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The presence of pesticide residues in waterbed sediments poses a significant concern for aquatic ecosystems' health. This study examined pesticide contamination in sediments of 38 water bodies, embedded in agricultural-dominated regions, across eight European countries. Three indicators were targeted: occurrence, type, and concentrations of multiple pesticide residues in sediments. 196 pesticide residues (including degradation products) were tested in the sediment samples. The analytical results showed that only one sample was 'pesticide-free', three samples contained a single pesticide residue, and the remaining 34 samples contained mixtures of residues. Overall, 99 different residues were found in the sediments, with a maximum of 48 in a single sample. Twenty-seven out of the 99 detected residues were not approved for agricultural use at the time of sampling. The numbers of detected residues and pesticide levels varied among countries. AMPA, glyphosate and DDTs were the most common residues in sediment samples with frequencies of 76, 61, and 52%, respectively. The sediments from the Czech Republic had the highest pesticide concentrations, with total pesticide concentrations ranging between 600 and 1200 µg kg-1. The lowest total pesticide concentrations were found in Slovenia, Switzerland, Croatia, and Denmark, ranging between 80 and 120 µg kg-1. Sediments presented a mix of non-persistent and persistent compounds. Twelve of the detected pesticides are very persistent/stable in sediments, raising concerns about the long-term impacts of pesticides. Our study on the distribution of pesticide residues in European sediments provides valuable insights into the extent of pesticide contamination and possible risks of pesticides to water bodies' health. It also underlines the need for monitoring, research, and policy efforts to mitigate the impacts of pesticides, and to evaluate potential risks of re-use of dredged sediments.
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Microplastic (MP) pollution constitutes an emerging type of pollution threatening both aquatic and terrestrial ecosystems. The impact on aquatic ecosystems has been extensively studied, but the effect on terrestrial ecosystems and their inhabitants is mostly underexplored. In this study, we explored the effect of MP pollution on gut bacterial microbiome of endogeic (Aporrectodea caliginosa) and anecic (Lumbricus terrestris) earthworms. The experiments were performed in sandy soil with 0.2% of low-density polyethylene MPs (LDPE MPs). We observed that the endogeic earthworms had 100% survival, while anecic earthworms survived 25 days in the control (i.e. in absence of MPs) and 21 days in the treatment with LDPE MPs. The main driver of shifts in the diversity and composition of the bacterial communities in the gut of tested earthworms was the lifestyle of the worms, followed by the presence of MPs. The bacterial microbiome diversity was significantly different among the two types of earthworms, and the highest bacterial diversity was found in the gut of the endogeic earthworms. The effect of MPs on gut bacterial microbiome was clearly observed in the changes in the relative abundance of several phyla and families of the bacterial communities in both types of earthworms, although it was most evident in the anecic earthworms. The Actinobacteriota, Proteobacteria, and Firmicutes were the main groups enhanced in the MP treatments, suggesting enrichment of the bacterial communities with potential plastic degraders.
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Microbioma Gastrointestinal , Microplásticos , Oligoquetos , Oligoquetos/microbiología , Oligoquetos/efectos de los fármacos , Animales , Microbioma Gastrointestinal/efectos de los fármacos , Microplásticos/toxicidad , Bacterias/clasificación , Bacterias/efectos de los fármacos , Bacterias/aislamiento & purificación , Bacterias/genética , Contaminantes del Suelo/toxicidad , Microbiología del SueloRESUMEN
During the growing season of 2021, 201 soil samples from conventionally and organically managed fields from 10 European countries and 8 cropping systems were taken, and 192 residues of synthetic pesticides were analyzed. Pesticide residues were found in 97% of the samples, and 88% of the samples contained mixtures of at least 2 substances. A maximum of 21 substances were found in conventionally managed fields, and a maximum of 12 were found in organically managed fields. The number and concentration of pesticide residues varied significantly between conventional and organic fields in 70 and 50% of the case study sites, respectively. Application records were available for a selected number of fields (n = 82), and these records were compared to the detected substances. Residues from 52% of the applied pesticides were detected in the soils. Only 21% of the pesticide residues detected in the soil samples were applied during the 2021 growing season. From the application data, predicted environmental concentrations of residues in soil were calculated and compared to the measured concentrations. These estimates turned out not to be accurate. The results of this study show that most European agricultural soils contain mixtures of pesticide residues and that current calculation methods may not reliably estimate their presence.
