COVID-19-related litter pollution on Greek beaches and nearshore shallow water environments.

COVID-19 pandemic has led to an increase in certain types of litter, many of which are expected to end up in the marine environment. The present study aimed to monitor the pandemic-related litter pollution along the Greek coastal environment. Overall, 59 beach and 83 underwater clean-ups were conducted. Litter was categorized as: PPE (face masks and gloves), COVID-19-related, single-use plastic (SUP) and takeaway items. PPE, dominated by face masks (86.21 %), accounted for 0.29 % of all litter. The average PPE density was 3.1 × 10-3 items m-2 and 2.59 items/ 100 m. COVID-19-related items represented 1.04 % of the total. Wet wipes showed higher densities (0.67 % of all litter) than in the pre-COVID era, while no increase in SUP and takeaway items was observed. Benthic PPE, dominated by gloves (83.95 %), represented 0.26 % of the total. The mean PPE density was 2.5 × 10-3 items m-2.

Vessel-based photographic assessment of beach litter in remote coasts. A wide scale application in Saronikos Gulf, Greece.

The abundance of marine debris was quantified for a total of sixty-two inaccessible beaches in the western Saronikos Gulf, Greece. High resolution images were obtained through vessel-based photography survey, merged into seamless photomosaics, and manually processed to quantify beach litter abundance. A sample of four selected beaches were subjected to detailed photography followed by beach macro-litter (≥ 2.5 cm) in-situ sampling surveys over a period of one year, to calibrate and validate the proposed method. Regression analysis between photographic and in-situ data showed a significant correlation, hence providing a highly accurate regression model to assess the real number of beach litter stranded on the rest of the investigated beaches, exhibiting clear correlations to the hydrodynamic status of the area and, provide an indication of the main litter sources. The proposed method is an easily applicable and useful tool for fast and low-cost macro-litter monitoring in extended, remote coastlines, when only photographic data are available.