Anthropogenic marine litter: An approach to environmental quality for India's southeastern Arabian Sea coast.

Anthropogenic marine litter (AML), mainly plastic, is a global concern that is persistent and widespread. To prevent and mitigate this threat, we need to understand the magnitude and source of AML. There is limited knowledge about AML pollution on the Indian Coast. In this context, the present study examined the distribution, abundance, typology, and beach quality based on AML along 22 beaches on the southeastern coast of the Arabian Sea. A total of 4911 AML items were classified into 9 categories, weighing 16.79 kg, and retrieved from a total area of 8000 m. The mean abundance and weight of AML in the current study were 0.45 ± 0.34 items/m and 1.53 ± 0.92 g/m, respectively. Thottapally showed the most abundant AML among the studied beaches with 0.96 items/m, followed by Azheekkal with 0.73 items/m. Plastic, being the most common item, accounts for 77.6 % of all items and has a mean density of 0.35 items/m comprising hard plastic (22 %), thermocol (13 %), food wrappers (7 %), cigarette butts (7 %), plastic rope (6 %), and plastic cutlery (6 %). Hazardous anthropogenic litter (HAL) was maximum at Thottapally (17.71 %; 85 out of 480 items collected). Based on the cleanliness of beaches, they are graded "moderately clean" (63 %) by the General Index (GI), "clean" (54 %), and "moderately clean" (40 %) as calculated by the Clean Coast Index (CCI). Hazardous Anthropogenic Beach Litter Index (HABLI) classifies 72 % of beaches as "moderately safe", while the Environmental Status Index (ESI) rates 68 % of beaches as "mediocre". Besides, model simulations demonstrated the pathways of AML propagation, which correlate to the littoral and coastal current flow patterns over the region. Land-based activities were the crucial factors influencing AML distribution. The study highlighted the need for effective regional litter management strategies, policy instruments for the litter impact pathways, economic, regulatory, and behavioural management tools, which were also discussed.