In common sea lettuce, there may be the solution to clean water contaminated by industry and domestic consumption. A team of researchers from the University of Aveiro (UA) discovered that this alga has a great ability to remove potentially toxic elements from water, most of them hazardous to human health and the environment.
“The removal achieved with the algae that we have been testing to remove from the water, among other elements, arsenic, mercury, cadmium and lead, is very high”, congratulates Bruno Henriques, the researcher at the Center for the Study of the Environment and the Sea ( CESAM) and the Department of Chemistry (DQ) of the Academy of Aveiro.
Bruno Henriques guarantees that, compared to other materials, natural or synthetic, currently used for the same purpose, the success rate of sea lettuce “is superior”.
Therefore, the researcher considers that “these algae are an efficient alternative, as they remove high percentages of contaminants in a short period of time, the methodology is economical and more ecological than the 'classic' methods for removing these elements, which are less effective and often more expensive, which translates into low cost-benefit”.
The AU study indicates that each gram of algae can simultaneously remove 120 micrograms of mercury, 160 micrograms of cadmium, 980 micrograms of lead, 480 micrograms of chromium, 660 micrograms of nickel, 550 micrograms of arsenic, 370 micrograms of copper and 2000 micrograms of manganese.
These chemical elements, explains the researcher, despite being called classics they continue to be currently “heavily used by various industries and their presence in the environment causes negative impacts, such as toxicity, observed even at very low concentrations”. Other problems associated with these elements “are related to their persistent character in the environment and their ease in bioaccumulating in the tissues of organisms”.
Algae grown in contaminated places
The secret of great ability to cleaning the seaweed is explained by sorption, a process through which sea lettuce manages to incorporate contaminants into its tissues.
The rapid growth of these algae, congratulates Bruno Henriques, "contributes to being able to remove contaminants in ever greater quantities, as the growth of the algae increases the number of surface sites to which these toxic elements can attach".
Thus, explains the researcher, "algae can be used to reduce the contamination of places very affected by discharges of these elements, by introducing the algae in the place to be decontaminated if the conditions are suitable for its growth or by cultivating algae in another location and transporting these to the places to be decontaminated”.
In addition to removing toxic elements, the UA researchers ensure that sea lettuce also reduce the content of phosphates and nitrates in water and, by using carbon dioxide as a carbon source, reduce the carbon footprint.
The work was carried out by a multidisciplinary team from the UA consisting of Bruno Henriques, Ana Teixeira, Paula Figueira, Joana Almeida and Eduarda Pereira (researchers from the DQ, CESAM, CICECO – Instituto de Materials de Aveiro and the Central Laboratory of Analysis), and with the cooperation of the University of Porto and the National Institute of Health Dr. Ricardo Jorge.
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