"Microplastics" may pose previously unrecognized pollution threat to marine environment
Microscopic particles of plastic debris that litter marine environments may pose a previously unrecognized threat to marine animals by attracting, holding, and transporting water pollutants, a new study by British researchers is reporting. The findings are scheduled for the November 15 issue of the American Chemical Society's Environmental Science & Technology journal, but are available already as an open access article.
Earlier, scientists warned for the damage done to marine environments by larger particles from petroleum based plastics - socalled 'mermaid's tears' - which invade the marine food chain and poison our seas. This has prompted the development of bioplastics that rapidly degrade in seawater (previous post).
The new research is focused on yet another type of petroleum based plastics. Emma L. Teuten and colleagues note long-standing awareness that large pieces of plastic waste, including cargo wrapping sheet plastic and six-pack rings, can sicken and kill fish, birds, turtles and other animals. Seawater eventually breaks down these large pieces into microplastics (image, click to enlarge), which can adsorb high levels of PCBs and other toxins. Microplastics also enter the environment directly from use as "scrubbers" in household and industrial cleaning products. However, little research has been done on the environmental impact of these tiny, pollution-packed pellets.
In the new study, researchers exposed several different types and sizes of microplastics to phenanthrene, a major marine pollutant, and used a model to predict their effects on a group of sediment-dwelling marine worms (lugworms). The scientists found that addition of just a few millionths of a gram of contaminated microplastics to the sediments caused an 80% increase in phenanthrene accumulation in the tissues of the worms:
energy :: sustainability :: biomass :: bioenergy :: petroleum :: plastics :: marine :: oceans :: bioplastics :: biodegradable :: bioeconomy ::
Since lugworms are at the base of the food chain, phenanthrene from microplastics would be passed on and biomagnified in other marine animals. The finding suggests that microplastics are an important agent in the transport of pollutants in marine organisms.
Many plastics are less dense than water and float at the sea-surface microlayer where hydrophobic compounds can be concentrated by up to 500 times that of the underlying water column. Buoyant plastics can be transported across oceans to remote locations; thus, plastics may provide a mechanism for transport of hydrophobic chemical contaminants to remote and pristine locations. Upon fouling, these plastics can sink, transporting any sorbed contaminants to the sediment. Given the rapid rate at which plastic debris is accumulating in the environment, plastics could therefore become important in contaminant transport at a global scale, they conclude.
Petroleum based plastics can take decades or even hundreds of years to degrade fully. A transition towards biobased plastics that degrade over a matter of weeks or months, would obviously be a major strategy to prevent the further poisoning of our oceans and the creatures that inhabit it.
Picture: Submicroscopic particles of PVC (shown via electron microscope) and other plastics may pose a previously unrecognized pollution threat. Credit: Courtesy of Emma Teuten, University of Plymouth, UK
References:
Emma L. Teuten, Steven J. Rowland, Tamara S. Galloway, and Richard C. Thompson, "Potential for Plastics to Transport Hydrophobic Contaminants", Environ. Sci. Technol., ASAP Article 10.1021/es071737s S0013-936X(07)01737-3
Eurekalert: "Microplastics" may pose previously unrecognized pollution threat - October 29, 2007.
Biopact: Bioplastics developed that degrade in seawater, boon to cruise industry - March 27, 2007
Biopact: Plastics are "poisoning the world's seas" - December 07, 2006
Earlier, scientists warned for the damage done to marine environments by larger particles from petroleum based plastics - socalled 'mermaid's tears' - which invade the marine food chain and poison our seas. This has prompted the development of bioplastics that rapidly degrade in seawater (previous post).
The new research is focused on yet another type of petroleum based plastics. Emma L. Teuten and colleagues note long-standing awareness that large pieces of plastic waste, including cargo wrapping sheet plastic and six-pack rings, can sicken and kill fish, birds, turtles and other animals. Seawater eventually breaks down these large pieces into microplastics (image, click to enlarge), which can adsorb high levels of PCBs and other toxins. Microplastics also enter the environment directly from use as "scrubbers" in household and industrial cleaning products. However, little research has been done on the environmental impact of these tiny, pollution-packed pellets.
In the new study, researchers exposed several different types and sizes of microplastics to phenanthrene, a major marine pollutant, and used a model to predict their effects on a group of sediment-dwelling marine worms (lugworms). The scientists found that addition of just a few millionths of a gram of contaminated microplastics to the sediments caused an 80% increase in phenanthrene accumulation in the tissues of the worms:
energy :: sustainability :: biomass :: bioenergy :: petroleum :: plastics :: marine :: oceans :: bioplastics :: biodegradable :: bioeconomy ::
Since lugworms are at the base of the food chain, phenanthrene from microplastics would be passed on and biomagnified in other marine animals. The finding suggests that microplastics are an important agent in the transport of pollutants in marine organisms.
Many plastics are less dense than water and float at the sea-surface microlayer where hydrophobic compounds can be concentrated by up to 500 times that of the underlying water column. Buoyant plastics can be transported across oceans to remote locations; thus, plastics may provide a mechanism for transport of hydrophobic chemical contaminants to remote and pristine locations. Upon fouling, these plastics can sink, transporting any sorbed contaminants to the sediment. Given the rapid rate at which plastic debris is accumulating in the environment, plastics could therefore become important in contaminant transport at a global scale, they conclude.
Petroleum based plastics can take decades or even hundreds of years to degrade fully. A transition towards biobased plastics that degrade over a matter of weeks or months, would obviously be a major strategy to prevent the further poisoning of our oceans and the creatures that inhabit it.
Picture: Submicroscopic particles of PVC (shown via electron microscope) and other plastics may pose a previously unrecognized pollution threat. Credit: Courtesy of Emma Teuten, University of Plymouth, UK
References:
Emma L. Teuten, Steven J. Rowland, Tamara S. Galloway, and Richard C. Thompson, "Potential for Plastics to Transport Hydrophobic Contaminants", Environ. Sci. Technol., ASAP Article 10.1021/es071737s S0013-936X(07)01737-3
Eurekalert: "Microplastics" may pose previously unrecognized pollution threat - October 29, 2007.
Biopact: Bioplastics developed that degrade in seawater, boon to cruise industry - March 27, 2007
Biopact: Plastics are "poisoning the world's seas" - December 07, 2006
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