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Residuos de Plaguicidas , Plaguicidas , Contaminantes del Suelo , Residuos de Plaguicidas/análisis , Residuos de Plaguicidas/química , Suelo/química , Agricultura , Plaguicidas/análisis , Europa (Continente)RESUMEN
Freshwater ecosystems face a particularly high risk of biodiversity loss compared to marine and terrestrial systems. The use of pesticides in agricultural fields is recognized as a relevant stressor for freshwater environments, exerting a negative impact worldwide on the overall status and health of the freshwater communities. In the present work, part of the Horizon 2020 funded SPRINT project, the occurrence of 193 pesticide residues was investigated in 64 small water bodies of distinct typology (creeks, streams, channels, ditches, rivers, lakes, ponds and reservoirs), located in regions with high agricultural activity in 10 European countries and in Argentina. Mixtures of pesticide residues were detected in all water bodies (20, median; 8-40 min-max). Total pesticide levels found ranged between 6.89 and 5860 ng/L, highlighting herbicides as the dominant type of pesticides. Glyphosate was the compound with the highest median concentration followed by 2,4-D and MCPA, and in a lower degree by dimethomorph, fluopicolide, prothioconazole and metolachlor(-S). Argentina was the site with the highest total pesticide concentration in water bodies followed by The Netherlands, Portugal and France. One or more pesticides exceeded the threshold values established in the European Water Framework Directive for surface water in 9 out of 11 case study sites (CSS), and the total pesticide concentration surpassed the reference value of 500 ng/L in 8 CSS. Although only 5 % (bifenthrin, dieldrin, fipronil sulfone, permethrin, and terbutryn) of the individual pesticides denoted high risk (RQ > 1), the ratios estimated for pesticide mixtures suggested potential environmental risk in the aquatic compartment studied.
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Residuos de Plaguicidas , Plaguicidas , Contaminantes Químicos del Agua , Agua , Ecosistema , Argentina , Contaminantes Químicos del Agua/análisis , Monitoreo del Ambiente , Plaguicidas/análisis , Ríos/químicaRESUMEN
Evidence of microplastic (MP) pollution in Antarctic terrestrial environments reinforces concerns about its potential impacts on soil, which plays a major role in ecological processes at ice-free areas. We investigated the effects of two common MP types on soil physicochemical properties and microbial responses of a marine terrace from Fildes Peninsula (King George Island, Antarctica). Soils were treated with polyethylene (PE) fragments and polyacrylonitrile (PAN) fibers at environmentally relevant doses (from 0.001% to 1% w w-1), in addition to a control treatment (0% w w-1), for 22 days in a pot incubation experiment under natural field conditions. The short-term impacts of MPs on soil physical, chemical and microbial attributes seem interrelated and were affected by both MP dose and type. The highest PAN fiber dose (0.1%) increased macro and total porosity, but decreased soil bulk density compared to control, whereas PE fragments treatments did not affect soil porosity. Soil respiration increased with increasing doses of PAN fibers reflecting impacts on physical properties. Both types of MPs increased microbial activity (fluorescein diacetate hydrolysis), decreased the cation exchange capacity but, especially PE fragments, increased Na+ saturation. The highest dose of PAN fibers and PE fragments increased total nitrogen and total organic carbon, respectively, and both decreased the soil pH. We discussed potential causes for our findings in this initial assessment and addressed the need for further research considering the complexity of environmental factors to better understand the cumulative impacts of MP pollution in Antarctic soil environments.
