# The effects of agriculture's environmental externalities on food systems

Etienne Hainzelin, Benoit Daviron

► To cite this version:

Etienne Hainzelin, Benoit Daviron. The effects of agriculture's environmental externalities on food systems. Dury Sandrine (ed.); Bendjebbar Pauline (ed); Hainzelin Etienne (ed.); Giordano Thierry (ed.); Bricas Nicolas (ed.). Food systems at risk. New trends and challenges, CIRAD; FAO, pp.63-66, 2019, 978-2-87614-751-5. 10.19182/agritrop/00094. hal-05174279

HAL Id: hal-05174279

https://hal.science/hal-05174279v1

Submitted on 21 Jul 2025

HAL is a multi-disciplinary open access
archive for the deposit and dissemination of sci-
entific research documents, whether they are pub-
lished or not. The documents may come from
teaching and research institutions in France or
abroad, or from public or private research centers.

L'archive ouverte pluridisciplinaire HAL, est
destinée au dépôt et à la diffusion de documents
scientifiques de niveau recherche, publiés ou non,
émanant des établissements d'enseignement et de
recherche français ou étrangers, des laboratoires
publics ou privés.

<figure><img src="image_1.png" /></figure>
<figure><img src="image_2.png" /></figure>

Food and Agriculture
Organization of the
United Nations

<figure><img src="image_3.png" /></figure>

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

cirad

AGRICULTURAL RESEARCH
FOR DEVELOPMENT

# FOOD SYSTEMS AT RISK
## NEW TRENDS AND CHALLENGES

<figure><img src="image_6.png" /></figure>
# FOOD SYSTEMS AT RISK
## NEW TRENDS AND CHALLENGES

Sandrine Dury,
Pauline Bendjebbar,
Étienne Hainzelin,
Thierry Giordano
and Nicolas Bricas (Eds)

Published by
the Food and Agriculture Organization of the United Nations
and
Le Centre de Coopération Internationale en Recherche Agronomique pour le Développement
and
the European Commission

Rome, 2019
Citation:

Dury, S., Bendjebbar, P., Hainzelin, E., Giordano, T. and Bricas, N., eds. 2019. *Food Systems at risk: new trends and challenges*. Rome, Montpellier, Brussels, FAO, CIRAD and European Commission. DOI: 10.19182/agritrop/00080

The designations employed and the presentation of material in this information product do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations (FAO), the Centre de coopération internationale en recherche agronomique pour le développement (CIRAD) or the European Commission (EC) concerning the legal or development status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products of manufacturers, whether or not these have been patented, does not imply that these have been endorsed or recommended by CIRAD, FAO or EC in preference to others of a similar nature that are not mentioned.

The views expressed in this information product are those of the author(s) and do not necessarily reflect the views or policies of CIRAD, FAO or EC.

ISBN 978-2-87614-751-5 (CIRAD)

ISBN 978-92-5-131732-7 (FAO)

© FAO, 2019

<figure><img src="image_7.png" /></figure>

Some rights reserved. This work is made available under the Creative Commons Attribution-
NonCommercial-ShareAlike 3.0 IGO licence (CC BY-NC-SA 3.0 IGO;
https://creativecommons.org/licenses/by-nc-sa/3.0/igo/legalcode).

Under the terms of this licence, this work may be copied, redistributed and adapted for non-commercial purposes, provided that the work is appropriately cited. In any use of this work, there should be no suggestion that FAO endorses any specific organisation, products or services. The use of the FAO logo is not permitted. If the work is adapted, then it must be licensed under the same or equivalent Creative Commons license. If a translation of this work is created, it must include the following disclaimer along with the required citation: "This translation was not created by the Food and Agriculture Organization of the United Nations (FAO). FAO is not responsible for the content or accuracy of this translation. The original English edition shall be the authoritative edition."

Disputes arising under the licence that cannot be settled amicably will be resolved by mediation and arbitration as described in Article 8 of the licence except as otherwise provided herein. The applicable mediation rules will be the mediation rules of the World Intellectual Property Organization http://www.wipo.int/amc/en/mediation/rules and any arbitration will be in accordance with the Arbitration Rules of the United Nations Commission on International Trade Law (UNCITRAL).

