Prevalence
Lead is now a common environmental pollutant. [1] For the birds, a common source is lead shot, eaten as grit.
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Animal lead poisoning (also known as avian plumbism, or avian saturnism for birds) is a veterinary condition and pathology caused by increased levels of the heavy metal lead in an animal's body.
Lead interferes with a variety of body and natural processes. It is toxic to many organs and tissues including the heart, bones, intestines, kidneys, and reproductive and nervous systems. It mainly affects the haematopoietic system. It also affects the sulfhydryl group containing enzymes and also thiol content of erythrocyte. Furthermore, it inhibits the enzyme delta amino levaminic acid dehydrogenase enzyme (ALA) which is present in the red blood cell. It is therefore particularly toxic to young animals, mainly dogs and cattle.
As in humans, animal lead poisoning may be acute (from intense exposure of short duration) or chronic (from repeat low-level exposure over a prolonged period). Acute intoxication can quickly lead to death.
Lead is now a common environmental pollutant. [1] For the birds, a common source is lead shot, eaten as grit.
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Those routes include contaminated air, water, soil, and food, and also, for birds, ingestion of grit (lead shots, lead bullets), ingestion of paints, materials that are left out from the factories, like batteries, etc..
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The use of alternative metals in shot such as steel and tungsten have been implemented since 1991 in the United States for all migratory bird hunting. Some ammunition manufacturers are producing bullets made of solid copper or a mix of 95% copper and 5% zinc, which are in ways superior to lead bullets. There have been efforts to dredge marshlands to remove the build-up of lead in the sediment from the past, however efforts such as this are expensive.
For precious animals;
The mainstays of treatment are removal from the source of lead and, for precious animals who have significantly high blood lead levels or who have symptoms of poisoning, chelation therapy with a chelating agent.
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Lead, one of the leading causes of toxicity in waterfowl, has been known to cause die-offs of wild bird populations. [2] When hunters use lead shot, waterfowl such as ducks and other species (swan especially) can ingest the spent pellets later and be poisoned; predators that eat these birds are also at risk. [3] Lead shot-related waterfowl poisonings were first documented in the US in the 1880s. [4] By 1919, the spent lead pellets from waterfowl hunting were positively identified as the source of waterfowl deaths. [5] Lead shot has been banned for hunting waterfowl in several countries, [4] including the US in 1991 and 1997 in Canada. [6] Other threats to wildlife include lead paint, sediment from lead mines and smelters, and lead weights from fishing lines. [6] Lead in some fishing gear has been banned in several countries. [4]
The critically endangered California condor has also been affected by lead poisoning. As scavengers, condors eat carcasses of game that have been shot but not retrieved, and with them the fragments from lead bullets; this increases their lead levels. [7] Among condors around the Grand Canyon, lead poisoning due to eating lead shot is the most frequently diagnosed cause of death. [7] In an effort to protect this species, in areas designated as the California condor's range, the use of projectiles containing lead has been banned to hunt deer, wild pig, elk, pronghorn antelope, coyotes, ground squirrels, and other non-game wildlife. [8] Also, conservation programs exist which routinely capture condors, check their blood lead levels, and treat cases of poisoning. [7]
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Cows and horses, [9] as well as pet animals are also susceptible to the effects of lead toxicity. [2] Sources of lead exposure in pets can be the same as those that present health threats to humans sharing the environment, such as paint and blinds, and there is sometimes lead in toys made for pets. [2] Lead poisoning in a pet dog may indicate that children in the same household are at increased risk for elevated lead levels. [4]
Toxicology is a scientific discipline, overlapping with biology, chemistry, pharmacology, and medicine, that involves the study of the adverse effects of chemical substances on living organisms and the practice of diagnosing and treating exposures to toxins and toxicants. The relationship between dose and its effects on the exposed organism is of high significance in toxicology. Factors that influence chemical toxicity include the dosage, duration of exposure, route of exposure, species, age, sex, and environment. Toxicologists are experts on poisons and poisoning. There is a movement for evidence-based toxicology as part of the larger movement towards evidence-based practices. Toxicology is currently contributing to the field of cancer research, since some toxins can be used as drugs for killing tumor cells. One prime example of this is ribosome-inactivating proteins, tested in the treatment of leukemia.
