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Article

Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland)

by
Agnieszka Medyńska-Juraszek
* and
Anna Szczepańska
Institute of Soil Science, Plant Nutrition and Environmental Protection, Wroclaw University of Environmental and Life Sciences, 53 Grunwaldzka Str., 50-357 Wrocław, Poland
*
Author to whom correspondence should be addressed.
Agriculture 2023, 13(9), 1733; https://doi.org/10.3390/agriculture13091733
Submission received: 15 August 2023 / Revised: 29 August 2023 / Accepted: 30 August 2023 / Published: 1 September 2023
(This article belongs to the Special Issue Emerging Contaminants in Soil Systems: Occurrence, Fate, Behavior and Impact)
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Abstract

:
Agricultural soils are considered as “hot-spots” of plastic particles; however, due to a lack of standardized method of microplastic determination in soils, as well as no legal regulations requiring the monitoring of the soil environment in the context of microplastic contamination, the data on MP abundance and occurrence in European soils are very limited. In this first study of MPs pollution in agricultural soils in Poland, we developed a method of microplastic extraction from soil samples with different properties (particle size distribution, clay and organic matter content) and used optical microscopy for MP determination and quantification. In this study, we analyzed 44 soil samples from five sampling site locations with differing soil type, agricultural activity, including farmland soils on floodplains and past records of sewage sludge and compost applications. We found evidence that 93% of cultivated soils in the SW part of Poland contained MPs. The content of MP varied between soil types and present/former use of the land. Loamy and clay soils contained more MPs, 1540 ± 912 particles per kg soil and 933 ± 682 particles per kg, respectively, compared with sandy soils at 383 ± 188 particles per kg of soil. The highest MP concentrations were determined in soils amended with sewage sludge, wastewaters and green-waste composts (up to 4050 ± 2831 particles per kg of soil). The wide distribution of MPs with a dominance of plastic fibers (up to 60% of determined MP types) can be associated with agricultural sources such as soil mulching, the use of organic fertilizers, seed coating or unintentional waste dumping and air deposition.

