How does the dose of a chemical affect its toxicity?

[kenny1999]

Hi all

It's said, the dose makes the poison, which is easy to understand. Under enough dose, the chemical would not cause harmful effects to us. However, when it's under dose, the toxin chemical is still there, even the amount is not much, how would our body handle the chemical ? Would it accumulate in our body for years or life or would it go out of our body after some time??

 

[jedishrfu]

I've not heard of that expression before.

My understanding of toxicity is that a low amount of some substance may be okay but a larger dose is not.

https://en.wikipedia.org/wiki/Toxicity

Do you have examples where one dose is okay but another lower dose is not?

I could see where low doses might stay in the body and add up but not where a low dose is poisonous.

Perhaps @berkeman knows.

 

[BillTre]

Potential accumulation would depend upon the particular chemical under consideration.
Mercury for example is well know for accumulating, other potential toxins (like alcohol) less so.

 

[berkeman]

I could see where low doses might stay in the body and add up but not where a low dose is poisonous.

Perhaps @berkeman knows.

Low doses of Narcan can be deadly, while high doses can keep some folks alive...

 

[pinball1970]

Low doses of Narcan can be deadly, while high doses can keep some folks alive...

Digoxin digitoxin? Also Chloramphenicol?

 

[Vanadium 50]

Too little arsenic and you die. Too much and you die.

 

[jrmichler]

Too little arsenic and you die. Too much and you die.

Same for every ingredient in a multivitamin pill.

Some chemicals, such as lead and mercury, bioaccumulate. Others, such as sodium chloride (salt), are excreted within hours in order to control the concentration in your body to the desired level.

 

[jim mcnamara]

@jrmichler you are correct if you eat a diet devoid of sodium, less than 500mg/day. Long term this would be fatal.

The other side of the coin. Too much sodium is also a problem.

The nephron (kidney workhorse) functions to preferentially retain sodium ions and chloride ions. It also increases potassium secretion.
Why?

The primary function of neurons (see link: the action potential) requires both K and Na in approximately 1:1 ratio. In the food supply humans had until recently the K/Na ratio was ~16:1. So kidney function in mammals fixed that problem. Pitch K, keep Na preferentially. Problem solved.

New problem for us human mammals: In first world countries NA/K ratio (due to "the Western Diet") is now: K << Na, drastically less K, way more sodium. Result - hypertension.

Ratio is what affects hypertension in patients. So. You can ingest more Na if you get concomitantly more K and not cause hypertension.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997395/Action potential: [media]

 

[DaveC426913]

Some chemicals, such as lead and mercury, bioaccumulate.
Others, such as sodium chloride (salt), are excreted within hours in order to control the concentration in your body to the desired level.

This.

jrm has hit the nail square on the head.

 

[Rive]

Paracetamol
Since it is one of the most common medications, it is also one of the most common cause of liver failure.

 

[pinball1970]

Insulin.

Knowledge of the lack of/too much of used maliciously in the cases below.

https://en.wikipedia.org/wiki/Beverley_Allitt

https://www.dw.com/en/germany-care-worker-charged-with-6-murders-by-insulin-injection/a-46272746

https://www.theguardian.com/uk-news/2015/may/18/stepping-hill-hospital-poisonings-operation-roxburg-manchester-police-victorino-chua

 

[chemisttree]

Water too. I’m thirsty. I think I’ll have a glass of poison; just a bit though!

 

[pinball1970]

Water too. I’m thirsty. I think I’ll have a glass of poison; just a bit though!

That’s actually a thing with mental illness and some auto immune diseases!

Primary polydipsia. EDIT: @chemisttree already gave link which I missed

 

[pinball1970]

Oxygen too

Too little, hypoxia too much hyperoxia.

Also alcohol

Some benefits in small doses.

 

[russ_watters]

While interesting, most of the responses don't appear to me to be related to the OP's question. I'll bump this answer:

Potential accumulation would depend upon the particular chemical under consideration.
Mercury for example is well know for accumulating, other potential toxins (like alcohol) less so.

Organic/food products like alcohol are processed and consumed and/or removed via normal bodily metabolism. But as Bill says, there are a wide variety of latencies and removal processes depending on the particular toxin.

 

[Bystander]

I've not heard of that expression before.

https://en.wikipedia.org/wiki/Paracelsus

 

[gary350]

Each chemical is different. Mercury stays in your body for ever with few symptoms until it becomes toxic enough. It has been proven people with silver teeth filings that are mercury can develop allergy symptoms to many things even food.

 

[Laroxe]

“The dose makes the poison” is a contraction of a basic principle of toxicology attributed to Paracelsus a Swiss physician from around 500 years ago. The original was more like “All things are poison and nothing is without poison; only the dose makes a thing not a poison.” There are of course other principles to consider as well as the dose, like how they receive the dose and the length of exposure, there are also lots of individual differences.

A lot of substances can be harmful because of secondary effects on our physiology like water but its interesting that much of what we eat contain specific poisons, things designed to cause harm. Plants have been waging a form of biological warfare against their predators, usually insects, since they developed. Its been estimated that we can eat around 2g of insecticides from plants every day, its one of the reasons our liver is so big, one of its jobs is to remove various toxins and drugs. We also produce poisons ourselves as normal parts of our metabolism, its a complicated business, this staying alive.

You can only really get more information by being specific about the compounds or chemicals in question, as lots of people have mentioned there is a variety of things to consider.

 

[sysprog]

The Wikipedia article on this: https://en.wikipedia.org/wiki/The_dose_makes_the_poison

 

[.Scott]

As @Laroxe mentioned, this is contraction to a quote from Paracelsus - often thought of as the father of toxicology. There are exceptions. If the toxic effect is only the result of radioactivity, then the detrimental effects are cumulative - starting from the very first tiny dose - with risk increasing proportionately to the additional dose.

 

[Swamp Thing]

Etymological Aside:

• The German word for poison is "Gift", which comes from the sense of "something that is given"
• The word "dose" comes (via Latin) from Greek dosis ‘gift’, from didonai ‘give’.

 

[gmax137]

If the toxic effect is only the result of radioactivity, then the detrimental effects are cumulative - starting from the very first tiny dose - with risk increasing proportionately to the additional dose.

google "radiation hormesis" for other viewpoints.