A simple and low-cost method using active radio frequency identification to survey the mobility of plastic debris in rivers

Rivers are the main method for plastic debris to be transferred from continental to marine environments. The aim of this study is to test the reliability of a low-cost methodology using active radio frequency identification (RFID) tags developed by the ELA Enterprise to assess travel distance and identify the preferential deposition areas of floating (n = 7) and submerged (n = 7) plastic bottles in a peri-urban river located downstream of the city of Strasbourg (France). Our study shows that the protocol tested is simple to set up, fast (1 h per 1,5 km of river length) and reliable, with a detection return rate of 86 %. Over 39 days, the plastic bottles travelled an average distance of 1100 m, with a maximal travel distance of 2100 m during low-flow conditions. All the tracked plastic bottles were trapped in logjams. With a detection range of up to 80 m, the method can be deployed on small to large European rivers by installing one antenna on each bank. Monitoring can be performed over short periods (weeks to months) to several years through the possibility of programming the tag emission frequency.