1. Introduction

Plastic pollution is considered to be one of today’s main environmental problems [1]. In 2022, Europe’s plastics production reached 57.2 million tons, while only 31% was recycled and used in new products (PlasticEurope, 2022). The amount of plastic disposed of in the terrestrial environments is largely unknown; however, there are some estimates showing that approximately 32% of plastic wastes is leaking into the soil environment [2]. Agricultural and urban soils are considered as “hot-spots” of plastics in terrestrial ecosystems, and as plastic wastes are accumulated in soil, they undergo several physical, chemical and biological actions, leading to plastic fragmentation into smaller pieces (<5 mm) called microplastics (MPs). Based on estimation, around 80% of plastic in aquatic ecosystems originates from land-based sources [3]. Microplastic (MP) presence in agricultural soils has recently gained more and more attention from researchers and societies due to the unknown risks related to its presence in soil environment and possible transfer in the food chain. Soil represents a large reservoir of microplastics [4], with many different sources such as atmospheric deposition [5], contaminated water courses, plastic mulching [6], fertilizer coatings irrigation [7], flooding, littering, street runoff and soil amendment application, e.g., compost and sewage sludge [8]. Both primary and secondary microplastics can be found in soil; however, the largest pool is represented by synthetic textile fibers from washing and drying clothes [9], wear and tear from car tires [10] and personal care products (PCPs) containing microbeads transferred through wastewaters and sewage sludge [11]. After entering the soil, MPs may accumulate, migrate and diffuse in the environment. Several factors affect these processes, such as anthropogenic activities (e.g., agricultural practices), climatic conditions (e.g., dry and wet depositions, rainfalls, soil freezing), soil type [12] or the presence of soil biota [13]. Soil biota, e.g., earthworms or collembolans, are able to transfer plastic debris in the terrestrial food chain [14]. The presence of MPs in soil has been reported to change soil physicochemical and biological properties [15]. Recent studies have shown that MP contributes to C pools, controlling similar processes to native soil organic matter, e.g., soil pH, bulk density or water retention, thereby affecting plant growth [16]. However, the effect varies based on not only the characteristic and properties of MP (size and shape), but also the quantity and time of residence in the soil environment [17]. It is also difficult at this moment to generalize positive or negative impacts on microbial activity or diversity, as most of the studies were conducted under controlled or limited factors conditions [2]. Finally, MPs are suspected to be toxic compounds in soil, as they release chemical additives, e.g., endocrine-disrupting compounds (EDC), like bisphenol A or phthalates [18], and are able to carry various toxic substances on its hydrophobic surface, e.g., heavy metals, antibiotics, PCBs or PAHs, acting as vectors of chemical contaminants in soil [19]. As MPs impact all functionalities of soil and carry potentially toxic compounds, they affect soil health and pose potential adverse effects to human health and crop production safety.
Although MP was detected in terrestrial environments more than two decades ago, to understand microplastic dynamics in soils, we must consider the spatial contexts of microplastics in soils [20], which requires the development of suitable strategies. Study site selection, methods of sampling, sample pre-processing, MP extraction from soil samples or methods of MP quantification in soil have not been fully described and implemented as a standard. The accuracy in MP measurement depends highly upon the consistency and uniformity of the analytical procedure. Generally, the analytical procedure of soil microplastics includes drying, sieving, density separation, extraction, organic matter (OM) digestion and filtration [21]. Hence, the composition of soil, mainly the content of organic matter and clay minerals, may have an impact on the effectiveness of MP extraction and separation from soil, while most of the developed methods are usually insufficient for organic-rich samples, e.g., sewage sludge, compost and organic soils, because the density of soil organic matter (SOM, 1.0–1.4 g/cm3) is similar to several types of plastic, including PET [22]. Instead, the content of MPs in soil can be predicted based on modeling [23], i.e., estimates of the amounts of MP entering the environment through sewage sludge or compost application per hectare [24] or based on regional use of different plastic polymers and inputs of MPs to surface waters [25,26]. However modeling brings uncertainty associated with each parameter used in the model, wherein overestimations are common and not comparable with field studies. The number of papers reporting the occurrence of microplastics in soil is still very limited.
The aim of this research was to investigate the occurrence, characteristics and potential sources of microplastic pollution in farmland soils in one of the most important agricultural regions of Poland in the central part of Europe.

2. Materials and Methods

2.1. Study Areas and Soil Samples Collection

The Lower Silesia part of Poland is characterized by a great variety of soils, and due to the longest growing season, the main crop production areas are located in this region of the country. Agricultural lands for soil sampling were selected randomly based on the location of cultivated soils. In the study, the following factors of variability were considered: soil type, land use type (farmlands, pastures, urban gardens used for vegetable growth) and type of crop. Figure 1 shows sampling sites (n = 44), collected during field studies 2015–2023. Sampling sites were divided into 5 locations differing in soil type and land use: A—farmlands on loamy soils; B—farmlands on sandy soils; C—farmlands on silty clays and clay soils; D—former floodplains on loamy and clay soils, flooded in 1997 and 2009, nowadays used as pastures and meadows; E—former irrigation fields on sandy clays, used between the years 1881 and 2013 for sewage sludge treatment, nowadays used as pastures and meadows; F—former industrial zones, nowadays allotment gardens on sandy and clay soils, used by Wroclaw city citizens for vegetable and fruit cultivation (Table 1). Triplicate soil samples were collected from a depth of 0 to 25 cm with a stainless steel soil probe. Soil subsamples were mixed together into one homogenized sample. In the lab, collected soils were air dried (10 days at temp. 25 °C) and kept in paper bags for analysis. The particle size distribution of soils was carried out via hydrometer sedimentation method ASTM D7928-21e1.

