The use of potassium hydroxide (KOH) solution as a suitable approach to isolate plastics ingested by marine organisms. Kühn Susanne,van Werven Bernike,van Oyen Albert,Meijboom André,Bravo Rebolledo Elisa L,van Franeker Jan A Marine pollution bulletin In studies of plastic ingestion by marine wildlife, visual separation of plastic particles from gastrointestinal tracts or their dietary content can be challenging. Earlier studies have used solutions to dissolve organic materials leaving synthetic particles unaffected. However, insufficient tests have been conducted to ensure that different categories of consumer products partly degraded in the environment and/or in gastrointestinal tracts were not affected. In this study 63 synthetic materials and 11 other dietary items and non-plastic marine debris were tested. Irrespective of shape or preceding environmental history, most polymers resisted potassium hydroxide (KOH) solution, with the exceptions of cellulose acetate from cigarette filters, some biodegradable plastics and a single polyethylene sheet. Exposure of hard diet components and other marine debris showed variable results. In conclusion, the results confirm that usage of KOH solutions can be a useful approach in general quantitative studies of plastic ingestion by marine wildlife. 10.1016/j.marpolbul.2016.11.034

Transport behavior of micro polyethylene particles in saturated quartz sand: Impacts of input concentration and physicochemical factors. Hou Jun,Xu Xiaoya,Lan Lin,Miao Lingzhan,Xu Yi,You Guoxiang,Liu Zhilin Environmental pollution (Barking, Essex : 1987) The long-term contamination of soil by microplastics may pose risks that are often still not well understood, and the ecological effects of microplastics are mainly dependent on their environmental behavior in environments. This study used saturated quartz sand as a solid porous medium to study the migration and influencing factors of 40-48 μm polyethylene (PE) particles in saturated porous media. The breakthrough curves at different injection concentrations (0.3, 0.4, 0.5 mg/L), flow rates (1.0, 1.5, 2.0, 2.5 ml/L), porous medium particle sizes (1-2, 2-4 mm), ionic strengths (0, 0.01, 0.05 mol/L) and concentrations of fulvic acid (FA) (0, 5, 10 mg/L) were compared and analyzed. The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory was used to more accurately explain relevant transport behaviors. The results showed that the input concentration, flow rate, and particle size can affect the migration of PE particles individually or in combination. As ionic strength increased, the repulsion between microplastics and quartz sand gradually disappeared according to DLVO theory, and their attraction gradually strengthened. As a result, fewer microplastics could penetrate the sand column and reach the water body. With the continuous addition of FA, the repulsive energy between microplastics and quartz sand rose from DLVO theory, and the migration ability of microplastics initially increased before becoming stable because of the effect of straining. In all cases, the migration ability of PE was low (C/C < 0.35), and most PE particles remained in the porous media during the whole experimental periods. This study provides new insights of understanding the migration of microplastics in environment. 10.1016/j.envpol.2020.114499

Microplastic footprints in the Qinghai-Tibet Plateau and their implications to the Yangtze River Basin. Feng Sansan,Lu Hongwei,Yao Tianci,Liu Yunlong,Tian Peipei,Lu Jingzhao Journal of hazardous materials Microplastics (MPs) are pervasive in the environment and have posed growing threat to ecosystems and human health. This study investigated MP abundances in surface water (fresh and salt lakes, urban and rural rivers, etc.) from 28 stations in the Qinghai-Tibet Plateau. MPs were detected in 25 out of 28 water samples with relatively low abundance (average 584.82 particles m). Fibers were the most frequently observed shape, particle sizes mostly ranged from 100 to 500 µm, and the greatest number of MPs was polypropylene. Source analysis identified the major sources of domestic wastewater and tourism in some areas. The concentration and proportion of small MPs (20-100 µm) in salty water were apparently greater than that in fresh water, indicating Salt intrusion accelerated MPs fragmentation. As the study area is the origin of the Yangtze River, we further compared the MP distribution throughout the watershed. Nearly two orders of magnitude in MP concentrations were increased associated with urban agglomeration in the middle and downstream areas, but the highest level was marked around the Yichang City (location of the Three Gorges Reservoir) due to interception associated with sedimentation and precipitation. This study provides data and theoretical bases for analyzing MPs migration and degradation processes in high altitudes. 10.1016/j.jhazmat.2020.124776

Microplastics undergo accelerated vertical migration in sand soil due to small size and wet-dry cycles. O'Connor David,Pan Shizhen,Shen Zhengtao,Song Yinan,Jin Yuanliang,Wu Wei-Min,Hou Deyi Environmental pollution (Barking, Essex : 1987) Microplastics (MPs) are an emerging concern and potential risk to marine and terrestrial environments. Surface soils are reported to act as a sink. However, MP vertical mobility in the subsurface remains uncertain due to a lack of scientific data. This study focused on MP penetration in sand soil column experiments. Here we report the mobility of five different MPs, which consisted of polyethylene (PE) and polypropylene (PP) particles of various sizes and densities. We observed that the smallest sized PE MPs (21 μm) had the greatest movement potential. Moreover, it was found that when these MPs were subjected to greater numbers of wet-dry cycles, the penetration depth significantly increased, with an apparent linear relationship between depth and wet-dry cycle number (r = 0.817). In comparison, increasing the volume of infiltration liquid or the surface MP concentration had only negligible or weak effects on migration depth (r = 0.169 and 0.312, respectively). Based on the observed wet-dry cycle trend, we forecast 100-year penetration depths using weather data for 347 cities across China. The average penetration depth was calculated as 5.24 m (95% CI = 2.78-7.70 m), with Beijing Municipality and Hebei, Henan and Hubei provinces being the most vulnerable to MP vertical dispersion. Our results suggest that soils may not only represent a sink for MPs, but also a feasible entryway to subsurface receptors, such as subterranean fauna or aquifers. Finally, research gaps are identified and suggested research directions are put forward to garner a better understanding MP vertical migration in soil. 10.1016/j.envpol.2019.03.092