Oireachtas Joint and Select Committees

Wednesday, 28 March 2018

Joint Oireachtas Committee on Housing, Planning and Local Government

Prohibition of Micro-Plastics Bill 2016: Discussion (Resumed)

9:30 am

Dr. Kevin Lynch:

I thank the committee for the invitation. I am here today representing both myself and Dr. Audrey Morley. Unlike Ms Mahon, we are not experts on microbeads. I am a coastal geomorphologist and Ms Morley is a climate scientist. Our interest in this is that we have had a number of MSc projects on this topic over recent years. This is based on interest among our students and a more general interest in microplastics and in understanding that pollution is a problem. When we began to examine this problem, we obviously read the literature to determine whether there was anything of note in an Irish context. Our first study was in 2015. Prior to 2014, there was really no published work on the Irish coastal waters or coast in this area. From that point on, Dr. Amy Lusher, Dr. Mahon and the team in GMIT have published quite a bit of work on microplastics in the water column and in the stomachs of fish and seabirds. There was nothing in some of the fauna that could potentially eat these. I refer also to the shellfish.

It was very obvious that this was a problem internationally. There is a lot of evidence that it is a problem internationally so we wanted to see whether it was a problem in Ireland. Around 2015, a UN Commissioner responsible for food was visiting. We brought her to a beach in Renvyle in County Galway to carry out an ecological survey. When we were there, the level of pollution on the beach was very obvious. As we were walking we said the sand looked interesting. When we bent down and picked up some of it, we noted it was not actually sand but 100% microplastics. Therefore, the sand on the beach is composed entirely of microplastics. The students were very interested in moving into this area. We were happy to supervise their projects. The rest of my presentation is really an exposition of their work.

Mr. Jake Martin and Dr. Audrey Morley worked on a project in which they examined marine sediment. On one of the cruises on the Celtic Voyager, they collected box cores, which are short cores of the sediments on the seabed, to investigate whether they could find any microplastics there. Members will see from the map on the slide the location from where the samples were taken.

Dr. Amy Lusher from GMIT developed a set of protocols based on international best practice on how to identify microplastics.

These are just a few examples of what Mr. Jake Martin found. Essentially one has to look under a microscope and identify every individual microplastic in a particular sample.

The images on the slide on display are a representation of the box cores he collected. The little blue ones at the top are the water column, and then one can see the sediments. What the team found was that there were microplastics throughout the sediments down to a certain depth, which correlated quite closely to the initial production of microplastics in the 1950s and onwards. As there is a certain amount of mixing in the surface layers due to trawling and ocean processes, the exact dates cannot be identified. From this it can be seen that microplastics are in the sediment and in the water column. The quantities in this area are in single figures for the most part; such as eight, nine, ten or 11 or that sort of quantity.

The type of microplastics was also looked at. The most common types are fibres and fragments. These are essentially secondary plastics from the breakdown but they might also be primary microplastics, such as for example microbeads. That is just a broad idea of what Martin et al. found.

As part of a separate project this year, Christine Loughlin and Audrey Morley went out and surveyed the same areas to check for the robustness of this particular methodology and found statistically similar results. That was really a check on the earlier work. The earlier work was also published in Naturemagazine, which is one of the highest impact magazines in the area. It has been peer reviewed.

As the sediments and the water column both have microplastics one might expect that fauna in these areas would ingest them, either accidentally by mistaking them for food or, if filter feeders, they might suck water out of the water column and ingest whatever happens to be in that water. They cannot differentiate between plastic and non-plastic. The next couple of projects were designed to directly sample some of the fauna. This slide shows a Dublin Bay prawn. Sonny and Morley had a look at these creatures, and took samples from the fishermen who caught them. I should point out that Dublin Bay prawns are also present in Galway, off the Aran Islands, and these samples came from areas that were similar to those from where Mr. Jake Martin took his sediment samples. Microplastics were found to be present and a percentage of each type of microplastic was identified in each individual sample. Fibres again were by far the most prevalent. For some reason there was a variation through time, and so it was not quite a straightforward process. The earlier study I mentioned was also carried out off the coast of Iceland as part of this study and considered many more variables, including the ocean current, the sedimentology of the substrate, the presence of vegetation etc. to see which variable impacted the deposition of the microplastics from the water column. There are many variables involved.

The message to take away is that they are present in the nephrops. In terms of the depuration process, the microplastics are found in the intestinal tract, which is normally not eaten, so for this particular species that perhaps is not a serious problem. However, there may be problems caused by toxins going into the muscle fibres of the nephrops themselves.

The next study considers blue mussels, which are eaten whole in that anything within the shell is eaten. This study was carried out in inner Galway Bay. The sample sites are shown on the slide. It was carried out close to Mutton Island, which is a wastewater facility and treatment outlet, as well as further along the coast in a special area of conservation, SAC, in Rusheen Bay. In 20 samples - which does not show up particularly well in these slides, which are screen grabs from the identification process - the plastic can clearly be seen when examined under the microscope. Going by the protocols, the number of plastics can be identified. To validate this information would require more work in infrared spectrophotometry, which costs a lot of money and so is not available to our students. It was not carried out in this case but is something that would need to be done at a later stage. Many microplastics were found in the 20 samples. There were over 5,000 individual microplastics identified by Ms Joanne Casserly in the 20 samples from this area. That could be a very serious issue, and perhaps the Food Safety Authority should look further into that. It could be a problem, and we would be concerned about that. I should have mentioned that the samples were also composed from off the shelf mussels. They were available for sale; Ms Joanne Casserly went to a shop and bought them. The wild stocks actually had more microplastics per gram because they are smaller individuals than the farmed stocks.

In summary, the evidence I have presented here suggests this could be a serious problem in our marine environment and should be looked at. It is likely to pose a risk to human health and habitat quality, based on international research and evidence at an international level. The evidence strongly suggests that we should be trying to reduce microplastics entering the environment. We support the Bill, notwithstanding some of the issues Mr. Harrington pointed out earlier regarding the terminology used to describe beads and microplastics.


No comments

Log in or join to post a public comment.