Substances accumulate in body?

ronbyrne2005

What chemicals/subtances can accumulate in body of an otherwise healthy individual? i know lead does but what else?

John

Most heavy metals do as they are lipophilic (fat soluble) so they can pass through cell membranes, blood brain barrier, etc. So lead, mercury, thallium will all accumulate. They can displace metals that the body needs like zinc and iron which leads to problems as many proteins and enzymes need these metals to perform their usual functions in the body.

Outside of metals, many drugs stay in the body. For example if you're taking an antidepressant and your doctor thinks you should change antidepressant then you'll have to wait 2-5 weeks depending on the drug your taking for it to clear out of your system. Drugs of abuse like cannabis stay in the body for a long time. Interestingly, this is a hypothesis for why cannabis isn't habit forming. As it doesn't come out of the body easily, it's suggested that it acts something like an internal cannabis patch (like a nicotine patch I mean).

Lipophilic vitamins like VitA can accumulat in the body. In fact VitA is toxic as it can build up to dangerous levels if you take too much of it. Hydrophilic (water soluble) vitamins like VitC are easily excreted in urine so they don't cause toxicity.

DrIndy

Many compounds do, in general as John2 said, lipophilic molecules dissolve in the fat and remain for longer, others get taken up by other organs.

DDT is a good example of something that is fat soluble and accumulates in the food chain.

The list is long and the time they remain for varies and the exact details are beyond my knowledge, although I encourage people to post with details.

homah_7ft

DrIndy wrote:

Many compounds do, in general as John2 said, lipophilic molecules dissolve in the fat and remain for longer, others get taken up by other organs.

DDT is a good example of something that is fat soluble and accumulates in the food chain.

The list is long and the time they remain for varies and the exact details are beyond my knowledge, although I encourage people to post with details.

Polychlorinated Biphenyls (PCB's) also are fat soluble and bioaccumulate. They are known to pass from mother to child in breast milk. Mainly they are ingested by eating fish from contaminated water.

Capt'n Midnight

Vitamins A,D,E and K are fat soluble so taking too much is not a good idea, especially of A if you are pregnant.

Carotenemia = when you turn yellow from eating too many carrots.

Did you see that documentary on TG4 about the high levels of nasties in the Arctic ?

John

Capt'n Midnight wrote:

Did you see that documentary on TG4 about the high levels of nasties in the Arctic ?

Unless you're referring to The Thing then no, I didn't see it. What was it about?

ronbyrne2005

Capt'n Midnight wrote:

Vitamins A,D,E and K are fat soluble so taking too much is not a good idea, especially of A if you are pregnant.

Carotenemia = when you turn yellow from eating too many carrots.

Did you see that documentary on TG4 about the high levels of nasties in the Arctic ?

yeah women cant eat the local delicacy -polar bear - untill they have had their children as the chemicals accumulated in food chain pass to child.

DrIndy

interesting side fact. Never eat a polar bears liver if you are trapped in the arctic and somehow managed to kill one with your bare hands, it contains a lethal dose of vitamin A. Discard and eat the rest.

Capt'n Midnight

another interesting side fact. If stuck in the arctic and the only thing you can eat is rabbits you will eventually starve to death, IIRC it's to do with the lack of nutrients , perhaps vitamins

John

Let's face it, if any of us were stuck in the arctic we're going to die anyway. Apart from Dr Indy with his Viking heritage. He'll just laugh it off and head to lands where he can pillage.

Capt'n Midnight

[off topic] Don't forget. Rape and pillage BEFORE you burn. [/off topic]

Metabolically, strontium is an analog of calcium.
http://www.epa.gov/radiation/radionuclides/strontium.htm

What does strontium-90 do once it gets into the body?

