Consistent Transport of Terrestrial Microplastics to the Ocean through Atmosphere

Abstract

Although atmospheric transport and deposition could be an important pathway of terrestrial pollutants to the ocean, little information concerning the presence and distribution of these suspended atmospheric microplastics in marine air is available. We investigated, for the first time, the occurrence and distribution of suspended atmospheric microplastics (SAMPs) in the west Pacific Ocean. In this study, the spatial distribution, morphological appearance, and chemical composition of suspended atmospheric microplastics were studied through continuous sampling during a cruise. SAMPs abundance ranged from 0 to 1.37 n/m3, the median of 0.01 n/m3. Fiber, fragment, and granule SAMPs quantitively constituted 60%, 31%, and 8% of all MPs, respectively. Interestingly, plastic microbeads with numerical proportion of 5% were also observed. A high suspended atmospheric microplastics abundance was found in the coastal area (0.13 ± 0.24 n/m3), while there was less amount detected in the pelagic area (0.01 ± 0.01 n/m3). The amount of suspended atmospheric microplastics collected during the daytime (0.45 ± 0.46 n/m3) was twice the amount collected at night (0.22 ± 0.19 n/m3), on average. Our observations provide field-based evidence that suspended atmospheric microplastics are an important source of microplastics pollution in the ocean, especially the pollution caused by textile microfibers.

Airborne microplastic particles detected in the remote marine atmosphere

“…Our findings indicate a new possible source and formation mechanism for AMP, different to those found for the terrestrial and coastal AMP detected to date 13,[22][23][24][25][26][27][28][29][30][31][32][33] . We have evidence from the open ocean, which suggest that AMP is emitted from the seawater into the atmosphere through wind related processes.…”

“…Estimates of recent years suggest that ∼5.25 trillion plastic fragments are currently floating on the oceans' surface 21 . Airborne microplastic particles (AMP) from terrestrial origins were found in both polluted and remote areas over land, as well as in coastal regions, ranging from micron to mm scales, and can travel tens of kilometers 12,13,[22][23][24][25][26][27][28][29][30][31][32][33] . However, despite the overwhelming amounts of marine MP and their effect on the marine environment, atmospheric microplastic particles over the ocean are given little attention 13 .…”

Atmospheric Micro and Nanoplastics: An Enormous Microscopic Problem

“…9721)). Besides, the active collection requires a pump for aspiration of air through filters with well-defined mesh, as usually performed for atmospheric particulate matter [53,54] and as described for airborne MP [37,42,55]; sampling devices with sequential filters with decreasing mesh size are also available (cascade impactor). Commonly, to avoid contaminations, sampling is performed using quartz fiber or polytetrafluoroethylene filters.…”

“…Indeed, both hydrogen peroxide and the Fenton reaction produce hydroxyl radicals, which were shown to react efficiently with some NP [50]. For this reason, separation and purification steps have not been employed in several studies, however this might increase the difficulties in the detection and the identification of MP [34,37,42,55].…”

“…Liu et al [55] and Wang et al [42] investigated atmospheric MP over the west Pacific Ocean and the South China Sea and the east Indian Ocean, respectively. Their results show a lower concentration of MP in aerosol over open ocean, compared to the concentration measured in urban sites (Table 2).…”