Plastics litter

In the South Pacific, man-made debris was surveyed on 24 islands in the Thousand Island archipelago north of Java in 1985 (66). Polyethylene bags, footwear and polystyrene blocks comprised more than 90% of the 27,600 items. The main source of this debris is the dumping of rubbish and domestic and industrial waste directly into the sea at Jakarta. On New Zealand beaches, plastic litter was widely distributed and predominantly in the form of polyethylene and polypropylene beads. Near Auckland and Wellington concentrations exceeded 10,000 and 40,000 beads m of beach, and the unweathered appearance of the beads implied a nearby source (66). 

The photosensitizing degradation may considerable contribute to the solution of the plastic-litter problem. In order to improye the standards of our enyironment the amounts of plastic litter should be reduced and this aim may easily be aohiyed by the use of plastics mhich would readily degradable by sunlight. This practioal problem has been fully reviewed by the following publioations (3,127). 

It is a fact that actinic deterioration of Degradable Plastic films will, in due course, lead to the crumbling of them into fine particles. Such disintegration obviates the plastics litter problem and provides the possibility of a solution to the agricultural plastics residue situation. There is evidence in this paper and elsewhere ( ) that there are commercially viable formulations with which packaging (and related) plastics can be made to have controlled, short embrittlement times outdoors but no indoor stability problems. 

Recent years have seen the development of prediction tools for the transport layers of plastic litter. These tools provide the facility to follow the trajectories of clusters that may be washed ashore. Evenmally, the development of an atlas of risk sensitivity will facilitate the improvment of the management of accidental risks. However, simulations performed globally over several years help in the identification of the most sensitive zones at the global scale, such as the Mediterranean, the Atlantic and Pacific convergence areas, and the Bay of Bengal. These areas on their own should receive within 30 years between 35 and 60% of all litter at sea [LEB 11],... 

An important use of PS is in foams and beads which are widely used as impact absorbing materials in packaging. Because of its very low bulk density, expanded PS is a very visible component of plastics litter and is often seen floating on the surface of water. For the same reasons it is particularly expensive to collect and reprocess. Biodegradable foamed plastics based on starch are being developed which promise to be an ecologically acceptable alternative to PS (Chapter 5). 

Not unexpectedly, in the light of the above, there are no published test methods for the biodegradation of plastics litter. The primary requirement is that the detritus breaks down into small particles in a matter of... 

The concept of biodegradable synthetic polymers was first proposed in the 1960s as a potential solution to the problem of plastics litter. This was initially welcomed by environmentally aware public, particularly in the USA, since it was perceived to be a possible solution to the landfill problem. Packaging producers in collaboration with corn growers were quick to respond to the public mood by adding corn starch to polyethylene. Carrier bags made from this material were claimed, without experimental evidence, to be biodegradable but the... 

This degradation reaction, supplemented by various subsequent oxidation steps, has found renewed interest in the form of the introduction of photodegrad-able plastics as part of the campaign to reduce plastic litter from throwaway packaging. Although as yet there has been no demand for photodegradable mb-bers, the incorporation of a small percentage of a vinyl ketone into a rubber copolymer or homopolymer would open the way to a useful synthesis of block copolymers. 

Figure 11.34 shows that the plasticizer structure arrd its amoirrrt determine biodegradation rate of the plastieized polylaetate. Figtrre 11.35 shows that plasticizer increases the degradation rate on expostrre to seawater. This is irrrportarrt for products in packaging applications developed to reduee threat to the marine life. It is estimated that about 100,000 marine animals and about 1-2 million sea birds are killed yearly by the toxic residues of a plastic litter. 

PLASTIC LITTER AND OTHER MARINE DEBRIS 10.2.1. Categories and Sources... 

TABLE 63 Main Environments in Which Plastic Litter is Found... 

Food packaging and food service plastics have the shortest service lifetime of any plastic product manufactured and end up in the waste or litter at a much faster rate compared to other plastic products. Packaging therefore has implications on sustainable development for several reasons. First, being a high-volume-use sector, plastic packaging produces waste that can end up in urban litter and even as ocean debris (see Chapter 10). There is no efficient mechanisms to collect, recycle, or dispose of most plastic litter. Secondly, some of the primary plastic packaging is used in contact with food or beverages, and the possibility of additives (and residual monomer)... 

Packaging waste from MS W and beach use About a third of the plastics resin produced globally ends up as plastic packaging of which less than 9% of waste in the MS W is recovered for recycling. Plastic litter on land can be transported to the oceans via storm drain runoff. Recreational use of beaches also results in beach litter that can be picked up by wind and tidal movements and transported into the water (Corcoran et al., 2009 Rosevelt et al., 2013 Ryan et al., 2009). Beach cleanup operations help reduce the litter but there is virtually no mechanism to collect such debris once they enter the water. 

The durability of plastics has been considered to be a positive attribute, but it is now commonly perceived by society as negative. Although photodegradability has been suggested as a solution for plastic litter, photodegradation has a limited practical application because UV light will not penetrate landfills [54]. 

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