Climate change and global warming are phenomena that we are witnessing with increasing frequency, with numerous news reports of places being affected by devastating floods, unprecedented snowstorms, or scorching droughts. In other words, a natural cyclical phenomenon, highly amplified by human action, is having a significant impact on economic and social conditions on a global scale.

This situation is not new, but it has become more and more noticeable over time, and yet a large number of individuals seek to deny or hinder practices that could mitigate this phenomenon. In the search for solutions at a global level, in 1997 an international agreement, the Kyoto Protocol, was signed by 84 countries seeking to reduce greenhouse gas emissions. Almost a decade later, in 2015, the Paris Agreement was signed with a similar purpose, including more countries, in addition to the developed ones, that were already signatories to the Kyoto Protocol.

Despite the relevance of these agreements, the results are still limited. Factors such as changes in political positioning and economic interests, especially in sectors like fossil fuels, end up hindering more consistent progress on the environmental agenda.

In spite of this bleak outlook, in recent decades there has also been a push toward more sustainable development on the part of some sectors of industry. In this quest for sustainability, the development of biodegradable products and substances has been a key focus.

What does it mean to be "biodegradable"?

The term biodegradable is extremely widespread, and you have certainly come across it before, whether in a product's Safety Data Sheet (SDS), in advertising materials, or in conversations with product suppliers. But what is the true meaning of labeling something as biodegradable? And does the sale of biodegradable items actually contribute to better environmental care?

In simple terms, when we say that a material is biodegradable, we are stating that this material will undergo decomposition by microorganisms. In other words, a biodegradable substance effectively serves as a substrate for microorganisms, so that it will be consumed by other living beings, being transformed into energy for them and returning to the environment in the form of simpler molecules that are almost always much less toxic than the original substance.

Based on this definition, it is possible to infer that the development of biodegradable products tends to reduce the time these substances remain in the environment, decreasing their potential impact window.

Up to this point, we have presented general concepts. Now, let's direct the discussion to a specific and relevant segment: surfactants.

When can we say that a surfactant is biodegradable?

According to the ABNT NBR 14725:2023 standard, which classifies chemical substances in Brazil, one of the most practical ways to determine if a substance is biodegradable is through scan tests. It is worth noting that results obtained exclusively under anaerobic conditions (absence of oxygen) are not sufficient for this classification, since such conditions are less representative of the real environment. Even water bodies, for example, are generally considered aerobic environments due to the presence of dissolved oxygen.

Furthermore, the standard addresses not only biodegradability but also the concept of rapid degradation. The environment is a complex system where different factors act simultaneously in the degradation of substances. In addition to the action of microorganisms (biotic degradation), factors such as sunlight, pH, and temperature also promote chemical transformations, characterizing what is called abiotic degradation.

When a combined action of biotic and abiotic degradation results in the degradation of at least 70% of the substance within 28 days in an aquatic environment, the substance is considered to be rapidly degradable.

One important point to note here concerns national standards and biodegradability: Anvisa requires that all anionic surfactants used in Brazil be biodegradable. Despite this requirement, it is not necessary to perform biodegradability tests on all anionic surfactants, as the current standard only requires that new-generation anionic surfactants lacking widely publicized studies be subjected to biodegradability assessment. Given this, an important question arises:

Are biodegradable or rapidly degradable products necessarily safer for the environment?

The answer to the question above, unfortunately, is no. In the environment, it is not possible to isolate variables; it is an environment in which biotic and abiotic actions act simultaneously, and it is not always easy to determine which action will be predominant. In this scenario where both types of degradation can occur simultaneously, the number of reactions and transformations that substances can undergo increases considerably, which makes it possible for some more toxic substances to be produced as well.

When degradation generates more impact

A classic example of this behavior is nonylphenol ethoxylate. During its degradation process, nonylphenols can be formed, which are significantly more toxic compounds. These compounds even exhibit reproductive toxicity and are classified as potential endocrine disruptors, affecting both humans and aquatic organisms.

The associated environmental impacts include feminization of organisms, reduced male fertility, and decreased offspring survival rates, even at extremely low concentrations, below 10 µg/L (0.00001 g/L).

What does the industry need to consider from this point on?

Investing in biodegradable products is a great way to deal with the serious environmental issues we face today and will face in the future.

However, the blind belief that biodegradable or rapidly degradable products are free from producing any ecotoxicological problems should be treated with caution: the structures of the substances in question and all forms of degradation they may undergo must be carefully evaluated. It is necessary to assess:

• The chemical structure of the substance
• The paths of degradation
• The byproducts formed
• Ecotoxicological impacts

At Macler, we believe that developing more sustainable chemical solutions requires technical expertise, responsibility, and a long-term vision. More than just meeting regulatory criteria, our commitment is to support our clients in building formulations that reconcile performance, safety, and reduced environmental impact at every stage of their lifecycle.

The real challenge for the industry lies in developing substances that are safe not only in their original form, but also at every stage of their transformation in the environment.