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Resinas Acrílicas , Microplásticos , Plásticos , Regiones Antárticas , Polietileno , Suelo/químicaRESUMEN
The risk characterization of microplastics (MP) in soil is challenging due to the non-alignment of existing exposure and effect data. Therefore, we applied data alignment methods to assess the risks of MP in soils subject to different sources of MP pollution. Our findings reveal variations in MP characteristics among sources, emphasizing the need for source-specific alignments. To assess the reliability of the data, we applied Quality Assurance/Quality Control (QA/QC) screening tools. Risk assessment was carried out probabilistically, considering uncertainties in data alignments and effect thresholds. The Hazardous Concentrations for 5% (HC5) of the species were significantly higher compared to earlier studies and ranged between 4.0 × 107 and 2.3 × 108 particles (1-5000 µm)/kg of dry soil for different MP sources and ecologically relevant metrics. The highest risk was calculated for soils with MP entering via diffuse and unspecified local sources, i.e., "background pollution". However, the source with the highest proportion of high-risk values was sewage, followed by background pollution and mulching. Notably, locations exceeding the risk threshold obtained low scores in the QA/QC assessment. No risks were observed for soils with compost. To improve future risk assessments, we advise to primarily test environmentally relevant MP mixtures and adhere to strict quality criteria.
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This work evaluated the biochemical responses of the endogeic earthworm Balanteodrilus extremus exposed for 14 and 48 days (d) to soils collected from two tropical agricultural systems: maize-sorghum (MS) and soybean-sorghum (SS). A soil without agricultural management (WAM) and the use of pesticides was selected as a reference. The presence of organochlorine (OC) and organophosphate (OP) pesticide residues was quantified in MS and SS soils. Biomarkers of detoxification [glutathione S transferase (GST)], neurotoxicity [acetylcholinesterase (AChE)] and oxidative stress [superoxide dismutase (SOD), catalase (CAT) and lipoperoxidation (LPO)] were evaluated in B. extremus. The concentration of OP pesticide residues was higher in SS than in MS. Activity of AChE in B. extremus exposed to SS soil for 14 d was significantly more inhibited (78%) than in MS soil (68%). B. extremus has been shown to be a good bioindicator of contaminated soils in tropical regions.
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Ascomicetos , Oligoquetos , Residuos de Plaguicidas , Sorghum , Animales , Suelo , Acetilcolinesterasa , Agricultura , Grano Comestible , Glycine max , Zea maysRESUMEN
Landfills are sources of soil, water, and air pollution due to the release of toxic compounds such as metals and metalloids. In both tropical and temperate environments, scavenger birds such as the Black Vulture (Coragyps atratus) that have learned to use these sites as a feeding area are probably exposed to metals, metalloids and other "persistent bioaccumulative toxic substances (PBTs)" released in open dumpsite (OD) and sanitary landfill (SL). The objective of this study is to evaluate the presence and distribution of toxic metals (Al, Sn, Hg, Cu, Pb, Cd, Cr) and As in OD and SL from urban, semi-urban and rural localities in Campeche, México, using molting feathers of C. atratus as bioindicators. A total of 125 Black Vulture primary and secondary wing feathers were collected from OD and SL. Metals were determined by voltammetry through acid digestion. The highest levels of metals occurred in landfills in urban, semi-urban, and rural localities. The elements with the highest concentrations were Al, with an average of 35.67 ± 33.51 µg g-1 from rural environments, and As, with 16.20 ± 30.06 µg g-1 from the urban localities. Mercury was the only element that had a very homogeneous distribution between the three environments we studied. In general, Pb, Hg, Cu and Cd were the elements that presented the lowest concentrations with 0.32 ± 0.35, 0.16 ± 0.22, 0.14 ± 0.31 and 0.06 ± 0.10 µg g-1, respectively regardless of any particular location or environment. Black Vultures from dumpsites are good bioindicators of what humans consume in urban, semi-urban, and rural environments. However, the conservation of vultures is of great importance since these scavenger birds perform ecosystem services by feeding on decomposing organic material.
