The Douro River

The Douro River is one of the major rivers of the Iberian Peninsula. It flows into the Atlantic Ocean through a highly dynamic funnel-shaped narrow estuary (21.6 km long; 9.8 km² of area) surrounded by two cities: Porto and Vila Nova de Gaia.

The estuarine dynamics is mainly forced by freshwater flows, being very dependent on highly variable natural conditions and on the hydropower production schedule of the last river dam. During high flow periods, small urban rivers flowing into the estuary usually carry considerable amounts of litter flushed after heavy rain from the urban areas. The estuary is very urbanized, with several wastewater treatment plants (WWTPs) draining into its waters, and highly modified by human activities such as marinas.

Microplastics are accumulated in the river from several anthropogenic sources, including vessel maintenance and paint washing from marinas activities, which also releases biocides and heavy metals.

In the Douro River, we will employ a Special membrane filtration unit to remove microplastics in marinas and shipyards waste streams before they can enter the river. Sampling from a boat to detect and quantify the plastic pollution will be conducted with Ferrybox and Mantanet.