Exposure (toxicology) facts for kids
Toxic exposure means that a toxin (poison) has touched or gotten inside a person's body. When this happens, we say the person has been exposed to the toxin.
After someone is exposed to a toxin, many things can affect how their body reacts. This reaction is called toxicity. Toxicity includes what symptoms a person might have. Exposure can happen by accident or on purpose.
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What is a Toxin?
Anything can be a toxin if too much of it gets into a person's body. For example, even water can be toxic! If someone drinks a lot of water (like more than 6 gallons in one day), they can get water toxicity. This is also called "water poisoning."
When this happens, the body's cells swell up with extra water. Swelling in the brain's cells can cause brain damage or even death. Normally, water helps us live. But in very large amounts, it can become a toxin and be harmful.
Types of Exposure
There are two main types of toxic exposure: acute and chronic.
- An acute exposure happens only one time. It usually lasts for 24 hours or less.
- A chronic exposure happens many times. It happens over a long period, often for more than three months.
How Toxins Enter the Body
Toxins can get into the body in four main ways. These are called "routes of exposure." The way a toxin enters the body affects how harmful it might be.
Breathing In Toxins
Toxins can enter the body through inhalation. This means the person breathes in the toxin. If a toxin is a gas, breathing it in is a common way it gets into the body.
When a toxin is breathed in, it can hurt the airways and the lungs. Some toxins can also go from the lungs into the bloodstream. The bloodstream then carries the toxin to all the organs in the body. This can damage those organs. Breathing in toxins is one of the fastest ways for them to get into the body.
Examples of Breathing In Toxins
One common example is smoke from cigarettes. This smoke has many toxins. Smoking is an example of chronic toxic exposure. This is because a smoker breathes in toxins many times over a long period.
Another example is smoke from house fires. This smoke contains toxins like carbon monoxide. Firefighters or people caught in fires can get sick from breathing in these toxins. This is an example of an acute exposure. The smoke was not breathed in for more than 24 hours.
Toxins on Skin or Eyes
If a toxin gets in a person's eyes or on their skin, it can be taken into the bloodstream. This is called absorption. Absorption through the skin is a very common way for toxins to enter the body.
Your skin can stop some toxins from getting in. But if there is a cut or wound on the skin, a toxin can get into the body more easily. It will also enter the bloodstream faster through a wound.
Examples of Toxins on Skin or Eyes
Exposure by absorption often happens in places where people work with chemicals. For example, if someone at a gas station spills gasoline on themselves, their body can quickly absorb the gasoline into the bloodstream. Some strong chemicals can also be absorbed through the skin and eyes.
Swallowing Toxins
Ingestion means that a person swallowed the toxin. Some chemicals cannot get into the bloodstream from the gastrointestinal tract (the stomach and intestines). But others are absorbed through the lining of the intestines into the bloodstream.
Examples of Swallowing Toxins
Swallowing toxins is common in developing countries. Many people there do not have safe drinking water. Water can carry many different toxins. These can be chemicals, like lead. They can also be tiny living things, like the bacteria that causes cholera, or viruses that cause Hepatitis A and polio. People swallow these toxins by drinking contaminated water or eating food made with it.
Food poisoning is also caused by swallowing toxins. For example, E. coli bacteria can live in foods like meat.
Toxins Injected into the Body
An injected toxin gets into the body when something carrying the toxin breaks the skin. Injections can go into a vein, a muscle, or just under the skin. Toxins injected into a vein have the fastest effects. This is because the toxin goes right into the bloodstream.
Examples of Injected Toxins
Some snakes, scorpions, and spiders carry venom. If they bite or sting a person, they are injecting that toxin into the person's body.
An example of a toxin that is sometimes injected on purpose is Botulinum. This toxin can cause a serious illness called botulism. However, it is also used in small amounts for medical or cosmetic reasons, like to smooth out wrinkles. When injected, it can make some muscles in the face relax.
More Than One Way
Some toxins can get into the body in more than one way. For example, if water is polluted, a person can be exposed to the toxins by drinking it (ingestion). They can also be exposed by showering or swimming in it (absorption).
What Affects How Harmful a Toxin Is?
Once a person has been exposed to a toxin, many things affect how harmful it is. Here are a few important ones.
The Exposure Itself
Many things about how a person was exposed affect how harmful the toxin is. Three important things are:
- How much of the toxin was there? (Concentration)
- How long was the person exposed? (Duration)
- How many times was the person exposed? (Frequency)
The way the toxin entered the body also matters. For example, if snake venom is injected, it can be very dangerous. But if it is swallowed, it is usually not harmful. The effects of this toxin are very different depending on how it gets into the body.
The Person Exposed
Toxins can affect different people in different ways. This is partly because people's bodies are different. A person's age, gender, genes, hormones, nutrition, and the strength of their immune system all affect how harmful a toxin might be. For example, infants, young children, and older adults are more likely to get sick from small amounts of toxins. These amounts might not make a healthy adult sick.
People with Health Issues
Some health problems can make toxins more harmful. For example, breathing in toxins is especially dangerous for people who already have lung diseases. If the lungs are already damaged, breathing in toxins can cause even more harm. This puts the person at risk for serious breathing problems.
Also, once a toxin gets into the bloodstream, the body tries to get rid of it. The main organs that do this are the kidneys, liver, and lungs. If a person has damage to any of these organs, they might not be able to get rid of the toxin as fast as a healthy person. The toxin will stay in their body longer and have more harmful effects.
The Type of Toxin
Many things about the type of toxin also affect how harmful it is. Two examples are how well it mixes with liquids (solubility) and its acidity (pH).
How Well It Mixes (Solubility)
A toxin's solubility is how well it can mix into a liquid. If a toxin cannot dissolve in water, it cannot be absorbed into the bloodstream. (The liquid part of blood is mostly water.) If someone swallows a toxin that cannot dissolve in water, it will not be absorbed into the bloodstream. It will just pass out of the body.
However, many toxins can dissolve in water and will be absorbed into the bloodstream. For example, the bacteria that causes cholera can dissolve in water. If a person swallows water or food with this toxin, they can get cholera.
Other toxins can dissolve in fats. Instead of going into the bloodstream, these toxins get stored in the body's fat. When the body uses fat for energy, these toxins are released and can harm the person. Examples of fat-soluble toxins include lead and mercury.
Acidity (pH)
The toxin's pH (how acidic or basic it is) is also important. For example, if a toxin is a strong acid or a strong base, it can cause severe chemical burns to the eyes and skin. Toxins that are more neutral (not very acidic or basic) will not burn the eyes or skin. But they can still harm the body by being absorbed into the bloodstream.
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