Cape wildlife hospitals treat over 50 waterfowl with lead poisoning each year

Asad Yung   Cape Cod Times

Published May 29, 2021 

Even though the use of lead shot for hunting waterfowl was banned in 1991, wildlife hospitals on Cape Cod continue to see 50-70 cases of lead poisoning a year. 

Most of these tend to be waterfowl, such as swans, ducks and geese. Lead poisoning in waterfowl is an issue with a long history, not just in the Cape area, but nationwide. 

Wild Care Cape Cod in Eastham receives and treats 10-20 patients per year, while the Cape Wildlife Center in Barnstable, a branch of New England Wildlife Centers, cares for around 50. 

There are probably thousands more with levels of lead in their system that go unnoticed, according to Zak Mertz, director of the Barnstable rescue.

“Probably 70% of waterfowl we test have some detectable amount of lead in their blood;” Mertz said. 

Although lead poisoning is treatable, it is a long and expensive process which can take multiple months and cost several hundreds of dollars for each case. This puts pressure on nonprofits like the New England Wildlife Centers and Wild Care, who aim to provide free veterinarian care for animals. 

An animal with lead poisoning would be treated with chelation therapy, which would allow molecules of calcium EDTA to bind to the lead and draw it out of the body through the urinary tract.  

Most serious lead poisoning cases brought in on Cape  are animals that have ingested lead-based fishing equipment, such as fishing sinkers, or lead-based hunting equipment such as lead shot, according to both Stephanie Ellis of Wild Care and Zak Mertz of the Cape Cod Branch of the New England Wildlife Centers.

Symptoms in waterfowl 

To tell if a waterfowl has lead poisoning, you can look for several symptoms. One is ataxia, or a “drunk-walk.” This would mean that a duck or goose is stumbling from one side to the other, suggesting that their coordination is impaired. 

Another symptom could be seizures, which happen at high levels of lead poisoning. 

GI distress could also be a symptom, as it suggests that an animal is not getting all the nutrients it needs. 

These symptoms are like what happens to humans with lead poisoning as well. 

Long-term consequences 

Long-term consequences on the ecosystem can be seen in the example of the California Condor. Lead poisoning has been a major factor in the decline of populations of the California Condor, according to the California Department of Fish and Wildlife. 

“From an ecosystem standpoint, it’s systemic” Mertz said.

There are exposure points for lead all over the food chain for different animals, Mertz said. This means that waterfowl can get it from one source, while rodents can get it from another, and predatory species can get it from consuming animals with levels of lead, it can become extremely difficult to manage and track, Mertz said. according to Zak.  

“Over time, you’re probably losing a lot of ecosystem services,” Mertz said. “We’re probably losing more animals and losing more services than we even understand.” 

By services, Zak means that certain functions in the environment can be lost. For example, if hawks and owls get sick and die off, there would be no one left to control rodent populations, since controlling the rodent population is a service that hawks and owls provide.

There are also significant risks to humans who use lead in hunting and fishing, according to Ronnie Levin, an instructor at the Harvard T.H. Chan School of Public Health.  

“When people go hunting, the explosion of the bullet volatilizes some of the lead. And so, hunters have personally high lead exposure” says Levin.  

This applies to those who shoot at ranges as well. 

The use of lead fishing equipment poses various risks as well. 

“Weights have typically been lead, and so as you handle them, part of what makes lead such a wonderful metal is that it's very soft, it's easy to fashion,” Levin said.  “People use the lead, they play with it, and so they’re exposed.” 

The lead then has a danger of being ingested when a person touches their mouth or nose after touching lead. 

What causes lead poisoning? 

There are two ways animals develop lead poisoning —  through a large dose, such as ingesting a lead fishing sinker or by accumulating small increments over a long period of time.

However, a large majority of the lead poisoning cases received by wildlife hospitals on the Cape are waterfowl who have ingested a single large dose of lead  in the form of a lead fishing sinker, or lead pellets from inside shotgun shells, Mertz said.

Do people still use lead fishing sinkers or lead shot? 

