A narrow relationship exists between biosphere evolution and PTE: really, all organisms, since their first evolutionary stages, made use of chemical properties of many metal ions for the development of their essential biochemical functions [18]. As a consequence, the metallic elements, even in low doses, are essential for the development of their vital functions. Their insufficient contribution leads to organisms-developmental anomalies; however, when their concentration is higher to optimum, they exert toxic effects on organisms, limiting their development. Cadmium is found in PTE in the same column as E[g and Zn, but its chemical properties are closer to Zn, which similarity affects Cd distribution and its toxic properties. Arsenic and P, found in the same PTE column, present a similar chemical behavior; however, oxidation state (OS) reduction 5 to 3 results easier in Arsenic.


Universitat de Valencia organized the exposition (Invisible Toxics, raising questions (cf Figure 5.1).

Q1. Which are the most dangerous toxins?

Q2. Which is their degree of toxicity?

Q3. What risks do they pose to people or to the environment?

Q4. What measures should be adopted to avoid damage and minimize future risks?

Q5. Via what mechanisms do actors interact to visualize substance toxicity or make it invisible?

The following conclusions (Cs) were provided:

Cl. Toxicity’s contingent/socially constructed character revealed mechanisms via which protagonists interact to visualize substance toxicity/make it invisible.

C2. Examples show that strong producers-victims imbalances mark toxic risk management.

Exposition (In)visible toxics

FIGURE 5.1 Exposition (In)visible toxics.


Heavy PTE Nb, Mo, Ru-Xe, Cs-Nd, Srn-Rn, and Fr-U (OSs 3,4,2, 1, 5, 6, etc.) were formed in merging neutron stars (NSs, cf. Figure 5.2).

In emergence of some heavy PTEs, most were formed merging NSs

FIGURE 5.2 In emergence of some heavy PTEs, most were formed merging NSs: Pt/Au factory in sky.


Some 2D materials PTE [B-N, P, S, Mo] (cf. Figure 5.3) shows OSs 6, 3, 5, -3, etc. [19].

Periodic table of the elements of some two-dimensional materials

FIGURE 5.3 Periodic table of the elements of some two-dimensional materials.


Rare-earth PTE fingerprints anthropogenic activities and drives chemical processes in archaeology: [Sc] (OS 3, cf. Figure 5.4, black), [Y] (OS 3, red), light lanthanoids [La-Gd] (OS 3, green) and heavy lanthanoids [Tb-Lu] (OS 3, blue) [20].


The periodic table’s endangered elements follow: limited availability and future risk to supply [Li, B, Mg, P, Sc, V-Mn, Co-Cu, Se, Sr-Mo, Pd, Cd, Sn, Sb, W, Au-Bi, Nd] (OS 2, 3, 5,4, etc., cf. Figure 5.5, black); rising threat from increased use [Ru, Rh, Та, Os-Pt, U] (OS 4,3,5,6, etc., orange); serious threat in the next 100 years [He, Zn-As, Ag, In, Те, Hf] (OS 3,4, etc., red).

PTE fingerprints antliropogenesis

FIGURE 5.4 PTE fingerprints antliropogenesis: Sc (blacky Y(red): light/heavy lanthanoids (green/bhie).

PTE's endangered elements

FIGURE 5.5 PTE's endangered elements: Limited availability (black): rising/serious threats (orangehed).

The PTE of conservation of critical elements shows remaining years until known reserves are depleted (based on current rate of use): 5-20 years [Zn, Se, Sn, Sb, Au, Tl, Pb] (OS 2, 3, 4 and 1, cf Figure 5.6, red), 20-50 years [Mn, Ga-As, Sr, Ru, Rli, Ag-In, Hf, W, Os-Pt, Bi, U] (OS 3, 4, 2, 6 and 1, orange), 50-100 years [P, S, Co-Cu, Zr-Mo, Pd, Те, Та, Re, Hg, Np] (OS 2, 5, 4, 6 and 7, blue) and 100-500 years [He-В, Mg, Al, Sc, V, Cr, Y, I, Ce-Lu] (OS 3, 2, -1, 0, 1 and 5, black) [21].

Remaining years of reserves

FIGURE 5.6 Remaining years of reserves: 5-20 (red); 20-50 (orange); 50-100 (blue); 100-500 (black).

A new version of PTE shows the elements under threat (cf. Figure 5.7) [22]. Element (e.g., Ag, He, Sr, OS 1,0, 2) are the most under thread (red, and many play an important part in smartphones). The PTE shows (black) elements that could be more ethically sourced (conflict minerals) because wars are fought and lives lost over their ownership.

A new version of the periodic table shows the elements under threat. Image credit

FIGURE 5.7 A new version of the periodic table shows the elements under threat. Image credit: European Chemical Society.

Reprinted from


The periodic table of C-X bonds in biology follow: [H, C-F, P-Cl, Fe-Ni, As-Br, I] (OS - 1, 2, 3,4, etc., cf. Figure 5.8).

The periodic table of C-X bonds in biology

FIGURE 5.8 The periodic table of C-X bonds in biology.

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