Climate Corner: How Plastic Impacts Brain Health

April 22 is Earth Day, and this year’s global theme is “Planet vs Plastics.” Let’s learn why reducing plastics waste can help safeguard brain health. Most plastics are fossil fuel-derived polymers processed with chemical additives that imbue desired physical properties. Applications include: packaging and single-use plastics (accounting for 31% of all plastics), buildings/construction (17%), transportation (14%), textiles (10%), and consumer/institutional products including medical products (10%). Once produced, plastics persist in the environment. Between 1950-2015, we produced 8.3 billion metric tons of plastics: 30% are still in use, 9% were incinerated, and 60% have accumulated as litter or landfill. Only 9% were recycled.

Negative health effects emerge at all stages of the plastics lifecycle. At the manufacturing stage, plastics account for 3.7% of global carbon emissions and contribute directly to climate change, which impacts mental health. Manufacturing also emits toxic air pollutants that worsen neurocognitive and behavioral outcomes in children and increase dementia risk. Factories often abut disadvantaged communities, exacerbating health inequities.

At the use stage, plastics can enter the human body via ingestion of contaminated food and water, inhalation, or skin contact. Research into the direct effects of plastics on brain health is still relatively nascent. Some plastics chemicals are implicated in the increasing prevalence of autism, attention-deficit hyperactivity disorder, and cognitive impairments due to direct neurotoxicity. Microplastics have been documented in human placentas, raising the question of their impact on brain development given the link between placental health and future risk of neuropsychiatric conditions. Plastics can disrupt endocrine processes; early research following a small cohort of children starting at gestation suggests that prenatal microplastics are associated with anxiety/depression in boys. It is not clear whether plastics increase dementia risk. Preclinical studies in mice show that nanoplastics can bind alpha-synuclein, leading to fibrils, and that drinking microplastics-contaminated water induces dementia-like behavioral and brain changes; new clinical research has just been funded.

At the disposal stage, plastics incineration produces more air pollution. Landfill and litter degrade into macro- and microplastics that leach into the environment: they have been found in the most remote areas of our Planet and also contaminate our water systems. 

There is hope: Maryland state and local laws have started addressing plastics pollution with bag bans, food container restrictions, and an extended producer responsibility program. And the United Nations is currently negotiating a Global Plastics Treaty. However, the petrochemical industry needs plastics as an alternative source of revenue given the push for clean energy and is actively hampering progress. 

So what can we do? Show support for the Global Plastics Treaty with an open letter from health professionals or general message to the U.S. Secretary of State in advance of the fourth negotiating meeting later this month; advocate for reduction of plastics in your workplace; and commit to personally reducing single-use plastics for food and drinks and to avoiding fast fashion and synthetic textiles.

The author thanks Maryland Psychiatric Society (MPS) for their editorial support; this article was first published in the April edition of “MPS News.”