In 1991, federal legislation mandated that hunters stop using lead shot to hunt waterfowl. However, this legislation only applied to waterfowl, meaning virtually all other hunting can still legally take place with lead.

Additionally, hunting that takes place at a shooting range can also utilize lead. This contributes a vast amount of lead to the environment, as the average person at a shooting range fires off many more bullets than the average hunter. Again, if the shooting range is located near water or shoots over marshes, this can pose a risk to waterfowl. 

Although fishing sinkers under 1 ounce are outlawed in the state of Massachusetts, this only applies to inland waters. So, if a person was fishing on the sea, they could still use fishing sinkers under 1 ounce, which are more likely to be ingested by waterfowl due to their smaller size.

Also, lead sinkers, weights, and jigs, over 1 oz. are completely legal. If this lead-based fishing equipment gets lost in the environment, which is common, it can sit in waterways, which leads to bioaccumulation of lead in sediments, invertebrates, vertebrates, etc. according to Ellis,  from Wild Care. Certain other waterbirds can also ingest larger amounts of lead.  

It is likely that lead has accumulated at the bottom of bodies of water where hunting and fishing were common practice. 

“Lead is really persistent” Mertz said. “It takes an incredibly long time to break down, so a lot of the sources of lead that get into the environment stay there and can be a hazard to animals for as long as they’re accessible.” 

 And although there is a sedimentation rate which will eventually push this old lead down to the point where it can’t be reached anymore, it is unclear how long this will take to happen. The number of cases being received by wildlife hospital on the Cape suggests that it has not happened yet. 

“We have the historic sources of lead, you know, the old stuff that’s out in the sediments and the marshes, but we have the new stuff that’s still being introduced every year,” said Mark Pokras, a retired professor at the Tufts School of Veterinary Science. 

What can be done? 

One of the most tangible things people can do is to simply pick up fishing equipment that may be left around bodies of water, Mertz said. This can help reduce the amount of lost fishing equipment in the environment and reduce the risks it poses to wildlife. 

“By simply walking the edge of a pond, or along the Cape Cod Canal, or you know, anywhere that is a big, heavily used fishing spot, you’re probably going to start seeing pieces of bits of lead, and old sinkers, and that kind of stuff. And so cleaning that up is a huge impact,” he said. 

Another important step is hunter and fisher education, according to Wild Care's Ellis, believes says hunters and fishers should be educated on the impact of lead in the environment, as well as to learn about nonlead alternatives.  

As far as the old lead that has accumulated, unfortunately there isn’t much we can do. Pokras said to attempt to remove the lead that has accumulated at the bottom of water would be impractical, wildly expensive, and could potentially destroy the habitat in the process. 

Pokras said an especially effective way to get hunters and fishermen to stop using lead-based products, is for environmentally conscious hunters and fishermen to convince their friends.

Current legislation 

A representative of Barnstable County’s Natural Resources Department said the county does not create its own regulations regarding lead, but rather enforces state regulations. 

A representative of the Massachusetts Department of Wildlife and Fisheries was not aware of any new legislative efforts on the state level. 

In the state of Massachusetts, lead sinkers, weights, and jigs under 1 ounce are outlawed for fishing on inland waters. The reason why smaller lead-based fishing equipment are outlawed is because they are more likely to be ingested by animals such as waterfowl. This does not include lead sinkers, weights, and jigs over 1 ounce. Additionally, lead sinkers, weights, and jigs, under 1 ounce can still be used on non-inland waters. 

On a federal level, an order to expand the use of nontoxic ammunition and tackle was released in 2017 as part of the Obama administration, according to wildlife.org. The director the U.S. Fish and Wildlife Service at the time, Dan Ashe, released Directors Order 219, which stated that it would: “require the use of nontoxic ammunition and fishing tackle to the fullest extent practicable for all activities on Service lands, waters, and facilities by January 2022, except as needed for law enforcement or health and safety uses, as provided for in policy.” 

This policy, however, was overturned by Department of the Interior Secretary Ryan Zinke, according to massaudubon.org. Zinke led several environmental rollbacks as part of the Trump administration, according to the New York Times. Zinke resigned from his position amidst multiple federal investigations.