Indicators of origin of marine litter

Litter that floats in the seas and oceans and is found in its bottoms has land and sea origin. Many of the materials identified in the different compartments: beaches / coastal areas, surface and water column and bottom, during the monitoring campaigns allow to identify or infer with significant precision the original source and are therefore used as specific indicators of the origin of the litter

The origin of some of the materials collected and identified during the various campaigns in the different locations are easily identifiable as they can be clearly and specifically associated with an economic or consumer sector (eg tourism, fishing, navigation, agriculture, etc.). Nets and ropes can be easily attributed to fishing activity just as crab/lobster traps can be attributed to the aquaculture sector. However, for many of the materials found, direct bonding to a particular source, a disposal medium and even the transport flow is not so obvious.

Many methods have been used over the years to classify the possible sources of marine litter identified in the various compartments monitored (beach, surface and water column and bottom). The national program for the monitoring of marine litter on beaches only follow the OSPAR Convention guidelines, so the list used to classify the litter items identified during the monitoring campaigns has been the OSPAR 100m and 1Km lists. Contudio, it has been verified that some items that are frequently identified are typical of Portuguese beaches and are not included in the OSPAR lists, so it was understood to adopt, as from 2019, for the monitoring program for marine litter on beaches, a guide list which will be complemented with some of the typical items present in the coastal zone of Portugal. Likewise, for the identification of the waste sources, an origins matrix will be used based on the OSPAR Convention and the DeFishGear project (Thomas Vlachogianni, Aikaterini Anastasopoulou, Tomaso Fortibuoni, Francesca Ronchi, Christina Zeri, "Marine Litter Assessment in the Adriatic and Ionian Seas ", 2017). This origins matrix includes the following sources and indicators:

SOURCES: Tourism and recreational activities on the coast and at sea (includes inadequate waste management), fishing & aquaculture, sanitation, navigation (operational and non-operational waste), random deposition, medicine related, agriculture and without source.

  1. Tourism and recreational activities - INDICATORS: Multiple packaging 4/6, plastic shopping bags, bottles and plastic containers and metal beverage containers, plastic bottles and food containers, glass bottles, bags of chips/delicacies and lollipop sticks, etc .;
  2. Fishing, including aquaculture - INDICATORS: Jerry cans, fishing tackle, fishing line, sinkers, buoys, cables/nets <50 cm and> 50 cm, entanglement of nets/ropes, traps for crabs/lobsters, for oysters and mussel sacks, etc .;
  3. Sanitation - INDICATORS: Condoms, swabs, cleaning wipes/diapers/dressings, tampons and tampon applicators;
  4.  Navigation (non-operational wastes, eg kitchen) - INDICATORS: Cardboard boxes / tetrapaks, aerosol cans, food cans, plastic crates, bottles and cleaning containers, etc .;
  5. Navigation (operational waste) - INDICATORS: Protective helmets, strips / bands for packaging, industrial packaging, wooden pallets, oil drums, round and tubular lamps, silicon cartridges, etc .;
  6. Random Deposition - INDICATORS: Plastic car parts, building material, small appliances, etc .;
  7. Related to medicine - INDICATORS: Containers/ blisters/wallets, syringes, needles, etc .;
  8. Agriculture - INDICATORS: Sacks of fertilizers, pruning remains, etc .;
  9. Without Source - INDICATORS: Plastic capsules/ caps/rings, plastic fragments and various sizes, plastic bag seals, etc.