Reacción a "A study of 10,000 marine animal necropsies reveals that one-third of birds and nearly half of turtles had ingested macroplastics"

This study uses a data review and modelling approach to estimate the risk of mortality in different species based on the amount of plastic present in their digestive tract. It is a methodologically sound approach to addressing a very specific part of the problem: the probability that ingesting certain types of plastic will result in lethal effects. This type of model is particularly relevant given the ethical and logistical challenges of experimenting with marine wildlife, and provides a useful tool for making progress without causing additional harm.

The study acknowledges the great complexity of assessing the biological impacts of plastic, which include physical, chemical and ecological dimensions, and focuses on a very specific parameter: the ingestion of relatively large fragments (>5 mm). This methodological choice favours data homogeneity and comparability, but it has a significant limitation: it leaves out smaller particles, which are ubiquitous and ingested by turtles, cetaceans, birds and fish. In most cases, these small fragments may be more common than large ones, so the actual risk is likely to be underestimated.

The study provides a key and very valuable message: not all plastics are equally dangerous. The likelihood of harm depends on the type of material, the size and shape of the ingested object, and the size of the animal itself. The research also highlights the difficulty in accurately quantifying the concentrations and types of plastic present in the environment. This reinforces the need to monitor marine litter and microplastics to generate solid data to feed into these types of models.

In the Spanish context, this work is directly relevant. Many of the species affected are common in our waters and frequently interact with plastic waste. The study highlights the urgent need to combine ingestion data with information on waste distribution, migratory routes and marine space use, which would enable more comprehensive risk assessments tailored to different regions.

The main recommendation that emerges from this and other recent studies is clear: the problem must be tackled at its source. In this regard, the accumulated scientific evidence, including that provided by this study, reinforces the importance of an ambitious and binding Global Treaty on plastics that addresses all dimensions of the problem and prioritises the protection of human health and marine ecosystems.