2.2. Extraction of Microplastics Using a Flotation Method

Density separation is a commonly used step of microplastic extraction from soil and sediment samples. Effective extraction using a floatation technique depends on the sample mass, mixing method and sample: volume (floatation solution) ratio [27]. In the study, a high-density solution of NaCl was used to detect microplastics, ranging from 0.8 to 1.2 g/cm3, after sample pre-treatment (Figure 2). The method was adopted from previous protocols described in other studies [8,22,28,29,30] and modified to increase the efficiency of organic matter removal and clay separation from tested soils. All reagents and filter materials were purchased from Sigma-Aldrich (Saint Louis, MI, USA). Figure 2 shows the main steps of the microplastic extraction procedure performed in this study.

2.3. Validation of Extraction Method

The accuracy and precision of the separation method was tested using recovery experiments of soil samples spiked with a known number of MP particles (fibers, glitters and PET bottle particles cut into pieces < 2 mm). To avoid additional plastic contamination, soils were collected from a 2 m depth. All spiking was performed in triplicates. For fibers and glitters with approx. a diameter of 1 mm, recovery was 90%, 9 out of from 10 particles were detected in blank samples, and for PET bottle particles with larger diameter sizes, the recovery was 80%.

2.4. Identification of Microplastics under the Microscope

The optical microscope is useful and widely used for the identification of MPs whose dimensions fall within the range of hundreds of microns [31]. Possible microplastic particles were examined under a Nikon Eclipse 400 microscope (Tokyo, Japan) coupled with a digital camera and an image capturing software ToupView (Touptek Photonics’s, Hangzhou, China) used for recording size, shape and color of each particle. Samples were examined under 5× and 10× magnification. For particle identification, we used the “Guide to microplastic identification” [32]. Numbers of fibers, microbeads and plastic fragments with irregular shapes were counted separately in each sample to determine the occurrence of different microplastic types in studied soils. Whole filter surface (Ø47 mm) was analyzed for MP particles.

2.5. Statistical Analysis

The results taken from each sampling site were averaged and standard deviation was calculated. The microplastic counts from the repeatability trial were analyzed after grouping different microplastic types in a sample. Tukey (p > 0.05) test was performed to determine significant difference between studies. All analyses were performed using STATISTICA version 13.2.

3. Results

3.1. Abundance of Microplastics in Soils

In 41 out of 44 tested samples, microplastic contamination was found in the microscope study. In typical farmland areas (A, B, C), the concentrations of microplastic varied between soil types. The content of MPs was statistically higher (p = 0.0379) in loamy soils from sampling site A (average 1540 ± 912 particles per kg soil) compared with sandy soils from sampling site B (average 383 ± 188 particles per kg of soil), but not statistically different from clay soils in sampling site C (933 ± 682 particles per kg of soil) (Table 2). Floodplain soils and former wastewater irrigation fields used as meadows contained much more MPs compared to typical arable soils with no records of sediments or sewage sludge deposition in the past. The average content of MPs in floodplain soils from site D was 1200 ± 234 particles per kg of soil, while in sewage-treated soils to MP concentrations reached 4050 ± 2831 particles per kg of soil. Also, a high content of microplastics was determined in urban soils of Wrocław city (site F). The average content of MPs reached values of 2116 ± 614 particles per kg of soil, indicating that the content of the pollution was much higher compared to arable and floodplain soils.

3.2. Spatial Variability of the Contamination

Spatial variability of MP content showed clear dependencies with anthropogenic activity in the studied area.
The content of MPs decreased with the distance from urban areas (Figure 3). More MPs were found in soils close to river banks and floodplains, which can be associated with sediment deposition during floods and the deposition of plastic litter from surface waters. Soils treated with sewage sludge were also highly impacted. With less anthropogenic activities (no sewage sludge deposition, urbanization, waste dumping) and a restricted use of the land due to law protection of the areas, e.g., NATURE 2000 Dolina Baryczy in the northeastern part of the region, the content of microplastics in soils decreased.

