Global concentrations of microplastic in soils, a review

Abstract

Abstract. Worldwide, microplastic (MP) has been commonly recognized as a threat for soil ecosystems. Terrestrial soils are widely contaminated by MP due to the application of sewage sludge and wastewater, plastic mulching, littering, the input of tire wear from roads and atmospheric deposition. Within the last decade, an increasing number of individual studies focused on item counts and masses of MP in different global soil environments. We reviewed these studies to achieve a representative picture of common degrees of contamination. The majority of the prospected agricultural and horticultural sites was exposed to sewage sludge and mulching film application and showed concentrations of

Microplastics in terrestrial ecosystems: Moving beyond the state of the art to minimize the risk of ecological surprise

“…The potential consequences of ecological surprise are especially acute in terrestrial agroecosystems, given their role in providing the vast majority of the human food supply. Current agricultural practices, plastic mulching and the application sewage sludge as fertilizers, are considered as major entry routes for microplastics into terrestrial ecosystems (Büks & Kaupenjohann, 2020; Corradini et al, 2019; Nizzetto et al, 2016). However, microplastics do not occur in isolation; other environmental pressures resulting from natural disturbances, for example, drought, flood and pest infestation (Food & Agriculture Organisation, 2017), anthropogenic activities, for example, global warming (Gornall et al, 2010), pesticide use (Aktar et al, 2009), invasive species (Paini et al, 2016) and heavy metal contamination (Li et al, 2019) also occur in agroecosystems.…”

“…Since then, attention has spread to freshwater (de Sá et al, 2018; Hoffman & Hittinger, 2017; Li et al, 2018) and terrestrial environments (de Souza Machado, Kloas, et al, 2018; Rillig & Lehmann, 2020; Windsor et al, 2019). Microplastic research in the terrestrial environment is still at an early stage, despite multiple lines of evidence indicating terrestrial systems as the major sinks of microplastics (Büks & Kaupenjohann, 2020; Evangeliou et al, 2020; Nizzetto et al, 2016). The development of terrestrial microplastics research has followed a similar trajectory to work on aquatic ecosystems.…”

“…Microplastics can enter the terrestrial environment through different pathways, including landfills (Geyer et al, 2017), atmospheric fallout (0.343 million tons per year globally; Evangeliou et al, 2020) and from different agricultural practices, for example, the use of plastic mulching (Büks & Kaupenjohann, 2020; Crossman et al, 2020). Agroecosystems are major entry routes for microplastics to the terrestrial environment, in particular when sludge (biosolids) from wastewater treatment are applied to the soil (Corradini et al, 2019).…”

Plasticisers in the terrestrial environment: sources, occurrence and fate

“…Research has shown that almost every environmental compartment on earth is contaminated with plastic (Howell et al 2012;Bergmann et al 2017;Horton et al 2017a;Hendrickson et al 2018;Büks and Kaupenjohann 2020). The majority of research to date has focussed on aquatic, particularly marine, environments, whereas the occurrence of microplastics in soils has only recently started to generate research interest.…”

“…For example, negative impacts on survival (Huerta Lwanga et al 2016;Cao et al 2017), biomass (Cao et al 2017;Zhu et al 2018a;Boots et al 2019) and reproduction (Zhu et al 2018a;Kim et al 2019) have been reported for terrestrial species including earthworms (Eisenia fetida, Eisenia andrei, Lumbricus terrestris), collembola (Folsomia candida) and nematodes (Caenorhabditis elegans). The exposure doses used in many studies likely represent 'worst-case scenario' environmental concentrations, although direct comparisons are uncertain owing to a relative scarcity of environmental concentration data and inconsistencies in how such data are reported (Büks and Kaupenjohann 2020). Some of these negative effects likely arise from the physical damage caused by the microplastic particles to dermal surfaces or within the organism itself.…”