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Lead poisoning from ingestion of fishing gear: A review

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Abstract and Figures

Many publications have investigated the ingestion and toxicity of metallic lead from hunting and the shooting sports. However, there is limited literature on toxicity associated with the ingestion of lead fishing weights, despite our knowledge of damage caused to many species from entanglement in lines, nets, and fish-hooks. This paper surveys current knowledge of species poisoned by ingestion of lead fishing gear and the types of gear that have been implicated. We review the impacts of lead fishing tackle on wildlife species and human health and describe the efficacy of efforts to reduce the use of lead tackle through voluntary, educational, and regulatory approaches to encourage adoption of non-toxic fishing gear. The authors emphasize the need for further research and policy initiatives to deal with this serious problem.
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Lead poisoning from ingestion of fishing gear: A review
Tiffany Grade, Pamela Campbell, Thomas Cooley, Michelle Kneeland,
Elaine Leslie, Brooke MacDonald, Julie Melotti, Joseph Okoniewski,
Elizabeth Jane Parmley, Cyndi Perry, Harry Vogel, Mark Pokras
Received: 3 December 2018 / Revised: 26 February 2019 / Accepted: 1 April 2019
Abstract Many publications have investigated the
ingestion and toxicity of metallic lead from hunting and
the shooting sports. However, there is limited literature on
toxicity associated with the ingestion of lead fishing
weights, despite our knowledge of damage caused to
many species from entanglement in lines, nets, and fish-
hooks. This paper surveys current knowledge of species
poisoned by ingestion of lead fishing gear and the types
of gear that have been implicated. We review the impacts
of lead fishing tackle on wildlife species and human
health and describe the efficacy of efforts to reduce the
use of lead tackle through voluntary, educational, and
regulatory approaches to encourage adoption of non-toxic
fishing gear. The authors emphasize the need for further
research and policy initiatives to deal with this serious
Keywords Jig Loon Lure Sinker Swan Waterbird
Lead has been used for fishing weights since ancient times
(Galili et al. 2013; Tyrrell 2015). Such weights are used to
sink nets and fishing lines below the water’s surface and
also to add mass to lines and nets to facilitate casting.
Nomenclature for the weights used in fishing tackle varies
regionally but includes such objects as split shot, sinkers,
jigs, lures, worm weights and trolling weights (Schroeder
Toxicity from ingested lead fishing tackle has been doc-
umented in many species including humans (Table 1; Blus
1994; Perry 1994; Scheuhammer and Norris 1995; Anderson
et al. 2000; Scheuhammer et al. 2003; Franson et al. 2003). It
is well documented as a leading cause of death for common
loons (great northern divers, Gavia immer) (Pokras and
Chafel 1992; Stone and Okoniewski 2001; Sidor et al. 2003;
Strom et al. 2009; Grade et al. 2018) and swans (Cygnus spp)
(Sears and Hunt 1991; Kirby et al. 1994; Newth et al. 2016).
The purpose of this paper is to review current knowl-
edge of the impact of lead fishing tackle on wildlife species
and human health and to investigate the efficacy of efforts
to reduce the use of lead tackle through voluntary and
regulatory approaches. After reviewing estimates of rates
of loss of lead tackle into the environment, we examine the
impact of lead tackle on wildlife, using swan species and
common loons as case studies. We then review the sub-
lethal impacts of lead tackle on wildlife and human health
before examining voluntary and regulatory efforts to limit
the use of lead tackle. We conclude by calling for increased
and more coordinated documentation of wildlife ingestion
of lead tackle and suggest approaches to reduce the input of
lead tackle into the environment.
In conducting our review of current literature on lead
poisoning from fishing gear, we searched initially for the
following keywords in Web of Science, Google Scholar,
PubMed, and SORA: ‘avian’ or ‘lead poisoning’, ‘lead
toxicosis’ and ‘fishing’, ‘fishing gear’, ‘sinker’. This initial
search allowed us to determine the most commonly
reported endpoints. We then conducted subsequent sear-
ches with ‘avian’ or ‘bird’ and ‘sinker’ or ‘weight’ and
each endpoint of interest. References from the publications
collected from these searches were also collected until we
were satisfied that all relevant references were included.
We included both field and experimental studies that
Electronic supplementary material The online version of this
article ( contains sup-
plementary material, which is available to authorized users.
Royal Swedish Academy of Sciences 2019 123
examined correlations between tissue or blood concentra-
tions of lead and endpoints of interest. Although we did not
set a limitation to how far back we went in time, we only
collected articles that were available electronically via the
portals listed above.
By their very nature, lead fishing weights are designed to
be used in aquatic environments where they can be irre-
trievably lost. This often occurs when the line to which
they are attached becomes caught or entangled and then
breaks or is cut. But it can also occur when larger fish break
the line, or when smaller lead tackle (e.g., split shot) are
inadvertently dropped and not retrieved.
Studies have documented that significant amounts of
lead can be deposited into lakes and rivers by the loss of
lead fishing tackle. Although not differentiating among the
various types of lead fishing weights, Duerr (1999) found,
‘Along heavily fished shorelines, we found an average of
0.05 sinkers/sqm. Anglers lost, on average, 0.2 sinkers
per hour spent fishing.’’ Twiss and Thomas (1998) stated,
‘An estimated average of 125 to 187 million lead sinkers
are deposited in Canadian waters annually, with about half
in Ontario.’’ A recent Canadian study (ECCC 2018) stated,
‘An average Canadian angler can lose 11 to 15 jigs and
sinkers per year while fishing due to snags and other rea-
sons. This adds up to about 460 metric tons of lead jigs and
sinkers lost every year into Canada’s lakes and waterways.
This represents the most significant source of lead releases
into Canadian waters.’’ Radomski et al. (2006) estimated
that during a single walleye (Sander vitreus) fishing season,
one metric ton of lead fishing weights entered five Min-
nesota waterbodies. Scheuhammer et al. (2003) calculated
that approximately 4384 tons of lead fishing tackle were
lost each year in U.S. waterways, and Jacks et al. (2001)
reported that, in Sweden, 100–200 metric tons of lead
sinkers are estimated to be lost annually. Similarly, in
Great Britain, Birkhead (1982) reported an estimated
annual loss of 250 metric tons of fishing sinkers each year.
At local sites in Great Britain, studies reported [15 000
lead split shots lost per hectare annually, with anglers
losing 2–7 split shot sinkers per visit (Bell et al. 1985;
Forbes 1986; Cryer et al. 1987). Lloret et al. (2014) doc-
ument that lead fishing weights accounted for 36% of lost
fishing gear recovered from the seabed in a coastal
Mediterranean area.
To date, more than 30 species of birds have been docu-
mented to have ingested lead fishing tackle, along with 3
mammal and 2 reptile species (Table 1). It is estimated that
75 North American bird species may be at risk of lead
Table 1 Animals documented to ingest lead fishing gear (modified
from Perry 1994)
Avian species
Trumpeter swan, Cygnus buccinator
Mute swan, Cygnus olor
Tundra (whistling) swan, Cygnus columbianus
Whooper swan, Cygnus cygnus
Canada goose, Branta canadensis
Wood duck, Aix sponsa (Scheuhammer et al. 2003)
Mallard, Anas platyrhynchos
American black duck, Anas rubripes
Redhead, Aythya americana
Greater scaup, Aythya marila
White-winged scoter, Melanitta deglandi
Long-tailed duck, Clangula hyemalis (Schummer et al. 2011)
Red-breasted merganser, Mergus serrator
Common merganser, Mergus merganser
Great blue heron, Ardea herodias
Great egret, Ardea alba
Snowy egret, Egretta thula
Green heron, Butorides virescens (Scheuhammer et al. 2003)
Black-crowned night-heron, Nycticorax nycticorax (Franson
et al. 2003)
White ibis, Eudocimus albus
Double-crested cormorant, Phalacrocorax auritus
Sandhill crane, Antigone canadensis (Windingstad et al. 1984)
Brown pelican, Pelecanus occidentalis
American white pelican, Pelecanus erythrorhynchos
Northern gannet, Morus bassanus (Pokras, unpubl.)
Laughing gull, Leucophaeus atricilla
Herring gull, Larus argentatus
Royal tern, Thalasseus maximus (Scheuhammer et al. 2003)
Common loon, Gavia immer
Red-throated loon, Gavia stellata (Twiss 1997)
Little penguin, Eudyptula minor (Harrigan 2016)
Bald eagle, Haliaeetus leucocephalus
Great horned owl, Bubo virginianus (MI DNR, unpubl.)
Non-avian species
Humans, Homo sapiens (Mowad et al. 1998, St. Clair and
Benjamin 2008)
Domestic dog, Canis lupus familiaris
(Bengfort and Carithers 1976)
Harbor seal, Phoca vitulina (Zabka et al. 2006)
Snapping turtle, Chelydra serpentina (Borkowski 1997)
Painted turtle, Chrysemys picta (Scheuhammer et al. 2003)
123 Royal Swedish Academy of Sciences 2019
tackle ingestion due to their foraging behavior (US EPA
1994). However, documentation of the extent of lead tackle
ingestion both across and within species has been generally
poor, due to the difficulty of detecting lead-poisoned ani-
mals as well as limitations of funding and research prior-
ities. Regarding the former, Pain (1991) referred to the
‘invisibility’’ of waterfowl that have died from lead poi-
soning, because ailing birds tend to hide in thick vegetation
and carcasses are quickly scavenged. Large numbers of
birds generally do not die in a single location from lead,
also making carcasses less conspicuous (Franson and
Cliplef 1992; Newth et al. 2013). As a result, lead poi-
soning is likely underrepresented as a cause of mortality
among wildlife (Franson and Cliplef 1992; Franson et al.
