Would the Oceans Become Toxic to Humanity Due to Use and Mismanagement of Plastics?

The production of plastics and associated products, including microplastics (MPs), has been surging over the past several decades and now poses a grave environmental threat. This is because when not appropriately recycled, incinerated, or disposed of in fully contained landfills, plastic waste manifests as a potent pollutant, with vast amounts finding their way into oceans annually, adversely impacting marine life and ecosystems. Additionally, research also confirms there are direct impacts from MPs on water, air, and soil, impacting ecosystem and human health. This study investigated all aspects of plastics and microplastics such as their generation and consumption, their presence in oceans, and their ultimate fate. Next, a comprehensive literature search was performed to identify impacts MPs have on watercourses and soils and eventually on the ocean, taking into consideration the coupled impacts of metals and emerging contaminants adsorbed onto MPs. Then, a model to estimate the number of MPs in oceans and then using toxicity of MPs to humans and aquatic life to estimate when oceans would become toxic to humanity is described. Utilizing the model, it is possible to estimate the year when MPs in the ocean could potentially become broadly toxic, for both humanity and marine life, under different emissions scenarios. The estimates conclude that with the current MP discharge growth, oceans would become toxic to humanity between 2398 and 2456, for MP discharge growth only until 2020, it could be reached between 2408 and 2472, and for emissions ending in 2020, oceans would not become toxic to the humanity. Finally, remediation strategies are described to prevent oceans from becoming toxic to humanity by focusing on various action items such as education and awareness, reducing the utilization of single-use plastic, and conventional and innovative strategies that can be used for the treatment of stormwater and wastewater.