Photo courtesy of Emanuela Pille da Silva and Anabel González Hernández.
Emanuela Pille da Silva and Anabel González Hernández are working at the nexus of land rehabilitation, soil health, and sustainable agriculture. Their project Agricultural Production in Recovered Areas After Coal Mining in Brazil was a finalist in the Barilla Center for Food & Nutrition (BCFN) Yes! Competition. The project assesses whether land that has been degraded by coal mining in southern Brazil is suitable for the production of safe and nutritious food. Their ongoing research at the Federal University of Santa Catarina, Brazil, uses plant microorganisms and soil microbes to monitor and aid the recovery of degraded lands.
Food Tank had the opportunity to talk with Pille da Silva and González Hernández about their project, the impact of coal mining on sustainable food production, and the links between soil and public health.
Food Tank (FT): What inspired you to become involved in food and agriculture research, and in particular to focus on soil microbiology?
Emanuela Pille da Silva & Anabel Gonzalez Hernandes (EPS & AGH): Our research team is multidisciplinary. We have experts in different areas from three universities in Latin America: a microbiologist from the University of Havana, Cuba, a biologist from the University of Antioquia, Colombia, and an agronomist from the Federal University of Santa Catarina, Brazil. We have all finished or are completing studies in the Plant Genetic Resources Graduate Program at the Federal University of Santa Catarina, which has been dedicated for almost 20 years to identifying conservation strategies and the sustainable use of plant genetic resources. Within the program, we chose to work on projects related to the recovery of degraded areas after mining, since the Brazilian mining industry is a significant contributor to the economy of Brazil. In the past, coal mining has been inadequately developed in southern Brazil, without observing the biotic and abiotic aspects necessary and indispensable to maintaining the quality of the environment around the mined areas. We believe that the land that has been degraded as a consequence of these mining activities can and should be reclaimed and regenerated for food production, especially for local communities. However, food quality and safety need to be monitored and ensured in this context.
FT: Congratulations on your project Agricultural Production in Recovered Areas After Coal Mining in Brazil making the BCFN YES! Competition finals in 2016. Can you tell us about the project?
EPS & AGH: Thank you. Our project is based on the idea that there may be a global scarcity of suitable farmland in the future. We believe that this scenario is even more likely in southern Brazil, where coal mining has put great pressure on land use and lead to environmental impacts, such as the contamination of soil and water with heavy metals. These elements are known to be bioaccumulative and pose a danger to human health. For these reasons, the Brazilian government and the coal industry were forced to conduct environmental recovery projects, implementing measures such as revegetation of affected areas and land reclamation for future use. Food production has been identified as a potential future use for these areas. However, there is uncertainty about the risk of transfer of toxic and heavy metals to humans, animals, and agricultural crops in these locations. The objective of the project was to assess the quality of food produced in these so-called recovered areas and their potential risks to human health. We hope that the monitoring of food contamination with heavy metals will be adopted as a public health policy in the region.
FT: What kind of impacts has coal mining placed on sustainable food production?
EPS & AGH: Coal mining can affect sustainable food production as it requires healthy soil capable of fulfilling its many functions over time, which can be impacted by the coal extraction method. For example, open-pit coal mining has led to the loss of soil surface horizons, and therefore the physical, chemical, and microbiological features of soil that are essential for the establishment and development of plant species. Currently, the recovery of those sites depends on human intervention and the application of inputs, such as the application of fertilizers and correctives, to increase the resilience of those sites and to allow the soil to resume and preserve its functions.
Also, many mine operators simply abandon mine without adequately disposing of waste, leaving barren piles of tailings and leading to acid mine drainage (AMD)—the outflow of acidic water from a mining site. Coal mines are filled with sulfides, and sulfides are exposed to water and air, they react to form sulfuric acid. This acid can dissolve other harmful metals from the surrounding rock and contaminate nearby water bodies making them unsuitable for use for a long time. The acid and metals can lower the water’s pH levels, which can have severe impacts on fish, animals, and plants that last long after mining activities have ceased. AMD is one of the most serious environmental impacts associated with mining activities.
FT: What are some of the main indicators of healthy soil and what methods do you use to measure it?
EPS & AGH: Soil quality can be assessed by different indicators that measure or reflect the environmental conditions of a given ecosystem. The indicators of a healthy soil can take into account different attributes of abiotic nature, such as those related to soil chemistry and physics, and those related to the biotic environment, which take into account, for example, microbiological attributes.
One of the main indicators of a healthy soil is the presence of organic matter and its contents. Various functions and biological processes, physical and chemical, that occur in the soil are directly related to the presence of organic matter. It can be easily measured in the laboratory using techniques that can determine, for example, the percentage of carbon and nitrogen or the microbial biomass, the living part of the organic matter. Physical indicators can determine soil structure, rate of infiltration, and soil density, as well as the soil moisture retention capacity.
The microbiological attributes of soil are particularly important in determining soil health. Microorganisms can give rapid responses to changes in soil quality, a characteristic that is not observed in other chemical or physical indicators. In some cases, changes in population and microbial activity, measured by microbial biomass, soil respiration, and the activity of certain enzymes, may be a clear signal of either soil improvement or degradation. No single indicator, however, will be able to describe and quantify all aspects of soil quality and health, since all soil attributes are interrelated.
FT: How are soil health and public health linked?
EPS & AGH: This is an interesting question. For many people, these themes seem disconnected, but they are not. Soils influence the availability and quality of the food supply, as well as come into contact with several chemical products that can be transferred into food. They can also propitiate exposure to various pathogens, which is something to be taken into account for public health.
A healthy soil should be able to provide both the necessary nutrients for the growth of plants and adequate nutritional value for the food produced in that soil. Healthy soils can have an important influence on human health since undernourishment can be prevented by providing quality, nutrient-dense food to the population.
Healthy soils are also capable of performing a variety of functions related to human health, for example, the detoxification of toxic compounds and heavy metals. Heavy metals can be absorbed by plants and animals and can accumulate in the food chain. These can have beneficial and/or toxic effects on humans, depending on the amount of intake. Public health policies and actors should pay attention to areas that increase the availability of these toxic elements in the environment and the harm they might cause to the health of the soil.
FT: What kind of public policies would encourage practices that foster soil health?
EPS & AGH: The increase in land degradation, internationally, is due to different pressures on land use. For these environments to exercise their socio-environmental role adequately in the future, policy measures that promote the improvement of soil quality should be encouraged.
For example, policy measures should aim to effectively recover the environments exploited and impacted by anthropic activities, such as mining. Policies have already been enacted in some areas in Brazil, where different activities are proposed for the impacted areas, and different future uses are allowed. However, for the success of the recovery process, an important measure to include is awareness raising and education of the local community. Local populations should be made aware of the importance of the recovery process of degraded areas, not to use these areas for any activity before they are effectively recovered, and should be fully included in the recovery process.
On the other hand, soils can also be degraded by agricultural activities. In this context, policy measures that favor and encourage more conservation practices, and therefore are less aggressive and more sustainable for the environment, should be adopted. Consumers can help this process by purchasing foods produced in an organic or environmentally sustainable way that encourage the production and maintenance of soil quality. Measures that support local production should also be adopted, so that food products do not have to be transported over long distances. Food should, therefore, be produced in sufficient quantity to meet the demands of the surrounding community.
In both cases, policies are needed to support ongoing research. Production alternatives that lower the need for fertilizers and corrective additions and encourage the use of microbial agents that favor the health and survival of plant species, should be promoted.