Styrene oligomers (SOs), of styrene (styrene monomer, SM), 1,3-diphenylpropane (styrene dimer, SD1), 2,4-diphenyl-1-butene (styrene dimer, SD2) and 2,4,6-triphenyl-1-hexene (styrene trimer, ST), had been detected in the natural environments far from industrial area. To confirm SOs formation through thermal decomposition of polystyrene (PS) wastes in the nature, purified polystyrene (SO-free PS) has been shown to decompose at 30 to 150 °C. The SO ratio of SM:SD:ST was about 1:1:5 with ST as the main product. Mass spectrometry with selected ion monitoring was used for the quantitative analysis of the trace amounts of SOs. The rate of PS decomposition was obtained as k ( year − 1 ) = 5.177   e x p ( − 5029 / T ( K ) ) based on the amount of ST. Decomposition kinetics indicated that not only does drifting lump PS break up into micro/nano pieces in the ocean, but that it also subsequently undergoes degradation into basic structure units SO. According to the simulation at 30 °C, the amounts of SOs in the ocean will be over 400 MT in 2050.

The accumulation of plastic litter in natural environments has become a serious global issue. Since 1972, mega to micro/nanosized drifting plastics have been determined to be highly a significant pollutant in all oceans worldwide. To clarifying numerous problems such as entanglement or improper ingestion due to drifting and debris plastic, the amounts of currently drifting plastics should be determined. For this purpose, chemicals derived from polystyrene (PS) degradation were analyzed for 4000 sand and water samples taken from around the world including open sea sites (surface to 5000 m depth) during the period from 2000 to 2018. All styrene oligomers (SOs) of styrene (styrene monomer, SM), 2,4-diphenyl-1-butene (styrene dimer, SD2), and 2,4,6-triphenyl-1-hexene (styrene trimer, ST) were found to contain products from PS degradation. On the basis of survey SO values, 1.4 × 109 metric tons (MT) of SO were found to have been released into world oceans between 1950 and 2018. This SO subsequently underwent conversion to 2.7 × 106 MT of PS. Twenty percent underwent degradation, while 1.2 × 107 MT of PS apparently continued to drift about in ocean water. Drifting PS has been clearly shown not only to be crushed into micro/nanoplastic particles but also to degrade into basic structural units of SOs constituting PS.

Since 1970, lumps of plastic breakage into micro/nano pieces has been clearly shown a serious and large source of ocean pollution. To clarify in detail the course of this impact, thermoplastics were decomposed at natural conditions kinetically. And field surveys conducted on four thousand sand and water samples including these at deep-sea sites from around the world during the period, 2000 to 2015. All samples were found to contain styrene oligomers (SOs), that had been generated from drifting polystyrene (PS) degradation. Lumps of plastic not only break up into micro/nano-fragments but also degrade into their basic structure units of plastic. From 1950 to 2015, 4.2 billion metric tons (MT) of SOs were shown to be generated from drifting PS. The monomers are newly and highly significant source of pollution of marine ecosystem directly and global warming of planet and should be given the utmost serious attention.

Since 1970, lumps of plastic breakage into micro/nano pieces has been clearly shown a serious and large source of ocean pollution. To clarify in detail the course of this impact, thermoplastics were decomposed at natural conditions kinetically. And field surveys conducted on four thousand sand and water samples including these at deep-sea sites from around the world during the period, 2000 to 2015. All samples were found to contain styrene oligomers (SOs), that had been generated from drifting polystyrene (PS) degradation. Lumps of plastic not only break up into micro/nano-fragments but also degrade into their basic structure units of plastic. From 1950 to 2015, 4.2 billion metric tons (MT) of SOs were shown to be generated from drifting PS. The monomers are newly and highly significant source of pollution of marine ecosystem directly and global warming of planet and should be given the utmost serious attention.

Since 1970, lumps of plastic breakage into micro/nano pieces has been clearly shown a serious and large source of ocean pollution. To clarify in detail the course of this impact, thermoplastics were decomposed at natural conditions kinetically. And field surveys conducted on four thousand sand and water samples including these at deep-sea sites from around the world during the period, 2000 to 2015. All samples were found to contain styrene oligomers (SOs), that had been generated from drifting polystyrene (PS) degradation. Lumps of plastic not only break up into micro/nano-fragments but also degrade into their basic structure units of plastic. From 1950 to 2015, 4.2 billion metric tons (MT) of SOs were shown to be generated from drifting PS. The monomers are newly and highly significant source of pollution of marine ecosystem directly and global warming of planet and should be given the utmost serious attention.