Third-party materials. Users wishing to reuse material from this work that is attributed to a third party, such as tables, figures or images, are responsible for determining whether permission is needed for that reuse and for obtaining permission from the copyright holder. The risk of claims resulting from infringement of any third party-owned component in the work rests solely with the user.

Sales, rights and licensing. FAO information products are available on the FAO website (www.fao.org/publications) and can be purchased through publications-sales@fao.org. Requests for commercial use should be submitted via: www.fao.org/contact-us/licence-request. Queries regarding rights and licensing should be submitted to: copyright@fao.org
CHAPTER 3.3
# THE EFFECTS OF AGRICULTURE'S ENVIRONMENTAL EXTERNALITIES ON FOOD SYSTEMS

Étienne Hainzelin<fnref n="1" /> and Benoit Daviron<fnref n="2" />

SUMMARY

A healthy environment is essential for the proper functioning of both natural and cultivated ecosystems and, as such, plays a major role in food systems. Many different sources, including the agricultural sector itself, emit and accumulate pollutants in different environmental compartments (soil, water and air). When there are excessive pollutant levels, ecological functioning is hampered by eroded biodiversity, disrupted nutrient cycling, toxicity and depleted soil fertility, and can lead to reduced yields and contaminated food products. Many pollutants end up in water through leaching and run-off and have negative impacts on aquatic ecosystems, reducing fish and seafood stocks. Pollutants can also contaminate the food chain and cause food toxicity risks, and this is particularly true when pollutants undergo gradual biological concentration along the food chain.

Pollutant diversity and sources

The environment is a major sink for numerous pollutants, derived mainly from human activities. All environmental compartments are concerned (soil, water and air), with specific and complex dynamics. Pollutants belong to two main categories (Edwards, 2002; OECD, 2017; FAO, 2015):

* Inorganic pollutants are mainly heavy metals (arsenic, cadmium, lead, mercury etc.). Cadmium is the most serious heavy metal likely to contaminate agricultural soils. Due to its high mobility in the soil, it can be easily absorbed and transferred to the food chain.

* Organic pollutants are highly diverse (hydrocarbons, phenolic compounds, fertilisers, pesticides, micro-plastics etc.) and their accumulation in the environment is due to the absence of any biological process to degrade them (xenobiotic molecules) or to the relative slowness of the degradation process. 'Chemicals of Emerging Concern' are new challenges, including products such as nanoparticles, pharmaceuticals, cosmetics, hormones, detergents and certain industrial chemicals whose effects are not always understood and/or measured.

Pollution may come from different sources (Thangavel, 2017); it can be a single discharge point, which means control strategies can be employed, or a more diffuse source at the landscape level via air-soil-water systems, which requires complex analyses involving these three compartments in order to tackle the pollution (IPES-Food, 2017):

* Large quantities of urban solid waste, mostly treated in landfills or incinerators, can eventually affect groundwater and the soil quality of cultivated ecosystems in the vicinity. Sewage sludge, sometimes applied on cropland, can also be highly contaminated with heavy metals and pesticides (Rodríguez-Eugenio, 2018).

* Many industrial chemicals pollute land near their production sites but can also be transported to other systems through discharges into aquatic systems or wind dispersal. These chemicals include heavy metals, inorganic gaseous emissions, and volatile organic compounds (Rojas et al., 2016).

* Agriculture is a major contributor to pollution in many regions of the world through the use of synthetic inputs, such as fertilisers and pesticides, and animal waste (Lelieveld et al., 2015). When applied in excess, only a fraction of fertilisers are absorbed by plants and the rest can contaminate groundwater or river systems through leaching or run-off. Phosphates generally also bring heavy metal contaminants, such as cadmium. Agrochemicals are also a major pollutant affecting soils and water. Organochlorine insecticides that can persist in the soil for decades can be bioconcentrated from the soil to final consumer along the food

<footnote n="1">1. CIRAD, DG, Gatineau J9H 4S7, Canada; University of Montpellier, F-34090 Montpellier, France.</footnote>

<footnote n="2">2. CIRAD, UMR MOISA, F-34398 Montpellier, France; University of Montpellier, F-34090 Montpellier, France.</footnote>
chain. Antibiotics, used on a large scale in animal and fish production, are causing growing concerns for the resistance they can generate (Rodríguez-Eugenio, 2018; IPES-Food, 2017)

## Effects on food systems

There are two main impact pathways on food systems: through degradation of the productive capacity of land or aquatic ecosystems and through contamination at different stages of food production. The impact of a pollutant will depend on its toxicity and its persistence. This means heavy metals have much more serious effects than relatively transient chemicals. An ecosystem's resilience to the effects of a pollutant depends in part on its biodiversity, stability and the existence of alternative processes for performing essential functions.

