There seems to be an view in society that chemicals are bad. This is both interesting and confusing to someone like me ―not least of all because I myself am am a mass of chemicals including some not so scary such as nitrogen, calcium, carbon, and oxygen as well as more toxic chemicals such as formaldehyde and acetone. So it is pretty clear that everything is chemicals and to be worried about chemicals in general is to worry about―well everything in existence really.
That aside, there is also a view that there are good chemicals― these are the “natural” chemicals than come from the plants and are used in naturopathy or just occur out in the environment; and the bad chemicals―these are the “unnatural” chemicals which are made by people. The problem is that bad chemicals can be natural and good chemicals can be one hundred percent man made. In order to illustrate this, I have put together a list of “natural” instances of very toxic chemicals out in the environment. They aren’t “good”. They aren’t even “bad”. But they are there and it wouldn’t be advisable to play in these natural environments all the same.
1. BTEX and PAHs
Petrochemicals are generally thought of as bad chemicals, manufactured by multi-national oil companies for massive profits at the expense of the environment. And this is reasonable enough because included in the petrochemical family are acutely toxic chemicals such as benzene, toluene, ethylbenzene, and xylenes, as well as polycyclic aromatic hydrocarbons (PAHs), among many others.
But these chemicals occur naturally and in abundance. The largest contributor of petroleum hydrocarbons to the oceans being natural seeps. These release approximately 600,000 tonnes of petroleum (that’s 46% of the total discharge) into the ocean every year. This is very much higher than the 160,000 per year (12%) lost in transport accidents or the 38,000 (3%) lost during extraction.
The impact of this? At both large and small scales, over short, medium, and long time periods, both lethal and sublethal effects occur when organisms in marine environments are exposed to petroleum hyrdocarbons. Whether some organisms can or have evolved to persist or even flourish in the presence of natural hydrocarbon seeps, however, is not known, as not enough monitoring data has been collected to understand the structure of the ecosystems in such environments.
The use of radioactive materials to create nuclear energy is highly controversial, despite the fact that all materials contain some concentration of radioactive chemicals. This is because even though radiation is natural, exposure to excessive concentrations of it can lead people to die in nasty ways.
That said nuclear energy has been around for a long time. Actually a very long time – two billion years in fact. And this was discovered in 1972, when France was mining uranium in Gabon.
During a routine measurement of uranium isotopes at the ore body being mined, the scientists and officials at the mine found that uranium-235―the type of uranium used to create nuclear power―was depleted. Although initially concerning, they figured out that the uranium-235 had been depleted as a result of spontaneous nuclear fission (the reaction which produces nuclear power) that happened at the site 2 billion years ago. These reactions continued for several hundred thousand years and maybe up to 1 million, with high concentrations of uranium remaining at the Site until they were discovered and mined by the French 2 billion years later.
Is this uranium toxic? Certainly! Is it natural? Yes!
3. Heavy metals
These days it is difficult for most of us to imagine stumbling across an untouched ore body like Broken Hill or those in the Pilbara or what the environment surrounding such ore bodies would have looked like compared to the acid oozing, toxic-metal producing mines which replace them.
But indeed, and of course, these ore bodies― by definition very high in potentially toxic metals―are natural phenomena and can produce very (as low as pH 2.6) acidic water. River water samples were collected from the Red Dog ore deposit in Alaska, for example, before mining started. In a river downstream of this Red Dog ore body, zinc concentrations were up to 272 mg/L, lead concentrations 2.25 mg/L, and cadmium up to 0.8 mg/L.
These are whopping concentrations at 34 000, 660, and 4000 times higher than the current Australian threshold values for the protection of 95% of freshwater species respectively, and concentrations of these metals in the groundwater at the Red Dog ore body were even higher.
So, imagine walking up to the Red Dog ore body say 100 years ago before it was discovered and looking at the stream, flowing through an untouched catchment in the (at the time) pristine arctic region. Natural water right? Yes! Good? Depends what you mean. But I certainly wouldn’t drink it.