Department of Environmental Health Science, Konkuk University, Seoul, 05029, South Korea.
Department of Environmental Engineering, Kunsan National University, Kunsan, 54150, South Korea.
Environ Pollut. 2020 Mar;258:113740. doi: 10.1016/j.envpol.2019.113740. Epub 2019 Dec 7.
Plastic polymers are widely used in various applications and are thus prevalent in the environment. Over time, these polymers are slowly degraded into nano- and micro-scale particles. In this study, the free-living nematode, Caenorhabditis elegans, was exposed to polystyrene particles of two different sizes (42 and 530 nm) in both liquid and soil media. The number of offspring significantly (p < 0.05) decreased at polystyrene concentrations of 100 mg/L and 10 mg/kg in liquid and soil media, respectively. In soil media, but not liquid media, C. elegans was more sensitive to the larger particles (530 nm) than the smaller particles (42 nm), and the median effective concentration (EC) values of the 42 and 530 nm-sized particles were found to be > 100 and 14.23 (8.91-22.72) mg/kg, respectively. We performed the same toxicity bioassay on five different field-soil samples with different physicochemical properties and found that the size-dependent effects were intensified in clay-rich soil samples. A principal component analysis showed that the bulk density, cation exchange capacity, clay content, and sand content were the dominant factors influencing the toxicity of the 530 nm-sized polystyrene particles. Therefore, we conclude that the soil composition has a significant effect on the toxicity induced by these 530 nm-sized polystyrene particles.
塑料聚合物在各种应用中被广泛使用，因此在环境中普遍存在。随着时间的推移，这些聚合物会缓慢降解成纳米和微尺度颗粒。在这项研究中，自由生活的秀丽隐杆线虫（Caenorhabditis elegans）在液体和土壤介质中分别暴露于两种不同大小（42 和 530nm）的聚苯乙烯颗粒中。在液体和土壤介质中，当聚苯乙烯浓度分别达到 100mg/L 和 10mg/kg 时，后代数量明显（p<0.05）减少。在土壤介质中，但不是在液体介质中，与较小的颗粒（42nm）相比，线虫对较大的颗粒（530nm）更为敏感，42nm 和 530nm 大小的颗粒的中位有效浓度（EC）值分别>100 和 14.23（8.91-22.72）mg/kg。我们在具有不同物理化学性质的五种不同野外土壤样品上进行了相同的毒性生物测定，发现大小依赖性效应在富含粘土的土壤样品中加剧。主成分分析表明，体密度、阳离子交换容量、粘土含量和砂含量是影响 530nm 聚苯乙烯颗粒毒性的主要因素。因此，我们得出结论，土壤成分对这些 530nm 聚苯乙烯颗粒引起的毒性有显著影响。
