Monday, June 17, 2013
HOW DOES MERCURY GET INTO FISH?
Mercury in the Environment
Mercury is an atmospherically deposited toxic metal, which has contaminated waterbodies. Mercury is emitted to the atmosphere during the combustion of fossil fuels and municipal and medical waste. It is deposited to watersheds where it transforms into methylmercury. Highly toxic methylmercury is easily assimilated by microscopic organisms at the bottom of the food web. Once in the food web, methylmercury bio-accumulates, reaching higher concentrations in the tissues of predatory fishes. Mercury is also directly assimilated by fish across the gill membrane.
Mercury and Health
Mercury has been found at levels in fresh water fish in many lakes and ponds in the northeast exceeding health guidelines. Scientific studies have linked mercury with developmental problems, and with kidney and nervous system damage. Women who are pregnant should not eat fish with high levels of mercury. Mercury affects fetal development, preventing the brain and nervous system from developing normally. Affected children show lowered intelligence, impaired hearing, and poor coordination. Walleye, smallmouth bass, and chain pickerel show the highest concentrations of mercury. Please see the Health Department’s website (www.healthvermont.gov) for the most current advisory.
More Information on Mercury in Fish
It is illegal to use lead sinkers weighing one-half ounce or less.
Loons and some other water birds can die from lead poisoning after swallowing lead fishing sinkers and jigs lost by anglers. You can help by switching to non-lead fishing tackle and by helping to spread the word for others to do the same.
A loon with lead poisoning may have physical and behavioral changes, including loss of balance, gasping, tremors, and impaired ability to fly. A weakened bird is more vulnerable to predators and it may have trouble feeding, mating, nesting, or caring for its young. After ingesting lead some loons lose weight and die within two to three weeks.
Research in the northeastern United States and Canada has documented that poisoning from lead sinkers and jigs can account for 10 to 50 percent of dead adult loons found. It is the leading cause of observed loon deaths here in the Northeast.
What can you do to help?
- Use non-lead fishing weights.
- Spread the word. Tell other anglers about the problem and encourage them to switch to non-lead alternatives.
- Remove lead sinkers and jigs from your tacklebox.
Some other ways to help loons:
- Remove spent fishing line and other materials from Vermont waters and shorelines to reduce entanglement, another cause of loon deaths.
- Maintain a respectful distance from wild animals. Use binoculars to get a great view.
- Observe and report loon sightings and nest activities, but do not approach a nest.
- Participate in the annual Vermont Loon Watch on the third Saturday in July. For information call 802-241-3700.
- Support continuing loon and other nongame wildlife management efforts by donating to the Vermont Nongame Wildlife Fund on your Vermont income tax form or on hunting and fishing license applications.
- Buy Vermont Conservation License Plates for your vehicle.
Preventing Human Lead Exposure from Fishing Sinkers
Some fishing sinkers contain lead. Lead can be dangerous to your body if breathed in or eaten. Prolonged and high levels of exposure to lead can cause brain and nerve damage, slowed growth in children, and reproductive problems and high blood pressure in adults.
In order to prevent exposure to lead, please handle lead sinkers with care and use the following guidelines:
- Wash hands with soap after holding or using lead sinkers
- Never put lead sinkers in your mouth. This includes biting down on or chewing lead sinkers.
- Never handle or eat food immediately after handling lead sinkers unless hands have been washed with soap first.
- Take proper precautions when melting lead and pouring sinkers at home.
- Switch to sinkers that do not contain lead or zinc. Alternatives to lead sinkers are made of steel, bismuth, tungsten, resin and glass.
If you suspect lead poisoning in your child or yourself, or you would like further information, call:
Vermont Department of Health
Childhood Lead Poisoning Prevention Program
800-439-8550 or 802-865-7786
This office provides screening, public information and technical assistance:
The National Lead Information Center