▁de br is ▁such ▁as ▁land - based , ▁marine - based , ▁and ▁other ▁anth rop oc ent ric ▁activities . ▁ ▁Mill ion ▁tons ▁of ▁land - based ▁waste ▁products ▁such ▁as ▁pl ast ics , ▁papers , ▁woods , ▁and ▁met als ▁end ▁up ▁in ▁se as , ▁o ce ans , ▁and ▁be aches ▁through ▁the ▁wind , ▁o ce ans ▁curr ents ▁( five ▁major ▁gy res ), ▁se w age , ▁run off , ▁storm - water ▁dra ins ▁and ▁rivers . ▁Mass ive ▁amount ▁of ▁marine ▁de br is ▁has ▁become ▁a ▁severe ▁men ace ▁to ▁the ▁marine ▁environment , ▁aqu atic ▁life ▁and ▁hum ank ind . ▁Most ▁land - based ▁sources ▁are ▁illegal ▁dump ing , ▁land fill s , ▁and ▁pet ro chem ical ▁and ▁other ▁industry ▁dispos als . ▁Also , ▁other ▁marine - based ▁sources ▁origin ate ▁from ▁anth rop oc ent ric ▁marine ▁activities ▁that ▁are ▁dr ift ed ▁fish ing ▁lines , ▁n ets , ▁pl astic ▁ro pes ▁or ▁other ▁pet ro chem ical ▁products ▁from ▁remote ▁islands ▁or ▁lands , ▁sh ipping ▁vessels ▁or ▁fish ing ▁boats ▁by ▁wind ▁and ▁ocean ic ▁curr ents . ▁What ’ s ▁more , ▁marine ▁de br is ▁source ▁is ▁also ▁anth rop oc ent ric ▁activities ▁of ▁local ▁populations ▁such ▁as ▁beach ▁go ers , ▁tour ists ▁and ▁city ▁or ▁town ▁se w age . ▁ ▁Mont es inos ▁et ▁al , ▁( 2 0 2 0 ) ▁study ▁of