Flame retardants
However, Rochman’s research team found that fish exposed to a mixture of polyethylene with chemical pollutants sorbed from the marine environment, bioaccumulate these chemical pollutants and suffer liver toxicity and pathology. “Evidence from laboratory studies include the bioaccumulation of polybrominated diphenyls (PBDEs), a flame-retardant added to synthetic textile fibres … concluding that plastic deployed in the marine environment does serve as a vector for the bioaccumulation of PBTs sorbed to plastic, suggesting that plastic debris serves as a vector for the bioaccumulation of PBTs in wildlife.”
Yet polyester fibres may not be as ‘bad’ as some other types of oceanic plastic according to Rochman’s team. Writing in the journal Environmental Science and Technology (2013, 47, 1646 – 1654) they noted: “Our conclusion that HDPE, LDPE, and PP (types of plastic) consistently sorbed greater concentrations of PCBs and PAHs than did PET (polyester) and PVC, implies that PET and PVC pose a reduced risk of concentrating these hazardous chemicals onto plastic debris ingested by animals. Because PET requires fewer additives and degrades faster than other polymers, it has been suggested as one of the least hazardous plastics. These inherent properties in combination with the relatively low sorption of PCBs and PAHs we measured suggest that plastic products made from PET … which might have fewer chemical impacts on marine life than products made from other types of plastic.”
As if to flag up how there is still conflicting advice on the subject of textile fibres and oceanic plastic waste, new research yet to published in the scientific journal Nature notes how microfibres derived from textiles in the main consumer markets are still a significant and growing problem.
Again, the new work comes from Rochman’s team at UoC Davis as part of a study on microplastics extracted from bony fish and shellfish. “In Indonesia, anthropogenic (human-derived) debris was found in 28 per cent of individual fish and in 55 per cent of all species,” says the report submitted to Nature. “Similarly, in the USA, anthropogenic debris was found in 25 per cent of individual fish and in 67 per cent of all species. Anthropogenic debris was also found in 33 per cent of individual shellfish sampled. All of this debris recovered from fish in Indonesia was plastic, whereas anthropogenic debris recovered from fish in the USA was primarily textile fibres. Variations in debris types likely reflect different sources and waste management strategies between countries.”
Interestingly, not a single textile fibre was detected in fish from Indonesia.
Speaking on the contamination from synthetic fibres in fish from the USA, the researchers put this down to more advanced waste management systems. “There are more than 200 wastewater treatment plants discharging billions of litres of treated final effluent just offshore in California,” they said. “Even though treatment results in a reduction of many contaminants, synthetic textile fibres from washing machines can remain in sewage effluent, and may be delivered to aquatic habitats in large concentrations via wastewater outfalls.”
“One study found one fibre per litre of wastewater effluent. In this sense, we might expect that billions of fibres are discarded into the Pacific Ocean from wastewater treatment plants in California every day.”/p>
The same Nature report raises some of the very first findings of plastic debris in fish directly sold for human consumption raising concerns regarding human health.
Filtration systems?
Meanwhile, Mallos pointed to research in San Francisco Bay which found that micro plastic debris was found in one in four fish on sale at local fish markets; 80 per cent of this was in the form of microfibres from textiles. This backs up the research from the UoD team, which cautions that these contaminants could also impact on human health.
“We need to start measuring the impact of micro fibres on fish health and population,” Mallos added. “We also need to test the effectiveness of proposed technologies for trapping micro fibres during laundering.”
Such logic stems from the fact the key sources of micro fibres are widely believed to be wastewater effluent and the laundering process. In both cases, Mallos suggested that solutions would be relatively easy to find – some are already available. However, the big question is what would consumers do with the fibres trapped in the filtration devices when they need unblocking. Would they be washed down the drain anyway?
Other research suggests that eight million metric tonne of metric plastic is now entering the oceans annually. Synthetic micro fibres are just one of the three major sources of micro plastics in our oceans, the other two being micro beads and the degradation of general plastic waste.