2003; Strom et al. 2009; Newth et al. 2013; Grade et al.
2018). Due to the difficulties of detecting lead-poisoned
wildlife, lead tackle ingestion has been best documented in
high profile, charismatic, and intensively studied large
species such as swans and common loons. Because of this,
we use these species as case studies for the impact of lead
tackle ingestion on wildlife.
Acquisition of lead tackle in swans and common
Methods of ingestion of lead fishing tackle for loons and
swans vary from acquiring tackle from current fishing
activity to ingesting lost tackle as grit. For common loons
in New Hampshire, Grade et al. (2018) found a peak of
lead tackle mortalities in July and August, coinciding with
a peak of fishing activity, and that the majority of loons
that died from lead fishing tackle ingestion also had
ingested non-lead associated tackle (i.e., hooks, fishing
line, swivels, leaders). This evidence suggests that current
fishing activity (e.g., eating a fish that has ingested a lead
jig or sinker and broken the line, or striking at tackle or a
fish being retrieved by an angler) is a primary mechanism
by which loons ingest lead fishing tackle (Grade et al.
2018). This is in contrast to speculations in previous
studies (Pokras and Chafel 1992; Scheuhammer et al.
2003; Pokras et al. 2009; Haig et al. 2014). These studies
noted that lead fishing gear ingested by common loons is
typically close in size to the pebbles which these birds
ingest to help break down food, suggesting that loons
ingest lost lead tackle from lake substrates (Franson et al.
Similar to mortality patterns in common loons, mute
swan (Cygnus olor) mortality from ingested lead tackle and
median blood lead levels in England peaked during fishing
season, prior to legislation banning lead fishing weights
(Birkhead 1982,1983; Sears 1988). Sears (1988) suggested
that, in addition to swans ingesting tackle as grit, some
swans likely ingested tackle from fishing lines, possibly
after becoming entangled in line caught in vegetation or
from eating bait attached to tackle. Fourteen percent of
dead swans in the Thames Valley had associated tackle in
their gizzards (Sears 1988). Subsequent to the ban, the
previously documented spike in lead exposure during
fishing season became less evident, suggesting that swans
may be ingesting lead weights as grit that were lost prior to
the ban rather than those recently lost or in current use
(Sears and Hunt 1991; Perrins et al. 2002; Kelly and Kelly
Lead tackle ingestion in swans
The problem of mortality in wildlife from lead fishing
tackle ingestion was first extensively documented in mute
swans in the United Kingdom (UK). Goode (1981) reported
that lead fishing tackle accounted for 50% of documented
swan mortalities throughout England in 1980–1981, and
estimated that approximately 3000–3500 swans in the UK
died annually as a result of lead poisoning. Researchers
also documented declines in local populations amid high
rates of mortality from lead tackle ingestion (Goode 1981;
Kirby et al. 1994). The majority ([70%) of documented
lead poisoned swans had ingested split shots (Birkhead
1982; Sears 1988; Sears and Hunt 1991) and *7% had
ingested larger weights (Sears and Hunt 1991). Less than
2% of cases of lead poisoning among mute swans in the
UK were attributable to ingested lead shot ammunition
(Sears and Hunt 1991). Lead tackle ingestion impacted
both adult swans and cygnets (Birkhead 1982; Sears 1988;
Kirby et al. 1994; Wood et al. 2019).
After legislation took effect in 1987 in England and
Wales to ban the sale and use of lead fishing weights,
mute swan deaths from lead poisoning declined from 34%
of documented mortalities between 1971 and 1986 to 6%
between 1987 and 2014 (Wood et al. 2019). The mute
swan population rebounded, more than doubling accord-
ing to a population index in the years following the leg-
islation, with a model including the legal status of lead
explaining 82% of the variation in population size (Wood
et al. 2019). Despite this, after an initial decline in median
blood lead levels among non-breeding flocks (Sears and
Hunt 1991), subsequent sampling of swans brought to
rescue centers in England (1994–2002) showed [60% of
birds still had lead levels that exceeded levels considered
elevated for lead ([1.21 lmol/l; Perrins et al. 2002; Kelly
and Kelly 2004). Researchers concluded that lead poi-
soning remains a threat to swans (Perrins et al. 2002;
Newth et al. 2013; Wood et al. 2019), but the regulation
Royal Swedish Academy of Sciences 2019 123
of lead tackle has resulted in the recovery of the popu-
lation (Wood et al. 2019).
Mortality from lead fishing tackle ingestion has been
documented in other swans, including trumpeter swans
(Cygnus buccinator;Blusetal.1989;Blus1994;
Degernes et al. 2006), tundra swans (Cygnus colum-
bianus; Owen and Cadbury 1975;Blus1994), and
whooper swans (Cygnus cygnus; Spray and Milne 1988;
Perry 1994). However, the majority of documented lead
poisoning in these species has resulted from ingested
lead ammunition (Blus 1994; O’Connell et al. 2008).
Mute swans may be more susceptible to poisoning from
ingested lead fishing tackle and less from ingested lead
ammunition owing to their preference for foraging in
aquatic habitats over agricultural fields in comparison
with other swan species (Ciaranca et al. 1997;Bowen
and Petrie 2007). The susceptibility of mute swans to
lead fishing tackle ingestion can also likely be attributed
to their habitation in urban areas, where they are fed by
humans and may be attracted to anglers’ baits and areas
in which lost lead tackle may accumulate (Sears 1989).
Lead tackle ingestion in common loons
Lead poisoning from ingested fishing tackle in common
loons was first documented in 1976 (Locke et al. 1982) and
has subsequently been documented to be a leading cause of
mortality for this species (Pokras and Chafel 1992; Stone
and Okoniewski 2001; Sidor et al. 2003; Strom et al. 2009;
Grade et al. 2018). Across the range of common loons in
North America, lead poisoning accounts for 11–49% of
documented mortality (Table 2). Differences among
regions should be interpreted with caution and are likely a
function of differing reporting methods, collection efforts,
and sample sizes, as well as real differences in fishing
pressures and loon populations. Mortality from ingested
lead fishing tackle primarily occurs among adult loons on
the summer breeding lakes (Ensor et al. 1992; Daoust et al.
1998; Sidor et al. 2003), although loon deaths from
ingested lead tackle have been documented on wintering
grounds (Sidor et al. 2003; Pokras, unpubl.; Loon Preser-
vation Committee, unpubl.) and among migrating loons in
Washington and on the Great Lakes (Cooley and Melotti,
Table 2 Mortality from lead poisoning in common loons in North America. Unless specified otherwise, ‘‘Total Mortalities Collected’’ include
all age classes
% Lead
Total mortalities
Population size (in most
recent year of study)
Years of
New Hampshire
48.6 253 (NH AD
population only)
638 1989–2012 Grade et al. (2018)
Maine 25.2 480 (AD only) 4100 (in 2010) 1990–2017 B. MacDonald, pers. com.;
Evers et al. (2010)
New York
20 261 1900–2300 1972–2017 Stone and Okoniewski (2001);
J. Okoniewski, pers. com.
New England 44 254 (Breeding AD
1987–2000 Sidor et al. (2003)
Canada 15.0 433 (AD only) *500,000 1992–2018 E.J. Parmley, pers. com.; CLLS
14.1 340 (AD only) 700–800 breeding pairs 1987–2017 J. Melotti, pers. com.
Wisconsin *20 *100 4350 2006–2017 Strom et al. (2009); S. Strom,
pers. com.
Minnesota 11.4 132 12,000 1976–1991, 2009–2015 C. Henderson, pers. com.
Washington 38% from 1996
to 2010; 0%
21 (AD only)
1996–2010; 5 AD
50 1996–2018 D. Poleschook and V. Gumm,
pers. com.
AD adult
Common loon mortality from lead poisoning is underrepresented in New Hampshire because the Grade et al. (2018) study included only loons
that were clearly from the New Hampshire loon population and for which multiple lines of evidence indicated that birds died from lead fishing
tackle ingestion. Thus, cases of lead-poisoned loons were excluded from this study that would have been included in studies and reporting from
other regions
Twenty-one additional loons that died from ingested lead fishing tackle were collected during type E botulism outbreaks on the Great Lakes in
New York. Because the total number of dead loons collected during these outbreaks in New York is unknown, these lead mortalities are not
included in the numbers reported in this table
Note that ‘‘% Lead mortalities’’ and ‘‘Total mortalities collected’’ in Michigan include loons collected from type E botulism events on the Great
123 Royal Swedish Academy of Sciences 2019
pers. com.; Poleschook, pers. com.). Datasets that combine
wintering and migrating adults generally result in lower
rates of lead tackle ingestion than datasets reporting mor-
tality among the breeding population. Lead poisoning has
not been documented in loon chicks (Sidor et al. 2003),
although it does occur in generally low rates among juve-
nile and sub-adult loons. An exception to this is in
Michigan, where 15 of 60 juvenile/sub-adult loons were
recorded to have died from lead poisoning (numbers not
included in totals reported for Michigan in Table 2, which
includes only adult loons; Cooley and Melotti, unpubl.). In
regions where mortality numbers reported in Table 2
include age classes other than adults, rates of lead tackle
mortality are diluted by younger age groups.
