Petroleum-derived plastics used in everyday life take more than 400 years to be decomposed by nature. This long period of degradation causes several problems, such as environmental pollution, animals’ death, food contamination and the consequent intoxication of the population – portrayal of how nature was not prepared to face such a powerful enemy, present worldwide in discarded manufactured materials. In the case of Amazon, the scenario is even worse due to the lack of adequate sanitation. In this biome, around 70% of cities lack an effective sewage service.

An estimate provided by local researchers points out that the Amazon river basin is the second most polluted in the world, since 182 thousand tons of plastic are dumped there every year. However, an innovative and pioneering solution has emerged as a hope in the face of the problem – the production of bioplastics derived from typical regional foods – in this case, the cassava starch. The initiative is from the Laboratório de Biossoluções e Bioplásticos da Amazônia (LABA) [Amazon Biosolutions and Bioplastics Laboratory], at the Federal University of Pará (UFPA), and coats grains, such as black pepper.

The total decomposition time of this sustainable material is 180 days – a  reduction of more than 99% compared to others that use oil in their manufacture. It is used to protect food against external pests – fungi, for example – that could harm the end consumer and cause economic losses. Thus, in addition to generating safety, bioplastic also contributes to the valorization of the starch production chain and helps to reduce the amount of plastic dumped into the environment. The total process has already been patented by UFPA researchers.

Results

Studies were conducted to achieve the result. Before the expected delivery deadline, LABA researchers reached good stability of the bioplastic so that it could be coated in black pepper. Davi Brasil, PhD professor at UFPA and coordinator of the Laboratory, explains that the work consisted of preserving the natural characteristics which make up the material to achieve a transparent aspect, in other words, one that would not visually change the food. The application is made using equipment ensuring full coverage.

This process is fundamental to one of the project's objectives: preventing the growth of pests and completely protecting the product. The researchers also thought about the aroma that would be exhaled. “During the process, we dry the material and extract some of the essential oil that becomes impregnated in the film itself, giving it a different aroma. When we smell it, it becomes very pronounced, being organoleptically important for food purposes”, explains Professor Brasil.

Visibility

The importance of bioplastic, highlighted by the Professor, is considered in all aspects, from the enhancement of the local economy to its environmental role. “Because we are working with materials that, if discarded in nature, will have a very short degradation time, when compared to petroleum-derived plastics. We know there is no natural enzyme which can destroy that quickly, unlike natural products, because nature is very intelligent”, he highlights. 

Now, with the production process already developed and patented, researchers are seeking to expand the directions that the product can take within the market. “We want this to reach the consumer, the society. It is a delivery that every university Professor aims at when doing their research, that this will, in some way, be valued by society, bring benefits. The benefits we are bringing are preservation for a longer time [of foods coated with bioplastic], appreciation of our regional material and environmental preservation”, adds the LABA coordinator.

Açaí seed is used for new bioplastic functionalities

Professor Davi Brasil is the advisor of the doctoral thesis that resulted in cassava starch bioplastic. The initial idea comes from José Rêgo, a PhD from the Faculty of Chemistry at UFPA. Previously, they only sought to coat black pepper with starch bioplastic, aiming to increase the food's shelf life. Now, new research is focusing on finding different functionalities for the product, making use of the açaí seed. The expectation is that the incorporation will generate firmer plastics to replace other products.

Professor José Rego explains that this mixture is essential for the bioplastic to become resistant. “We are functionalizing the starch bioplastic, adding good characteristics that come from the açaí seed. It is difficult to replace petroleum plastic because it is inert. There is no organism that attacks it, nor an enzyme that degrades it. If I have bioplastic of natural origin, it tends to be attacked by organisms that would normally attack starch. So, I have to add something that inhibits this property. Due to the richness of tannins, which give the taste [to the product]”, he highlights.

Use in medicine

In addition to the food purposes that bioplastic has been designed for, the functionalities can also reach the health sector. Professor Rego details that one specific healing property of the açaí seed is being studied, an initiative that could accelerate the process. “Several people, several laboratories, several researchers around the world are studying the natural properties, so, let's imagine that it had a healing property, I could wrap that cut with a starch biofilm functionalized with the substances that come from the açaí seed.", he adds.