3.3. Microplastic Morphology

With the microscopy method, we were able to distinguish the shapes and forms of MPs present in soil samples. Pellets, fibers, films, microbeads and irregularly shaped fragments were easy to distinguish in the sampled materials. However, density separation with NaCl and Fenton organic matter removal was not fully satisfying, especially in samples with a high organic matter content. Moreover, at times, burned pieces of wood cellulose fibers, charcoals or silica would be present in the analyzed samples, making appropriate particle identification more difficult. For example we were unable to distinguish microplastics from tires, as both charcoal, wood chips and tire particles looked like black dots with irregular shapes. Despite this, the most isolated microplastic form was fiber, accounting for 60% of the total types of microplastics indicated in the microscope study (Figure 4 and Figure 5). In second place were the irregularly shaped plastic fragments (ISFs), which were probably secondary MPs from PET, HPLE and LDPE defragmentation in soil. Primary microplastics like microbeads (MBs) and micropellets (MPTs) were also found (Figure 4); however, the content of these particles in the studied soils was highly variable. The highest content of MBs and MPTs was found in loamy soils, but also in urban soils, and this contamination can be associated with microplastic deposition from air or water.

4. Discussion

Most of the results describing microplastic abundance in soils come from China and Eastern Asia. On the other hand, on the European continent, the data about MP concentrations on soil are very limited, and only some countries (e.g., Switzerland, Germany, Netherlands, Italy and Norway) published data [1,33,34,35] about MP concentrations in soil, but were mainly based on modeling, e.g., inputs of microplastics through sewage sludge, compost or mulching. Results from 11 studies in China, focused on mixed-origin soils, showed that the number of MP particles detected in soil with similar methods (density separation and microscopy) may vary from 78 particles per kg, up to 2500 particles per kg, or even in some extreme cases, 69,000 particles per kg, when soils receive plastic mulching [36] and sewage sludge applications [37]. Our results are below-average values indicated for European soils at 2914 particles per kg (based on 30 studies). However, results vary depending on the method of measurements. Scheurer and Bigalke [33] studying Swiss floodplains at 29 sites across Switzerland indicated MP concentrations between 55.5 and 593 particles per kg—less in mountain and non-inhibited areas. Dahl et al. [38] studying soils located in the Almería region of Spain indicated an increase in MP accumulation of surface soil layers following the intensification of the agricultural industry in the area (average content of MPs: 3819 particles per kg). Findings of both studies remain in agreement with our results. However, some published data and estimations show thousands or even millions of greater magnitude of MP occurrence in soils. In Austrian soils, the average content of MPs is 12.7 million particles per kg of soils [39], while in Danish farmlands, the average content of MPs is 236,000 particles per kg of soil [40]. Studies comparing the content of MPs in soils with different particle size distributions are rare; therefore, our results indicate significant differences in the accumulation of microplastics in soils of different texture. The spatial distribution of MP concentrations varied between soil types, and as expected, loose sandy soils contained less microplastics than soils with a more fine structure like loamy and clay soils. This evidence suggests that MPs in soils with more clay fractions and more stable aggregates are less prone to the leaching process. In sandy soils with more macropores (pores > 0.08 mm), the movement of MP particles is enhanced, causing quick vertical transport to deeper soil layers [15], reducing their content in the surface layers. On the other hand, microplastics may affect soil physical properties, i.e., aggregation, bulk density, porosity or water-holding capacity, changing plastic particle distribution in soil profile with time. As microplastic particles are able to imitate some soil actions performed by organic matter, i.e., influence soil aggregation and aggregate stability [41], possible interactions between microplastic particles and the soil matrix cannot be ignored. It is highly likely that some microplastic shapes and sizes will contribute