Monitoring of styrene oligomers as indicators of polystyrene plastic pollution in the North-West Pacific Ocean.

Styrene oligomers (SOs) as global contaminants are an environmental concern. However, little is known on the distribution of SOs in the ocean. Here, we show the distribution of anthropogenic SOs generated from discarded polystyrene (PS) plastic monitored from the coastal ocean surface waters (horizontal distribution) and deep seawaters (vertical distribution) in the North-West Pacific Ocean. SOs concentrations in surface seawater and deep seawater ranged from 0.17 to 4.26 µg L-1 (total mean: 1.48 ± 1.23 µg L-1) and from 0.31 to 4.31 µg L-1 (total mean: 1.32 ± 0.87 µg L-1), respectively. Since there is no significant difference in the mean concentrations, SOs seems to be spread across marine environment selected in this study. Nevertheless, regional SOs appears to persist to varying degrees with their broad horizontal and vertical distribution in the ocean. Each horizontal and vertical distribution of SOs differs by approximately 1.95-2.57 times, probably depending on the events of weather and global ocean circulation. These results provide the distribution pattern of SOs for assessing environmental pollution arising from PS plastic.

Global styrene oligomers monitoring as new chemical contamination from polystyrene plastic marine pollution.

Polystyrene (PS) plastic marine pollution is an environmental concern. However, a reliable and objective assessment of the scope of this problem, which can lead to persistent organic contaminants, has yet to be performed. Here, we show that anthropogenic styrene oligomers (SOs), a possible indicator of PS pollution in the ocean, are found globally at concentrations that are higher than those expected based on the stability of PS. SOs appear to persist to varying degrees in the seawater and sand samples collected from beaches around the world. The most persistent forms are styrene monomer, styrene dimer, and styrene trimer. Sand samples from beaches, which are commonly recreation sites, are particularly polluted with these high SOs concentrations. This finding is of interest from both scientific and public perspectives because SOs may pose potential long-term risks to the environment in combination with other endocrine disrupting chemicals. From SOs monitoring results, this study proposes a flow diagram for SOs leaching from PS cycle. Using this flow diagram, we conclude that SOs are global contaminants in sandy beaches around the world due to their broad spatial distribution.

Regional distribution of styrene analogues generated from polystyrene degradation along the coastlines of the North-East Pacific Ocean and Hawaii.

Beach sand and seawater taken from the coastlines of the North-East Pacific Ocean and Hawaii State were investigated to determine the causes of global chemical contamination from polystyrene (PS). All samples were found to contain styrene monomer (SM), styrene dimers (SD), and styrene trimers (ST) with a concentration distribution of styrene analogues in the order of ST > SD > SM. The contamination by styrene analogues along the West Coast proved more severe than in Alaska and other regions. The Western Coastlines of the USA seem be affected by both land- and ocean-based pollution sources, which might result from it being a heavily populated area as the data suggest a possible proportional relationship between PS pollution and population. Our results suggest the presence of new global chemical contaminants derived from PS in the ocean, and along coasts.

New analytical method for the determination of styrene oligomers formed from polystyrene decomposition and its application at the coastlines of the North-West Pacific ocean.

The pollution caused by plastic debris is an environmental problem with increasing concern in the oceans. Among the plastic polymers, polystyrene (PS) is one of the most problematic plastics due to the direct public health risk associated with their dispersion, as well as the numerous adverse environmental impacts which arise both directly from the plastics and from their degradation products. Little is known about their potential distribution characteristics throughout the oceans. For the first time, we report here on the regional distribution of styrene monomer (SM), styrene dimers (SD; 2,4-diphenyl-1-butene, SD1; 1,3-diphenyl propane, SD2), and styrene trimer (2,4,6-triphenyl-1-hexene: ST1), as products of PS decomposition determined from samples of sand and seawater from the shorelines of the North-West Pacific ocean. In order to quantitatively determine SM, SD (=SD1+SD2), and ST1, a new analytical method was developed. The detection limit was 3.3 µg L(-1), based on a signal-to-noise ratio of three, which was well-suited to quantify levels of SM, SD, and ST1 in samples. Surprisingly, the concentrations of SM, SD, and ST1 in sand samples from the shorelines were consistently greater than those in seawater samples from the same location. The results of this study suggest that SM, SD, and ST1 can be widely dispersed throughout the North-West Pacific oceans.