Occurrence Characteristics, Source Analysis, and Beach Quality Assessment of Marine Litter in Daya Bay

• • Beach litter density reached 4.41×10^5 items·km−2 (large/very large) and 5.39×10^6 items·km−2 (medium), indicating moderate-to-low pollution compared to global hotspots; plastics comprised 74.0% of beach litter, necessitating targeted plastic waste management. • • Sea surface litter densities (5.82×10^2 and 9.90×10^3 items·km−2 for large/very large and medium) were moderate-to-high, with plastics accounting for 96.0%, highlighting the need for surface cleanup and source reduction. • • Seafloor litter density was 5.20×10^3 items·km−2, relatively low, but 78.8% was plastic, and source analysis linked it to shipping/fishing, indicating the need for port reception facilities and fisher engagement. • • Beach quality assessment showed 63.6% of beaches were moderately clean or better (grades II–IV) and 90.9% were moderately safe or better (grades I–III), providing a baseline for prioritizing management interventions.