more to the process. At present, the information is very limited; however, some authors suggest that microplastic fibers [42], detected in tested soil in the highest amounts, likely disturb soil aggregate formation more than other MPs. The concentration of MPs in 0–20 cm can be also correlated with former use of the area, the impact of flooding or multisource impact of urban areas. Use of biosolids as agricultural amendments or for the deposition of bottom sediments during floods contribute to the release of plastic particles into the soil, but also affect soil texture, which in turn affects MP displacement in the soil profile, causing an increased MP accumulation in the surface layer. The results of our study showed that in farmland soils (sites A, B, C) with no land use changessince the plastic revolution beganand no additional inputs of microplastics typical to urban and industrial areas were less impacted by microplastic contamination. Past and present human activities, i.e., the use of farmland soils for wastewater treatment, sewage sludge and compost application, contributed more to the process of soil contamination with microplastics. Floodplain soils (study site D) and soils irrigated with wastewaters (study site E) contained more MPs than less-impacted farming areas in the northeastern part of the Lower Silesia region. Also, allotment gardens (study site F), formerly agricultural soils located at the suburbs of Wrocław city, contained more microplastics, which can be associated with intensive soil fertilization, mainly with compost, but also with air and water deposition from urban areas. van Schothorst et al. [35], studying the impact of long-term compost application and mulching on MP concentrations in soil, found that samples from both Spanish and Dutch soils contained 2242 ± 984 particles per kg and 888 ± 500 particles per kg of microplastics, respectively. The findings of our study are similar, showing an average of 2116 ± 614 particles per kg in compost-amended soils. It has been suggested that compost from bio-waste particularly contains plastic, which originates from improper disposal and insufficient waste separation [22]. This finding was confirmed by our own observations made during garden and green waste collection in Wrocław city. Approximately 1–2% of compost mass was fragmented plastic from grass cutting and accidental plastic waste shredding, from throwing kitchen wastes in plastic bags or the accidental placement of plastics in biodegradable wastes bins. A majority of microplastics found in tested samples were fibers (up to 60%). Recent studies suggest that the main sources of synthetic fibers in soil come from sewage sludge application [34,43] and synthetic fabric fibers have been proposed as indicators of the past spreading of wastewater sludge [44]. However, due to the law regulations in the EU, sewage sludge application is not a common form of agronomic practices in the Polish farming system; therefore, other sources of microplastic fibers should be considered. Landfills and urban and industrial centers contribute to the process of soil microplastic contamination by the accidental loss of particles, illegal waste disposal and improper landfill leachates utilization [13]. The sources of microplastics in Poland are not well recognized; however, based on environmental management characteristics, we suggest that the main sources of soil microplastic contamination in Poland are depositions from the air and surface runoffs. However, we should not avoid linking emissions with other sources, such as agricultural activity and the use of mineral and organic fertilization (mainly the use of coated granulates and manures) and polyethylene mulches for crop covering. Plastic films are widely used because they could regulate soil temperature and increase water use efficiency, thereby promoting and improving crop growth and quality [45]. Although some commercially available mulches are biodegradable, a large amount of plastic textiles is disposed in soil during soil tillage and during the in-soil degradation of plastic mulches, which depends on soil biota. However plastic biodegradation depends on soil biological activity and optimal for decomposers moisture and nutrients conditions [46]. It is also suggested that film-coatings applied to agronomic seeds can contribute to the process of soil contamination with MPs. Accinelli et al. [47] found that the degradation of microplastic coating fragments detached from seeds coated with polymer mixtures have a low degradation rate.

