Zacharias Steinmetz

I combine environmental chemistry, analytics, ecotoxicology, and soil science to unravel the complexities of anthropogenic pollutants in the environment, scrutinizing their fate and effects from source to sink.

My research focuses on the impact of agriculture on land and water.

main research interests

Investigating the sources, sinks, and pathways of plastics and other anthropogenic pollutants in agroecosystems
Developing novel methods for characterizing and quantifying synthetic polymers in heterogeneous matrices, for example, using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and Fourier-transform infrared spectroscopy (FTIR) in combination with advanced data science applications
Elucidating the indirect effects of anthropogenic pollutants on ecosystem functions using biomarkers.

selected publications

2021

AChem

Microplastic Spectral Classification Needs an Open Source Community: Open Specy to the Rescue!

Win Cowger, Zacharias Steinmetz, Andrew Gray, Keenan Munno, Jennifer Lynch, Hannah Hapich, Sebastian Primpke, Hannah De Frond, Chelsea Rochman, and Orestis Herodotou

Analytical Chemistry 93(21), 7543–7548, 2021

Abstract DOI Request PDF Code

Microplastic pollution research has suffered from inadequate data and tools for spectral (Raman and infrared) classification. Spectral matching tools often are not accurate for microplastics identification and are cost-prohibitive. Lack of accuracy stems from the diversity of microplastic pollutants, which are not represented in spectral libraries. Here, we propose a viable software solution: Open Specy. Open Specy is on the web (www.openspecy.org) and in an R package. Open Specy is free and allows users to view, process, identify, and share their spectra to a community library. Users can upload and process their spectra using smoothing (Savitzky–Golay filter) and polynomial baseline correction techniques (IModPolyFit). The processed spectrum can be downloaded to be used in other applications or identified using an onboard reference library and correlation-based matching criteria. Open Specy’s data sharing and session log features ensure reproducible results. Open Specy houses a growing library of reference spectra, which increasingly represents the diversity of microplastics as a contaminant suite. We compared the functionality and accuracy of Open Specy for microplastic identification to commonly used spectral analysis software. We found that Open Specy was the only open source software and the only software with a community library, and Open Specy had comparable accuracy to popular software (OMNIC Picta and KnowItAll). Future developments will enhance spectral identification accuracy as the reference library and functionality grows through community-contributed spectra and community-developed code. Open Specy can also be used for applications beyond microplastic analysis. Open Specy’s source code is open source (CC-BY-4.0, attribution only) (https://github.com/wincowgerDEV/OpenSpecy).

2016

STOTEN

Plastic mulching in agriculture. Trading short-term agronomic benefits for long-term soil degradation?

Zacharias Steinmetz, Claudia Wollmann, Miriam Schaefer, Christian Buchmann, Jan David, Josephine Tröger, Katherine Muñoz, Oliver Frör, and Gabriele E. Schaumann

Science of The Total Environment 550, 690–705, 2016

Abstract DOI Request PDF

Plastic mulching has become a globally applied agricultural practice for its instant economic benefits such as higher yields, earlier harvests, improved fruit quality and increased water-use efficiency. However, knowledge of the sustainability of plastic mulching remains vague in terms of both an environmental and agronomic perspective. This review critically discusses the current understanding of the environmental impact of plastic mulch use by linking knowledge of agricultural benefits and research on the life cycle of plastic mulches with direct and indirect implications for long-term soil quality and ecosystem services. Adverse effects may arise from plastic additives, enhanced pesticide runoff and plastic residues likely to fragment into microplastics but remaining chemically intact and accumulating in soil where they can successively sorb agrochemicals. The quantification of microplastics in soil remains challenging due to the lack of appropriate analytical techniques. The cost and effort of recovering and recycling used mulching films may offset the aforementioned benefits in the long term. However, comparative and long-term agronomic assessments have not yet been conducted. Furthermore, plastic mulches have the potential to alter soil quality by shifting the edaphic biocoenosis (e.g. towards mycotoxigenic fungi), accelerate C/N metabolism eventually depleting soil organic matter stocks, increase soil water repellency and favour the release of greenhouse gases. A substantial process understanding of the interactions between the soil microclimate, water supply and biological activity under plastic mulches is still lacking but required to estimate potential risks for long-term soil quality. Currently, farmers mostly base their decision to apply plastic mulches rather on expected short-term benefits than on the consideration of long-term consequences. Future interdisciplinary research should therefore gain a deeper understanding of the incentives for farmers and public perception from both a psychological and economic perspective in order to develop new support strategies for the transition into a more environment-friendly food production.