This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Decommissioning pipelines used by the oil and gas industry could result in substantial quantities of microplastics being released into the UK's marine environment annually, a new study suggests. Conducted by scientists at the University of Plymouth, the research examined the degradation of plastics in subsea oil and gas pipelines and umbilicals (including hoses and cables) as a previously underexplored source of microplastic pollution.
The research is published in the Journal of Hazardous Materials. They estimated that almost 220,000 tonnes (243,000 tons) of plastics have been deployed in subsea pipeline and umbilical coatings on the UK Continental Shelf—an area that includes parts of the North Sea, where most oil and gas activity is located, in addition to the North Atlantic, the Irish Sea and the English Channel. They then estimated that more than half of those plastics, 120,000 tonnes (132,000 tons), were likely to remain in the ocean after decommissioning and would be subject to physical and chemical degradation, caused largely by sand abrasion on the seabed.
Using a range of modeling approaches, the study suggests that, due to degradation, between 4.5 tonnes (5 tons) and 500 tonnes (550 tons) of microplastics could be released into the UK North Sea each year, depending on prevailing environmental conditions. For context, between 4 tonnes (4.4 tons) and 16.5 tonnes (18 tons) of plastics are estimated to be released into the North Sea from UK rivers every year, and 500 tonnes (550 tons) is more than seven times the annual microbead releases from cosmetics into the North Sea before they were banned in the UK. Using a technique called Predicted No-Effect Concentration (PNEC) analysis, the research also indicated that, over time, microplastics accumulating from legacy oil and gas plastics have the potential to affect marine life across substantial areas, adding to the effects of plastic contamination from other sources.
Based on the research, the team recommends that the environmental consequences of legacy plastics be formally integrated into decommissioning decision-making and planning and consenting for new energy-related installations and other marine infrastructure. The research, which also involved the University of North Carolina, was funded as part of the INSITE North Sea Programme and builds on existing research led by scientists in Plymouth that has examined the sources and effects of microplastics, as well as the potential ecological benefits of decommissioned offshore structures. Freija Mendrik, a research fellow in the School of Biological and Marine Sciences and the new study's lead author, said, "Our research is the first to estimate the mass of plastics contained in oil and gas infrastructure on the UK Continental Shelf, with more than 120,000 tonnes of plastic potentially remaining in the marine environment after decommissioning.
We believe the findings mark an important step forward in understanding the possible environmental risks posed by these plastics and highlight a previously unrecognized potential source of microplastic pollution. Our findings have relevance outside the oil and gas sector and for decommissioning decision-making all over the world, not just the UK." Discover the latest in science, tech, and space with over 100,000 subscribers who rely on Phys.org for daily insights. d research that matter—daily or weekly. Sarah Gall, a lecturer in marine conservation in the School of Biological and Marine Sciences and principal investigator for the INSITE-funded project, said, "Decommissioning decision-making is hugely complex.
For decisions to represent the best possible outcomes for the environment and society, it is essential they are informed by robust and independent science. Our study makes a crucial contribution to developing an evidence base for decision-making for plastics in pipelines and umbilicals on an international scale. It highlights the potential risks involved with decommissioning in situ, and the importance of recognizing the potential environmental burden of plastics, both when planning for decommissioning old infrastructure and planning for installation of new." Professor Richard Thompson OBE FRS, head of the university's International Marine Litter Research Unit, has previously led research highlighting how microbeads in cosmetics, tire particles and washing clothes lead to significant quantities of microplastics entering the ocean.
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