The degradation of plastic litter in rivers: implications for beaches -
Fig. 4. LDPE degradation trial (four months): sample tensile strength for three exposure areas.
Measurements of both tensile strength and elonga- tion showed that significant degradation occurred during the first month of exposure for bank-side and tree sam- ples (Fig. 3). Subsequent months, indicated little change in the tensile properties. Figs. 4 and 5 show a close relationship between bank-side and suspended samples, which deviate from that shown by the buried specimens.
The obvious differences in tensile properties of the specimens after burial are likely to result from sunlight exclusion. Other factors such as less physical abrasion must also be considered. Slight decreases in tensile properties for the buried samples may have resulted from biodegradation. This process would have been limited without prior breakdown by photodegradation.
Fig. 5. LDPE Degradation trial (four months): sample % elongation at break for three exposure areas.