When people ingest Sr-90, about 70-80% of it passes through the body. Virtually all of the remaining 20-30% that is absorbed is deposited in the bone. About 1% is distributed among the blood volume, extracellular fluid, soft tissue, and surface of the bone, where it may stay and decay or be excreted.
...
Strontium-90 is chemically similar to calcium, and tends to deposit in bone and blood-forming tissue (bone marrow). Thus, strontium-90 is referred to as a "bone seeker." Internal exposure to Sr-90 is linked to bone cancer, cancer of the soft tissue near the bone, and leukemia.

Other substances that behave chemically similarly to natural ones can be accumulated by they body. Carbon Monoxide binds to haemoglobin just like oxygen does except it don't want to let go.


Other things to watch - background levels of micronutrients. This is why Selenium is added to fertiliser in some regions, usually for the benefit of non-native species who have evolved in other areas.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3945960&dopt=Abstract

Beryllium (Be+2), a divalent metal ion, is toxic to both man and animal. Although the molecular basis for its toxicity is unknown, it is well established that micromolar concentrations of beryllium specifically inhibit certain enzymes. Previous in vitro studies have shown that the presence of ferritin, an iron-storage protein, reactivated these enzymes by sequestering beryllium

Maybe we'd be able to colonise planets like the one in Asimov's Sucker Bait. Or maybe that is something that could have killed off martians in a war of the worlds type story.

ronbyrne2005

What about food additives ,is there any that accumulate in body? im paranoid about synthetic food additives and the chemicals in the likes of deoderants , although most food additives are "safe" in isolation the effects of three of four additives toghether at one time are less understood,maybe theres some negative synergies

Chucky

Hasn't DDT and PCB usage been eliminated?

Chucky

Capt'n Midnight wrote:

another interesting side fact. If stuck in the arctic and the only thing you can eat is rabbits you will eventually starve to death, IIRC it's to do with the lack of nutrients , perhaps vitamins

Another interesting fact - Rabbits eat their own faeces.

DrIndy

Chucky wrote:

Another interesting fact - Rabbits eat their own faeces.

They do and dogs do so as well, it harkens back to them eating the faeces of herbivores like deer/moose and got lots of digestible starches and vitamins from such poo.

/back on topic

remember that all food additives have to pass stringent EU safety laws prior to being able to be used in food, once a dangerous substance is identified, it gets pulled

Chucky

What about Benzene? That was recently found to be contained in soft-drinks in the USA. Does Benzene accumulate or is it excreted quickly?

ronbyrne2005

Chucky wrote:

What about Benzene? That was recently found to be contained in soft-drinks in the USA. Does Benzene accumulate or is it excreted quickly?

the levels of benzene were not enough to cause problems.

Capt'n Midnight

ronbyrne2005 wrote:

the levels of benzene were not enough to cause problems.

Caused problems for Perrier. They had to recall 160,000,000 bottles.

Since benzene can affect your DNA it's best avoided
http://www.probeinternational.org/ebi/contaminants/benzene.html

Benzene is a known human carcinogen. Benzene has been shown to cause cancer of the blood-forming organs (leukemia). There may be no safe level of exposure to a carcinogen.

Benzene is a mutagen and a possible human teratogen.

Tree

Chucky wrote:

Hasn't DDT and PCB usage been eliminated?

in the developing world yes. you can still find some floating around in the not so developed world as companies sell off their now useless stock to poorer places

Chucky

Thanks for the Benzene link Capt'n Midnight - It is more concise than the Wikipedia article.

Pet

Dioxins (caused by incinerators, coal fires and yes, even barbecues) are also fat-soluble and build up over time. That Ukrainian guy who was gonna become president (whatsisname?) was poisoned with dioxins recently, it caused him to age terribly.

What's worse about dioxins is that they pass from mother to child through breastmilk, so they're really hard to get rid of.

John

Pet wrote:

What's worse about dioxins is that they pass from mother to child through breastmilk, so they're really hard to get rid of.

Pretty much all lipophilic molecules enter the breastmilk and can enter the placenta.