Evidence of microplastic accumulation in agricultural soils from sewage sludge disposal
Evidence of microplastic accumulation in agricultural soils from sewage sludge disposal
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DOI：
10.1016/j.scitotenv.2019.03.368
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发表时间：
2019-06-25
影响因子：
9.8
通讯作者：
Geissen, Violette
中科院分区：
文献类型：
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作者：
Corradini, Fabio;Meza, Pablo;Geissen, Violette
微塑料正在成为一种日益严重的环境威胁。污水处理厂有效地去除污水中的微塑料，将颗粒困在污泥中，防止它们进入水环境。然而，处理厂基本上是将微塑料从废水中提取出来，并将其浓缩到污泥中。在农业土壤上使用这种污泥作为肥料已经成为一种常见的做法。目前研究的目的是通过这种做法来评估土壤的微塑料污染，通过观察土壤样品中微塑料颗粒的总数来评估连续使用污泥的影响。对31个不同施泥记录和相似土壤气候条件的农田进行了评价。污泥施用量的现场记录涵盖了十年的时间。对于所有油田，历史处置事件使用相同数量的污泥(40吨ha(-1)干重)。通过浮选提取微塑料，然后在显微镜下对颗粒进行计数和分类。在研究期间，在接受污泥应用的田野中收集了七个污泥样本。施加1、2、3、4和5次污泥的土壤的干土壤颗粒数的中位数分别为1.1、1.6、1.7、2.3和3.5粒g(-1)。微塑性含量与施药次数有统计学差异(1、2、3和lt；4、5)。污泥中微塑性含量范围为18~41个颗粒g(-1)，中位数为34个颗粒g(-1)。观察到的大多数微塑料是纤维(90%在污泥中，97%在土壤中)。我们的结果表明，在连续进行污泥应用的地方，微塑料数量随着时间的推移而增加。在土壤样品中观察到的微塑料强调了污泥作为土壤微塑料污染的驱动因素的相关性。(C)2019年提交人。爱思唯尔出版公司(Elsevier B.V.)
Microplastics are emerging as a steadily increasing environmental threat. Wastewater treatment plants efficiently remove microplastics from sewage, trapping the particles in the sludge and preventing their entrance into aquatic environments. Treatment plants are essentially taking the microplastics out of the waste water and concentrating them in the sludge, however. It has become common practice to use this sludge on agricultural soils as a fertilizer. The aim of the current research was to evaluate the microplastic contamination of soils by this practice, assessing the implications of successive sludge applications by looking at the total count of microplastic particles in soil samples. Thirty-one agricultural fields with different sludge application records and similar edaphoclimatic conditions were evaluated. Field records of sludge application covered a ten year period. For all fields, historical disposal events used the same amount of sludge (40 ton ha(-1) dry weight). Extraction of microplastics was done by flotation and particles were then counted and classified with the help of a microscope. Seven sludge samples were collected in the fields that underwent sludge applications during the study period. Soils where 1, 2, 3, 4, and 5 applications of sludge had been performed had a median of 1.1, 1.6, 1.7, 2.3, and 3.5 particles g(-1) dry soil, respectively. There were statistical differences in the microplastic contents related to the number of applications that a field had undergone (1, 2, 3 < 4, 5). Microplastic content in sludge ranged from 18 to 41 particles g(-1), with a median of 34 particles g(-1). The majority of the observed microplastics were fibers (90% in sludge, and 97% in soil). Our results indicate that microplastic counts increase over time where successive sludge applications are performed. Microplastics observed in soil samples stress the relevance of sludge as a driver of soil microplastic contamination. (C) 2019 The Authors. Published by Elsevier B.V.