Protect our soil to preserve food safety

by Maria Chiara Rosace, Ciro Gardi¹ | 20 Ottobre 2020.

1. Scientific officer at European Food Safety Authority (EFSA).

Soil has a significant impact on human health and activities, whether those effects are positive or negative, direct or indirect. Life and human evolution itself have always been linked to soil: since the time of the first hunter-gatherers, or later farmers, the soil has been the source of food and most of the raw materials necessary for human life. This bond is reflected by the cult of Mother Earth or Pachamama, common to many cultures of the past. Nevertheless, following the onset of industrial society, as well as the radical change in lifestyles that occurred in recent decades, the sacredness was given to soil, together with the awareness of its importance, has been progressively lost.

“Essentially, all life depends on the soil … There can be no life without soil and no soil without life; they have evolved together.”

Charles E. Kellogg, USDA Yearbook of Agriculture, 1938

However, soil remains an essential component of our life: similarly to how it used to be, today it is still the source of almost all the food used by the planet’s population (95% of food products, according to the FAO, are produced in our soils). Properly managed soils can support the production of healthy and nutritious food, necessary to feed people and ensure their well-being. Apart from food, agriculture and farming, soils also offer other services that help to ensure human health. These are the so-called ecosystem services, which include climate mitigation, qualitative and quantitative regulation of the water cycle, conservation of biodiversity, as well as the aesthetic and cultural values offered by the landscape and the production of drugs from soil microorganisms such as “good” bacteria and yeasts from which numerous antibiotics are derived. Anthropic pressures on the environment are constantly increasing, causing a rapid change in soil use and an intensification of agricultural activities. This has a significant impact on soil functionality and indirectly on human wellbeing, which is strictly linked to the quality of this resource. 

A crucial ally to food safety

The COVID-19 pandemic has plagued us for months and is having deep socio-economic, political, cultural and scientific impacts. Somehow the environment seems to have been affected in a positive way: air quality has improved (Kroll et al., 2020), emissions into the atmosphere have decreased (Le Quéré et al., 2020) and animals have regained space in our cities due to the absence of humans. Nevertheless, this pandemic has also highlighted and exacerbated the problem of food safety (Béné, 2020), showing that even in developed and scientifically more advanced countries, a large piece of the society is not able to have access to healthy and safe food, a risk which also increases due to climate change and scarcity of healthy soils.

“95% of our food is produced directly or indirectly on our soils”.

(FAO, 2015a)

Soils play an essential role in all areas of food production. Living and healthy soils are therefore fundamental allies in guaranteeing the safety of the food we eat. In order to support crop growth, soils must be fertile. This property is influenced by numerous factors, including:

• nutrient availability;
• organic matter content;
• porosity and stability of the soil structure;
• water availability;
• and last but not least, the presence of soil organisms who can facilitate root and plant growth, in addition to the fundamental role they play in the degradation of organic matter.

Fertility can also be improved by agronomic practices (tillage, crop rotation, use of fertilisers and soil improvers) (Stockdale et al., 2013). These practices need to be implemented correctly in order to secure that they do not have a negative impact on soil health. Soils provide crops with a nutrient-rich means of growth that turns into plant tissue containing most of the elements necessary for human life. In particular, out of the approximately 29 elements considered essential for human life, 18 are also essential to plants and are obtained from soil (Figure 2). Most of the other elements, although not essential for the growth of the plants themselves, can also be taken up from the soil and thus become part of the food chain (Brevik, 2013).

“The lack of micronutrients in the soil leads to nutritional deficiencies in humans”.

(FAO, 2015a)

Only a limited part (about 20%) of the soils present on our planet are naturally fertile and on these soils, most of the anthropic activities are concentrated that often trigger degradation phenomena. Among the main soil degradation processes, it is possible to include water and wind erosion, loss of organic matter, physical and chemical degradation, loss of biodiversity and soil sealing or consumption. The latter in particular represents one of the sneakiest and most irreversible forms of degradation (Gardi, 2017) due to urbanisation processes: in Italy, it reached 8 m² per second in the 2000s and then slowed down as a result of the cooling of the Italian and international economy. In absolute terms, over 20,000 km² have been completely lost following urban development in Italy (ISPRA, 2013), equal to the area covered by 2.8 million football pitches!

All these processes cause serious risks to food security. This is a critical problem as it is estimated that the food demand will increase by 60% within 2050 (FAO, 2015b).

Soil pollution … in the food we eat

Soil pollution affects various aspects of our lives: from the food we eat to the water we drink to the air we breathe – our health and the health of all organisms on the planet is dependent on healthy soil (FAO, 2018).

