Gallium is not toxic to humans in its pure form.
In this article, we’ll go into detail regarding the properties of gallium itself, its history, how it’s extracted, where it comes from, its compounds, its uses in everyday life, and the effects it can have on the environment.
Is Gallium Toxic? (EXPLAINED)
What Is Gallium?
Pure gallium metal is silvery or blue-gray in appearance, and stays solid at room temperature.
However, even in its solid state, it can be cut through with a simple knife.
As this metal is safe for you to touch with your bare hands, if you were to hold a piece of it in your palm, the warmth from your body would melt the metal!
In comparison to other metals, the melting point of gallium has been found to be a mere 29.8 degrees centigrade.
When gauging its reactivity, the metal will remain stable if left in air or submerged in water.
However, it has been known to react with substances with acidic and/or alkaline properties.
In the early days of modern chemistry, gallium was at first predicted to exist in 1871 by a Russian chemist, Dimitri Mendeleev, judging by an empty spot on the periodic table he made.
The name we know for the metal today didn’t exist until 1875, five years after its prediction, and was instead called “eka-aluminium” by Dimitri.
Its true discovery was by the French Chemist Paul Emile Lecoq de Boisbaudran using spectroscopy inside a sample of sphalerite.
Using electrolysis, he was also able to obtain gallium using a potassium hydroxide solution.
Paul first named it “Gallia,” the Latin word for Gaul, his native French homeland.
Where Gallium Comes From
Pure gallium does not exist in its pure form within the Earth’s crust, but is a by-product of ore processing.
It’s most common source is bauxite, an ore known to have high aluminum content.
Small amounts of gallium can also be found within sulfidic zinc ores, and the above mentioned sphalerite being the most common type.
It can also be found in minor amounts within coal. How much of the metal can be available for use depends on the rate of bauxite, sulfidic zinc ore and coal extraction.
The total abundance of gallium within the planet is estimated to be around 16.9 ppm.
Today, gallium is primarily extracted using the Bayer process, where the metal will accumulate within sodium hydroxide liquor, a compound important to its extraction.
A secondary process will then be needed, such as using an ion-exchange resin, an organic polymer substrate, to gather more gallium.
The actual metal can then be collected via electrolysis.
As for where it comes from, everything depends on where its known ores are extracted.
The primary contender for bauxite ore possession goes to Australia with 86,400 tonnes.
Next is China, Guinea, Brazil, and India to name a few.
However, processing gallium for commercial use requires specialized equipment and processes, meaning the countries that extract bauxite ore may not also extract gallium.
The leading producers of gallium in 2017 were the Ukraine, China, Russia, South Korea, and Japan.
Germany was also a known country for gallium production, but ceased to continue doing so in 2016.
When it comes to its compounds, the original question of whether gallium is toxic can be challenged.
Even though shown to be harmless in small doses, experts warn not to consume the metal in large amounts.
The estimated lethal amount is about 140g (or 5oz), and it would react with the acid within your stomach to create 300g (12.5oz) gallium trichloride, a poisonous compound also known to kill rats.
Such a dangerous act will produce toxic fumes that can make you pass out and perish if medical attention isn’t sought immediately.
And yet, gallium itself will not cause a toxic reaction within your body, as it has 0.7 milligrams of the metal naturally!
So, unless you decide to eat the above-mentioned amount, gallium is relatively safe to handle on your bare skin, and will not harm you if a tiny bit is accidentally (or intentionally) swallowed.
You might have a nasty metallic stain on your hand to deal with though.
Another compound that can be potentially harmful is gallium chloride, which, upon acute exposure, can cause chest pain, throat irritation, and even pulmonary edema due to the toxic fumes.
However, once again, it’s the gallium compound that’s shown to be toxic, not the pure metal by itself.
Uses Of Gallium
Since its discovery, gallium has been added to various alloys to decrease the overall melting temperature.
Today, the metal is primarily used in the semiconductor industry, allowing many of our electronics to function and exist.
Two such gallium compounds, gallium nitride and gallium arsenide, are used in up to 66% of integrated circuits within the U.S.
The metal and its two most common semiconductor compounds are also used in the creation of ultra-high-speed logic chips, optoelectronics, fiber-optics, automotives, and even some military applications.
Out of the two, 95% of global gallium consumption consists of gallium arsenide.
The other compound, gallium nitride, is used in the manufacturing of Blu-ray discs.
Fortunately, this compound is safe and used in many biomedical applications, while gallium arsenide has been shown to be carcinogenic to humans.
Speaking of biomedical applications, gallium metal is known to function in the body in similar ways to iron(III) (Fe3+), prompting research into gallium salts for use in radiopharmaceuticals and pharmaceuticals.
Another compound of gallium, Ga(III) citrate, has been shown to conglomerate in animal tumor cells, revealing potential anticancer properties.
Gallium has been shown to be within the Pacific and Atlantic oceans in trace amounts.
The metal makes its way into the water via “Aeolian input,” a large process that involves dust from land blowing into open water.
As the metal is almost geochemically identical to aluminum, gallium can be used to trace aluminum distribution within the oceans due to its lower reactivity, allowing scientists to keep careful track of any aluminum pollution within our waters.
There is concern, however, about potential pollution from gallium pairing with nuclear weapons.
The metal is sometimes used to keep nuclear bomb pits in one piece.
Specifically, pollution occurs when the bomb pits are cut up, and the metal mixes with plutonium, the nuclear fuel source being sought.
The gallium then has to be removed or else the plutonium is useless for energy applications, thus resulting in radioactive water pollution.
So, whereas gallium on its own is not a known toxin, or a pollutant, certain chemical compounds and other elements that include gallium can be.
You may be able to handle the metal safely with your bare hands, just don’t swallow 140g (5oz) of it.