Humans are pillaging the periodic table, researchers said, while turning a blind eye to the dangers of doing so

For millions of years, nature has dealt mainly with a few elements from the periodic table. Carbon, calcium, oxygen, hydrogen, nitrogen, phosphorus, silicon, sulfur, magnesium and potassium are the building blocks of almost all forms of life on our planet (tree trunks, leaves, hair, teeth, etc.). However, to build a world of humans — including cities, healthcare products, railroads, planes and their engines, computers, smartphones, and more — many chemical elements are needed.

A recent article, published in Trends in ecology and evolution Written by researchers from CREAF, the Universitat Autònoma de Barcelona (UAB) and the Spanish National Research Council (CSIC), they warn that the set of chemical elements needed by humans (something known scientifically as the anthropon) is increasingly diverging from nature’s. require (biological component).

In 1900, approximately 80% of the elements used by humans came from biomass (wood, plants, food, etc.). This number had fallen to 32% by 2005 and is expected to stand at around 22% in 2050. We are heading towards a situation where 80% of the items we use will be from non-biological sources.

Non-biological elements are rare or practically absent in living organisms, and generally scarce; In many cases, its main reserves are located in only a few countries. It must be obtained from geological sources, necessitating extraction, trade between countries, and the development of efficient recycling technologies, while its scarcity and location create the potential for social, economic, geopolitical, and environmental conflicts.

Thus, what may at first appear to be a purely scientific issue actually has far-reaching ramifications. “The preservation of the human element will be more and more complex and dangerous; it will have to be done in terms of environmental justice and, of course, with a more rational use of the elements of the earth.” Limited resourcesJaume Terradas, Founder of CREAF, Professor Emeritus at UAB and one of the article’s three authors.

Humanity, deeply committed to its expanded use of the periodic table

The study looks at the history of mankind in relation to its use of the elements of the periodic table. “Humans have shifted from using common materials, such as clay, stone and lime, whose elements are constantly recycled in the earth, in nature and in the atmosphere, to using a lot of other elements, including elements known as rare earth elements,” says Jordi Sardin. , researcher at Al-Kif Organization and co-author of the study. According to the article, human and biological elements began to diverge in the decade of the 20th century, as a result of the continued growth in the use of abiotic materials (fossil fuels, mineral/industrial materials, and building materials).

In 1900, 79% of all materials used annually by humans were biomass materials, compared to 32% in 2005, and the number is currently projected to be 22% for 2050. Items used in construction, transportation, industry, and more recently, new technologies, Like computing, photoelectric devices, and mobile phones, they have been added to the human element over the course of the 20th century.

They include silicon, nickel, copper, chromium, and gold, as well as other, less common ones, such as samarium, ytterbium, yttrium, and neodymium. In the past two decades, there has been an increase in the use of these trace elements, due to the implementation and expansion of new technologies and clean energy sources.

“Consumption/extraction of mineral elements is rising at a rate of about 3% annually, and this will continue until 2050,” says Josep Benuelas, researcher in the field of agriculture, electricity and chemicals, and co-author of the study, Josep Benuelas. “In this scenario, it is possible that we will have exhausted all our reserves of some of these elements (gold and antimony) by 2050, and others (molybdenum and zinc) within a hundred years.”

Environmental, economic, social and geopolitical risks

The article leaves no doubt: land extraction chemical elements It can be a limiting factor and lead to crises at all levels. Using more elements of the periodic table involves extracting more metals, increasing energy consumption and associated carbon dioxide₂ emissions. Moreover, the increasing rarity of the items in question poses a threat to their availability, especially where they are poorer countries Which makes maintaining production difficult even for rich countries, affecting economic development.

Against this background, there are also important and problematic geopolitical considerations. Natural reserves of some elements, including rare earth elements, exist in a limited number of countries (China, Vietnam, Brazil, the United States, Russia, and the Democratic Republic of the Congo); China already controls more than 90% of the world’s supply and nearly 40% of reserves. Thus, their availability is subject to fluctuations in supply and prices due to conflicting geopolitical interests, with the consequent risk of conflicts.

Programmed obsolescence disposal, recycling and recovery

The authors emphasize the need to end programmed obsolescence (the policy of planning or designing a product to have an artificially limited useful life), as well as to develop new technologies that contribute to more profitable use of scarce elements and allow for their widespread and efficient recycling and reuse.

Nowadays, there are few if any substitutes for many of these items, and their recycling rates are low because they are used in small amounts with other materials in a wide range of products. Existing recovery techniques have low efficiency levels and carry a high risk of contamination due to the toxicity of rare earth elements.

The article mentions the different techniques that can be used to recover rare items. The first is biological bleaching, which is the extraction of minerals from their ores using living organisms, such as bacteria, which can accumulate rare earth elements if they come into contact with industrial waste.

To avoid contamination, meanwhile, scientists are studying biosorption, a physicochemical process that occurs naturally in certain organisms and enables them to filter out pollutants, such as heavy metals, in wastewater.

Other possibilities include cryo-treatment, where recovery is achieved through electrochemical deposition; the use of various carbon-based nanomaterials as adsorbent media to pre-concentrate rare earth elements from dissolved solids in wastewater; Metallurgical treatment for intrinsic recovery of Rare earth elements And Heavy metals from apatite and various tailings; and pyrometallurgy, or supercritical fluid extraction using carbon dioxide₂.

In any case, the development of new ways to produce and recycle these items on a large scale is essential.