Collection efforts for dead loons are known to vary widely
among different areas in North America (Table 2). In New
Hampshire, the Loon Preservation Committee (LPC) con-
ducts intensive monitoring of the state’s loon population and
has extensive public outreach to encourage reporting of
moribund or dead loons. LPC estimated that its recovery of
deceased loons on breeding grounds is *60%, resulting in
mortality rates that are representative of causes of death
(Grade et al. 2018). Less intensive collection efforts in other
regions depend on a variety of factors, such as available
funding and differing agency priorities and levels of public
outreach, resulting in smaller sample sizes and less repre-
sentative samples of loon mortality. In some states and
regions, mortality sampling may occur in association with
outbreaks of type E botulism in migratory birds. In general,
increased rates of lead fishing tackle mortality are associated
with more intense collection efforts and sample sizes that are
more representative of overall mortality rates (Stone and
Okoniewski 2001; Strom et al. 2009).
Fishing pressure in a given region appears to play a sig-
nificant role in the rate of lead fishing tackle mortality.
Although collection effort can be a confounding factor,
resulting in areas with high fishing pressure but low docu-
mented rates of lead tackle mortality, the role of angling
pressure in rates of lead tackle mortality is evident. Portions
of southern Ontario with high rates of fishing pressure had
the most frequent incidence of lead fishing tackle mortality
among common loons in Canada (Scheuhammer et al. 2003).
Similarly, in New England, New Hampshire’s high rate of
lead tackle mortality compared with the rate in Maine is
likely accounted for by high fishing pressure in the state
(Scheuhammer et al. 2003), although a more intense effort to
collect loon cadavers in New Hampshire likely plays a role.
The correlation between the annual peak in lead tackle
mortality in New Hampshire with months of peak fishing
activity (Grade et al. 2018) likewise suggests the role of
fishing pressure on loon mortality from lead poisoning.
Differences in body size across the range of the common
loon may contribute to regional differences in mortality
rates from lead tackle ingestion as well. Larger loons
inhabiting regions near the coasts (Gray et al. 2014) may be
more likely to ingest larger fish, which, in turn, may be
more likely to break fishing lines and ingest tackle. The
role of body size in lead tackle ingestion may also be
reflected in the skewed sex ratio towards males (Grade
2011), which average [20% larger than females (Gray
et al. 2014). For the datasets represented in Table 2for
which the sex ratio of lead tackle mortalities is known, an
overall average of 66.1% of lead mortalities are males,
28.6% are females, and 5.3% are unknown or unrecorded
sex (total n= 469; range: males = 56.9–77.5%, females =
12.5–36.6%, and unknown sex = 0.0–33.3%).
While many factors influence rates of lead tackle mor-
tality, results reported in Table 2need to be interpreted
with caution due to varying collection efforts, differences
in reporting methods, and different criteria for including
loons in studies (e.g., breeding vs. migrating and/or win-
tering loons) and assigning cause of death as lead poison-
ing (e.g., required presence of lead object vs. other
criteria). Given high collection rates and a focus on adults
of the breeding population, the studies for New Hampshire
(Grade et al. 2018) and New England (Sidor et al. 2003)
likely provide the most accurate assessment of the impact
of mortality from lead fishing tackle ingestion on breeding
loons. In New Hampshire, Grade et al.’s (2018) data
indicate that toxicosis from ingested lead fishing tackle has
had a population-level effect on the state’s common loons,
reducing the population by 43% during the years of the
study (1989–2012), and has inhibited the recovery of loons
in the state. For all regions, the numbers presented in
Table 2likely underestimate the impact of lead poisoning
from fishing tackle ingestion on loon populations.
Tackle types and sizes reported in loons
Jigs and sinkers account for the majority of tackle objects
ingested by loons (Table 3), although loons are also known
to ingest swim baits, internal weights from lures, and other
types of tackle (Grade et al. 2018). Typical sizes of eroded
tackle documented in loons ranged from 0.3 to 30.4 g for
sinkers and 0.3 to 20.9 g for eroded jigs (Stone and Oko-
niewski 2001; Pokras et al. 2009; Grade et al. 2018),
although loons can ingest much larger tackle. An eroded
sinker weighing 78.2 g was reported by Franson et al.
(2003) and several previously unreported eroded, saltwater
jigs each exceeding 100 g were removed from loons
recovered on the coasts of Massachusetts and California
(Fig. 1; Grade et al. 2018; Pokras unpubl.).
The high proportion of ingested jigs recorded from
across the range of the common loon highlights the
importance of including lead-headed jigs in legislation
restricting lead tackle to ensure effective protections for
Royal Swedish Academy of Sciences 2019 123
loons and other wildlife. Grade et al. (2018) recommend
substituting non-lead alternatives for lead sinkers and jigs
weighing B28.4 g to protect loons and other wildlife.
While erosion rates of many metal objects in avian gizzards
are unknown, studies of erosion of lead shot (Cook and
Trainer 1966; Finley et al. 1976) and lead tackle suggest
that erosion may take place fairly rapidly due to the
grinding action with the pebbles that are virtually always
present in adult loon gizzards (Franson et al. 2001; Pokras,
pers. comm.).
While direct mortality from lead ingestion can be signifi-
cant for wildlife, it is also important to consider the sub-
lethal impacts to individuals and populations. The insidious
effects of sub-acute lead exposure can add to the multiple
stressors already affecting wildlife health, and even low
levels of lead exposure may contribute to mortalities
attributed to other causes (Newth et al. 2016; Ecke et al.
2017). Veterinarians and wildlife professionals are just
beginning to investigate the potential effects of sublethal
lead levels in animals, so some of our most detailed
understanding of the sublethal effects from lead comes
from the human medical literature where low level lead
toxicosis is documented to impair a wide variety of meta-
bolic processes (Wani et al. 2015).
In light of associations between low level lead exposure
and impaired neuropsychological function in humans,
similar cognitive effects of sublethal lead poisoning are
beginning to be studied in wildlife. In herring gulls (Larus
argentatus), effects on locomotion, food begging, feeding,
treadmill learning, thermoregulation, and individual
recognition were observed in chicks dosed with lead
(Burger and Gochfeld 1994). The development of aggres-
sive behaviors has been documented in great tits (Parus
major) and northern mockingbirds (Mimus polyglottos)
exposed to heavy metals (Janssens et al. 2003; McClelland
et al. 2019). Just as lead exposure has been found to affect
the human humoral immune response (Metryka et al.
2018), mallards (Anas platyrhynchos) experimentally
exposed to lead shot were found to have impaired antibody
production following antigen challenge compared to con-
trols (Trust et al. 1990). Immunosuppression secondary to
lead exposure may contribute to lowered disease resistance
in wildlife.
Although subtle effects of sub-lethal lead exposure in
wildlife species have been best documented in controlled
laboratory settings, some studies are beginning to investi-
gate how lead exposure may affect the complex behaviors
of animals in their natural environment. For example, Ecke
et al. (2017) identified lead-induced behavioral effects in a
population of free-ranging golden eagles (Aquila chrysae-
tos). Sublethal lead concentrations were associated with
impaired flight performance and increased mortality risk. A
retrospective study of mute swans admitted to a wildlife
Table 3 Types of fishing tackle removed from loons that died from lead poisoning. Data from the same mortality datasets in Table 2. Pokras
et al. (2009) uses the mortality dataset from Sidor et al. (2003)
% Jigs % Sinkers % Unknown/
other lead object
Total n of lead
tackle objects
New Hampshire 52.6 38.8 8.6 116 Grade et al. (2018)
New York 68.7 20.9 10.5 67 Stone and Okoniewski (2001);
J. Okoniewski, pers. com.
New England 19.0 60.0 21.0 222 Pokras et al. (2009)
Canada 25.6 39.5 34.9 43 E.J. Parmley, pers. com.
Michigan 53.2 25.5 21.3 47 J. Melotti, pers. com.
Fig. 1 Lateral radiograph of large (116 g) lead jig ingested by
common loon. (Steel shot identified on radiograph and recovered at
necropsy had been present for an extended period and were not
associated with significant pathology.)
123 Royal Swedish Academy of Sciences 2019
care center for rehabilitation suggested that birds with
elevated but moderate blood lead levels suffered an
increased risk of collision with powerlines or other over-
head cables. Those with intermediate to high levels had a
reduced risk of collision, possibly because they were too
weak to fly (Kelly and Kelly 2005). Karstad (1971), Hunter
and Haigh (1978), and de Francisco et al. (2016) docu-
mented significant effects of lead on the cardiovascular and
nervous systems of birds.
Pattee and Pain (2003) documented an increasing use of
lead worldwide and state that ‘‘lead concentrations in many
living organisms may be approaching thresholds of toxicity
for the adverse effects of lead.’’ Environmental lead
exposure, even at low levels, could very well contribute to
wildlife mortality by impairing organ functions, increasing
susceptibility to trauma and disease, and hindering the
complex mental processes and social behaviors required
for reproductive success and survival.
In regard to consumer lead products and public health, we
are at a critical moment where regulations urgently need to
catch up with the science. In human health, current science
asserts that no safe exposure level exists for lead, which
contributes to 0.6% of the global burden of disease (WHO
2009). Given the growing body of evidence that even low
doses of lead exposure over time can lead to multiple
health and cognitive impairments, one should not under-
estimate the human health hazards associated with han-
dling lead fishing gear.
Sahmel et al. (2015) found that simply handling fishing
sinkers resulted in deposition of lead on the skin and that an
average of 24% of this lead could be transferred from the
hands to the mouth. Practices such as biting lead split-shot
to secure onto the line and melting down scrap lead to
produce home-made fishing weights are both examples of
significant public health concerns directly related to lead
fishing weights. Molds to cast homemade sinkers, jigs,
bullets, lead soldiers, and other items are readily available
for purchase, and there are numerous internet videos
illustrating such techniques without providing any mean-
ingful safety and health information. Indeed, many sources
document significant lead exposure from the melting of
lead at home to make fishing gear and other objects
(Olivero-Verbel et al. 2007; Khan 2014). These cases
expose people to lead via fumes and small particulates that
can be inhaled or may contaminate food and water.
