Recent trends on microplastics abundance and risk assessment in coastal Antarctica: Regional meta-analysis

We investigated sources, abundance and risk of microplastics (MPs) in water, sediments and biota around Antarctica. The concentration of MPs in Southern Ocean (SO) ranged from 0 to 0.56 items/m3 (mean = 0.01 items/m3) and 0-1.96 items/m3 (mean = 0.13 items/m3) in surface and sub-surface water. The distribution of fibers in water was 50%, sediments were 61%, and biota had 43%, which were followed by fragments in the water (42%), sediments (26%), and biota (28%). Shapes of film had lowest concentrations in water (2%), sed-iments 13%), and biota (3%). Ship traffic, drift of MPs by currents, and untreated waste water discharge contributed to the variety of MPs. The degree of pollution in all matrices was evaluated using the pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk index (PERI). PLI at about 90.3% of lo-cations were at category I followed by 5.9% at category II, 1.6% at category III, and 2.2% at category IV. Average PLI for water (3.14), sediments (6.6), and biota (2.72) had low pollution load (<10). Mean PHI for water, sediments, and biota showed hazards level V with a higher percentage of 84.6% (>1000) and 63.9% (PHI:0-1) in sediments and water, respectively. PERI for water showed 63.9% minor risk, and 36.1% extreme risk. Around 84.6% of sediments were at extreme risk, 7.7% faced minor risk, and 7.7% were at high risk. While 20% of marine organisms living in cold environments experienced minor risk, 20% were in high risk, and 60% were in extreme risk. Highest PERI was found in the water, sediments, and biota in Ross Sea, due to high hazardous polymer composition of polyvinylchloride (PVC) in the water and sediments due to human activity, particularly use of personnel care products and waste water discharge from research stations.

Automated summary

We conducted a study on sources, abundance, and risk of microplastics (MPs) in water, sediments, and biota around Antarctica. The concentration of MPs in the Southern Ocean ranged from 0 to 0.56 items/m3 in surface water and 0-1.96 items/m3 in sub-surface water. The distribution of fibers, fragments, and film varied among the different matrices, with fibers being most abundant in sediments, and fragments being most abundant in water. The pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk index (PERI) were used to assess the degree of pollution and ecological risk, with overall low pollution load but high ecological risk observed in the study area.