The Influence of Ocean Acidification on The Surface Alteration of Microplastics

Abstract

Ocean acidification is the decreasing pH of seawater due to the absorption of excessive atmospheric carbon dioxide (CO2) by the ocean. Plastic pollution is an emerging environmental issue, caused by careless disposal and intense use of plastic products that eventually ended up in the ocean. Microplastics can be intentionally manufactured or exist from the breakdown of larger plastic pieces due to weathering in the form of sunlight and mechanical actions from wave and wind, also known as secondary microplastics. This work aims to understand the influence of ocean acidification (OA) towards surface alteration of microplastics surface changes in the ocean. In this work, virgin microplastics (< 5mm) are exposed in two different filtered seawater conditions for 10 days: normal (pH 8.0±0.2) and acidified condition (pH 7.7±0.2). The microplastic surface was analysed by using the Field Emission Scanning Electron Microscope (FESEM) and our findings revealed that all exposed microplastics experiences permanent aging and surficial damage. The aging of the microplastic surface was prominent in acidified conditions compared to normal condition. It is suggested that microplastics submerged in marine waters potentially release chemicals and in turn increase its toxicity. This condition can be further accelerated with increasing acidity of seawater. More study is needed to be carry out to further understand the mechanism of chemical release from plastic into the ocean during normal and acidified conditions.