There are somewhere in the region of 118 elements that are known of. The reason for being vague is that some are thought to exist but have never been observed. Of these 98 occur naturally. Very few of these elements are completely harmless and most present some risk in sufficient doses.
There are no hard,fast rules as to which elements are likely to prove most dangerous but we can divide the risks into three general categories. Those that are toxic, radioactive or highly reactive. Some even fit all three categories.
The thirty or so heaviest elements are all radioactive to some degree. Generally, the heavier the more radioactive. Listing those wouldn’t make for a very interesting top 10 deadliest elements so I’ve skipped a bunch of these and gone for the most exciting dangerous chemical elements.
10. Chromium (Cr)
Mention chromium and most people are thinking shiny car parts. It is also one of the elements that is essential to most higher organisms. But chromium has a dark side.
In one of its forms (hexavalent) chromium becomes a genotoxic carcinogen – that is something that can interfere with your DNA, increasing your chances of developing cancer.
Alarmingly there seem to be plenty of examples of industrial pollution involving hexavalent chromium, even in “developed” countries. Dangerous levels have been recorded within the past 5 years in both Australia and the USA.
9. Hydrogen (H)
The smallest and most abundant of all the elements, Hydrogen might not seem like the most obvious choice. However, if nothing else, hydrogen is incredibly flammable. Perhaps the most infamous case of hydrogen combustion was the Hindenburg airship disaster after which it didn’t seem like such a good idea to fly around attached to a massive tank full of highly flammable gas.
An added danger of hydrogen fires is that the flames are almost invisible. This means you could be incinerated before you even saw the fire.
The main reason I’ve included hydrogen on this list is that it is the key ingredient to all things acidic. The hydrogen ion or proton (H+) is what gives acids their acidic properties, some of which are considered extremely harmful. Chief amongst these are acids’ high affinity for water – upon contact with organic matter (e.g. human skin) intense dehydration will occur which is pretty much equivalent to burning. Sulfuric acid, for example, can cause deep burns within seconds. If you think that sounds bad the superacid, fluoroantimonic acid, is over one billion times stronger…
8. Lead (Pb)
Lead used to be used for everything; paint, eating utensils, toys and water pipes just for starters. Then someone noticed it was highly toxic. Whilst it might not be the most toxic element it is probably the most likely of these nasties you’ll come across
In high enough doses lead can be lethal. Symptoms include vomiting, staggering, weakness, seizures, coma and death. But this is rare, it is long term exposure that gets most people. Whilst still serious in adults, lead poisoning is particularly destructive in children. This is because it stunts the developing nervous system leading to irreversible damage. In short lead can permanently reduce your IQ.
7. Beryllium (Be)
Despite its pretty sounding name and the fact beryllium is made in stars it has some rather nasty properties. The dust from beryllium is so bad for you when inhaled that they even named a disease after it; berylliosis. This incurable condition causes lesions in the lungs similar to those found in tuberculosis. The symptoms are in fact often confused with TB and the long term effects may result in lung cancer.
Beryllium is a category 1 carcinogen, it is also very useful in a number of industries.
6. Fluorine (F)
Fluorine is a generally unpleasant substance. The unappealing pale yellow gas is corrosive, highly poisonous and will try to react with almost anything – often explosively. It is chlorine’s more unstable big brother and as we know chlorine makes bleach and mustard gas, amongst other things.
Just 25 parts per million (0.000025%) concentration of fluorine is potentially lethal. It acts by attacking the lungs, airways and eyes, effectively blinding and suffocating the victim. Think mustard gas, but worse and that’s fluorine.
On the positive side, fluorine is great for your teeth!