Portugal: Study finds heavy metals, microplastics in Algarve sea

Heavy metals and microplastics are some of the pollutants detected on the continental shelf off the Algarve as part of an international study led by researcher Pedro Costa, the University of Coimbra (UC) announced on Wednesday.

“The human presence has left a polluting signature in the coastal area of the Algarve, with negative impact, for example, at the level of biodiversity,” said Pedro Costa, of the Department of Earth Sciences, Faculty of Science and Technology, University of Coimbra (FCTUC), quoted in a UC note sent to Lusa news agency.

The “OnOff” project, which involves more than 20 researchers, carried out “the chronography of extreme events [such as tsunamis and storms] and the effects of human contamination” in this area of Portugal, over the past 12,000 years.

The study “alerts to the impacts of anthropogenic pollution on the continental shelf off the Algarve”, says the FCTUC press release, according to which “heavy metals and organic contaminants were detected along the coastal area of the Algarve, between Sagres and Portimão”, and the results of the research were published in the specialised magazine Marine Pollution Bulletin.

“The data obtained seems to indicate that in the 1960s there was a peak in pollution, but, curiously, in recent years, this pollution seems to be slowing down slightly, with the exception of the Arade river area, due to regular discharges that are made”, Pedro Costa, co-author of the scientific article, said.

The study reports the presence of “various inorganic and organic pollutants related to human activity, among which are different heavy metals, and even microplastics”.

Due to climate change, “it is expected that we will have more high-energy events, either in precipitation or in storms, which will cause more intense erosive phenomena”.

“In Portugal, several areas are under pressure, which means this problem will inevitably become more acute. We have always had pollution, but with the changing climate forcings and with the energy levels of these extreme events, phenomena that would be of little intensity may cause serious negative consequences and serious imbalances in coastal systems,” warned the FCTUC researcher.

Besides the UC, the “OnOff” involved the University of Lisbon, the University of Algarve, the Hydrographic Institute and the Portuguese Environment Agency, besides the University of Aachen (Germany) and the United States Geological Survey.

Called “Contemporary pollution of surface sediments from the Algarve shelf, Portugal”, the project, which began in 2018, “essentially aims to fully reconstruct extreme events, such as tsunamis and storms, and their impacts on the Portuguese coast, based on geological evidence”.

“In other words, it seeks to get information from the underwater seabed to carry out the reconstruction of extreme events, whether of tsunamis, storms or floods, and also of more recent phenomena, such as pollution,” explains Pedro Costa.

To do this, the scientists have carried out “a series of sea campaigns”, with underwater soundings, along the Algarve coast, collecting water samples, sediments and geophysical data between 500 and 30 metres deep.

“This is the innovative aspect of the project because it shows a different archive that was not normally paid attention to and allowed for a detailed reconstruction of the evolution of this region. The information obtained at sea is combined with data obtained on land, in lagoon and estuary areas of the Algarve”, says the project leader.

OnOff can support “government authorities with useful data for planning, organisation and operationalisation”.

The project is funded by the Foundation for Science and Technology (FCT), the European Union and the Foundation for Research Support of the State of Rio de Janeiro, Brazil.