How abiotic plastic leaching contributes to ocean acidification



by LORENZO CIOTTI

How abiotic plastic leaching contributes to ocean acidification

Abiotic plastic leaching contributes to ocean acidification, a research published in The Science of the total environment, has tried to get to the bottom of an issue that is involving our oceans and is progressively destroying them.

The researchers said: "Ocean acidification and plastic pollution are considered as potential planetary boundary threats for which crossing certain thresholds could be very harmful to the world's societies and ecosystems well-being.

Surface oceans have acidified around 0.1 units since the Industrial Revolution, and the amount of plastic reaching the ocean in 2018 was quantified to 13 million metric tons.Currently, both ocean threats are worsening with time.

Plastic leaching is known to alter the biogeochemistry of the ocean through the release of dissolved organic matter. However, its impact in the inorganic chemistry of the seawater is less studied.Here we show, from laboratory experiments, that abiotic plastic degradation induces a decrease in seawater pH, particularly if the plastic is already aged, as that found in the ocean.

The pH decrease is enhanced by solar radiation, and it is probably induced from a combination of the release of organic acids and the production of CO2. It is also related to the amount of leached dissolved organic carbon, with higher acidification as leaching increases.

In coastal areas, where plastic debris accumulates in large quantities, plastic leaching could lead to a seawater pH decrease up to 0.5 units. This is comparable to the projected decrease induced in surface oceans by the end of the twenty-first century for the most pessimistic anthropogenic emissions scenarios." According to current data, the IPCC predicts a further decrease in pH of 0.3-0.4 by the end of this century resulting in an increase of up to 150% in acidity and a decrease in the amount of carbonate ion.

The long-term results due to the impact of ocean acidification need further study, but will certainly continue to increase the negative effects on living organisms. The problem is the fact that the oceanic acidification process is happening too fast not allowing the adaptation of the species present.

There are numerous proposals to reduce ocean acidification still being tested which will also be very expensive. Surely the natural processes will be able to recreate the conditions of equilibrium but this will take place over a very long time in the order of hundreds of thousands of years.