
exposure data were made available.
Hunters expressed a greater
willingness to help if asked by a
credible source like sportsmen’s
groups & the state wildlife agency.
(D. J. Case and Associates 2005)
85% of hunters
in condor range
voluntarily use
non-lead
Hunter Survey
81% surveyed used the free non-
lead ammunition during their hunts.
97% of respondents who tested the
non-lead ammunition (n = 796)
stated its accuracy was average to
excellent.
56% indicated they would purchase
it on their own in the future.
72% said they would recommend
non- lead ammunition to other
hunters.
The „Green Ammo‟ future
“Green shooting is growing at a rate of about
20% a year…”
“Government agencies and even the Dept. of
Defense are switching to lead-free shooting…It
just makes range operation so much easier and
training so much more practical and effective.”
“…concerns about the environment, and the
need for effective training scenarios are
going to drive the green and frangible
bullet movement much larger.”
(excerpts from Sapp 2010)
Special Thanks
Jon Schulz for providing slides and information.
Dick Kimmel, MN DNR
Questions?
Cartoon by Nick D Kim, nearingzero.net