The ingestion hazard to humans posed by small fishing
weights should not be overlooked. Poison control centers are
commonly consulted on cases of ingestion of lead foreign
bodies, and previous studies have noted that some of these
are fishing weights (Cole et al. 2010). In 2016, 2412 of the
poisoning cases reported to poison control centers in the US
were due to single exposures to lead, typically due to the
ingestion of small lead items (Gummin et al. 2017). In many
cases the lead item ingested was not defined. However, in 38
cases reported to US poison control centers in 2016 the item
ingested was specifically recorded as lead fishing tackle and
most of these (28 cases) were due to ingestion by children
under 6 years of age (Gummin et al. 2017). Note that not all
ingestions of lead sinkers will result in reports to poison
control centers and the toxic impacts of the exposure may not
be immediately evident. It is likely that the poison control
center numbers underestimate of the total number of children
exposed to lead via this route. Significantly elevated blood
lead levels have been documented in children exposed to
lead for very short periods of time. For example, blood lead
levels in a 4-year old child were found to exceed 65 lg/dl the
day following ingestion of a single fishing sinker (Cole et al.
2010). Retention of lead fishing sinkers in the stomach and
intestines of children following ingestion has been demon-
strated and can result in long-term elevation of lead levels
(Mowad et al. 1998).
Concerns regarding the public health impacts of lead
exposure have resulted in regulations on other lead prod-
ucts including paint, toys, and gasoline additives (Stroud
2015). The human health perspective should also inform
the risk management strategy for other lead products
including lead fishing gear (Health Canada 2013).
Over more than three decades and in multiple jurisdictions,
many approaches have been used to try to reduce the toxic
impacts of lead fishing gear on wildlife. In our ESM
(electronic supplementary materials), we summarize the
effectiveness of key voluntary and legislative measures that
have been used thus far. We assessed the effectiveness of
each measure in terms of reduced uses of lead tackle and/or
reduced mortality wherever data are available (Table S1).
We then used this review to develop recommendations for
the design of a risk management strategy to reduce the
toxic impact of lead fishing gear on wildlife (Table 4).
In reviewing data on effectiveness of risk management
measures, it is important to note that there can be high year
to year variability in the number of mortalities recorded in
any population, and many animals killed by lead tackle
ingestion may not be recovered or subject to post mortem
examination (Pain 1991). Long term monitoring programs
and assessment of trends over many years are essential to
determine the impact of risk management measures. Such
data are not available for all jurisdictions. Several case
Royal Swedish Academy of Sciences 2019 123
studies are discussed in detail as these examples have the
advantage of long-term monitoring data linked to voluntary
and legislative approaches that evolved over time, allowing
us to learn from their sustained efforts and experience. As
Thomas and Guitart (2003) said, ‘resolving lead expo-
sure and toxicosis of wildlife is more about the develop-
ment of appropriate social and governmental policy than
the state of science.’’ This was reinforced by Arnemo et al.
(2016) who stated, ‘‘Our understanding of the deleterious
impacts of lead exposure on wildlife and humans will
change little with further scientific research, no more evi-
dence is required.This is now a socio-political issue.’
Voluntary and education-only approaches to manage
risks from lead fishing gear have proved ineffective,
including efforts in the UK, Sweden, Denmark, and several
US states (LPC 2012; Wood et al. 2019). As a result,
legislative restrictions have been introduced in many
jurisdictions (Table S1). In Washington State, it was noted
that a sizable portion of anglers given on-site education
about the toxicity of lead fishing tackle indicated that they
would change in the future but only when an actual ban
was in place (Poleschook and Gumm 2009). This attitude
has also been noted in other jurisdictions. For example,
following a 15-year outreach effort in Sweden to encourage
the sale and use of non-toxic tackle, retailers stated that
they did not intend to start selling alternatives until legis-
lation banning lead tackle was introduced (KEMI 2007). In
Minnesota, a well-funded 10-year outreach program was
initiated to reduce mortalities from ingested of lead fishing
tackle. This program was described as, ‘‘one of the most
ambitious in the country’’ (LPC 2012). The campaign
included over 200 tackle exchange programs which col-
lected 8000 lbs. of lead, the distribution of 50 000 sample
packages of lead-free tackle, displays at retail stores, and
extensive media coverage. Despite such efforts, this pro-
gram failed. At the end of the program, the supervisor of
the Sustainable Development Unit of the Minnesota Pol-
lution Control Agency concluded, ‘‘I believe no one
Table 4 Recommendations for risk management strategy development for regulating lead fishing tackle. Developed from the review of existing
international voluntary and legislative approaches found in Table S1 for this publication
Conclusions based on international efforts to date Recommended instrument design features
Voluntary/education only approaches ineffective Use a combination of legislation (regulatory restriction on lead sinker/
jig sales and uses) with education to support regulation
Limited product restrictions based on size can be inadequate If a size range is specified in the regulation, ensure that it covers
ingestion hazard for all sizes that are typically ingested by receptors
of concern, or restrict all sizes of lead terminal tackle (note that sizes
specified in most existing legislation are based on heavily impacted
species such as loons but other wildlife species and children can also
ingest these lead products)
Risk management strategies that are very limited in geographical scope
have little, if any, impact on the overall market for lead fishing gear.
If the scope of the restriction excludes large numbers of the angling
community, it will be ineffective in driving change
Restrictions should be applied at the state or national level wherever
possible to ensure the fishing tackle market transitions from lead to
lead-free non-toxic alternatives. Restrictions should apply equally to
all anglers
Stockpiles of existing lead sinkers/jigs continue to be problematic years
following introduction of restrictions
Restriction should be applied to both sale and use and be combined
with effective enforcement. Enforcing a ban on uses also prevents the
continued manufacture and use of home-made lead fishing weights
and prevents purchasing from other jurisdictions that do not have
restrictions on sales. Use education and enforcement, combined with
buy-back programs, to ensure anglers cease use of lead in existing
supplies. In some jurisdictions effective enforcement at the point of
use may require cooperation between different levels of government
Lack of availability of non-lead alternatives for purchase by anglers and
higher cost of alternatives can be a deterrent for switching to non-
Restrictions on sale ensure a guaranteed market for non-lead
alternatives, hence manufacturers will produce them and retailers
will stock them. Costs of non-lead alternatives expected to fall in any
market with effective regulatory restrictions on lead due to increased
economy of scale for non-lead options
Exclusions for coated lead products in some restrictions not supported
by science, as coating is readily eroded after ingestion and is
ineffective in limiting exposure or toxicity
Restrictions should not include exclusions for coated products
Wildlife are exposed to lead from multiple sources, toxicosis and
mortalities occur from many
Coordinated action on a variety of lead products may be required for a
comprehensive and effective risk management strategy
123 Royal Swedish Academy of Sciences 2019
knowledgeable about our concerted and sustained educa-
tional efforts in Minnesota would make the claim that
education alone will sufficiently reduce or eliminate
avoidable loon deaths as a result of lead ingestion’’ (LPC
This review of voluntary and legislative approaches
concurs with the conclusion that, ‘‘a comprehensive solu-
tion involving legislation backed by intensive educational
efforts will be required to address this issue’’ (LPC 2012).
It is also clear that legislation developed must be appro-
priately designed to effectively address the issue (see
Table 4). For example, legislation that fails to ban all sizes
and types of lead tackle documented to be regularly
ingested by wildlife will fail to adequately address the
issue. Legislation that bans sale but not use will be much
less effective since existing stocks of lead tackle will
continue to be used, may continue to be purchased from
jurisdictions outside the ban, and may continue to be cast at
home (also resulting in public health concerns regarding
lead exposure). Conversely legislation that bans use but not
sale would leave lead tackle readily available, make
enforcement difficult and discourage anglers from adopting
nontoxic alternatives. Legislation that is limited in geo-
graphical scope and does not include both sale and use bans
will have little, if any, impact on overall market demand
for lead fishing gear. Enforcement throughout supply-
chains is also critical. Even in Denmark, a jurisdiction with
complete bans on importation and sale of all sizes of lead
fishing tackle since 2002, lead fishing gear was found on
sale in 2012 and 2013 (Danish EPA 2014). In this case,
active enforcement and fines applied in recent years appear
to be gradually reducing violations.
Ideally one might wish to advocate for elimination of all
fishing tackle containing lead. But given historical oppo-
sition to attempts to limit lead sinkers and jigs by some
fishing groups, tackle retailers, and tackle manufacturers,
regulators have been reticent to extend bans beyond the
sizes and types of ingested tackle documented to harm
wildlife. Elected officials find themselves trying to recon-
cile the sometimes conflicting goals represented by the
scientific data and jurisdictional economic priorities and
political realities. Therefore, it is important to document
sizes and types of ingested tackle and to press for science-
based restrictions to protect wildlife.
The most effective risk management instrument is
expected to be one that includes a prohibition on
importation, manufacturing (including home casting),
sale, and use of fishing tackle items made from lead.
This needs to be combined with educational outreach to
support the legislation and effective enforcement
throughout the supply chain (at domestic manufacturing
facilities, at importation, at points of sale, and at points
of use).
The role of human dimensions: Social science
research and communication
Management decisions regarding lead fishing tackle have
the potential to be very controversial, and legislation
designed to protect wildlife is often met with resistance
(Kneeland and Pokras 2008). Stakeholders are diverse, as
this issue concerns government agencies, conservation
non-profits, anglers, wildlife-viewers, fishing tackle retail-
ers, manufacturers, and others. Stakeholder involvement in
decision-making processes has increased the demand for
human dimensions research in order to understand and
predict stakeholder positions (Vaske and Manfredo 2012).
