Madeleine Jönsson1, *and Eva Nordberg Karlsson1
1Biotechnology, Department of Chemistry, Faculty of Engineering, Lund University,
PO Box 124, 221 00 Lund, Sweden
Healthy. Sustainable. Novel. Seaweed is a front figure for the green transition in the blue revolution. Yet, it is widely recognized that the prevalence of potentially toxic elements (PTEs) in many seaweed species constitutes a threat to their role as a sustainable food resource. From this starting point, we focus on inorganic arsenic (iAs), cadmium (Cd), lead (Pb), and mercury (Hg), as these compounds are considered ‘chemicals of public health concern’ by WHO. Analysis was performed by accredited labs: element analysis using HR-ICP-MS and arsenic speciation HPLC-ICP-MS. Our study shows that the levels of these compounds vary in four different species (Saccharina latissima, Alaria esculenta, Palmaria palmata, and Ulva lactuca), between three growth locations (Sweden, Norway, and Ireland), and within the algae itself (top, base, and stipe). Ultimately, six different extraction methods were employed to reduce levels of these PTEs. Up to 92 % iAs, 2 % Cd, and 47 % Pb could be removed by the different methods. Hg was concentrated in all samples after treatment, although present only in small quantities. iAs comprise a minor fraction of total arsenic (tAs) in untreated seaweed, ranging between 0-9 %. The results suggest that some PTEs can easily be removed by scalable industrial extraction methods. Biosorption mechanisms are seemingly different for the various compounds. And of the studied compounds, Cd represents the biggest threat to seaweed food safety. Accordingly, standardized acceptance criteria are required, and further analysis on Cd removal might be of interest.