Like did someone find a cave of uranium, come home and have their skin melt off or whatever? Are there documented stories about a place to avoid because being in it would kill you?
So I do not know if you would be able to find some historical sources linking a uranium deposit or somesuch to an environmental hazard, but I don't think it is reasonable to suspect that ancient humans could have appreciated radioactivity in even a rudimentary way. And while radioactivity obviously played, and continues to play, a major role in political events, its discovery revolutionized science, not just physics but also chemistry and biology. There's a reason Marie Curie got two nobel prizes for this stuff. Discovering radioactivity required a pretty sophisticated scientific understanding, as did learning about what its dangers were.
First of all, it's worth noting how radioactivity was discovered in the first place: Henri Becquerel put uranium salts in front of photographic plates and found that, even in the absensce of any sources of light, the uranium sample left an image of itself in the film. But even this was not enough to distinguish it from other forms of radiation, like X-rays. He then found that the some of the emissions from uranium carried an electrical charge because they could be deflected in a magnetic field, and furthermore that this had the property of very weakly electrifying the surrounding air.
This electrification of the air is what enabled Marie and Pierre Curie's experiments. The current produced in this way is incredibly tiny, so the Curie's built upon this finding by using an extremely sensitive electrometer. They then used this tool to screen new compounds for radioactivity and characterize their properties.
If you think about any of the steps I have mentioned previously, you will note that they are not things one could just casually notice - an ancient person would not have the tools to even conceive of detecting radioactivity.
'But what about glowing rocks?', you might ask. In pop culture, radioactivity is associated with glowing compounds - this idea again originates with the work of the Curies. Purified radium glows blue. However, purifying radium is not an easy thing to do - it was enough to win another nobel prize. It took the Curies close to FOUR YEARS to isolate tiny amounts from tons of pitchblende. Isolating the substance required then-modern chemical techniques as well as the ability to measure the levels of radioactivity after each step to make sure they were headed in the right direction. All in all, an ancient person would not have been able to stumble across radiation.
While ancient peoples may not have been able to notice radioactivity per se, they might have been able to notice the hazard, but this again is unlikely. When radioactivity was first discovered, people did not immediately gather that it was dangerous. Marie Curie herself, who had spent as much time as anyone around radioactive materials, lived to be 67.
By 1905, Pierre Curie had come to realize that radioactivity was not fully benign. He noted:
'If one leaves a small glass ampoule with several centigrams of a radium salt in ones pocket for several hours, one will feel absolutely nothing. But 15 days afterwards, a 'redness' will appear on the epidermis and then a sore which will be very difficult to heal. A more prolonged action could lead to death. Radium must be transported in a box of lead.'
This realization that radium rays could damage tissue led to scientists exploring if they could be used in medicine for purposes such as killing cancerous cells. Again, this was with a purified form of a rare element.
The true horrors of the health risks of radiation came to be apparent through the story of the so-called Radium Girls, women whose job it was to paint radium-infused pigments onto watch components to make them glow-in-the-dark. These unfortunate women started to exhibit horrific symptoms, but this was only after being exposed to extremely radioactive substances - namely, radium that had been purified on an industrial scale - all day everyday for years. What's more, they had also been ingesting radium, as they were taught to lick the tips of their paintbrushes, which likely greatly accelerated and exacerbated the effects of radiation poisoning.
It is therefore unlikely that anyone in ancient times would have been exposed to sufficient levels to make any kind of one-to-one association with the minerals and the hazard. Especially as mining, the profession most likely to put an ancient person at radiation risk, was such a hazardous career for a million other reasons that it would be implausible to link it to radioactivity.
Another major factor that contributed to the modern world realizing the risks of radiation comes from the work of H.J. Muller, a famed pioneering geneticist. At the times he was working (the early decades of the 20th century), genetics was just getting off the ground. Gregor Mendel's work on heritability had been rediscovered, and geneticists working on fruit flies, most famously T.H. Morgan and his students (including Muller), discovered that genes were carried on chromosomes by studying the inheritance patterns of mutations and also by examining the 'polytene' chromosomes found in fruit fly salivary glands, which are both unusually large and exhibit distinctive bands, allowing scientists at the time to follow individual chromosomes and even identify where a mutated gene was on the chromosome. Importantly, Muller found that exposing his fruit flies to X-rays dramatically increased the appearance of new mutations. This was a landmark discovery in genetics for a lot of reasons (Muller won the nobel prize for this work), and 'mutagenizing' fruit flies became a standard laboratory technique thereafter. From this, scientists began identifying all sorts of environmental factors that cause mutations, including radioactive compounds like radium.
Again, the unique hazard posed by radioactivity, namely that it causes mutations, is not an immediately obvious thing, and it in fact took a very gifted geneticist testing that hypothesis very specifically to prove it.
Radioactivity is a very modern concept: detecting it and characterising it took a lot of sophisticated science. And the discovery of radioactivity really, really openned up whole new worlds of discovery to scientists across a range of fields - note how like everyone I mentioned got a nobel prize? None of this stuff was easy or obvious. Radioactivity has only really become a major hazard in the world because people discovered it and found interesting uses for it, and therefore it, and its dangers, has become more commonplace.
Citations:
Since u/Zoidinho gave an excellent answer, I'm just going to add that there was indeed a natural nuclear reactor that existed in what is now Gabon, West Africa, some two billion years ago. Essentially, water flowed over a uranium deposit in such a way to promote fission. Of course, two billion years ago, there was no one to witness it or get their skin melted off; it was only discovered in the 1970s when the uranium was discovered to have been depleted.
Ancient Greeks did not know about radioactivity but the type of concrete they used in the tanks in the mines of Laurio were impenetrable to radioactivity also due to présence of lead. It was even more sturdy than the Portland variety. This according to Martha Goodway at Smithsonian who is both physicist chemist métallurgiste and archaeologist, in a conference in Boston in 1992.
Blog though in Greek, goes into technical details and there was also research and in 1987 a dam in Utah was built combining both Portland (40) and ancient Greek (60) built variety in concrete.
https://difernews.gr/oi-archaioi-ellines-eichan-ftiaksei-tsimento-adiaperasto-apo-tin-radienergeia/