Also, since human behavior is the root cause of lead in
freshwater environments from fishing tackle, understanding
angler behaviors is essential for accomplishing conserva-
tion goals (Ross-Winslow and Teel 2011), such as
increased legislative awareness and elimination of lead
tackle use.
Human dimensions research applies social psychology
to understand stakeholder thoughts and actions towards
wildlife (Vaske and Manfredo 2012). With this under-
standing, agencies can create more targeted outreach ini-
tiatives and increase message effectiveness, improve
conservation strategies, as well as managing conflicts
among stakeholders (Redpath et al. 2015). Leszek (2015)
found that anglers not using lead-free fishing tackle believe
it is too expensive and were unsure if it would perform as
well as lead. In this case, it may be more effective to frame
communication messages that minimize perceived barriers
(Ross-Winslow and Teel 2011), rather than focus solely on
traditional educational efforts involving lead toxicity or
wildlife conservation.
Other approaches measure connections between atti-
tudes and broad value scales, such as altruistic (i.e., caring
about others), egoistic (maximizing individual outcomes),
and biospheric (caring for non-human nature and the bio-
sphere itself) (Stern et al. 1999; DeGroot and Steg 2007).
Altruistic and biospheric values tend to be positively
related to environmental policy acceptability, while ego-
istic values appear to be negatively related (Stern et al.
1999). Changes to values are unlikely to occur after edu-
cation and informational campaigns because values are
central to one’s identity and are relatively stable over the
course of a lifetime (Fulton et al. 1996). Therefore, rather
than attempting to change environmental values, another
strategy is to promote messages that match those values. In
the case of lead fishing tackle, it may be beneficial to focus
on messages that appeal to egoistic values in addition to
biospheric. Implementing message campaigns that focus on
Royal Swedish Academy of Sciences 2019 123
the human health hazards of lead, for example, might
appeal to those expressing fewer concerns about wildlife
health but are more concerned about their own personal
Many anglers may simply be unaware that lead fishing
tackle causes ecological harm (Kneeland and Pokras 2008),
but cognitive-based outreach approaches (i.e., presenting
scientific information to the public) may not always be
effective. Human behaviors are also influenced by beliefs,
attitudes, value orientations, emotions, social norms,
experience, and many other complex factors (Vaske and
Manfredo 2012). An understanding of these factors is
essential for designing effective communication messages.
Since behaviors and attitudes of stakeholders regarding
lead fishing tackle are still largely unknown (Thomas 1997;
Ross-Winslow and Teel 2011), the authors recommend
future studies to explore these relationships.
The taxonomy of fishing gear
In crafting educational and regulatory efforts on lead
fishing gear, one of the problematic issues has been that
manufacturers, marketers and anglers use a wide variety of
terms for different fishing weights. Lead can be cast in
many forms for fishing including items such as split shot,
worm weights, trolling weights, jigs, ad infinitum. Initial
attempts to regulate lead fishing gear focused on ‘‘sinkers,’
but the term ‘‘sinker’’ only applies to certain types of
fishing weights. In the U.S., many fishing groups were able
to avoid proposed regulations by claiming that other types
of fishing weights are not ‘‘sinkers.’’ The gear identified as
‘jigs’’ or ‘‘jigheads’’ in the U.S. is referred to as ‘‘lures’’ in
the UK. Thus, in developing regulatory and educational
materials, we should either make exhaustive lists of types
of fishing gear that contain lead or consider a more inclu-
sive terminology; perhaps something like, ‘‘any tackle,
weights or lures containing lead used for fishing’’.
The authors also note that there is potential for mis-
classification of lead objects retrieved from avian GI tracts.
Larger or more intact objects like bullets, jigs and sinkers
are unlikely to be confused. But there is significant
opportunity for inaccurate classification of smaller
deformed or eroded objects, and it can sometimes be hard
or impossible to tell if original objects were of fishing or
shooting origin. Some of us have spent significant time
using dissecting microscopes, magnets and other tools in
attempts to differentiate eroded split shot or small jigs from
gunshot, bullet fragments, or lead fragments from non-
sporting origins. Over time we have improved our skills,
but there are still items that end up being classified as
‘unknown Pb.’’ Because of the challenges associated with
the identification of some deformed lead objects, we sus-
pect that some things identified in other studies as being
firearm projectiles may in fact have been fishing gear.
Coatings for lead fishing gear
Some groups have claimed that coating fishing gear with
paint or other materials would prevent lead from being
absorbed after ingestion. USFWS (1986) detailed extensive
testing (some going back to the 1940s and 1950s) that had
been done to see if lead shot could be coated to make them
non-toxic when ingested by waterfowl. Those experiments
concluded that for most practical purposes, coatings were
uniformly unsuccessful and were quickly ground off in
waterfowl gizzards. Thomas et al. (2015) reinforce the
ineffectiveness of coatings for gunshot. To model what
takes place with coated fishing gear ingested by common
loons, Pokras (unpubl.) is currently testing commercially
available painted or coated fishing weights in rock tumblers
containing simulated gastric acid and the types of pebbles
usually found in loon gizzards (Franson et al. 2001). Work
to date has found that within 24 h, even heavily applied,
multi-layer paint coatings are eroded enough to expose the
metallic lead to gastric fluids. Thus, any legislation
excluding coated or painted fishing tackle will be ineffec-
tive in preventing mortalities from lead poisoning.
Alternative materials
It may be that only metals have suitable characteristics for
the temperatures and pressures encountered inside firearms.
Thomas (2019) reviews the advantages and disadvantages
of a variety of metals for ammunition and angling. For
fishing, a variety of non-metallic materials can be suit-
able substitutes including natural rock and porcelain
An internet search for topics such as ‘‘rock fishing
sinkers,’’ ‘‘biodegradable sinkers,’’ or ‘‘non-metal fishing
weights’’ shows numerous alternative products. Most pri-
ces are similar to those of lead products. Sinkers and jigs
made of non-toxic metals are also on the market, including
tackle made of tungsten, tin, bismuth, and steel. Tungsten’s
high density makes it a preferred material among profes-
sional anglers. However, fishing weights containing other
toxic metals including zinc and cadmium have been found
in U.S. stores, often bearing labels such as, ‘‘This Product
Does Not Contain Lead.’’ Regulators and educators must
be aware of this practice and take steps to avoid having
these or other toxic substitutes enter the marketplace.
Appendix S1 for this paper contains information on some
sources for non-toxic fishing gear.
123 Royal Swedish Academy of Sciences 2019
Other fishing-related issues
Clearly fishing activities deposit large amounts of metallic
lead and other materials into a variety of aquatic environ-
ments (Bell et al. 1985; Forbes 1986). In addition to
ingestion of such fishing gear by non-target species, under
some conditions a great deal of lead can enter sediments
and the water. Jacks et al. (2001) discuss the erosion of lead
fishing gear in a Swedish river. Binkowski (2017) discusses
environmental conditions, especially low pH, under which
lead from spent gunshot or fishing gear may be transferred
to sediments and the water column. The effects of this lead
on aquatic organisms is deserving of further study but
should be similar to lead deposited into aquatic systems
from mining activities, shooting, industrial effluent, or
other sources.
Effects of lead on individual animals
Traditionally wildlife managers have primarily been con-
cerned about threats to animal health in two circumstances.
First, if such threats are shown to have population-level
effects on the species in question, and second, if these
threats may serve a sentinel function to protect human
health. There is no doubt that both of these are good rea-
sons to replace lead in fishing gear with non-toxic
But the authors would be remiss if we did not point out
the significant benefits to individual animals of switching
to non-toxic fishing gear. Hunters and anglers have long
been some of our most ardent conservationists and tra-
ditionally abhor the unnecessary killing of non-target
animals (Reiger 1975). Even if lead poisoning is not
having a population-level effect on a particular species, it
is killing large numbers of animals in a manner that is
often prolonged, painful, and cruel. This flies in the face
of two of the historic central tenets of sporting traditions:
first, that we should avoid harm to non-target species, and
second, that wild animals being taken for food or sport
should, whenever possible, be afforded a quick death.
Lead poisoning is inhumane and causes unnecessary
stress, pain, and suffering in a wide variety of species
including people, dogs, horses, ruminants, and birds.
There is abundant literature over many years to demon-
strate acute abdominal pain, peripheral muscle pain and
weakness, incoordination, seizures, anemia and weakness,
gout, and other clinical problems seen in many taxa
(Oliver 1914;Walker1981;Nriagu1983; Needleman
2000;Blakley2019). It is worth considerable money and
effort to eliminate this poison from our outdoors
There is a significant need to improve the development,
marketing, adoption and regulatory approaches for non-toxic
fishing gear. Those of us interested in reducing the use of
lead need to develop strategies to increase the acceptance of
non-toxic alternatives and educate anglers about:
1. The dangers of lead fishing gear to human and animal
2. The availability and costs of non-toxic alternatives
3. The fact that non-lead fishing gear is suitable for their
angling goals. This may include funds for demonstra-
tion activities such as lead fishing gear exchange
programs, lead-free fishing derbies, and other
4. Dramatically improve the marketing of non-lead
fishing gear.
Part of the solution may be developing novel business
models. One suggestion, based on the regulatory desire to
reduce the health threat from tobacco use, would be
introduce a significant ‘‘sin tax’’ on the manufacture or sale
of lead (or other toxic) fishing gear. Funds generated from
such taxes could be dedicated to such things as research on
non-toxic alternatives, public education, and other goals.