5. Conclusions

Results from our investigation showed that microplastic is a ubiquitous contaminant of farmland soils in this region, posing a possible threat to human health and crop production. The concentrations of MPs varied between soil types and present/former land use. Sandy soils contained less MPs compared to silty and clay soils, suggesting that microplastics are more prone to leaching in loose soils, with low clay minerals and organic matter content. The accumulation of microplastics was higher in soils impacted by flooding, wastewaters and sewage sludge application, but also those which were impacted by some present activities, e.g., the use of compost or plastic mulching for plant cultivation. These findings were supported by further analysis, showing that the most common MP types found in farmland soils were fibers, followed by defragmented plastics with irregular shapes, probably deposited into soil from agronomic activities, runoffs and air deposition. Despite the ubiquity of microplastics in agricultural soils used for food production, very few large-scale monitoring data from European soils are available. This is partially due to the lack of standardized methods for MP analysis in soil and sediment samples, as well as the absence of law regulations. As microplastics have become an emerging contaminant in soils, more actions should be taken by the EU authorities to report environmental microplastic and possible threats.

Author Contributions

Conceptualization, A.M.-J.; methodology, A.M.-J.; validation, A.M.-J.; investigation, A.M.-J. and A.S.; data curation. A.M.-J.; writing—original draft preparation, A.M.-J. and A.S.; writing—review and editing, A.M.-J.; visualization, A.M.-J.; supervision, A.M.-J.; funding acquisition, A.M.-J. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by Wroclaw University of Environmental and Life Sciences (“MISTRZ” project no N090/0002/21). The APC/BPC is co-financed by Wroclaw University of Environmental and Life Sciences.

Institutional Review Board Statement

Not applicable.

Data Availability Statement

Data sharing is not applicable to this article.

Acknowledgments

The authors would like to thank Dorota Kawałko, Irmina Ćwieląg-Piasecka and Dariusz Gruszka for providing soil samples for microplastic analysis and Moritz Bigalke and Alexandra Foetisch for providing the opportunity to learn microplastic extraction techniques at University of Bern, Switzerland.

Conflicts of Interest

The authors declare no conflict of interest.