### Agroecosystem degradation and reduction of production potential

While some degradation processes can be observed directly, soil contamination cannot, making it an insidious hazard, a 'hidden danger' (FAO, 2018). The analysis is further complicated by the diversity of contaminants (in particular persistent organic pollutants, constantly changing due to developments in agrochemistry), their random circulation, their transformation through biological activity in soils and the ability of soils to store, immobilise and degrade. However, the effects may appear suddenly after changes in land use that alter environmental conditions.

The impacts of soil pollutants are highly diverse and chemicals such as pesticides can have direct toxicity effects on surface and subsoil biota. These in turn can have major influences on soil ecology by changing the availability of organic matter that provides nutrients to other living organisms, modifying the plant rhizosphere or altering the soil pH. These changes can have an impact not only on population size but also on the functions of terrestrial ecosystems that affect production (Rodríguez-Eugenio, McLaughlin and Pennock, 2018).

### Impact on aquatic ecosystems and fish resources

Acute or chronic pollution with a wide range of organic and inorganic compounds entering the aquatic ecosystem is likely to impact both wild and farmed aquatic species through direct (toxicity) or indirect effects (Ryder, Karunasagar and Ababouch., 2014). Aquaculture might allow for better control of the risk through ensuring the composition of fish feed and monitoring water quality.

Another source of pollution likely to affect ecosystem and production systems is eutrophication, which results from organic and inorganic nutrients rich in

nitrogen and phosphorus being released into water bodies. Depending on its intensity, eutrophication can lead to changes in the assemblage of species (with micro- or macro-algae proliferation), reduced biodiversity, changes in trophic food webs or massive fish kills as a result of deoxygenation and the release of toxic gases by anoxic bacteria (van Beusekom, 2018).

A rapidly growing concern is plastic pollution, especially micro- and nanoplastics, as they have become ubiquitous in inland waters and oceans and are of growing significance. Evidence is still lacking on their real impact and additional research is required for nanoplastics, as their size could allow some of them to cross cell membranes and enter blood circulation (Lusher, Hollman and Mendoza-Hill, 2017).

### Food system contamination

Food represents the main source of human exposure to some of these pollutants and, despite the lack of comprehensive data, food contamination is a serious threat to human health (WHO, 2015). Heavy metals are ubiquitously distributed in the environment, reach plant and animal-derived food and can cause chronic or acute toxicity and serious human pathologies (Rodríguez-Eugenio, 2017). Numerous organic pollutants can contaminate human food, even at very low concentrations, exemplified by endocrine-disrupting chemicals (EDCs). The risks can increase through the biomagnification process, where some pesticides stored in the fatty tissues of animals are gradually concentrated along the food chain until their consumption by humans.

### Synergic effects

In nature, organisms are exposed not only to a single pollutant but often to many chemicals in large quantities or in trace amounts. Interactions between various chemicals (for example, antibiotics and cadmium) can increase or decrease the overall effect (Wang et al., 2018). In other words, the resulting effect may be greater or lesser than the simple combined effect or be unchanged. It is also possible that a compound may not be toxic itself but may become so in the presence of another compound. Ecotoxicology struggles to address these possible complex cocktail effects.

## Trends in developing countries

Asian countries experiencing rapid industrialisation are confronted with considerable contamination of their agricultural soils. For example, large quantities of mercury from the chemical industry and gold mines are released into the environment (Sari et al., 2016). Arsenic is also naturally present in groundwater in many parts of Bangladesh and western India (Rahman, Dong and Naidu, 2015; Mojid et al., 2016).
This poses a threat to agriculture, particularly in rice fields. Intensive pesticide and fertiliser use has also resulted in the accumulation of organic pollutants in the region's soils and eutrophication in water. In China alone, heavy metal contamination may result in a reduction of more than 10 million tonnes of food supplies each year (FAO, 2015). Many studies have shown the existence of high levels of organochlorines in vegetables and other food products (Lam, Pham and Nguyen-Viet, 2017).

