Report Paul Murphy
A Navan-based priest who is a campaigner on environmental and social issues has raised an alert about a link between plastic waste and the incidence of Alzheimer’s and Parkinson diseases. Fr Sean McDonagh, a member of the Society of St Columban at Navan is an outspoken critic of the degradation of the environment, linking this to global poverty and the increased suffering of the poor. His understanding of environmental issues and the relationship between faith, justice and ecology was awakened during his work with the indigenous T’boli people on the Philippine island of Mindanao in the 1970s and 1980s.
Fr Sean McDonagh ( Credit; The Irish Catholic)
He has strongly urged the Catholic church to undergo an “ecological conversion” advocating that environmental justice must be a core Christian activity. He has been instrumental in offering a master’s degree in ecology and faith at the Columban Centre in Dalgan Park.
Writing in the Christmas 2025 issue of The Sacred Heart Messenger magazine Fr McDonagh traces the history of the invention of plastic in the 1860s to widespread popularity after the Second World War and its integration into everyday life. He writes that in 2023 plastic production reached over 413 million tons and it has been forecast that that number will double within the next 20 years.
“Unfortunately, only about 9% of plastic waste is recycled and 79% ends up in landfills or the environment”. He says that it is estimated that 11-14 billion metric tons have ended up in the ocean and points to a major study by the Royal Netherland Institute for Sea Research and Utrect University has revealed that 27 million tons of plastic, much of it smaller than one micrometer, are floating in the Atlantic
Ocean. “It is estimated that plastic debris is massive”.
“The main problem with plastics is that, unlike organic materials, they are not broken down by microorganisms. Plastics persist in the environment and accumulate, disrupting many ecosystems. Over time weathering breaks large plastics into smaller pieces, first into microplastics (les than 5mm) and the nanoplastics (smaller than 1 micrometer). Everyone is aware that plastics accumulate in oceans, rivers, land, and even in the atmosphere”.
Fr McDonagh maintains that nanoplastics affect wildlife, habitats and human health because many animals and plants mistake plastic for food. There are concerns that plastic pollution affects the human food chain. He says that the professor of biochemistry at Trinity College Dublin, Gavin Davey and his students, especially Devin Seward, are looking at how mitochondria in the brain are disrupted by tiny pieces of plastic which may be contributing to the increased global levels of Alzheimer and Parkinson’s. The priest says that, unfortunately, nanoplastics are everywhere,. “They are in the air, in the rivers and in the sea. That is why people are exposed to them while cycling to
school or drinking from plastic bottles.”
