PLASTICS IN THE MARINE ENVIRONMENT

Marine debris is generally defined as any manufactured or processed solid waste material (typically inert) that enters the marine environment from any source. Marine litter and floatables are considered equivalent terms [1], Marine pollution is defined as the introduction by man, directly or indirectly, of substances into the marine environment (including estuaries) resulting in such deleterious effects as harm to living resources, hindrance to marine activities including fishing, impairment of quality for use of sea water and reduction of amenities [2], Marine debris is dominated by persistent synthetic materials, most of which are plastics. 

Plastics and the Environment, Edited by Anthony L. Andrady. ISBN 0-471-09520-6 2003 John Wiley Sons, Inc. 

Strength, durability, and relative inertness virtually indestructibility in the marine 

General resistance to microbial and other degradation processes 

Transparency, biological inertness, low density, and cost effectiveness 

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ASTM D7081-05 Standard Specification for Non-Floating Biodegradable Plastics in the Marine Environment... 

Standard specification for non-floating biodegradable plastics in the marine environment, ASTM Standard D7081-05, ASTM International, West Conshohocken, PA, 2005. 

Gregory MR, Andrady AL. Plastics in the marine environment. In Andrady AL, editor. Plastics and the Environment. Hoboken John Wiley Sons 2003. 

Plastics in the marine environment have become inescapable and include everything from fishing nets to tampon applicators to household waste. Commercial fisherman alone purposely dump 52 million lbs of plastic packing into the ocean every year and lose an additional 298 million lbs in the form of plastic nets, lines and buoys [8]. 

Hammer, J., Kraak, M., and Parsons, J.R. 2012. Plastics in the marine environment The dark side of a modem gift. Reviews of Environmental Contamination and Toxicology. New York Springer, pp. 1-44. 

ASTM D7021 Specification for nonfloating biodegradable plastics in the marine environment... 

Poly-3-hydroxybutyrate-co-3-hydroxyvalerate [P(3HB-co-3HV)] copolymers have a variety of uses as single use, bulk-commodity plastics, in the marine environment and in biomedical applications (2/). Normally, P(3HB-co-3HV) is synthesized in bacteria grown on a mixture of glucose and propionate (22). Although demonstrated in plants. Figure 1C shows a pathway which could potentially be used in bacteria for the conversion of threonine (derived from the TCA cycle) to 3-hydroxyvalerate by threonine deaminase, IlvA, to 2-ketobutyrate, followed by reduction to propionyl-CoA by pyruvate dehydrogenase. BktB then catalyzes the formation of the 3-(7 )-hydroxyvaleryl-CoA substrate which can be polymerized into a P(3HB-co-3HV) copolymer (23). 

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