Arsenic in marine macroalgae and implications for commercial uses (AsMARA)

Himanthalia elongata (Sea Spaghetti) Image credit to Dr Dagmar Stengel

This project is a collaboration between the Marine Institute (PI Dr Evin McGovern) and the National University of Ireland Galway (PI Dr Dagmar Stengel). It is funded under the Department of Agriculture, Food and the Marine's Food Institutional Research Measure (FIRM), reference number 14 SF 860.

Arsenic (As) is a naturally occurring chemical element, existing in a number of inorganic and organic forms or species. Inorganic arsenic (Asi) is much more toxic than organic forms. Long-term oral exposure to low levels of Asi may cause a variety of health effects, including an increased risk of certain cancers.

Ascophyllum nodosum (Knotted wrack) Image credit to Dr Dagmar StengelSeafood is a primary dietary source of arsenic, contributing over 50% of total daily dietary intake. This arsenic predominantly occurs, with some exceptions, as relatively non-toxic organic forms, but the actual risk to consumers cannot be assessed without data on toxic inorganic forms. While marine algae can contain high levels of total arsenic, they are generally considered to contain very low levels of Asi, with the exception of some species of brown algae, which can contain high Asi levels. Non-compliance of algal-based feed products with EC regulatory limits for total arsenic (rather than Asi) presents a problem for developing Ireland's seaweed industry.

The AsMARA research project aims to:
  • Develop a sensitive, quality controlled method to quantify toxic inorganic and total arsenic in marine algae.
  • Conduct a survey of total and inorganic arsenic in a number of commercially important seaweeds from Irish waters.
  • Assess potential variability and fluctuations in seaweeds by studying the effects of season and environmental factors on arsenic content.
  • Study the potential effects of processing and storage on arsenic content.
  • Provide information and recommendations.

The information generated Fucus serratus (Serrated Wrack). Image credit to Dr Dagmar Stengelwithin this research project will support industry in developing strategies to minimise arsenic concentrations in products and assist policy makers in risk management and developing practical regulation for consumer protection. An information leaflet entitled 'Arsenic in Marine Macroalgae, implications for industry' will be published in 2015. For more information please contact Dr Jenny Ronan by email ( An advisory group has been established consisting of industry, regulatory stakeholders and an international technical expert.

Arsenic in Irish marine macroalgae - implications for Industry