Impacts of Tourism on Marine Debris and Microplastic Detection at Samui Island, Southern Thailand

We investigated types, amounts and sources of marine debris and microplastics, and compared how tourism, by means of different levels of beach cleanup, affecting them. We collected marine debris and microplastics at three beaches based on frequencies of beach cleanup: high (Chaweng Beach), intermediate (Lamai Beach) and no beach cleaning (Hua Thanon Beach). Marine debris was counted from a ground survey using the applied Trash Free Sea® data card and the International Coastal Cleanup (ICC) method. Microplastics with a size larger than 1 mm were examined and photographed using a clip-type mobile phone microscope. The Clean Coast Index (CCI) was used for the assessment of beach cleanliness. Over 95% of the marine debris was plastic, and microplastics were ubiquitous, which calls for classification of the plastics as hazardous materials. Hua Thanon Beach had the highest (CCI> 20) (extremely dirty), followed by Lamai Beach (2-5 CCI) and the least CCI was at Chaweng Beach (CCI<2) (clean beach). This is because the popular tourism beach (Chaweng Beach) had the highest beach cleaning frequencies even during the 3-month lockdown of the covid-19 situation. This rapid-survey method could be developed and applied for a citizen-science project on the survey of marine debris and microplastics and on monitoring the condition of our beaches.