# What is the Italian ‘Acido Psammico’ (Psammic acid?)

I am reading an Italian detective novel — Lo stato delle anime by Giorgio Todde — in which someone is poisoned with ‘acido psammico’.

Marini trova nello stomaco della vittima un ostia con all’interno dell’acido psammico (usato per conciare le pelli), l’acido ha ucciso la donna avvelenandola.

Which I think translates into English as:

In the stomach of the victim Marini finds a communion wafer, inside of which is ‘psammic acid’ (used to tan hides): the acid had killed the woman by poisoning.

I have spent quite a time with dictionary and Google searches using the Italian, French (acide psammique) and English (psammitic acid comes up but is not defined) terms without success. The term ‘psammico’ seems to come up in a geological context, but infrequently and without clarifying things.

I should add that the novel is set in rural Sardinia in the 1890s and the implication is that shepherds would have access to it.

Does anyone know what the modern name and chemical composition of this is?

I am now reading further in the book (slowly, very slowly) and on p. 101 the protagonist (Marini) is in the capital city (Cagliari) and enters a chemist’s (pharmacist’s) shop to ask for ‘acido psammico’. He receives the following reply:

La sabbiolina mortale?

In which ‘sabbiolina’ (not in my dictionaries) appears to be a diminutive related to ‘sabbia’ — sand. (‘mortale’ = ‘deadly, fatal’, of course.)

Consistent with this, further down the page we have:

La sabbia velenosa…

“The poisonous sand…”

• @RaoulKessels — Yes, although I'm not quite sure whether it is arsenic or what. However thanks for your contribution which I found very interesting. – David Feb 19 '18 at 22:39
• Did you get to the end? If it was As related please accept my A :) – Alchimista Apr 14 '18 at 12:56
• @Alchimista — I did get to the end, and it doesn't add anything else except the social class of the people using the term. I'll give you the points by accepting your answer, but before that I will write my own, explaining why I think the author invented the term so that he could ascribe whatever properties he wanted to it. – David Apr 15 '18 at 17:05
• It was more for curiosity than for points :) do not worry – Alchimista Apr 15 '18 at 17:08
• @Alchimista — There were two subsequent murders in the novel, not involving poison, and the only additional fact relating to the poison was where it was purchased (a pharmacist's at Cagliari), by whom (femme fatale), for what ostensible purpose (tanning hides) and at whose request (that would be giving the plot away). Although the author has pretensions to be writing more than a ‘giallo’ (detective novel) with an interest in the backwardness of rural Sardinia, psychology and the historical embalmer, Efisio Marini, I found the plot rather a cheat. I much prefer Gianrico Carofiglio. – David Apr 15 '18 at 20:27

(Edit: this answer turned indeed to be the right one)

Italian Psammico - from the greek Psámmos for Sand - reads as "sandy". It can thus refer to a soil or the organisms living in or about sandy soils and waters, or to something derived from sands.

We as chemists know that sand is mostly silicates, so it seems difficult to think of a poison.

However if we take "sand" as to mean "from the soil, mineral, inorganic" and combine this with the fact that the most historical and literary mineral poison is Arsenic, than I would suggest that the character has been killed by As2O3 or some other compound containing this element.

Arsenic and its compounds can (were) indeed use to tan skins and leathers, to preserve wood and timbers, and even in mummification processes.

In particular Wikipedia mentions cupper arsenochromate as a (modernly banned) ingredient in non-tannin based tanning.

At least in XIX century Italy, the word "acid" could have referred to non formally and/or non chemically acid compounds. Given the negative connotation of the word among those workers with no chemistry background, acid could have referred to any dangerous substance. Alternatively, it could have referred as it does today, to accepted traditional nomenclature or dehydrated forms, like in the case of tannic acid or in that of As2O3, respectively.

My answer remains speculative but I think has quite reasonable bases. The novel author in this case did not use any license, just found a more cryptic and archaic but "original" name for arsenic as poison.

