Deheyn Lab

We analyze airborne microplastics for their content in microbes and viruses, to assess how much these particles contribute to spreading pathogens and chemicals around. This research spreads from the Tijuana Estuary all the way to Oceanside (with emphasis in La Jolla Shores to assess the effect of beachgoers), along the coast, and also more inland. Research is developed together with the Venter Institute. In fact, any pathogenic aspect associated with microplastics in the projects listed below involve the Venter Institute, where sequencing is performed. The outcome would show how microplastics in the air contribute to possible public health issues, which can be apply to other places.

This project originates from the fact that sportswear is made of polyester for the most part, which let small pieces break away when worn, especially during movement. The project has a public health dimension in analyzing microplastics in indoor sports arenas versus outdoor stadium, and during popular games versus during regular training. The “crowd effect” on the release of microplastics will indicate how much plastics does one inhale when attending such events (we measure microplastics from the air but also from saliva), and what consequences could arise from such acute exposure (based on pathogen analysis done with the Venter Institute). This would help the sport industry address the issue with regards to air filtration but also providing alternative sportswear to the athletes, for the better health of everyone, the athletes themselves and the spectators).

Eggs have been in the news lately for their increase in price, but here we look at their possible content in microplastics. Indeed, microplastics tend to be “excreted” by the body as the case for most contaminants, which could then be the case for eggs. We are comparing eggs from organic single-family farms versus eggs available from the supermarket. As a comparison, we plan to also be looking at other eggs, including those of sea turtles penguins and birds. Would microplastics in the eggs (shell or the inside) affect the egg integrity to pass on life?

A good way to estimate microplastic exposure to the food web is to look at their numbers in feces, which thus represents how much was ingested (inhaled, or through water or food) and not absorbed by the digestive system. Here we measure microplastics from feces of wildlife around San Diego County, although this approach has also been applied to wildlife species in the Alps. The results will indicate how much wildlife is exposed to plastic, whether in vicinity or far away from communities, yet also being a proxy for ourselves, humans. The outcome here will also indicate how pervasive microplastics are through the terrestrial foodweb.

This project addresses the effect of secondhand textiles in Ghana for example, where millions of donated garments are sent every week and end up in the ocean. Some of these garments are also burned, and we therefore also look at the effect on air quality (airborne microplastics from burning textiles) in addition to the effect on the coastal ecosystem. One can see that analyzing the content of microplastics in smoke can be critical also from situations of wildfires that destroy human-built structures, since housing for example usually contains large amount of plastics.

Microplastic are indeed all around us and the idea here is to quantify this more carefully, by looking at our regular supermarket food, from vegetables to meats, and drinks (water, sodas, but also wine and beer). The concept is to provide quantification of these means of exposure. Not that we can change anything about it, but at least we know what we ingest and can monitor this especially if subject to chronic issues, which microplastics could exacerbate. This becomes critical when considering exposure for our children. It is also possible that certain brands will be more or less prone to contain microplastics, based on how the food and drinks processing are managed. 

Microplastics are indeed pervasive to the physical and biological worlds, and the big question is of course related to “And so what?!”. The toxicity testing on microplastics has been very controversial and here, we address the issue using exposure to cells in Petri dish, which offer a rapid and firsthand assessment of toxicity. This can be done with a variety of cells, from bacteria (to mimic the water or soil environments) to human cell cultures (whether skin, lung or intestine cells). These are alternative toxicity models that we study together with colleagues at the UCSD School of Medicine, but also with colleagues at Yale. Providing the nuances on the toxicity is critical for legislation and policies. It is possible that the material itself is inert, while the toxicity originates from the many additives included in the materials. We need to know this as a society!

Samples for microplastic analysis can be collected by citizen scientists, including high school students, which we strongly promote. We started a platform called MicroMarGlobal, which regroups high schools from all around the world. With their science teachers, we use microplastics to learn processes, foodweb concepts as well as watershed ecology, circularity and more. The various thematic can be addressed using microplastics as vectors to connect disciplines and ecosystems, while bringing relevant fieldwork to the classroom, even it is only to look at microplastics from the water fountain down the hallway. These high school students can then perform internships in institutions involved, thus promoting global community thinking. In parallel, our lab also aims to equip this new generation of citizens with the information needed to help people answer everyday questions, especially about how to reduce microplastic exposure. For example, we often get asked the best ways to store plastic bottles of drinking water or what alternatives exist to synthetic materials especially clothing. We therefore seek to empower individuals and families with practical, sustainable choices that reduce single-use plastic consumption, limit excessive purchase of fast-fashion, and improve long-term habits and health. In a larger scale, through a program called EcoMente (for “environmental consciousness”), the citizen science approach expands beyond high schools, working with sailors, climbers, hikers and other environmentally-conscious individuals that go around the world, and collect samples for microplastics analysis. We only have one planet, and we need to know the invisible threat it holds.

Textiles are a major source of microplastics, which are released upon wearing garments, or through their washing/drying. Here, we quantify the amount of microplastics (microfibers) released in the aquatic environment, assessing the biodisintegration process (the fact of a functional entity falling apart into non-functional pieces). The idea is to provide this assessment for all kinds of materials, especially those aiming to be ecofriendly and with limited impact on the environment. Most of the plastic waste reaches the coastline and thus this project helps identify the fraction of invisible microplastic this visible plastic waste releases in the surroundings, when left behind. The fashion industry, especially the fast fashion, relates to over consumerism, which in turns affects ecosystems and their services, which this projects addresses. 

Microplastics are so small that one hypothesis is that they travel around the world. This is mainly highlighted by the fact that microplastics are found everywhere, even in the most remote areas, and also that they are found in snow and rain. However, to this day, no one has quantified airborne microplastics “around the earth”. We have embarked onto the journey to fill this gap and have, in the past few years, measured microplastics from the atmosphere using airplanes going around the world, from pole to pole or around the equator. Although this provides evidence of atmospheric microplastic, our next step is to use airship blimps to assess the distribution of microplastics with altitude (do they form a layer?), above cities versus above farmland or wilderness (including oceans or lakes). This project is developed with the Prince Albert of Monaco Foundation and the World Air League (www.worldskyrace.com), who are major players in the field of environmental awareness and key partners to push this project forward. Indeed, the cost associated with the science is about 10% of what is needed to rent the airship for a 6-weeks expedition, which is the reason behind the time needed for such an expedition to be implemented. Any interest to travel on a blimp for this research, please let me know!

Scripps Oceanography is located in an idyllic place, and relies on the quality of the water we pump from ocean to maintain our organisms, including at the Birch Aquarium. In this project, students are trained to kayak and take samples of water (from surface, bottom and mid-water using specific gear), in order to analyze the amount of microplastics in the water column. We also take samples closer to the shore and the surf zone. The idea here is to follow amounts of microplastics over time (every two weeks) as a function of number of beachgoers, considering that sunscreens (and other cosmetics, lotions) as well as bathing suits (or rash guards, wetsuits) can release pieces of microplastics in the water. Ultimately, we would like to have financial support for this monitoring to continue over the years, and the counts to be posted on our websites, for people to use as a reference. It is even more important considering that Scripps researchers as well as Birch Aquarium, but also private people and businesses, collect the seawater off Scripps for various usage. Knowing the levels of microplastic contamination thus becomes relevant and maybe critical for some uses. So far, our analyses show several hundreds of pieces of microplastics (per 1L of water). Would this increase with a busy summer?