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Falconiformes , Mercurio , Metaloides , Metales Pesados , Humanos , Animales , Biomarcadores Ambientales , Metaloides/análisis , Ecosistema , Cadmio , Plumas , México , Plomo , Monitoreo del Ambiente , Aves , Metales Pesados/análisisRESUMEN
Intensive and widespread use of pesticides raises serious environmental and human health concerns. The presence and levels of 209 pesticide residues (active substances and transformation products) in 625 environmental samples (201 soil, 193 crop, 20 outdoor air, 115 indoor dust, 58 surface water, and 38 sediment samples) have been studied. The samples were collected during the 2021 growing season, across 10 study sites, covering the main European crops, and conventional and organic farming systems. We profiled the pesticide residues found in the different matrices using existing hazard classifications towards non-target organisms and humans. Combining monitoring data and hazard information, we developed an indicator for the prioritization of pesticides, which can support policy decisions and sustainable pesticide use transitions. Eighty-six percent of the samples had at least one residue above the respective limit of detection. One hundred residues were found in soil, 112 in water, 99 in sediments, 78 in crops, 76 in outdoor air, and 197 in indoor dust. The number, levels, and profile of residues varied between farming systems. Our results show that non-approved compounds still represent a significant part of environmental cocktails and should be accounted for in monitoring programs and risk assessments. The hazard profiles analysis confirms the dominance of compounds of low-moderate hazard and underscores the high hazard of some approved compounds and recurring "no data available" situations. Overall, our results support the idea that risk should be assessed in a mixture context, taking environmentally relevant mixtures into consideration. We have uncovered uncertainties and data gaps that should be addressed, as well as the policy implications at the EU approval status level. Our newly introduced indicator can help identify research priority areas, and act as a reference for targeted scenarios set forth in the Farm to Fork pesticide reduction goals.
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Residuos de Plaguicidas , Plaguicidas , Humanos , Agricultores , Productos Agrícolas , Polvo , Suelo , Agua , Monitoreo del AmbienteRESUMEN
Pesticides are widely used as plant protection products (PPPs) in farming systems to preserve crops against pests, weeds, and fungal diseases. Indoor dust can act as a chemical repository revealing occurrence of pesticides in the indoor environment at the time of sampling and the (recent) past. This in turn provides information on the exposure of humans to pesticides in their homes. In the present study, part of the Horizon 2020 funded SPRINT project, the presence of 198 pesticide residues was assessed in 128 indoor dust samples from both conventional and organic farmworker households across Europe, and in Argentina. Mixtures of pesticide residues were found in all dust samples (25-121, min-max; 75, median). Concentrations varied in a wide range (<0.01 ng/g-206 µg/g), with glyphosate and its degradation product AMPA, permethrin, cypermethrin and piperonyl butoxide found in highest levels. Regarding the type of pesticides, insecticides showed significantly higher levels than herbicides and fungicides. Indoor dust samples related to organic farms showed a significantly lower number of residues, total and individual concentrations than those related to conventional farms. Some pesticides found in indoor dust were no longer approved ones (29 %), with acute/chronic hazards to human health (32 %) and with environmental toxicity (21 %).
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Contaminación del Aire Interior , Residuos de Plaguicidas , Plaguicidas , Humanos , Residuos de Plaguicidas/análisis , Monitoreo del Ambiente , Polvo/análisis , Agricultores , Argentina , Plaguicidas/análisis , Europa (Continente) , Contaminación del Aire Interior/análisisRESUMEN
Plastic mulch films and biofertilizers (processed sewage sludge, compost or manure) have helped to increase crop yields. However, there is increasing evidence that these practices significantly contribute to microplastic contamination in agricultural soils, affecting biodiversity and soil health. Here, we draw attention to the use of hydrolase enzymes that depolymerize polyester-based plastics as a bioremediation technique for agricultural soils (in situ), biofertilizers and irrigation water (ex situ), and discuss the need for fully biodegradable plastic mulches. We also highlight the need for ecotoxicological assessment of the proposed approach and its effects on different soil organisms. Enzymes should be optimized to work effectively and efficiently under the conditions found in natural soils (typically, moist solids at an ambient temperature with low salinity). Such optimization is also necessary to ensure that already distressed ecosystems are not disrupted any further.
