NUI Galway study finds that wet wipes and sanitary towels are an underestimated source of white microplastic fibres in the marine environment and that 50 percent of wet wipe brands tested in this study that were labelled ‘flushable’ contained plastic fibres.
Researchers from Earth and Ocean Sciences and the Ryan Institute at NUI Galway carried out the study on the contribution of widely flushed personal care textile products (wet wipes and sanitary towels ) to the ocean plastic crisis.
Dr Liam Morrison led the study, which showed that sediments adjacent to the wastewater treatment plant (including Mutton Island ) are consistently strewn with white microplastic fibres that are comparable to those from commercially available consumer sanitary products (wet wipes and sanitary towels ). The article has been published in the international journal Water Research and was co-authored by NUI Galway PhD student Ana Mendes and Maynooth University graduate Oisín Ó Briain.
Speaking this week, President of NUI Galway, Professor Ciarán Ó hÓgartaigh said the University has made sustainability a strategic priority, and for the world to address climate change, they have a duty to examine the behaviour of individuals and corporations that can help our planet.
An urban rural gradient involving three locations from Galway City (close to Mutton Island and adjacent to a wastewater treatment plant ) to counties Clare (Bell Harbour ) and Mayo (Bellacragher ) were investigated in this study. The total number of fibres found near Mutton Island was 6083 microplastics fibres per kilogram of sediment, while the rural sites had much lower levels (Bell Harbour, 1627 and Bellacragher 316 ).
The total number of white fibres was 5536, 788, and 265 per kilogram of sediment for Mutton Island, Bell harbour and Bellacragher respectively. Incredibly, 91% of microplastic fibres at Mutton Island are likely derived from wet wipes and sanitary towels.
Lead researcher of the study, Dr Liam Morrison from Earth and Ocean Sciences and Ryan Institute at NUI Galway, said: “COVID-19 may have brought its own challenges for the oceans including the increased use of disinfectant wipes during the pandemic which potentially may end up as microplastic fibres in the sea. It is widely known that microplastics can act as vectors for contaminants including bacteria and viruses and are potentially harmful for public health and marine life.”
The nearby intertidal zone at Mutton Island is prone to the accumulation of high volumes of washed-up sewage-derived debris on a frequent basis. Excessive microplastic loading in sediments in December 2017 was likely induced by heavy precipitation episodes during a south-westerly storm front.
Elevated debris loading on this occasion may result from combined sewer overflows, where excessive input of drainage water exceeds wastewater treatment effluent capacity and is released untreated in the overflow. Dr Morrison said: “This was significant in the context of climate change, where we are likely to see increased rainfall events and flooding.”
While most microplastics may be removed by the wastewater treatment process, combined sewage overflows associated with periods of heavy rainfall give rise to the release of sewage waste containing wipes and sanitary towels, impacting on public health and the environment. Combined sewer overflows and the subsequent shoreline deposition of sanitary waste have not previously been thoroughly investigated as a source of white microplastic fibres in the marine environment.
The study found that wet wipes and sanitary towels are a source of unaccounted white microplastic fibres in the marine environment and not all flushable wipes are biodegradable. In fact 50% of the wipes labelled “flushable” in this study were shown to contain microplastics. The lack of regulation for hygiene and sanitary products results in a failure to identify the plastic composition of these materials. This demonstrates the consequences of misleading labelling of non-woven textile personal care products.
