We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Seasonal variations in microplastic abundance and key driving factors in the aquatic environment of a typical river-connected lake
Summary
A seasonal study of Poyang Lake, China's largest river-connected lake, found microplastics in over 90% of water and sediment samples, with abundances rising 35% during high-water periods driven by hydrological connectivity, zooplankton activity, and weather conditions. These findings reveal that natural lake systems are significant and dynamic microplastic reservoirs, with seasonal flooding cycles redistributing contamination across broader freshwater networks and into the organisms that depend on them.
River-connected lakes play a vital role in maintaining freshwater ecological functions because of their dynamic hydrological connectivity and biodiversity support. However, the distribution and environmental driving factors of microplastics (MPs) in river-connected lakes remain poorly understood. In this study, we investigated the abundance, morphology, size, and polymer composition of MPs across different hydrological periods in the Poyang Lake, the largest river-connected lake in China. MPs were detected in more than 90% of the water and sediment samples, with average abundances of 386.36 ± 179.00 items/m3 and 327.45 ± 258.36 items/kg, respectively. The abundance of MPs in both the water and sediment samples was significantly greater during the high-water period than during the low-water period, increasing by 35% (water) and 21.26% (sediment) from the low- to high-water periods. Fragmented particles were predominant (73.72%–83.99%), with sizes mostly ranging from 100 to 500 µm. Polymer analysis revealed polypropylene (PP), fluororubber (FB), and polyurethane (PU) as the major components. Structural equation modelling (SEM) revealed aquatic organisms and meteorological conditions as key factors influencing MP distribution in the water column. During the low-water period, zooplankton had a significantly negative effect (path coefficient, −0.916; response proportion, −39.78%), whereas chlorophyll a had a significantly positive effect (path coefficient, 0.890; response proportion, 38.63%). During the high-water period, water temperature and water level jointly shaped the MP distribution (path coefficient, 0.635; response proportion, 16.67%). These findings provide valuable insights into MP pollution patterns and influencing factors in river-connected lakes around the world.