Abstract:
The system of fertilizing agricultural soils with sludge or compost from wastewater treatment processes, as one of the principles of the circular economy, can lead to microplastic (MP) contamination. The existing technical standards for fertilization are very recent and do not consider this problem, although there is scientific evidence of their existence. Therefore, this study, on the one hand, evaluates the presence of MPs in agricultural soils, previously treated with sludge or compost from wastewater treatment plants for fertilization, and on the second hand, it studies the effect of these MPs on earthworms in three different locations in the south of Spain. For the study, selected composts deriving from the different stages of the composting process and three fertilized soils with increasing MP doses were followed. Samples were taken from different sections in depth (0-5, 5-10, and 10-20 cm) to study the shape, size, type, and abundance of MPs using infrared spectroscopy (FTIR). The results showed that the most abundant shape was fiber, followed by fragment and finally bulk, for both composts and soils. Regarding size distribution, 100 µm was the predominant size in composts (64.3% ± 9.8), while in the case of soils, the predominant range was from 100 to 500 µm. The prevalent polymers in both, composts and soils, were PTFE, TPE, PP, and PET, with four times higher amounts in composts than in soils. Ingestion of common MPs were also verified in two earthworm species, which ingested concentrations higher than 2.1% w/w. PP was the most ingested MP and Eisenia fetida was more voracious compared with Lumbricus terrestris. Therefore, it can be considered a suitable bioindicator for monitoring microplastic contamination in agricultural soil.
摘要:
用污水处理过程中的污泥或堆肥为农业土壤施肥的系统,作为循环经济的原则之一,可导致微塑料(MP)污染。现有的施肥技术标准很新,没有考虑到这个问题,尽管有科学证据证明它们的存在.因此,这项研究,一方面,评估农业土壤中MP的存在,先前用污水处理厂的污泥或堆肥处理过施肥,而在第二手,它研究了这些国会议员对西班牙南部三个不同地点的蚯蚓的影响。对于这项研究,遵循堆肥过程不同阶段的精选堆肥和三种MP剂量增加的施肥土壤。从不同深度(0-5,5-10和10-20厘米)的切片中取样以研究形状,尺寸,type,和丰富的MPs使用红外光谱(FTIR)。结果表明,最丰富的形状是纤维,其次是片段,最后是散装,堆肥和土壤。关于大小分布,100µm是堆肥中的主要尺寸(64.3%±9.8),而在土壤的情况下,主要范围从100到500µm。两者中普遍存在的聚合物,堆肥和土壤,是PTFE,TPE,PP,PET,堆肥中的含量是土壤中的四倍。在两种蚯蚓中也证实了常见的MP的摄入,其摄入浓度高于2.1%w/w。PP是摄入最多的MP,与龙boricus相比,fiseniafetida更贪婪。因此,它可以被认为是监测农业土壤微塑料污染的合适生物指示剂。