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Ecosistema , Suelo , Microplásticos , Agricultura/métodos , Ecotoxicología , Aguas del Alcantarillado , PlásticosRESUMEN
Tropical agriculture produces large amounts of lignocellulosic residues that can potentially be used as a natural source of value-added products. The complexity of lignocellulose makes industrial-scale processing difficult. New processing techniques must be developed to improve the yield and avoid this valuable resource going to waste. Hemicelluloses comprise a variety of polysaccharides with different backbone compositions and decorations (such as methylations and acetylations), and form part of an intricate framework that confers structural stability to the plant cell wall. Organisms that are able to degrade these biopolymers include earthworms (Eisenia fetida), which can rapidly decompose a wide variety of lignocellulosic substrates. This ability probably derives from enzymes and symbiotic microorganisms in the earthworm gut. In this work, two substrates with similar C/N ratios but different hemicellulose content were selected. Palm fibre and coffee husk have relatively high (28%) and low (5%) hemicellulose contents, respectively. A vermicomposting mixture was prepared for the earthworms to feed on by mixing a hemicellulose substrate with organic market waste. Xylanase activity was determined in earthworm gut and used as a selection criterion for the isolation of hemicellulose-degrading bacteria. Xylanase activity was similar for both substrates, even though their physicochemical properties principally pH and electrical conductivity, as shown by the MANOVA analysis) were different for the total duration of the experiment (120 days). Xylanolytic strains isolated from earthworm gut were identified by sequence analysis of the 16S rRNA gene. Our results indicate that the four Actinobacteria, two Proteobacteria, and one Firmicutes isolated are active participants of the xylanolytic degradation by microbiota in the intestine of E. fetida. Most bacteria were more active at pH 7 and 28 °C, and those with higher activities are reported as being facultatively anaerobic, coinciding with the microenvironment reported for the earthworm gut. Each strain had a different degradative capacity.
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Oligoquetos , Animales , Bacterias/genética , Humanos , Intestinos , ARN Ribosómico 16S , SueloRESUMEN
Plastics are produced by the millions of tons worldwide each year, with their final deposition in landfills (LFs). Plastics deposited in LFs can fragment over time, giving rise to mesoplastics and later to microplastics (MPs), in which toxic chemicals such as heavy metals, organochlorine pesticides, and polycyclic aromatic hydrocarbons can adhere. MPs can be vectors for the exposure to pollutants of black vultures (Coragyps atratus) due to feeding in LFs, resulting in accidental ingestion of MPs. It is also possible that MPs can adsorb pollutants from vultures during the digestion process. The aim of this study was to estimate the risk of black vulture exposure to MPs, heavy metals (HMs), organochlorine pesticides (OCPs) and polycyclic aromatic hydrocarbons (PAHs). Fifty-eight black vulture pellets were collected at the Campeche LF during 2019 (n = 24) and 2020 (n = 34). The pellets, on average, had an MP load per pellet of 6.7 ± 5.8 MPs/total pellets. The greatest abundance of MPs was detected in 2019, with 225 particles in total. The concentrations of Cd, Pb, Cu, Cr, Hg, As, and Al were detected in the MPs, with the greatest average concentration of 35.59 ± 32.39 µg·g-1 (2019) and 15.82 ± 17.47 µg·g-1 (2020) for Al. In 2020, ∑endosulfans were present in all MPs at 0.97 ± 1.47 ng·g-1. Among the PAHs, 15 of the 16 compounds indicated as priorities by the US EPA were quantified. The compound with the greatest total concentration for both years was acenaphthylene (3 rings), with 10.51 ± 7.88 ng·g-1 (2019) and 10.61 ± 18 ng·g-1 (2020). More research is needed regarding the origin of the contaminants detected in the MPs extracted from the pellets, since the contaminants may come from the environment or possibly from the digestion processes in the stomach of avian raptors and scavengers.
