Research & Publications

Alice answering questions about her Master's research on microplastics pollution in San Francisco Bay as part of a panel at the symposium, Science & Solutions for Microplastics Pollution, in Berkeley, California in October of 2019. From left to right: Alice, Meg Sedlak (SFEI), Diana Lin (SFEI), Alicia Gilbreath (SFEI), and Carolynn Box (5 Gyres).

Alice collecting samples of surface water in San Francisco Bay in 2017 to study microplastics pollution in collaboration with San Francisco Estuary Institute (SFEI) for her Master's research.

Research Areas of Interest

I am interested in better understanding the sources and fate of plastic pollution in the marine environment. My Master's research was focused on source apportioning microplastic pollution in San Francisco Bay. In collaboration with the San Francisco Estuary Institute (SFEI), we found high concentrations of microplastic contamination in the Bay and proposed mitigation strategies to reduce the inputs of plastics into the Bay.

My PhD research aims to determine the sources, distribution, and transport mechanisms of plastic pollution on a broader scale - the oceans. I will collaborate with researchers from both academia and the non-profit sector to put a number to important entities of the Global Plastic Cycle in order to better understand the behaviour of plastic pollution in the marine environment. This research is crucial to help researchers determine exposure concentrations of plastic to animals in the environment and thus inform risk, and also help pinpoint areas to target for mitigation strategies of plastic.

I am an environmental analytical scientist with extensive training in environmental sampling methods and analytical chemistry. I am proficient in using instrumentation for the monitoring of environmental contaminants. Examples include CRDS greenhouse gas analysis for measuring methane and carbon dioxide concentrations, AIMS-ion chromatography (IC) for measuring ions in water and snow, passive sampling and IC for measuring NO2 (a precursor for smog and thus an indicator of air quality) in the Greater Toronto Area, Raman and FTIR for identifying microplastic pollution, GC-MS for quantifying organic compounds in ancient groundwater, and LC-MS for detecting aldehydes and other volatile organic compounds released from the heating of cooking oil. In addition, I also love working with big data such as complex environmental datasets - I can be described as a "data miner" and "data wrangler" - and I conduct extensive statistical modelling in R and work with geospatial data in ArcGIS.

My Story and Motivation

In my final year of high school in 2013 I remember hearing on the news about Captain Charles Moore's study of plastic pollution in the "North Pacific Garbage Patch". Specifically, the study found that the mass of plastic in the North Pacific Gyre outweighed the mass of plankton. I was very upset at the news of plastic contamination in the environment and it really motivated me to become more interested in marine debris research. Around that time, I watched TEDx talks by Professor Sam Mason of SUNY and Boyan Slat, founder of The Ocean Cleanup, as well and became even more engaged in the issue. The reason why I am so interested in marine debris research is because my idols - the founders of the field of plastic pollution research - are all oceanographers or marine scientists. And I was truly honoured to meet almost all of them at the Sixth International Marine Debris Conference (6IMDC) in March of 2018. *I was ecstatic!! :)*

Publications and Themes of Research

1. Biogeochemistry and impact of anthropogenic activities on global cycles

I study how plastic pollution moves carbon. A main narrative throughout my research is that plastic is an unknown branch of the global carbon cycle, and that both plastic pollution and climate change are consequences of human interference to carbon cycling.

Select publications:

Zhu, X. (2021) The Plastic Cycle - an unknown branch of the Carbon Cycle. Frontiers in Marine Science, doi: https://doi.org/10.3389/fmars.2020.609243.

Zhu, X. (2021) Plastic is part of the carbon cycle and needs to be included in climate calculations. The Conversation, https://theconversation.com/plastic-is-part-of-the-carbon-cycle-and-needs-to-be-included-in-climate-calculations-154730

2. Monitoring of environmental contaminants

I quantify and characterize plastic pollution in the environment using analytical chemistry instrumentation and best practices. I also investigate their sources and fate to help inform policy, and develop novel methods for the quantification and identification of plastic in environmental samples.

Select publications:

Zhu, X., Munno, K., Grbic, J., Werbowski, L., Bikker, J., Ho, A., Guo, E., Sedlak, M., Sutton, R., Box, C., Lin, D., Gilbreath, A., Holleman, R.C., Fortin, M., Rochman, C. M. Holistic assessment of microplastics and other anthropogenic microdebris in an urban bay sheds light on their sources and fate. Environmental Science & Technology Water, doi: https://pubs.acs.org/doi/full/10.1021/acsestwater.0c00292

Zhu, X., Nguyen, B., You, J.B., Karakolis, E., Sinton, D., and Rochman, C. (2019). Identification of microfibers in the environment using multiple lines of evidence. Environmental Science & Technology, doi: https://doi.org/10.1021/acs.est.9b05262

Zhu, X. (2015). Optimization of an elutriation device for the filtration of microplastic particles from sediment. Marine Pollution Bulletin, 92(1-2): 69-72. doi: https://doi.org/10.1016/j.marpolbul.2014.12.054

Werbowski, L.; Gilbreath, A.; Munno, K.; Zhu, X.; Grbic, J.; Wu, T.; Sutton, R.; Sedlak, M.; Deshpande, A.; Rochman, C. (2021) Urban stormwater runoff: a major pathway for anthropogenic particles, black rubbery fragments, and other types of microplastics to urban receiving waters. Environmental Science & Technology Water, Accepted.

Hung, C., Klasios, N., Zhu, X., Sedlak, M., Sutton, B., and Rochman, C. (2020). Methods Matter: Methods for Sampling Microplastic and other Anthropogenic Particles and Their Implications for Monitoring and Ecological Risk Assessment. Integrated Environmental Assessment and Management, doi: 10.1002/ieam.4325

3. The Global Plastic Cycle: reservoirs, fluxes, and rates

In my research, I aim to fill in the unknowns in the global cycling of plastic pollution. I combine knowledge from the fields of statistical sciences, hydrodynamics, watershed sciences, and oceanography to answers questions pertaining to the transport and fate of plastic pollution in the environment.

Select publications:

Zhu, X. (2021) The Plastic Cycle - an unknown branch of the Carbon Cycle. Frontiers in Marine Science, doi: https://doi.org/10.3389/fmars.2020.609243.

4. Environmental policy

One of my key research goals is to inform policy on environmental pollutants, including microplastic particles, anthropogenic debris, litter, and derelict fishing gear. I connect science to management actions and propose policy tools to help tackle global environmental issues.

Select publications:

Zhu, X. and Rochman, C. (2022). Emissions inventories of plastic pollution: a critical foundation of an International Agreement to inform targets and quantify progress. Environmental Science & Technology, 56 (6): 3309-3312. doi: https://pubs.acs.org/doi/10.1021/acs.est.2c01038

Zhu, X. (2021) "Polluter Pays Principle": Stopping fishing gear loss to our oceans requires greater accountability from fishers. The Starfish, https://thestarfish.ca/journal/2021/05/polluter-pays-principle-stopping-fishing-gear-loss-to-our-oceans-requires-greater-accountability-from-fishers

Zhu, X. (2021) The social, environmental, and economic impacts of space colonization. The Starfish, https://thestarfish.ca/journal/2021/11/the-social-environmental-and-economic-impacts-of-space-colonization

Rochman, C., Munno, K., Box, C., Cummins, A., Zhu, X., and Sutton, R. (2020) Think global, act local: local knowledge is critical to inform positive change when it comes to microplastics. Environmental Science & Technology, doi: https://pubs.acs.org/doi/full/10.1021/acs.est.0c05746.