Compiling information for this paper has also made it
clear that further efforts should be made to improve our
knowledge and data collection about the ingestion of lead
fishing gear. To paraphrase Sainsbury et al. (2001), with
few exceptions, current programs to investigate morbidity
and mortality of wildlife are fragmented and uncoordi-
nated, often being limited to specific narrow taxonomic
foci, large-scale outbreaks, or focal geographic areas. Due
to limited time, personnel and funding, data collected in
one jurisdiction are often not easily comparable with those
collected elsewhere. Enhancements in citizen science
efforts (including some STEAM education programs—
Science, Technology, Engineering, the Arts, and Math)
may provide opportunities to correct some of these defi-
ciencies in the future.
We recommend that the following points can be
important when developing scientific, educational and
regulatory efforts for managing the risks associated with
lead fishing gear:
1. It is important to specify what alternative materials are
safe and non-toxic based on best available science and
not simply to say ‘‘non-lead’’
2. Scientists and agencies should work collaboratively
with anglers’ groups, retailers, manufacturers and
regulators to accelerate the development, marketing
and acceptance of nontoxic fishing tackle
Royal Swedish Academy of Sciences 2019 123
3. Anglers, manufacturers, sellers and regulators should
be helped to understand that coatings will not render
lead fishing gear safe and non-toxic
4. To enhance long-term data compatibility and sharing,
researchers and agencies should consider more widely
circulating their study plans, priorities and protocols.
This will have the effect of more rapidly advancing
science and accelerating the development of sound,
science-based policies.
5. Voluntary and educational approaches alone are not
effective for risk management and must be combined
with legislative approaches which incorporate the
features summarized in Table 4of this paper.
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Publisher’s Note Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations.
Tiffany Grade (&) is a biologist at the Loon Preservation Com-
mittee (LPC). Her research interests include causes of mortality in
loons, particularly issues related to lead fishing tackle mortality, and
impacts of contaminants on loon survival and breeding success.
Address: Loon Preservation Committee (LPC), P.O. Box 604,
Moultonborough, NH 03254, USA.
Pamela Campbell is a Principal at ToxEcology – Environmental
Consulting Ltd. Research interests include chemical risk assessment
and risk management, chemical lifecycle and cost–benefit analyses,
and science-based policy development.
Address: ToxEcology – Environmental Consulting Ltd., 204-53 West
Hastings St, Vancouver, BC V6B 1G4, USA.
Address: Vancouver, Canada.
Thomas Cooley is a Wildlife Biologist/Pathologist at Michigan
Department of Natural Resources. His research interests include
wildlife disease/pathology.
Address: Michigan Department of Natural Resources Wildlife Dis-
ease Lab, 4125 Beaumont Rd, Lansing, MI 48910, USA.
Michelle Kneeland is a veterinarian and Director of the Wildlife
Health Program at Biodiversity Research Institute. Her research
interests include implementing a One Health approach to wildlife
health, and network building among professionals across the realms
of human, environmental, and wildlife health.
Address: Wildlife Health Program, Biodiversity Research Institute,
276 Canco Road, Portland, ME 04103, USA.
Elaine Leslie is Chief of Biological Resources for the US National
Park Service, overseeing wildlife conservation and health, at-risk
species, non-native species and their impacts, landscape-level
restoration and issues affecting ecological integrity in the national
park system. Elaine has long been involved in issues of lead toxicity,
including work on California condors, bald and golden eagles.
Address: Biological Resources, Natural Resource Stewardship and
Science, National Park Service, 1201 Oakridge Drive Suite 200, Fort
Collins, CO 80525, USA.
Brooke MacDonald is a master’s student in Ecology and Environ-
mental Sciences at the University of Maine, Orono. Her research
interests are in applied ecology and human dimensions of conserva-
tion biology and resource management.
Address: Department of Ecology and Environmental Sciences,
University of Maine, 251 Nutting Hall, Orono, ME 04469, USA.
Julie Melotti is a Laboratory Technician with the Michigan
Department of Natural Resources, Wildlife Disease Laboratory
(WDL). Her duties include performing gross necropsies on birds and
mammals for cause of death determinations, monitoring reports of
sick and dead wildlife from the public, and conducting disease
surveillance for bovine tuberculosis and chronic wasting disease.
Address: Michigan Department of Natural Resources Wildlife Dis-
ease Lab, 4125 Beaumont Rd, Lansing, MI 48910, USA.
Joseph Okoniewski is a wildlife biologist recently retired after
37 years of necropsies and investigations. Research interests included
the effects of environmental contaminants on wildlife.
Address: New York State Department of Environmental Conserva-
tion, Wildlife Health Unit, 108 Game Farm Road, Delmar, NY 12009,
Royal Swedish Academy of Sciences 2019 123
Elizabeth Jane Parmley is a veterinarian and epidemiologist. She works
in surveillance programs, risk assessments, and wildlife conservation and
management projects. Research interests include emerging threats and
opportunities at the human–animal-environmental interface.
Address: Canadian Wildlife Health Cooperative, University of Guelph,
Guelph, ON N1G 2W1, USA.
Cyndi Perry is a biologist, retired from the US Fish & Wildlife
Service. She serves on the Board of Directors of the Wildlife Center
of Virginia. Her research interests include working in communities to
understand the challenges they face while living in close connection
with wildlife and how they can benefit.
Address: US Fish & Wildlife Service, Wildlife Center of Virginia,
Waynesboro, VA 22980, USA.
Address: Oakton, USA.
Harry Vogel is a Senior Biologist/Executive Director at the Loon
Preservation Committee. His research interests include effects of
anthropogenic stressors on loon survival and reproductive success,
and efficacy of management and education to mitigate stressors and
recover loon populations.
Address: Loon Preservation Committee (LPC), P.O. Box 604,
Moultonborough, NH 03254, USA.
Mark Pokras is an Associate Professor Emeritus at the Cummings
School of Veterinary Medicine at Tufts University. His research
interests include medicine and surgery of native wildlife, birds as
indicators of environmental health, and conservation biology.
Address: Wildlife Clinic & Center for Conservation Medicine,
Cummings School of Veterinary Medicine, Tufts University, North
Grafton, MA 01536, USA.
123 Royal Swedish Academy of Sciences 2019
... Acute and chronic toxicity in birds results from the ingestion of lead either by primary ingestion of lead particles or secondary ingestion of contaminated food. 52,53 Less information on lead poisoning is available for mammals, but a list of species at risk regarding haematological and cardiovascular effects, renal functions, and neurotoxicity has been collected. 54 Endocrine-disrupting chemicals (EDCs) ...
Full-text available
Chemical pollution poses a threat to biodiversity on a global scale. This has been acknowledged in the Post-2020 Global Biodiversity Framework, which proposes to regulate the release of chemicals to the environment and names specific indicators focusing on pesticides, nutrients and plastic waste. We fully welcome the inclusion of these substances but would like to further emphasize that in order to protect biodiversity from hazardous chemicals, the scope of Target 7 should feature a wider range of pollutants that can contribute to biodiversity loss. We propose the inclusion of non-agricultural biocides, per- and polyfluoroalkyl substances (PFASs), toxic metal(loid)s, and endocrine-disrupting chemicals (EDCs). Furthermore, data on emerging pollutants (e.g., rare earth elements, toxic and persistent industrial chemicals, liquid crystal monomers, pharmaceuticals, personal care products) need to be regularly reviewed with the aim to integrate additional pollutants to Target 7 in the case of biodiversity risk. We suggest to amend Target 7 to postulate the aim for the overall reduction of chemical production and emissions, as well as the addition of the aforementioned substance groups of high concern to biodiversity for integration in the Post-2020 Global Biodiversity Framework. We further elaborate on different strategies for the reduction of emissions of hazardous chemicals through chemical simplification and grouping, reduction of chemicals with non-essential use, and innovative synthesis strategies (e.g., “benign-by-design”). In this context, the full life cycle of chemicals (i.e., production, use, and end of life) needs to be considered. Lastly, we propose to set up transparent data inventories, in cooperation with the industry, to inform about the production, transport and emissions of chemicals, which can serve as a basis for indicators related to monitoring the progress towards achieving the goals set under Target 7.
... For wildlife, there is an extensive body of literature on the impacts of Pb exposures from ammunition and fishing weight sources for avian species (Mateo, 2009;Ganz et al., 2018;Grade et al., 2019;Pain et al., 2019). Regulation to restrict Pb shot use in wetland habitats was adopted across the EU in January 2021, in response to high levels of mortality and morbidity in waterbirds in Europe (European Commission, 2021). ...
Full-text available
Ammunition and fishing weight usage is the greatest largely unregulated contributor of lead (Pb) deposition to the European environment. While the range of negative impacts of Pb exposure to humans and avian wildlife are relatively well documented, little is known about risks to wild mammals despite recent scientific interest and publications. A qualitative risk assessment of the potential Source-Pathway-Receptor linkages for European mammal exposure was conducted, based on literature reviews and existing evidence and discussions with experts from the fields of wild mammal feeding ecology, behaviour and health. The assessment identified 11 pathways for mammal exposure to Pb, with all 243 European species likely to be potentially exposed via one or more of these. All species were identified as potentially exposed via ingestion of water with elevated Pb from degraded ammunition/fishing weights. Ingestion of vegetation with elevated Pb from degraded ammunition/fishing weights potentially exposed many species (158), 78% of which had a potentially high risk of exposure when feeding in areas of high Pb deposition. Ingestion of retained ammunition in previously shot prey and/or discarded kill/gut piles with embedded ammunition was another significant pathway, contributing to predatory and scavenging carnivorous mammal exposure where an individual exposure event would be expected to be high. The mechanisms by which Pb from ammunition and fishing weight sources are moved up trophic levels and ‘transferred’ from areas of high deposition into wider food chains e.g. via water, flying invertebrates and herbivores being subsequently preyed upon requires further investigation. In conclusion, there are multiple and diverse Source-Pathway-Receptors linkages for European mammal exposures to Pb and evidence of exposure, from Europe and elsewhere, exists for some herbivores, carnivores, omnivores and insectivores. Both fatal but more likely non-fatal chronic and acute exposures may be expected to occur in wild European mammalian species, including those in poor conservation status.