A toxic heavy metal is any relatively dense metal or metalloid that is noted for its potential toxicity, especially in environmental contexts. The term has particular application to cadmium, mercury and lead, all of which appear in the World Health Organization's list of 10 chemicals of major public concern. Other examples include manganese, chromium, cobalt, nickel, copper, zinc, silver, antimony and thallium.
Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance faster than it can be lost or eliminated by catabolism and excretion. Thus, the longer the biological half-life of a toxic substance, the greater the risk of chronic poisoning, even if environmental levels of the toxin are not very high. Bioaccumulation, for example in fish, can be predicted by models. Hypothesis for molecular size cutoff criteria for use as bioaccumulation potential indicators are not supported by data. Biotransformation can strongly modify bioaccumulation of chemicals in an organism.
Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a substructure of the organism, such as a cell (cytotoxicity) or an organ such as the liver (hepatotoxicity). Sometimes the word is more or less synonymous with poisoning in everyday usage.
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertility, and tingling in the hands and feet. It causes almost 10% of intellectual disability of otherwise unknown cause and can result in behavioral problems. Some of the effects are permanent. In severe cases, anemia, seizures, coma, or death may occur.
Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashes, anxiety, memory problems, trouble speaking, trouble hearing, or trouble seeing. High-level exposure to methylmercury is known as Minamata disease. Methylmercury exposure in children may result in acrodynia in which the skin becomes pink and peels. Long-term complications may include kidney problems and decreased intelligence. The effects of long-term low-dose exposure to methylmercury are unclear.
A pesticide poisoning occurs when pesticides, chemicals intended to control a pest, affect non-target organisms such as humans, wildlife, plants, or bees. There are three types of pesticide poisoning. The first of the three is a single and short-term very high level of exposure which can be experienced by individuals who commit suicide, as well as pesticide formulators. The second type of poisoning is long-term high-level exposure, which can occur in pesticide formulators and manufacturers. The third type of poisoning is a long-term low-level exposure, which individuals are exposed to from sources such as pesticide residues in food as well as contact with pesticide residues in the air, water, soil, sediment, food materials, plants and animals.
Chelation therapy is a medical procedure that involves the administration of chelating agents to remove heavy metals from the body. Chelation therapy has a long history of use in clinical toxicology and remains in use for some very specific medical treatments, although it is administered under very careful medical supervision due to various inherent risks, including the mobilization of mercury and other metals through the brain and other parts of the body by the use of weak chelating agents that unbind with metals before elimination, exacerbating existing damage. To avoid mobilization, some practitioners of chelation use strong chelators, such as selenium, taken at low doses over a long period of time.
Acceptable daily intake or ADI is a measure of the amount of a specific substance in food or drinking water that can be ingested (orally) daily over a lifetime without an appreciable health risk. ADIs are expressed usually in milligrams per kilograms of body weight per day.
Cadmium is a naturally occurring toxic metal with common exposure in industrial workplaces, plant soils, and from smoking. Due to its low permissible exposure in humans, overexposure may occur even in situations where only trace quantities of cadmium are found. Cadmium is used extensively in electroplating, although the nature of the operation does not generally lead to overexposure. Cadmium is also found in some industrial paints and may represent a hazard when sprayed. Operations involving removal of cadmium paints by scraping or blasting may pose a significant hazard. The primary use of cadmium is in the manufacturing of NiCd rechargeable batteries. The primary source for cadmium is as a byproduct of refining zinc metal. Exposures to cadmium are addressed in specific standards for the general industry, shipyard employment, the construction industry, and the agricultural industry.
