Project: Understanding and reducing the environmental impact of single-use plastics

Pioneering research demonstrated the impacts of biodegradable plastics and microplastics and of cigarette butts on the environment.

This research was used to strengthen national and international policy on plastics, raise awareness amongst policymakers and the general public and reduce the plastic footprint of key businesses at DP World London.

Single-use plastics account for 40% of global plastic production annually, and 50-70% of the plastic litter in marine, freshwater and terrestrial environments. Microplastics (pieces <5mm) are the most abundant solid waste on Earth.

The threat that (micro)plastic litter can pose to individual organisms is quite well understood, but less is known about the harm caused to biodiversity and ecosystem functioning. Furthermore, the effects of bio-based, biodegradable plastics, which have been increasingly adopted as an alternative to conventional, single-use plastics, are not well understood.

Research by Dr Dannielle Green and Dr Bas Boots was the first to evaluate how plastic pollution can affect entire communities of organisms and ecosystem functioning, rather than individual species in isolation.

Another type of single-use plastic litter is smoked cigarette butts. Research by Dr Green and Dr Boots demonstrated that smoked cigarette butts reduced the germination success and shoot length of Trifolium repens (white clover) by 27% and 28% respectively, and that of Lolium perenne (perennial ryegrass) by 10% and 13%.

Moreover, the root biomass of clover was 60% less when butts were present. By comparing smoked cigarette butts with unsmoked ones, our research also found that the plastic filter itself, composed of cellulose acetate, had an inhibitory effect on the measured variables.

A key observation from our research is that microplastics made from polymers that are marketed as biodegradable or compostable (e.g. polylactic acid: PLA) can have similar effects on marine and terrestrial ecosystems as those of commonly-used non-biodegradable polymers (e.g. high density polyethylene: HDPE; and polyvinyl chloride: PVC).

Based on experimental work, our research provided evidence that these types of microplastics have similar effects on organisms, by disrupting the immune system of blue mussels, filtration rates of blue mussels and Pacific oysters and biomass of terrestrial earthworms.

Bergmann, M, Carney Almroth, B., Brander, S. M., Dey, T., Green, D. S., Gundogdu, S., Krieger, A., Wagner, M., Walker, T. R., 2022. A global plastic treaty must cap production. Science, 376(6592), pp. 469. doi: 10.1126/science.abq0082

Green, D., Boots B., 2022. The ecological impacts of discarded cigarette butts. Trends in Ecology & Evolution, 37(2), pp. 183-192. ISSN 0169-5347. doi: doi: 10.1016/j.tree.2021.10.001

Blackburn, K., Green, D. S., 2021. The potential effects of microplastics on human health: What is known and what is unknown. Ambio, 51(3), pp. 518-530. doi: 10.1007/s13280-021-01589-9

Green, D. S. Kregting, L., Boots, B., 2021. Effects of cigarette butts on marine keystone species (Ulva lactuca L. and Mytilus edulis L.) and sediment microphytobenthos. Marine Pollution Bulletin, 165; 112152. doi: 10.1016/j.marpolbul.2021.112152

Green, D. S., Jefferson, M., Boots, B., Stone, L. 2021. All that glitters is litter? Ecological impacts of conventional versus biodegradable glitter in a freshwater habitat. Journal of Hazardous Materials. doi: 10.1016/j.jhazmat.2020.124070

Green, D. S., Boots, B., Kregting, L., 2020. Smoked cigarette butt leachate impacts survival and behaviour of freshwater invertebrates. Environmental Pollution. doi: 10.1016/j.envpol.2020.115286

Oliveira, A. R., Sardinha-Silva, A., Andrews, P. L. R., Green, D. S., Cooke, G. M., Hall, S., Blackburn, K., Sykes, A. V., 2020. Microplastics presence in cultured and wild-caught cuttlefish, Sepia officinalis. Marine Pollution Bulletin, 160, 111553. doi: 10.1016/j.marpolbul.2020.111553

Dunn, C., Owens, J., Fears, L., Nunnerley, L., Kirby, J., Amstrong, O., Thomas, P., Aberg, D., Gilder, W., Green, D. S., Antwis, R., Freeman, C., 2020. An affordable methodology for quantifying waterborne microplastics - an emerging contaminant in inland-waters. Journal of Limnology, 79(1). doi: 10.4081/jlimnol.2019.1943

Kratina, P., Watts, T. J., Green, D. S., Kordas, R. L., O'Gorman, E. J., 2019. Interactive effects of warming and microplastics on metabolism but not feeding rates of a key freshwater detritivore. Environmental Pollution, 255(2), 113259. doi: 10.1016/j.envpol.2019.113259

Peberdy, E., Jones, A., Green, D. S., 2019. A Study into Public Awareness of the Environmental Impact of Menstrual Products and Product Choice. Sustainability, 11(2), pp. 473. doi: 10.3390/su11020473

Boots, B., Russell, C. W., Green, D. S., 2019. Effects of Microplastics in Soil Ecosystems: Above and Below Ground. Environ. Sci. Technol., 53(19), pp. 11496-11506. doi: 10.1021/acs.est.9b03304

Green, D. S., Boots, B., Da Silva Carvalho, J., Starkey, T., 2019. Cigarette butts have adverse effects on initial growth of perennial ryegrass (gramineae: Lolium perenne L.) and white clover (leguminosae: Trifolium repens L.). Ecotoxicology and Environmental Safety 182, 109418. doi: 10.1016/j.ecoenv.2019.109418

Green, D. S., Colgan, T. J., Thompson, R. C., Carolan, J. C., 2019. Exposure to microplastics reduces attachment strength and alters the haemolymph proteome of blue mussels (Mytilus edulis). Environmental Pollution, 246, pp. 423-434. doi: 10.1016/j.envpol.2018.12.017

Green, D. S., Kregting, L., Boots, B., Blockley, D. J., Brickle, P., da Costa, M., Crowley, Q., 2018. A comparison of sampling methods for seawater microplastics and a first report of the microplastic litter in coastal waters of Ascension and Falkland Islands. Marine Pollution Bulletin, 137, pp. 695-701. doi: 10.1016/j.marpolbul.2018.11.004

Green, D. S., Boots, B., O'Connor, N., Thompson, R., 2017. Microplastics affect the ecological functioning of an important biogenic habitat. Environmental Science and Technology, 51(1), pp. 68-77. doi: 10.1021/acs.est.6b04496

Green, D. S., 2016. Effects of microplastics on European flat oysters, Ostrea edulis and their associated benthic communities. Environmental Pollution, 216, pp. 95-103. doi: 10.1016/j.envpol.2016.05.043

Green, D. S., Boots, B., Sigwart, J., Jiang, S., Rocha, C., 2016. Effects of conventional and biodegradable microplastics on a marine ecosystem engineer (Arenicola marina) and sediment nutrient cycling. Environmental Pollution, 208, pp. 426-434. doi: 10.1016/j.envpol.2015.10.010

Green, D. S., Boots, B., Blockley, D. J., Rocha, C., Thompson, R. C., 2015. Impacts of discarded plastic bags on marine assemblages and ecosystem functioning. Environmental Science and Technology, 49(9), pp. 5380–5389. doi: 10.1021/acs.est.5b00277