To what extent are microplastics from the open ocean weathered?
Environ Pollut
; 227: 167-174, 2017 Aug.
Article
in En
| MEDLINE
| ID: mdl-28460234
ABSTRACT
It is necessary to better characterize plastic marine debris in order to understand its fate in the environment and interaction with organisms, the most common type of debris being made of polyethylene (PE) and polypropylene (PP). In this work, plastic debris was collected in the North Atlantic sub-tropical gyre during the Expedition 7th Continent sea campaign and consisted mainly in PE. While the mechanisms of PE photodegradation and biodegradation in controlled laboratory conditions are well known, plastic weathering in the environment is not well understood. This is a difficult task to examine because debris comes from a variety of manufactured objects, the original compositions and properties of which vary considerably. A statistical approach was therefore used to compare four sample sets reference PE, manufactured objects, mesoplastics (5-20 mm) and microplastics (0.3-5 mm). Infrared spectroscopy showed that the surface of all debris presented a higher oxidation state than the reference samples. Differential scanning calorimetry analysis revealed that the microplastics were more crystalline contrarily to the mesoplastics which were similar to references samples. Size exclusion chromatography showed that the molar mass decreased from the references to meso- and microplastics, revealing a clear degradation of the polymer chains. It was thus concluded that the morphology of marine microplastic was much altered and that an unambiguous shortening of the polymer chains took place even for this supposedly robust and inert polymer.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Plastics
/
Water Pollutants, Chemical
/
Weather
/
Environmental Monitoring
Language:
En
Journal:
Environ Pollut
Journal subject:
SAUDE AMBIENTAL
Year:
2017
Document type:
Article