• Very good!!! +1 We will have to read the book to see if there is some other hint. Unfortunately, for finding which acid it is, my Italian is not even basic ;-) – Raoul Kessels Feb 8 '18 at 13:55
• @Raoul Kessels. Couldn't be As2O3? Perhaps we shall look for what Agatha Christie used? Can't Google now but later. .. – Alchimista Feb 8 '18 at 13:58
• I think both are possible since the acido psammico is unknown. I just wanted to say that now I am curious from where the murderer has obtained the poison. Maybe in the book there is some hint if it came from organic or inorganic sources. – Raoul Kessels Feb 8 '18 at 14:08
• It is certainly related to sand! See my addendum. But relating that to a specific chemical? And I think that’s about all the info I will get, unless anyone would be helped by my describing the pathological effects as revealed by the autopsy… – David Feb 19 '18 at 22:23
• @Alchimista Congrats!!! You were right – Raoul Kessels May 23 '18 at 9:29

Actually, the meaning is:

used to tan leather.


The acid used traditionally in tanneries is tannic acid, from there its name.

Tannic acid can be found in several plants one of which is the Sicilian Sumac (Rhus coriaria). This plant is also found in Sardegna (as per Flora Italiana), where the novel is placed. The Italian name for this shrub is Sommacco siciliano. The description of this plant is:

piccolo albero tipico di luoghi sassosi e rupestri, con fiori giallastri in
pannocchie, le cui foglie e corteccia, ricche di tannino, si adoperano nella
concia delle pelli (fam. Anacardiacee)


[the last part says: the leaves and bark, rich in tannin, are used in the tanning of leather.]

From sommacco to psammicco there is not too much distance. But I agree that it is speculative.

Tannic acid is toxic, but the oral LD50 in rats is 2.26±0.083 g/kg body weight, so too much to hide in an ostia. However, that can be a writers license.

Tannic acid is a complex polyphenol with structure:

• Many Thanks. Seems very probable. Will check a few things myself before accepting. Have an Italian class on Friday and the teacher is Sardinian, but no chemist. – David Feb 7 '18 at 23:26
• it is indeed a very interisting question ! I need to research a bit more since my parents are from Sardinia and I'm a chemist. In sardinia the most common plan used for the tanning of the leather was Pistacia Lentiscus (that is very abundant) I need to research a bit more to be sure ;) – Jojostack Feb 8 '18 at 11:01
• checked ! I think it's correct it is indeed a very interesting topic (at least for me) – Jojostack Feb 8 '18 at 11:14
• Plus 1 and bravo! for the sommaco psammico catch. However I am on a more poisonous trace as in my answer below. – Alchimista Feb 8 '18 at 13:40

The term ‘acido psammico’ is from the Greek and literally means an acid derived from sand, as @Alchimista explains in his answer. He argues that it could be a term for arsenic, and, although I do not think there is strong evidence for this, I think it fair to accept his answer, especially as my own answer is speculative. However, for the record, here it is.

I believe that ‘acido psammico’ is not a genuine Italian chemical (or psuedo-chemical) expression, nor a Sardinian dialect term, but a name invented by the author so that he could ascribe particular properties to the poison that suited his story.

My reasons for thinking this is the term is used and recognized by a pharmacist, a doctor, a midwife, a priest and a professor of medicine. One would therefore expect it to have been in common use at the time and some record of it would have been found by an internet search or in the heavy-weight Italian dictionaries I have consulted. It is further understood by the daughter of a shepherd (although she, exceptionally had a formal education) in relation to tanning of hides, again suggesting wide general use not supported by any sources I have consulted.

The author of the book — Giorgio Todde — is still alive and there is an interview with him and a presentation by him on YouTube, so it may be possible to contact him and ask him directly. I will try to follow that avenue, with the help of colleagues with better written Italian, and update this answer if I have any successs.