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Figure 1. Study sites’ localization on the map of the Lower Silesia region of Poland.
Figure 1. Study sites’ localization on the map of the Lower Silesia region of Poland.
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Figure 2. Extraction of MPs via density method.
Figure 2. Extraction of MPs via density method.
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Figure 3. Spatial variability of microplastic concentrations in sampled soils.
Figure 3. Spatial variability of microplastic concentrations in sampled soils.
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Figure 4. Percentage of microplastic shapes isolated from soil samples collected at different sampling sites. Capital letter (A–F) mean study site.
Figure 4. Percentage of microplastic shapes isolated from soil samples collected at different sampling sites. Capital letter (A–F) mean study site.
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Figure 5. Microplastic particles captured with optical microscope (10× magnification). Fibers (a–c); microfragments (d) (size 1000 μm); microbeads (e) and films (f) (size 500 μm).
Figure 5. Microplastic particles captured with optical microscope (10× magnification). Fibers (a–c); microfragments (d) (size 1000 μm); microbeads (e) and films (f) (size 500 μm).
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Table 1. Sampling points’ location and land use type.
Table 1. Sampling points’ location and land use type.
LpSampling PointSampling LocationLand Use/Main Plant
1A150°49′54.6″ N 17°11′43.2″ EFarmland/sugar beet
2A250°48′06.8″ N 17°05′57.3″ EFarmland/barley
3A350°53′38.7″ N 17°00′28.1″ EFarmland/oats
4A450°48′15.2″ N 17°05′34.4″ EFarmland/winter wheat
5A550°53′19.1″ N 17°02′14.7″ EFarmland/maize
6A650°53′02.3″ N 17°02′10.9″ EFarmland/potato
7B151°27′10.7″ N 16°54′53.5″ EFarmland/fallow
8B251°30′25.2″ N 16°54′44.3″ EFarmland/sugar beet
9B351°36′48.9″ N 16°58′41.7″ EFarmland/rye
10B451°36′21.1″ N 16°54′06.4″ EFarmland/barley
11B551°36′56.9″ N 17°02′41.3″ EFarmland/cover crop legumes
12B651°37′54.0″ N 17°09′24.3″ EFarmland/cover crop legumes
13B751°18′41.8″ N 16°19′45.9″ EFarmland/rye
14B851°33′18.1″ N 17°15′25.2″ EFarmland/fallow
15B951°22′23.7″ N 17°09′55.3″ EFarmland/rapeseed
16B1051°16′25.5″ N 17°02′38.4″ EFarmland/rapeseed
17B1051°16′26.9″ N 17°02′20.0″ EFarmland/rye
18B1151°16′26.9″ N 17°02′20.0″ EFarmland/rye
19B1251°20′46.8″ N 17°06′17.6″ EFarmland/cover crop legumes
20B1350°53′57.8″ N 17°07′50.4″ EFarmland/maize
21C151°30′23.1″ N 16°54′11.4″ EFarmland/cover crop legumes
22C251°23′39.8″ N 16°37′23.3″ EFarmland/winter wheat
23C351°25′27.7″ N 16°37′28.0″ EFarmland/winter wheat
24C451°29′12.4″ N 16°37′32.7″ EFarmland/legumes
25C551°32′48.1″ N 16°40′14.5″ EFarmland/maize
26C651°37′02.5″ N 16°38′27.1″ EFarmland/sugar beet
27C751°37′22.7″ N 16°30′39.4″ EFarmland/rye
28C851°31′18.2″ N 16°32′20.8″ EFarmland/winter wheat
29C951°26′09.6″ N 16°30′06.2″ EFarmland/rye
30D151°14′46.1″ N 16°41′12.5″ EFloodplain/hay meadow
31D251°14′47.0″ N 16°40′47.3″ EFloodplain/hay meadow
32D351°14′38.9″ N 16°41′01.4″ EFloodplain/pasture
33D451°14′36.6″ N 16°41′33.6″ EFloodplain/pasture
34D651°14′41.2″ N 16°41′51.7″ EFloodplain/hay meadow
35E151°10′26.5″ N 16°58′38.0″ EFormer irrigation fields/hay meadow
36E251°10′21.0″ N 16°58′33.1″ EFormer irrigation fields/hay meadow
37E351°10′50.6″ N 16°58′14.5″ EFormer irrigation fields/hay meadow
38E451°10′53.4″ N 16°58′13.2″ EFormer irrigation fields/hay meadow
39F151°07′53.1″ N 17°03′58.4″ EAllotment garden/spring onion
40F251°04′07.5″ N 17°04′16.8″ EAllotment garden/lettuce
41F351°04′0.75″ N 17°04′16.8″ EAllotment garden/beet root
42F451°06′18.3″ N 16°58′27.0″ EAllotment garden/carrot
43F551°08′19.2″ N 17°04′57.8″ EAllotment garden/beet root
44F651°06′18.3″ N 16°58′27.0″ EAllotment garden/spring onion
Table 2. Soil texture and concentration of microplastics in tested soils.
Table 2. Soil texture and concentration of microplastics in tested soils.
Sampling PointSoil TextureAbundance (Particles per kg)Sampling PointSoil TextureAbundance
(Particles per kg)
A1loam2400B3sand400
A2loam1100B4loamy sand<100
A3loam2600B5sand300
A4loam1100B6sand<100
A5loam500B7sand400
A6clay loam<100B8sand800
B9sand400
B1loamy sand600B10sand200
B2loamy sand200B10sand400
B11sand200
B12sand400
B13loamy sand300E1 (2)sandy clay3600
E2sandy clay9600
C1loamy sand1600E3sandy clay1400
C2silty clay800E4sandy clay1600
C3loamy sand300
C4silty clay<100F1 (3)loamy sand1400
C5loamy sand200F2loamy sand3200
C6silty clay<100F3loamy sand2200
F4silty clay2000
D1 (1)sandy clay1400F5loamy sand1700
D2sandy clay1000F6silty clay2200
D3silt loam1000
D4silt loam1500
D5silt loam1100
(1) Soils flooded in the years 1997 and 2009; (2) soils treated with sewage sludge in the past; (3) urban soils, mainly Technosols in the city center.
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Medyńska-Juraszek, A.; Szczepańska, A. Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland). Agriculture 2023, 13, 1733. https://doi.org/10.3390/agriculture13091733

AMA Style

Medyńska-Juraszek A, Szczepańska A. Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland). Agriculture. 2023; 13(9):1733. https://doi.org/10.3390/agriculture13091733

Chicago/Turabian Style

Medyńska-Juraszek, Agnieszka, and Anna Szczepańska. 2023. "Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland)" Agriculture 13, no. 9: 1733. https://doi.org/10.3390/agriculture13091733

APA Style

Medyńska-Juraszek, A., & Szczepańska, A. (2023). Microplastic Pollution in EU Farmland Soils: Preliminary Findings from Agricultural Soils (Southwestern Poland). Agriculture, 13(9), 1733. https://doi.org/10.3390/agriculture13091733

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