Blog written by Dr Peter Matthews CBE OBE HonFSE CEnv, following his attendance at the Mott McDonald Ocean Plastics Conference on the 29th June 2017.
Photo credit: Alamy
I have rarely seen a topic grasp the imagination of both the scientific community, lay media and public concern as quickly as this topic, and I was pleased to be able to go to this [Ocean Plastics] Conference in Cambridge in my capacity as Chair of the Society. Although I could not stay for the whole event, I found it stimulating and enlightening.
I think that there still needs to be some greater clarity in the wider community on what the problems are and how we might set about resolving them. It is a classic case of ‘humanity cannot be green by regulation alone’.
The physical consequences for wildlife such as suffocation, strangulation, ensnarement, beach pollution and marine landscape despoilment. Marine plastics are then part of a bigger problem of litter management which embraces land as well as sea. Turtles can strangle as easily on abandoned rope nets as well as synthetic ones for example. But, synthetic nets may have different dispersion and flotation characteristics and will survive much longer, being less biodegradable. Plastic bags are a particular problem but may disintegrate in a marine environment. These problems can be controlled by litter management techniques on land and at sea, and is part of wider efforts on waste management including packaging.
Litter may break down physically in the marine environment, but the debris can cause physical and physiological problems to wildlife and marine landscape by the creation of adventitious small particles, particularly micro particles including microfibers. Therefore, plastic products have either got to be biodegradable or be sufficiently robust that physical degradation is slow enough to allow litter recovery before long term harm is caused.
Discharge into the Marine Environment - Microbeads
Planned use of micro particles added to products particularly plastic microbeads, then contributed adventitiously through waste discharges into the marine environment. A full ban in all products and shift to biodegradable beads will be the answer.
Discharge into the Marine Environment – Micro Particles
Other micro particles which are not added to products, but arise through other adventitious routes – particularly fibres from synthetic clothes in washing waters – and then discharged into the marine environment. This is a new issue and this may need some innovation in wastewater treatment technology. Changes in clothing materials will be really difficult.
As far as I can see, there is less known about these than microbeads. But, concerns have been expressed about the use of TiO2 in cosmetics and ointments for example (not a plastic admittedly) and then discharged to the marine environment in waste water. It may well be that a ban on the use of these materials, except in the most essential medicines, would assist. And what about paint decoration products?
We need to ensure that these are not ecotoxic.
The Way Forward
So, it seems to me that there are four key ways forward:
The reduction of waste and litter in the first place including even more attention to packaging. For example, biodegradable wipes come in non-biodegradable sachets, and some food canisters have too many materials to recycle, greater attention to use and disposal by changing our habits, and tougher litter control. These might be helped by deposit schemes as we used to have and is now being trialled on bottles by Coca-Cola.
The notion of biodegradability should move to being the norm rather than being the alternative to plastic. In the case of plastic bags, biodegradability is the notion which provides exemption from the levy. It raises the issue of whether we need a statutory direction or whether it would be left to behaviour. If we had an outright statutory or voluntary ban on plastic there could still be a levy on biodegradable bags to encourage the use of ‘life bags’. Biodegradability should apply wherever practicable to all plastic products. Biodegradability must come in two parts – land based decomposition and aquatic decomposition.
The slow progress on standard methodology leads one to muse as to whether there is a need to have a fresh look at the roles of BSI and the Standing Committee of Analysts in these matters. We await the outcome of the on-going review by Defra on methodology in the context of carrier bags.
We need a review of all household and personal products with a risk rating in terms of micro and nanoparticles and consideration being given to a registration system. This might need a review of how REACH will work post Brexit and whether new tests and regulated conditions are needed for consents to discharge industrial effluents in future legislation post the Great Repeal Act. I welcome the role of the Hazardous Substances Committee, in the context of microbeads, in the announcement of the forthcoming statutory ban next year.
New insights are needed on the ability of detergents or similar chemicals (with no ecotoxicity obviously) to form microfiber micelles, which would then be more susceptible to being removed by conventional or modified used water treatment.
A Final Thought
One final thought about the small particles whether macro, micro or nano; they disrupt the marine food chains either by entering alongside phytoplankton in consumption by zooplankton or by co-ingestion alongside zooplankton. Either way they are artificial contributors to plankton and so I am proposing the formal title of ersatz-plankton.
The presentation slides from the Mott McDonald Ocean Plastics Conference can be downloaded here.