In Africa, mining, the oil industry and poor urban waste management are highly significant sources of pollution. According to a study of ten Ogoni communities in southeast Nigeria, pollution from oil spills has led to concentrations of hydrocarbons and heavy metals in water, air and soil that are 900 times higher than allowable levels (UNEP, 2007). However, soil pollution through agrochemicals is of less concern than in other parts of the world because of their low level of use, with the exception of intensified peri-urban horticulture where groundwater is often contaminated (Sorensen et al., 2015). There are also several examples of mismanagement, as illustrated by reported cases in Botswana and Mali, where more than 10,000 tonnes of pesticides, including very dangerous organochlorine compounds such as dichlorodiphenyltrichloroethane (DDT), aldrin and heptachlor, have leaked from damaged containers and contaminated the soil (Cachada et al., 2018).

The growing threat of lead pollution, through petrol additives or battery recycling, also illustrates contexts where regulations are weak or absent (Gottesfeld et al., 2018).

In the Near East and North Africa, in addition to the excessive use of chemical fertilisers and pesticides, a frequent source of soil and water pollution is the use of wastewater for irrigation and sewage sludge as a fertiliser (Mekki and Sayadi, 2017).

<figure><img src="image_8.png" /><figcaption>**Figure 17:** Least Developed Countries: chemical inputs used in agriculture from 1990 to 2016 (1,000 tonnes).</figcaption></figure>

Source: FAOSTAT, consulted on February 15, 2019.

## BOX 7

### PESTICIDE USE IN HORTICULTURE IN SUB-SAHARAN AFRICA: AN INCREASING RISK FOR FOOD SYSTEMS¹

Even though sub-Saharan African countries are the smallest users of pesticides in the world, African agriculture is far from being 'organic by default'. Since the 1970s, farmers have been using pesticides on their crops to prevent pest invasions and crop losses. Back then, the use of pesticides was mainly dedicated to export crops, such as cotton, coffee, tea, bananas and other tropical fruits. Driven by urbanisation and changes in diet as well as the growing population, the demand for fruit and vegetables in urban markets is continuously increasing. In order to meet this demand, peri-urban horticulture is increasing and the import value of pesticides in Central, East and West Africa grew by 261 percent between 2000 and 2010.

The risks associated with this growing pesticide use are being increasingly documented. First, there are risks in terms of the quality of the pesticides used. Indeed, they are often not adequate for the crop targeted. For instance, studies have shown that farmers in Benin generally spray cotton pesticides on vegetable crops in Cotonou. In addition, most of the time the products used are not good quality pesticides; sometimes they come from international out-of-date stock, which means they are no longer effective. Sometimes products used by farmers are forbidden on international markets, but still sold in African markets.

The study on market gardens in Cotonou showed that of 15 pesticides used, only two were officially allowed by the national regulations. Furthermore, the study reports inadequate farmers' practices and misuse of pesticides that are a threat to their own health and for their families and final consumers. Pesticides are often sprayed at the wrong moment and the period between spraying and sale is often not respected. This means that consumers buy vegetables on the market that should not be consumed. Additionally, farmers' lack of awareness, poor equipment and reuse of pesticide containers for other family uses, the absence of instructions (sometimes due to repackaging or illiteracy) and the difficulty for farmers in converting dosages usually prescribed for hectares for their small farms generate high risks for human and environmental health. Finally, the overuse of pesticides on certain crops can cause a high risk of pest resistance, as has been illustrated with tomato bollworm in Benin.

The increasing use of pesticides in horticulture, combined with urban sprawl, competition for land (involving the production of more food on smaller plots), as well as industrial and transport pollution, are aggravating risks for food systems seeking to comply with food security objectives and environmental integrity.
References

De Bon, H., Huat, J., Parrot, L., Sinzogan, A., Martin, T., Malézieux, E. & Vayssières, J.F. 2014. Pesticide risks from fruit and vegetable pest management by small farmers in sub-Saharan Africa. A review. *Agronomy for Sustainable Development*, 34(4): 723–736.

