Investigation on plastic waste utilization and management in fishery harbors of Sri Lanka

Abstract

Fishery harbors (FH) are recognized as hot spots for coastal pollution as intensive anthropogenic activity takes place there. According to previous beach surveys conducted in the country, plastic was recognized as the major polluter. However, there are no studies being conducted which target plastic waste generation inside FH located in Western Province of Sri Lanka. The study was conducted from October 2022 to September 2023. For this study, weekly accumulation study method was followed along the land-water interface to collect primary data. Throughout the study period, a total of 34,188 anthropogenic debris pieces weighing 2650.47 kg were recorded from 59 data collection points within five FH. Plastic has become the major polluter both by count and by weight. By count it was 29,141 (85.24%) and by weight it was 1578.07 kg (59.53%). Therefore, plastics was recognized as the major polluter in FH located in the Western Province of Sri Lanka. By count only, rubber, metal, glass, processed wood and fabric represented 7.99%, 1.98%, 1.95%, 1.78% and 1.06% of the total anthropogenic debris respectively. The spatial variation in plastic debris accumulation was statistically significant in all five FH, while seasonal variation was statistically significant at Beruwala, South Dikkowita and Panadura FH. Plastic debris accumulation rates were 1.45, 2.21, 1.57, 0.98 and 0.17 items/m2/week for Beruwala, North Dikkowita, South Dikkowita, Panadura and Negombo FH respectively. The top ten debris, fishery industry related plastic debris, single use plastics and transboundary plastic products represented 84.64%, 10.71%, 60.94% and 0.27% of the total plastic debris collected from the five FH. Lower percentage of transboundary plastic products highlights that the problem is primarily a result of mismanagement of plastic waste within the harbor. There was a strong positive (r=0.883) correlation between number of plastic debris recorded and plastic weight. Correlation between monthly rainfall and monthly average number of plastic debris recorded had a very weak positive correlation for Beruwala, North and South Dikkowita FH whilst being negative for Panadura and Negombo FH. Correlation between the tide level and number of plastic debris recorded was weakly negative (r= -0.280). Stranding debris count was significantly higher than the floating debris at FH. Therefore, conducting cleanup projects at FH during low tide will be much more effective, with a priority on addressing stranding debris. A Stakeholder workshop and a questionnaire survey were conducted as a secondary data collection method. This was to reveal the perceptions and, attitudes of stakeholders as well as to find policy gaps related with plastic debris generation inside FH. Over half of the fishermen (51%) believe that the poor waste management of plastic within the FH by the Ceylon Fishery Harbors Corporation is the primary contributing factor for large amount of plastic waste generation. It highlighted the requirement of improving awareness among fishery communities, properly implementation of existing regulations and integrated stakeholders involvement. Key words: Fishery harbors, Plastic pollution, Coastal environment, Coastal contamination, Anthropogenic debris