"Not only is it important to ask questions and find the answers, as a scientist I felt obligated to communicate with the world what we were learning"
- Stephen Hawking -
Poster presentation at ISME18 Microbes
14 - 19 August 2022
Integrated and rapid sampling method for simultaneous analysis of microplastic and microbial communities in the aquatic environment
The composition and functional capacity of the microbial communities on microplastics, especially in the smaller size range (<1 mm), have largely been unexplored. As microplastic is a relatively newly discovered pollutant, sampling technique has not been well-established for the marine environment and is especially arduous due to equipment material incompatibility. The difficulty level increases when the microbial aspect should be considered in the sampling. Earlier studies have typically sampled microplastics either using manta-trawling or pumping water through a cascade of sieves, while collecting the microbiological samples separately either pre- or post- microplastic sampling. To simultaneously capture microplastic and microbial community from discrete samples, we developed an integrated and rapid sampling method using an in-house designed microplastic surface sampler, a series of filter cartridges, and a OSMO autosampler. A Proactive Mini-Typhoon pump is attached to the surface sampler and pumps water through a series of stainless-steel filter cartridges with mesh sizes 300, 100 and 20 µm. The output from the filter cartridges is then channelled into a peristaltic pump to sample for bacterial analysis on Sterivex filters simultaneously. This method allows for the collection of microplastics and bacteria from different depths without interferences from waves and vertical mixing. It is also able to support the collection of large water volumes, which is necessary for reliable quantification of microplastics and associated microbiome. With this sampling technique, marine microplastics and its associated microbial composition are determined for the Southeast Asia region to understand the role of microplastics as vector for pathogens.
Oral presentation at Micro 2020 conference
23 - 27 November 2020
Lifetime accumulation of microplastic in children and adults
A probabilistic lifetime human exposure assessment for microplastics is essential for quantifying the magnitude, diversity and uncertainty of microplastic exposure. We review 134 studies on microplastic concentrations in nine intake sources, constituting 20 % of the human diet by mass. We simulate microplastic exposure in children and adults using probabilistic models for the gut passage that account uptake via dietary sources and inhalation, intestinal absorption and biliary excretion. To evaluate the potential chemical risk, we perform physiologically based pharmacokinetic modelling with and without chemical intake via microplastics. Microplastic median intake rates range from 553 to 883 #/capita/day and can accumulate up to 50100 #/capita (~0.041 µg/capita) in the body at the end of 70 years. The contribution of microplastics to total chemical intake is negligible. In conclusion, there is a large variation in exposure and accumulation, and these estimates are subject to increase due to other unknown sources.