Succimer, sold under the brand name Chemet among others, is a medication used to treat lead, mercury, and arsenic poisoning. When radiolabeled with technetium-99m, it is used in many types of diagnostic testing. A full course of Succimer lasts for 19 days of oral administration. A second course should be given when more than two weeks pass after the first course.
Fipronil is a broad-spectrum insecticide that belongs to the phenylpyrazole chemical family. Fipronil disrupts the insect central nervous system by blocking the ligand-gated ion channel of the GABAA receptor and glutamate-gated chloride (GluCl) channels. This causes hyperexcitation of contaminated insects' nerves and muscles. Fipronil's specificity towards insects is believed to be due to its greater binding affinity for the GABAA receptors of insects than to those of mammals, and for its action on GluCl channels, which do not exist in mammals. As of 2017, there does not appear to be significant resistance among fleas to fipronil.
Shot is a collective term for small spheres or pellets, often made of lead. These have been projected from slings since ancient times and were the original projectiles for shotguns and are still fired primarily from shotguns and grenade launchers, while it's less commonly used in riot guns. Shot shells are also available in many handgun calibers in a configuration known as "birdshot", "rat shot", or "snake shot".
Metal toxicity or metal poisoning is the toxic effect of certain metals in certain forms and doses on life. Some metals are toxic when they form poisonous soluble compounds. Certain metals have no biological role, i.e. are not essential minerals, or are toxic when in a certain form. In the case of lead, any measurable amount may have negative health effects. It is often thought that only heavy metals can be toxic, but lighter metals such as beryllium and lithium may also be in certain circumstances. Not all heavy metals are particularly toxic, and some are essential, such as iron. The definition may also include trace elements when abnormally high doses may be toxic. An option for treatment of metal poisoning may be chelation therapy, a technique involving the administration of chelation agents to remove metals from the body.
Environmental toxicology is a multidisciplinary field of science concerned with the study of the harmful effects of various chemical, biological and physical agents on living organisms. Ecotoxicology is a subdiscipline of environmental toxicology concerned with studying the harmful effects of toxicants at the population and ecosystem levels.
Ethylene glycol poisoning is poisoning caused by drinking ethylene glycol. Early symptoms include intoxication, vomiting and abdominal pain. Later symptoms may include a decreased level of consciousness, headache, and seizures. Long term outcomes may include kidney failure and brain damage. Toxicity and death may occur after drinking even in a small amount as ethylene glycol is more toxic than other diols.
Copper toxicity is a type of metal poisoning caused by an excess of copper in the body. Copperiedus could occur from consuming excess copper salts, but most commonly it is the result of the genetic condition Wilson's disease and Menke's disease, which are associated with mismanaged transport and storage of copper ions. Copper is essential to human health as it is a component of many proteins. But hypercupremia can lead to copper toxicity if it persists and rises high enough.
Toxic abortion is a medical phenomenon of spontaneous abortion, miscarriage, or stillbirth caused by toxins in the environment of the mother during pregnancy, especially as caused by toxic environmental pollutants, though sometimes reported as caused by naturally occurring plant toxins
Occupational toxicology is the application of toxicology to chemical hazards in the workplace. It focuses on substances and conditions that people may be exposed to in workplaces, including inhalation and dermal exposures, which are most prevalent when discussing occupational toxicology. These environmental and individual exposures can impact health, and there is a focus on identifying early adverse affects that are more subtle than those presented in clinical medicine.
Lead poisoning is a significant health issue affecting the raptor population, amongst other species. Without rehabilitation, many raptors will succumb to the symptoms of lead poisoning once affected. While the general public may not know how they are possibly contributing to the problem, nearly 100% of lead poisoning can be prevented if humans paid close attention to their hunting and angling practices. There are two major contributors to these avian species being affected by lead poisoning and they are through hunters using lead ammunition, or through anglers using lead tackles.
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