Cachada, A., Rocha-Santos, T. & Duarte, A.C. 2018. Soil and pollution: an introduction to the main issues. In A. Cachada, T. Rocha-Santos & A.C. Duarte, eds. *Soil pollution*, Academic Press. pp. 1-28

Edwards, C.A. 2002. Assessing the effects of environmental pollutants on soil organisms, communities, processes and ecosystems. *European Journal of Soil Biology*, 38 (3-4): 225-231.

FAO & Intergovernmental Technical Panel on Soils (ITPS). 2015. *Status of the world's soil resources (SWSR) - Main Lamreport*. Rome, FAO. 599 pp.

IPES-Food. 2017. *Unravelling the food-health nexus: addressing practices, political economy, and power relations to build healthier food systems*. The Global Alliance for the Future of Food and IPES-Food.

Lam, S., Pham, G. & Nguyen-Viet, H. 2017. Emerging health risks from agricultural intensification in Southeast Asia: A systematic review. *International Journal of Occupational and Environmental Health*, 23(3): 250–260.

Lusher, A.L., Hollman, P.C.H. & Mendoza-Hill, J.J. 2017. *Microplastics in fisheries and aquaculture: status of knowledge on their occurrence and implications for aquatic organisms and food safety*. FAO Fisheries and Aquaculture Technical Paper No. 615. Rome. 147 pp. (also available at www.fao.org/3/a-i7677e.pdf).

Mekki, A. & Sayadi, S. 2017. Study of heavy metal accumulation and residual toxicity in soil saturated with phosphate processing wastewater. *Water, Air & Soil Pollution*, 228(6): 215.

Mojid, M.A., Hossain, A.B.M.Z., Cappuyns, V. & Wyseure, G.J.S.R. 2016. Transport characteristics of heavy metals, metalloids and pesticides through major agricultural soils of Bangladesh as determined by TDR. *Soil Research*, 54(8): 970-984.

OECD. 2017. *Diffuse pollution, degraded waters: emerging policy solutions*. OECD Studies on Water. Paris, OECD.

Rahman, M.M., Dong, Z. & Naidu, R. 2015. Concentrations of arsenic and other elements in groundwater of Bangladesh and West Bengal, India: potential cancer risk. *Chemosphere*, 139: 54–64.

Rodríguez-Eugenio, N., McLaughlin, M. & Pennock, D. 2018. *Soil pollution: a hidden reality*. Rome, FAO.

Rojas, R.V., Achouri, M., Maroulis, J. & Caon, L. 2016. Healthy soils: a prerequisite for sustainable food security. *Environmental Earth Sciences*, 75(3): 180.

Ryder, J., Karunasagar, I. & Ababouch, L., eds. 2014. *Assessment and management of seafood safety and quality: current practices and emerging issues*. FAO Fisheries and Aquaculture Technical Paper No. 574. Rome, FAO. 432 pp.

Sari, M.M., Inoue, T., Matsumoto, Y., Yokota, K., Isrun, I.J.E. & Research, E. 2016. Assessing a mercury affected area from small-scale gold mining in Poboya, Central Sulawesi, Indonesia. *Environment and Ecology Research*, 4(4): 223-230.

Sorensen, J., Lapworth, D., Nkhuwa, D., Stuart, M., Gooddy, D., Bell, R., Chirwa, M., et al. 2015. Emerging contaminants in urban groundwater sources in Africa. *Water Research*, 72: 51–63.

Thangavel, P. & Sridevi, G. 2017. Soil security: a key role for sustainable food productivity. In A. Dhanarajan A., ed. *Sustainable agriculture towards food security*, pp. 309–325. Singapore, Springer.

United Nations Environment Programme (UNEP). 2007. *Global Environment Outlook 4 (GEO-4)*. Nairobi, UNEP.

van Beusekom, J.E.E. 2018. Eutrophication. In M. Salomon & T. Markus, eds. *Handbook on marine environment protection*. Springer, Cham [online]. https://doi.org/10.1007/978-3-319-60156-4_22

Wang, J., Wang, L., Zhu, L. & Wang, J. 2018. Individual and combined effects of enrofloxacin and cadmium on soil microbial biomass and the ammonia-oxidizing functional gene. *Science of the Total Environment*, 624: 900–907.

World Health Organization (WHO). 2015. WHO estimates the global burden of foodborne diseases. Geneva, 255 pp.