Microplastic is a recurring problem in the Amazon

The bioplastic produced at UFPA can be a solution to another problem: microplastics – plastic particles that have two origins:  what is already manufactured in small sizes by the industry and what is derived from a fragmentation process. To gain definition, it must be less than five millimeters. Some can be smaller than bacteria. According to José Eduardo Martinelli Filho, Professor at the UFPA Institute of Geosciences, the smaller the particle, the bigger the problem.

The accumulation of microplastics in cells can be a reality, causing harm to humans and animals – some studies already indicate the damage caused by these particles. Martinelli Filho explains that most of these materials are non-toxic, that is, they do not cause harm. However, the increase in substance (in them) can make them an even greater danger. “Especially those formed by polymers, they can cause some effect. An example is fishing nets. Nylon itself is non-toxic, but the dye that gives it color is potentially harmful.”

Demages

According to studies, among the harmed species by the presence of plastics are birds. The Japu, from the same family as crows, found in the Amazon – in Salinas and Algodoal, in Pará, for example – is one of the species that has been suffering these effects. “They are using plastics to build nests. They use fishing material and trash discarded on the beach, however, this can be toxic to birds, because they contain dyes with levels of toxicity in their composition. The hatched egg [in the nests] is possibly exposed to this and it has effects, because, from the egg to the baby bird, they are exposed”, points out the Professor.

“Microplastics, when they remain in water for a long time, months, years and decades, can absorb a series of chemical contaminants, heavy metals, bacteria that can be pathogenic and grow. So, the longer it stays in the ocean, the more dangerous it becomes. The longer it ages at the bottom of the sediment, river, sea or water, the greater the risk of it becoming more toxic, because it can absorb contaminants that are in the water, it can absorb pesticides. Research on human beings is recent. The particle has been found in different tissues and organs, breast milk, blood, placenta, fatty plaques in the heart…”, he states.

Microplastic is spread across different parts of the biome

Studies regarding the damage that microplastics can cause in the Amazon are recent and are gaining more and more strength. In 2018, work was carried out to analyze the ingestion of particles by fish in the biome's estuary. In 2020, research was carried out with sea anemones, animals considered potential bioindicators of pollution – they are not selective and ingest what is nearby. The species is found in São Caetano, Algodoal and Salinas, cities in the state of Pará, but also observed in Uruguay, a country in Latin America.

The igapós in the biome also accumulate particles. Although research in the region is accompanied by several difficulties, such as access to places, it is now possible to have an idea that, in small or large quantities, microplastic is present in different parts of the Amazon. “What we know is that microplastic has been found. This occurs in sediments, such as beach sand, in the mud at the bottom of rivers, such as the Amazon, in urban channels, such as in Macapá, in Guajará Bay, as well. The largest quantity is on the right bank, close to Belém. On the islands, there is a smaller quantity”, concludes Professor José Filho.

Survival

Other impacts of microplastics on species living in the Amazon can be observed by means of an experimental study carried out by PhD in Zoology Viviane Firmino, from the UFPA Laboratório de Ecologia e Conservação da UFPA [Ecology and Conservation Laboratory. The research showed that aquatic insects that are important in the functioning dynamics of Amazonian rivers can also suffer damage. Known as fragmenters, they inhabit small streams in the biome and consume organic matter – such as leaves and branches –, thereby  promoting the flow of energy within the environments. Fish and other invertebrates ingest the material.

The research was carried out in controlled environment, with the aim of filling a gap in knowledge. “Increased concentrations of microplastics reduce the survival of fragmenters and reduce the risk of mortality. However, we did not observe an independent or isolated effect of microplastics on fragmenter’s consumption. Regarding this result, microplastics do not affect consumption, but they interact with climate change and can lead to its reduction. If the fragmenter dies, the function it plays in the ecosystem will no longer be performed,” says Professor Firmino.