[Edd314159]

Sure, "toxic" is word that means bad things. But I don't think you read the article.

It only talks about the levels in the soil. It says nothing about what impact this has on the food we eat from that soil (in fact it explicitly states that the level in food was not measured).

It also doesn't quite agree with your use of the word "we". The article does not conclude whether the elevated levels of metals were down to natural processes or humans (e.g. it suggests that weathering could be at least a contributing factor).

I get what you're saying, if someone says something is "toxic", it means something somewhere is at a level which is dangerous in some context. But the original comment on what the article itself is saying is not wrong. There is no information on real-world implications.

[redczar]

I did read the article. It’s always the same response: “Can you show this is bad?”, where this is microplastics, metals in the soil, forever chemicals, etc. At some point we will we get to the stage where the standard response is, “Yes it’s bad but there’s nothing we can do about it.”

[hilbert42]

"It also doesn't quite agree with your use of the word "we". The article does not conclude whether the elevated levels of metals were down to natural processes or humans…"

That point is key from the perspective that natural levels of dangerous metals act as a reference for comparison.

That said, science tells us that some elements are both toxic and carcinogenic and that humans have contributed to their increased levels in the environment is not in any doubt.

The dangers heavy metals from anthropogenic sources pose to human health depends on many factors, location, concentration, dispersabity, etc.

The point the article makes about "chromium (in its highly toxic hexavalent form, often released by leather tanning and pigment industries)…" is particularly poignant for me. I recall seeing a documentary on WWI military archeology—a new factory was being built in Belgium over a WWI battlefield. When builders discovered soldiers' graves during construction work had to stop until all archeological evidence had been collected and documented.

The grave of one soldier was particularly revealing, except for his skeleton, his boots and a small purse containg a few coins nothing much else remained. What's particularly interesting and relevant to this discussion is that his leather boots were in almost perfect condition, so too was his tiny leather purse.

That these articles were still so intact after nearly 100 years buried under earth was directly because of the high levels chromium used in the tanning of the leather. The chromium was so toxic that after all that time microorganisms were still unable to attack the leather without being killed. (I found this distressing to watch because of the almost pristine condition of those leather items, especially so the purse with its tiny cache of small coins, they vividly brought home the tragedy that had befallen this poor unfortunate soldier.)

Moreover, it also brought home the fact that one didn't have to know an iota of chemistry to know hexavalent chromium is highly toxic. It was so damn obvious.

That said, it's clear from the nature and location of the chromium that it's been largely contained at its source, if it had been dispersed widely then the concentration would have fallen by a significant amount, by now the residual level would such that microorganisms would have been able to attack the leather.

We have to use forensic evidence such as this on a wide scale to ascertain the actual danger these heavy metals pose to human health.