Toward monitoring and estimating the size of the HFO-contaminated seabed around a shipwreck using MBES backscatter data.

Despite a progressive reduction of oil spills caused by the activity of maritime transportation, the latent sources of pollution still exist. Although the harmful impact of heavy fuel oil (HFO) on the marine environment is widely known, many shipwrecks cause contamination of the surrounding areas. In this paper, an approach to monitor the area of the HFO spill around a shipwreck is made using a bottom backscattering strength (BBS) obtained by a multibeam echosounder (MBES). As a case study, the s/s Stuttgart wreck located in the Gulf of Gdansk (Poland) is verified. Two different measurement campaigns have been carried out in shallow waters using low (190 kHz) and high (420 kHz) MBES frequency. The results indicate that the polluted area around s/s Stuttgart was estimated at 49.1 ha, which is around 18.3% more in comparison to the geological surveys made four years earlier. • MBES backscatter is utilized for monitoring and estimating the size of the contaminated area around a known shipwreck. • The case study of the shipwreck lying in the shallow waters in the Gulf of Gdansk (Poland) was selected. • Two operational MBES frequencies (190 kHz and 420 kHz) have been used to investigate how this factor impacts the HFO detection. • The backscatter data were compared with the results collected in 2016 using other survey methods. • The MBES backscatter utilization seems to be a promising solution for periodic monitoring contaminated seabed around high-priority shipwrecks. [ABSTRACT FROM AUTHOR]