... Besides the damage to the fishing industry, ingestion of fish items and other synthetic materials has the potential to accumulate in the digestive tract, reducing feeding stimuli (Di Beneditto and Ramos, 2014;Kühn et al., 2015), injuring the digestive tract (Kühn et al., 2015), potentially causing the death of individuals (et al. Di Beneditto and Ramos, 2014;Gomerčić et al., 2009;Jacobsen et al., 2010;Kühn et al., 2015) or affecting animals by slower sublethal physical and chemical effects (Grade et al., 2019;Kühn et al., 2015). Jacobsen et al. (2010) attributed the death of two sperm whales (Physeter macrocephalus) on the northern California coast to ingestion of fishing net scraps (bait nets, gill nets, and shrimp and fish trawl nets), rope, and other plastic debris in their stomachs. ...
The conflicting interactions between pinnipeds (seals, fur seals and sea lions) and fishing activities generate economic losses to the fishing industry by depredation of catch and damage to fishing gear. The latter in turn is an underreported problem for many species of pinnipeds that interact with fisheries. In this context, the present study aims to evidence gear damage caused by the South American sea lion (Otaria flavescens) during the depredation of catch, analyzing fishing items found in the stomachs of sea lions in southern Brazil. For this purpose, 46 stomachs of male South American sea lions found stranded on the southern coast of Brazil between 1993 and 2013 were analyzed. The fishing items found in the South American sea lion stomachs were identified and categorized. In 17.4% of the stomachs analyzed, fishing items were recorded. Gillnet fishing was the most representative item, being recorded in 15.2% of stomachs, followed by fishing lines (2.3%) and fishing hook with line (2.3%). The recorded items represented 79 fragments (gillnets = 88.6%, fishing line = 10% and fishing hook with line = 1.3%). The results also demonstrate an increase in the ingestion of fishing items by South American sea lions over time. The results presented here show that this type of interaction between the South American sea lion and the fishing industry, which has never been investigated in South America before, deserves more attention from researchers and fisheries managers. In this context, for a real understanding of the magnitude of the impact that South American sea lions can cause on fisheries, studies are urgently needed to estimate the impacts of these interactions, estimate the monetary costs of repairing fishing gear, and seek alternatives to minimize these problems. Still being important to mention that ingesting fishing items can cause injuring the digestive tract of sea lions, potentially causing the death of individuals or affecting animals by slower sublethal physical and chemical effects.
... Unlike some other well-studied toxic metals, such as mercury (Hg) and arsenic (As), Pb is not generally known for biomagnification in the food chain (Hoffman et al., 2001). Lead exposure in waterfowl and granivorous species frequently occurs through direct ingestion of Pb shot and fishing tackle when they swallow grit and pebbles (gastroliths) to aid in digestion (Fisher et al., 2006;Pain et al., 2019;Grade et al., 2019). Lead pellets and bullet fragments may also be accidently ingested by predatory and scavenging birds when consuming animals killed by hunters (e.g., Ishii et al., 2017;Helander et al., 2021). ...
Lead (Pb) exposure is a widespread wildlife conservation threat, but impacts on reptile populations remain poorly documented. In this study, we examined Pb exposure and accumulation in a wild population of Nile crocodiles (Crocodylus niloticus) at Lake St Lucia, South Africa. Recreational angling has occurred in the area since the 1930s and incidental ingestion of Pb fishing weights has previously been identified as a major source of Pb poisoning in the local crocodile population. In 2019, we sampled blood and tail fat tissues from wild (n = 22) and captive (n = 3) crocodiles at Lake St Lucia to investigate potential impacts of chronic Pb exposure on crocodilian health. Lead was detected in blood samples of all wild crocodiles, although concentrations varied widely between individuals (86–13,100 ng ml⁻¹). The incidence of Pb poisoning was higher in male crocodiles, with mean blood lead (BPb) concentrations in males (3780 ± 4690 ng ml⁻¹) significantly (p < 0.001) higher compared to females (266 ± 230 ng ml⁻¹). Blood Pb concentrations were correlated with concentrations measured in tail fat tissue (n.d – 4175 ng g⁻¹ wet wt.). Although most of the crocodiles sampled appeared to be in good physical condition, highly elevated BPb concentrations (>6000 ng ml⁻¹) were associated with markedly suppressed packed cell volumes (4.6–10.8%) and severe deterioration in tooth condition. These findings suggest that anaemia and tooth loss may be clinical signs of long-term environmental exposure to Pb. Although previously undocumented in crocodilians, these symptoms are consistent with Pb poisoning observed in birds and mammals, and suggest that crocodilians may be more susceptible to the long-term toxic effects of Pb than previously thought. In light of these findings, we suggest that the impact of accumulated Pb on crocodilian fitness, reproduction and mortality requires urgent attention.
... Once on the seabed, derelict hooks and short sections of monofilament line may be buried in soft sediment or incorporated into hard substrate, or may snag on a three-dimensional surface [85]. While posing minimal risk of ghost fishing, the derelict gear, however, risks causing other adverse consequences, include transporting and transferring toxins (e.g., from lead in branchline weights, and chemicals used in light-sticks, [91,142,150,201]) and microplastics into marine food webs; altering and damaging habitat; and reducing the socioeconomic value of coastal and nearshore habitats [85]. ...
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There has been increasing recognition of the need to address adverse ecological and socioeconomic effects of abandoned, lost and discarded fishing gear (ALDFG). This component of marine debris has been progressively problematic over recent decades with the rapid expansion of global fisheries’ footprint and effort, and the transition to synthetic and more durable materials for gear components. ALDFG drivers and consequences vary substantially by gear type, region, scale and individual fishery within these and other broad categories, including by the robustness of the fisheries management framework and influence of market-based incentives. Therefore, relevant interventions to avoid, minimize and remediate ALDFG depend on the fishery-specific context. This study compiled comprehensive, cross-referenced databases of causes of ALDFG production, and mitigation methods and enabling conditions for effective ALDFG management. Management interventions were categorized within a sequential mitigation hierarchy, where approaches to avoid and minimize ALDFG production and adverse consequences are considered before potentially less effective and more costly interventions for remediation and offsets. The linked databases enable discovery of the most promising ALDFG mitigation methods and priority fisheries management improvements so that a broader range of ALDFG policy interventions can be tapped. Illustrative case studies of ALDFG drivers and interventions were explored for gillnet, pelagic longline, trap and anchored fish aggregating device fisheries. By enabling stakeholders to identify the subset of alternative interventions that are relevant to fishery-specific ALDFG drivers and enabling conditions, the cross-referenced databases guide the allocation of resources to mitigate this especially problematic component of global marine litter.
The abundance and characteristics of marine debris originating from recreational fishing were examined across 55 sites in four different regions in Korea. The result shows that the average abundance of debris was 4.3 ± 4.2 (n/m2) in terms of the number and 13.4 ± 18.1 (g/m2) in terms of the weight, and the most often found item was fishing lines (<1 m). Detrimental fishing debris such as fishing lines, hooks and weights comprised 50.9 % of the total debris, suggesting significant impacts on wildlife. A questionnaire survey was conducted with 374 anglers across all four regions to understand their behaviors, perceptions, and preferences regarding government policies. Most of the respondents were aware of the adverse impacts of recreational fishing debris on the environment, and >50 % agreed with the introduction of recreational fishing licenses. This study highlights the urgent need to raise awareness and address the undervalued problem of recreational fishing debris.
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Legal regulation of human activities is a key mechanism for alleviating anthropogenic impacts on wildlife populations. Conservationists frequently request the regulation of toxic substances such as lead, which can be harmful to animals even at low levels of exposure. However, without assessments of the effectiveness of legislation , such regulations may be undermined or revoked and opportunities to make amendments to improve the legislation may be missed. Here we carried out a population-level study of the effectiveness of regulating the use of lead. We show that the increase in population size of a charismatic waterbird (the mute swan Cygnus olor) in Great Britain over 39 years was best explained by the regulation of lead fishing weights, rather than by changes in food supplies, habitat quality, or winter temperature. The proportion of individuals dying of lead poisoning dropped following regulation, from 0.34 to 0.06, suggesting that higher survival rates were the demographic driver of increased population size. Legal restriction therefore succeeded in alleviating, although not eliminating , the impact of poisoning on mute swans. Restrictions on the use of toxic substances, and their release into the environment, would provide an effective conservation mechanism for reducing negative effects of human activities on wildlife populations. At a time when many policy makers prefer to rely on voluntary actions or market forces to achieve change, our study highlights that legal regulations on human activities can be an effective means of alleviating anthropogenic impacts on wildlife.