Soil pollution affects various aspects of our lives: from the food we eat to the water we drink to the air we breathe – our health and the health of all organisms on the planet is dependent on healthy soil (FAO, 2018).
So, what is causing soil pollution? Human activities are the main cause of soil contamination, including agriculture, industrial production, transport, tourism and other activities carried out during our daily life. Contamination is mainly caused by the intentional or accidental release of xenobiotic (i.e. man-made products) chemicals into the environment, which can also have negative effects on human health and natural ecosystems. The main risk for humans consists primarily in the intake of these substances through the food chain or, secondary, through direct contact that may occur through ingestion, breathing and skin absorption (Brevik, 2013), especially for specific professional categories. The pollutants present in the soil can therefore easily enter our bodies through the food chain, causing serious health risks associated with the onset of diseases, food intolerances or allergies. For example, soil contaminated by heavy metals is an environmental problem both for the effects that these elements have on the quality of the soil itself and for the negative effects on crops and humans (Rossi and Pantanella, 2016). Some metals are essential for plant growth (e.g. copper, iron, zinc), but their presence in high concentrations can induce toxicity to the plants themselves and expose humans to health problems (Brevik et al., 2020), as the last recipient of the food chain. Heavy metals are harmful when released into the environment but there are also other chemical products, such as pesticides, industrial chemicals and unintentional by-products formed during industrial processes that may cause detrimental effects. For instance, pesticide-residues are associated with an increased risk of developing several chronic diseases such as diabetes, cancer and asthma, as well as a variety of short-term problems (e.g. dizziness, nausea, skin and eye irritation and headaches) (Brevik et al., 2020). This risk arises mainly from the presence of pesticide residues in food.

Food and agriculture, but there is much more!

Being informed defines the level of awareness and understanding of any problem. This is why it is so important that scientific research is shared and made accessible to everyone. Being able to have access to safe and healthy food is fundamental for human health, and in order to meet this goal, our soils must be healthy as well. As mentioned above, soils play a major role in providing us with food. However, this is not the only service soils provide: there are countless equally important ecosystem services that certainly deserve to be explored in order to highlight the importance of soil, not for humans only, but also to maintain and preserve the balance of the entire planet. In conclusion, a mention is worth to the emblematic words pronounced in 1937 by F.D. Roosevelt: “The nation that destroys its own soil destroys itself”. Clear, isn’t it?

References

1. Béné C, 2020. Resilience of local food systems and links to food security – A review of some important concepts in the context of COVID-19 and other shocks. Food Security, 12, 805–822. doi: 10.1007/s12571-020-01076-1.
2. Brevik EC, 2013. Soils and human health: an overview. In: Soils and Human Health. EC Brevik and LC Burgess (eds.). CRC Press, Boca Raton, FL, pp. 29–56.
3. Bevik EC, Slaughter L, Singh BR, Steffan JJ, Collier D, Barnhart P and Pereira P, 2020. Soil and Human Health: Current Status and Future Needs. Air, Soil and Water Research, 13, 1-23. Doi: 10.1177/1178622120934441.
4. FAO (Food and Agriculture Organisation of the United Nations), 2015a. La salute dei suoli rappresenta la base per una produzione alimentare sana. Available online: http://www.fao.org/fileadmin/user_upload/soils-2015/docs/IT/IT_Print_IYS_food.pdf [Accessed 15 Settembre 2020].
5. FAO (Food and Agriculture Organisation of the United Nations), 2015b. Il suolo è una risorsa non rinnovabile. Available online: http://www.fao.org/3/i4373it/i4373it.pdf [Accessed: 15 Settembre 2020].
6. FAO (Food and Agriculture Organisation of the United Nations), 2018.  Polluting our soils is polluting our future. Available online: http://www.fao.org/fao-stories/article/en/c/1126974/ [Accessed: 15 Settembre 2020].
7. Gardi C, (Ed.). 2017. Urban expansion, land cover and soil ecosystem services. Taylor & Francis.
8. ISPRA (Istituto superiore per la protezione e la ricerca ambientale), 2013. Capitolo 9: Suolo e Territorio. Available online: https://www.isprambiente.gov.it/files/pubblicazioni/statoambiente/tematiche2013/9_Suoloeterritorio.pdf [Accessed: 18 ottobre 2020].
9. Kroll JH, Heald CL, Cappa CD, Farmer DK, Fry JL, Murphy JG and Steiner AL, 2020. The complex chemical effects of COVID-19 shutdowns on air quality. Nature Chemistry, 12, 777–779. doi: 10.1038/s41557-020-0535-z.
10. Le Quéré C, Jackson RB, Jones MW, Smith AJP, Abernethy S, Andrew RM, De-Gol AJ, Willis DR, Shan Y, Canadell JG, Friedlingstein P, Creutzig F and Peters GP, 2020. Temporary reduction in daily global CO₂ emissions during the COVID-19 forced confinement. Nature Climate Change, 10, 647–653. doi: 10.1038/s41558-020-0797-x.
11. Rossi G and Pantanella Fm 2016. I metalli pesanti nel sistema suolo-pianta. Ecoscienza, 1.