1 Introduction
2 Plastics and Microplastics: An Overview
2.1 A Brief Overview of Plastic Development
Year | Polymer type | Inventor/notes |
---|---|---|
1839 | Natural rubber latex | Charles Goodyear |
1839 | Polystyrene | Discovered by Eduard Simon |
1862 | Parkesine | Alexander Parkes |
1865 | Cellulose acetate | Paul Schützenberger |
1869 | Celluloid | John Wesley Hyatt |
1872 | Polyvinyl chloride | First created by Eugen Baumann |
1894 | Viscose rayon | Charles Frederick Cross |
1909 | Bakelite | Leo Hendrik Baekeland |
1926 | Plasticised PVC | Walter Semon |
1933 | Polyvinylidene chloride | Ralph Wiley |
1935 | Low-density polyethylene | Reginald Gibson and Eric Fawcett |
1936 | Acrylic or polymethyl methacrylate | |
1937 | Polyurethane | Otto Bayer and co-workers |
1938 | Polystyrene | As a commercially viable polymer |
1938 | Polyethylene terephthalate | John Whinfield and James Dickson |
1942 | Unsaturated polyester | John Whinfield and James Dickson |
1951 | High-density polyethylene | Paul Hogan and Robert Banks |
1951 | Polypropylene | Paul Hogan and Robert Banks |
1953 | Polycarbonate | Hermann Schnell |
1954 | Styrofoam | Ray McIntire |
1960 | Polylactic acid | Patrick Gruber is credited with inventing a commercially viable process |
1978 | Linear low-density polyethylene | DuPont |
2.2 Describing Plastic Materials
Additive compounds | Function |
---|---|
Plasticisers | Renders the material pliable |
Flame retardants | Reduces flammability |
Cross-linking additives | Links together polymer chains |
Antioxidants and other stabilisers | Increases the durability of plastics by slowing down the rate at which oxygen, heat, and light degrade the material |
Sensitisers (e.g. pro-oxidant transition metal complexes) | Used to give accelerated degradation properties |
Surfactants | Used to modify surface properties to allow emulsion of normally incompatible substances |
Inorganic fillers | Used to reinforce the material to improve impact resistance |
Pigments | For colour |
2.3 Microplastics as Contaminants of Emerging Concern
3 Sources of Plastics and Microplastics into the Freshwater Environment
4 Occurrence in Freshwater Systems
5 Fate and Transport in Freshwater Systems
5.1 Environmental Transportation
5.2 Environmental Persistence and Degradation
Polymer type | Density (g cm−3) | Crystallinity |
---|---|---|
Natural rubber | 0.92 | Low |
Polyethylene–low density | 0.91–0.93 | 45–60% |
Polyethylene–high density | 0.94–0.97 | 70–95% |
Polypropylene | 0.85–0.94 | 50–80% |
Polystyrene | 0.96–1.05 | Low |
Polyamide (PA6 and PA66) | 1.12–1.14 | 35–45% |
Polycarbonate | 1.20 | Low |
Cellulose acetate | 1.28 | High |
Polyvinyl chloride | 1.38 | High |
Polylactic acid | 1.21–1.43 | 37% |
Polyethylene terephthalate | 1.34–1.39 | |
Polyoxymethylene | 1.41 | 70–80% |
5.3 Interactions with Other Compounds
6 Effects of Plastics and Microplastics on Freshwater Ecosystems
6.1 Uptake and Biological Effects
6.2 Effects of Leaching Chemicals
6.3 Biological Effects of Sub-micrometer Plastics
7 Considerations for Assessing Environmental Risks
Monomer 1 | Monomer 2 | Monomer 3 | Additive 1 | |
---|---|---|---|---|
Propylene oxide | Ethylene oxide | Toluene diisocyanate | TBBPA | |
LC50 algae | 307 | 502 | 3.79 | 0.19 |
LC50 daphnid | 188 | 278 | 2.61 | 0.02 |
LC50 fish | 45 | 58 | 3.91 | 0.02 |
PNEC (AF = 1000) | 0.045 | 0.058 | 0.003 | 0.000002 |
PEC (dissolved compound) | 0.00067 | 0.00067 | 0.00067 | 0.0000032 |
RQPEC/PNEC
| 0.015 | 0.012 | 0.257 | 0.160 |
Mixture RQ | 0.443 |