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The chemical composition of non-lead, non-toxic, gunshot used for hunting waterfowl is regulated only in Canada and the USA. No nation regulates the composition of non-lead fishing weights, rifle bullets, and gunshot used for upland game hunting. Compositional criteria for these non-lead products are proposed here, based on established experimental toxicity protocols. Because of the demonstrated acute toxicity of ingested zinc shot to birds, fishing weights and gunshot should never be made of this pure metal. Nickel should be avoided as an incidental component of gunshot because of potential carcinogenicity concerns about such embedded shot in birds and other animals. These compositional criteria could be adopted by all nations undertaking the transition to non-lead fishing weights and hunting ammunition. The listed criteria would facilitate production and international trade in non-lead products, and promote easier enforcement and user compliance with non-lead standards.
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The human immune system is constantly exposed to xenobiotics and pathogens from the environment. Although the mechanisms underlying their influence have already been at least partially recognized, the effects of some factors, such as lead (Pb), still need to be clarified. The results of many studies indicate that Pb has a negative effect on the immune system, and in our review, we summarize the most recent evidence that Pb can promote inflammatory response. We also discuss possible molecular and biochemical mechanisms of its proinflammatory action, including the influence of Pb on cytokine metabolism (interleukins IL-2, IL-4, IL-8, IL-1b, IL-6), interferon gamma (IFNγ), and tumor necrosis factor alpha (TNF-α); the activity and expression of enzymes involved in the inflammatory process (cyclooxygenases); and the effect on selected acute phase proteins: C-reactive protein (CRP), haptoglobin, and ceruloplasmin. We also discuss the influence of Pb on the immune system cells (T and B lymphocytes, macrophages, Langerhans cells) and the secretion of IgA, IgE, IgG, histamine, and endothelin.
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Lead poisoning of animals due to ingestion of fragments from lead-based ammunition in carcasses and offal of shot wildlife is acknowledged globally and raises great concerns about potential behavioral effects leading to increased mortality risks. Based on analyses of tracking data, we found that even sub-lethal lead concentrations in blood (25 ppb, wet weight), can likely negatively affect movement behavior (flight height and movement rate) of free-ranging scavenging Golden Eagles (Aquila chrysaetos). Lead levels in liver of recovered post-mortem analyzed eagles suggested that sub-lethal exposure increases the risk of mortality in eagles. Such adverse effects on animals are probably common worldwide and across species, where game hunting with lead-based ammunition is widespread. Our study highlights lead exposure as a considerably more serious threat to wildlife conservation than previously realized and suggests implementation of bans of lead ammunition for hunting.
Lead (Pb) is a nonessential, highly toxic heavy metal, whose known effects on biological systems are always deleterious. Lead is very soft (< 35 diamond pyramid hardness) and dense (11.34 g/cm) and occurs as an important constituent of more than 200 minerals. The average concentration in the earth’s crust is 0.016g Pb/kg soil, making it a relatively rare metal. Small amounts of lead are released into the environment by natural processes, including the weathering of rocks, igneous activity, and radioactive decay. Present anthropogenic lead emissions have resulted in soil and water lead concentrations up to several orders of magnitude higher than naturally occurring concentrations.
Many urban areas have elevated soil lead concentrations due to prior large-scale use of lead in products such as paint and automobile gasoline. This presents a potential problem for the growing numbers of wildlife living in urbanized areas as lead exposure is known to affect multiple physiological systems, including the nervous system, in vertebrate species. In humans and laboratory animals, low-level lead exposure is associated with neurological impairment, but less is known about how lead may affect the behavior of urban wildlife. We focused on the Northern Mockingbird Mimus polyglottos, a common, omnivorous North American songbird, to gain insights into how lead may affect the physiology and behavior of urban wildlife. We predicted that birds living in neighborhoods with high soil lead concentrations would (a) exhibit elevated lead concentrations in their blood and feathers, (b) exhibit lower body condition, (c) exhibit less diverse and consistent vocal repertoires, and (d) behave more aggressively during simulated conspecific territorial intrusions compared to birds living in neighborhoods with lower soil lead concentrations. Controlling for other habitat differences, we found that birds from areas of high soil lead had elevated lead concentrations in blood and feathers, but found no differences in body condition or vocal repertoires. However, birds from high lead areas responded more aggressively during simulated intrusions. These findings indicate that sub-lethal lead exposure may be common among wildlife living in urban areas, and that this exposure is associated with increased aggression. Better understanding of the extent of the relationship between lead exposure and aggression and the consequences this could have for survival and reproduction of wild animals are clear priorities for future work in this and other urban ecosystems.
Introduction: This is the 34th Annual Report of the American Association of Poison Control Centers’ (AAPCC) National Poison Data System (NPDS). As of 1 January 2016, 55 of the nation’s poison centers (PCs) uploaded case data automatically to NPDS. The upload interval was 9.50 [7.33, 14.6] (median [25%, 75%]) min, facilitating a near real-time national exposure and information database and surveillance system. Methods: We analyzed the case data tabulating specific indices from NPDS. The methodology was similar to that of previous years. Where changes were introduced, the differences are identified. Cases with medical outcomes of death were evaluated by a team of medical and clinical toxicologist reviewers using an ordinal scale of 1–6 to assess the Relative Contribution to Fatality (RCF) of the exposure. Results: In 2016, 2,710,042 closed encounters were logged by NPDS: 2,159,032 human exposures, 54,019 animal exposures, 490,215 information cases, 6687 human confirmed non-exposures, and 89 animal confirmed non-exposures. US PCs also made 2,718,022 follow-up calls in 2016. Total encounters showed a 2.94% decline from 2015, while health care facility (HCF) human exposure cases increased by 3.63% from 2015. All information calls decreased by 12.5% but HCF information calls increased 0.454%, and while medication identification requests (Drug ID) decreased 29.6%, human exposure cases were essentially flat, decreasing by 0.431%. Human exposures with less serious outcomes have decreased 2.59% per year since 2008 while those with more serious outcomes (moderate, major or death) have increased by 4.39% per year since 2000. The top five substance classes most frequently involved in all human exposures were analgesics (11.2%), household cleaning substances (7.54%), cosmetics/personal care products (7.20%), sedatives/hypnotics/antipsychotics (5.84%), and antidepressants (4.74%). As a class, sedative/hypnotics/antipsychotics exposures increased most rapidly, by 10.7% per year (2088 cases/year), over the last 15 years for cases showing more serious outcomes. The top five most common exposures in children age 5 years or less were cosmetics/personal care products (13.3%), household cleaning substances (11.1%), analgesics (9.21%), foreign bodies/toys/miscellaneous (6.48%), and topical preparations (5.07%). Drug identification requests comprised 28.1% of all information calls. NPDS documented 1977 human exposures resulting in death; 1492 (75.5%) of these were judged as related (RCF of 1 – undoubtedly responsible, 2 – probably responsible, or 3 – contributory). Conclusions: These data support the continued value of PC expertise and need for specialized medical toxicology information to manage more serious exposures, despite a decrease in cases involving less serious exposures. Unintentional and intentional exposures continue to be a significant cause of morbidity and mortality in the US. The near real-time, always current status of NPDS represents a national public health resource for collecting and monitoring US exposure cases and information calls. The continuing mission of NPDS is to provide a nationwide infrastructure for surveillance for all types of exposures (e.g. foreign body, infectious, venomous, chemical agent, or commercial product), and the identification and tracking of significant public health events. NPDS is a model system for the real-time surveillance of national and global public health.
Poisoning from lead fishing tackle has been identified as the leading cause of mortality in adult common loons (Gavia immer). As a K-selected species, adult survival is a critical component in the population demography of loons, but the population-level effects of mortality from ingested lead tackle on loons have not been quantified. We used a long-term dataset (1989–2012) on common loon mortality in New Hampshire, USA, to describe the types of lead tackle ingested by loons, investigate methods of ingestion of lead tackle, document the number and rate of adult mortalities resulting from lead tackle, and test for a population-level effect of lead tackle on the loon population in New Hampshire. Nearly half (48.6%) of collected adult mortalities resulted from lead toxicosis from ingested lead fishing tackle, representing an adjusted annual mortality rate of 1.7 ± 0.6% (SD) of the statewide population. Jigs accounted for 52.6% and sinkers for 38.8% of the archived lead tackle objects removed from loons, a higher proportion of jigs than has been reported in previous studies. The timing of lead tackle mortalities and a high incidence of accompanying non-lead associated fishing gear (hooks, fishing line, leaders, swivels, wire), which peaked in July and August, suggest that loons obtain the majority of lead tackle from current fishing activity rather than from a reservoir of lead tackle on lake bottoms. To project the statewide loon population in the absence of lead fishing tackle as a stressor, we constructed a retrospective population model, which re-inserted loons that died from lead tackle into the population, and used linear regression to test for a population-level effect. We defined a population-level effect as a difference in the population growth rate (λ). We estimated that lead tackle mortality reduced the population growth rate (λ) by 1.4% and the statewide population by 43% during the years of the study. This study suggests that replacing lead fishing sinkers and jigs weighing ≤28.4 g with non-toxic alternatives would result in an immediate benefit to the loon population in New Hampshire.
Lead (Pb) from spent gunshot and fishing sinkers is recognized as the main source of Pb poisoning among waterfowl. It is also suspected to directly pollute water and sediments, but no appropriate, comprehensive evaluation of this issue has so far been carried out. An experiment on Pb pellets in microcosms (n = 160) with two sediment types (mud and gravel), three water pH values (4, 7 and 9) and two wind levels (wind and windless simulation) was therefore run. Substantial differences in Pb transfer (measured with ICP-OES) between sediment types and pH levels of water were observed. Simulated wind conditions were a significant factor only for some variables and circumstances. The strongest Pb deposit to water and sediments occurred in mud microcosms with water of pH value of 4. Median pellet erosion during the experiment differed little between sediment types. The experiment revealed that Pb transfer from spent gunshot to the environment occurs only in specific environmental conditions.