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Hidrocarburos Clorados , Metaloides , Plaguicidas , Hidrocarburos Policíclicos Aromáticos , Contaminantes Químicos del Agua , Animales , Monitoreo del Ambiente , Hidrocarburos Clorados/análisis , México , Microplásticos , Plaguicidas/análisis , Plásticos , Hidrocarburos Policíclicos Aromáticos/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
The rapid and silent emergence of microplastics (MPs) in the environment has recently become a global problem with more and more studies are showing the harmful effects of MPs on different ecosystems. The aim of this study was to investigate the presence of MPs in agricultural soils, wastewater effluents and sewage sludge in Mauritius. The soil samples were collected randomly from three different agricultural lands which have been used for conventional agriculture for more than 25 years. Wastewater effluents and sewage sludge were collected once, using the grab sampling method, from three main operating wastewater treatment plants (WWTP) across the island and were analysed in triplicate. MPs were extracted using the flotation technique, followed by hydrogen peroxide digestion. The abundance of MPs was found to be 320.0 ± 112.2 and 420.0 ± 244.0 particles.kg-1 in shallow and deep soils, respectively, out of which 42.4% and 95.8% were less than 1 mm in size, respectively. Site 3 had the highest abundance of MPs due to cumulated plastic debris dumped on the field. In addition, the average MPs concentration in sewage sludge and in wastewater effluents were 14,750 ± 8612.9 particles.kg-1 and 276.3 ± 137.3 particles.L-1, respectively, whereby 90% of the MPs were less than 0.5 mm in size. WWTP 1 had the largest share of MPs in both sewage sludge and wastewater effluents. The attenuated total reflection Fourier transform infrared spectroscopy revealed that polypropylene (fibres, fragments, and flakes) was in abundance in agricultural soil samples by 56.26%, while in WWTP polyamide (fibres) was predominant by 88.85%. The findings of this preliminary study confirmed the presence of MPs in Mauritian lands, wastewater effluents and sewage sludge and therefore provide salient data to advocate for subsequent research on MPs.
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Microplásticos , Contaminantes Químicos del Agua , Agricultura , Ecosistema , Mauricio , Plásticos , Aguas del Alcantarillado , Suelo , Aguas Residuales , Contaminantes Químicos del Agua/análisisRESUMEN
Polylactic acid (PLA) bioplastic was introduced to the market as an environmentally friendly potential solution for plastic pollution. However, the effects of bioplastic debris mixed with composts on soil macroinvertebrates, plant growth and soil conditions are still unknown. Soil macroinvertebrates are soil health indicators. A reduction in their abundance is a sign of soil degradation. The objectives of this study were (i) to assess PLA debris in greenhouse composts, and (ii) to test the ecotoxicological effects of PLA debris mixed with compost on Lumbricus terrestris, a soil organism model, and on Triticum aestevium, a plant growth model. The study was comprised of three stages: (1) determine the PLA debris size distribution in composts; (2) assess the ecotoxicological effects of real-world concentrations (0% to 5%) of PLA mixed with compost on earthworm mortality and reproduction; and (3) assess the influence of compost mixed with real-world PLA concentrations on plant growth and physicochemical soil conditions. One percent of PLA debris was found in green composts, 40% of composted PLA debris measured between 1-10 mm, with a concentration of 82.8 ± 17.4 microplastics.gram-1 compost. A concentration of 1% PLA in composts resulted in significant mortality in earthworms. No significant effects of PLA mixed with composts were observed on plant growth or soil physicochemical conditions. Further studies are required in order to test the effect of this biopolymer on different earthworm and plant' species.
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One of the main sources of plastic pollution in agricultural fields is the plastic mulch used by farmers to improve crop production. The plastic mulch is often not removed completely from the fields after harvest. Over time, the plastic mulch that is left of the fields is broken down into smaller particles which are dispersed by the wind or runoff. In the Region of Murcia in Spain, plastic mulch is heavily used for intensive vegetable farming. After harvest, sheep are released into the fields to graze on the vegetable residues. The objective of the study was to assess the plastic contamination in agricultural soil in Spain and the ingestion of plastic by sheep. Therefore, three research questions were established: i) What is the plastic content in agricultural soils where plastic mulch is commonly used? ii) Do livestock ingest the microplastics found in the soil? iii) How much plastic could be transported by the livestock? To answer these questions, we sampled top soils (0-10 cm) from 6 vegetable fields and collected sheep faeces from 5 different herds. The microplastic content was measured using density separation and visual identification. We found ~2 × 103 particlesâkg-1 in the soil and ~103 particlesâkg-1 in the faeces. The data show that plastic particles were present in the soil and that livestock ingested them. After ingesting plastic from one field, the sheep can become a source of microplastic contamination as they graze on other farms or grasslands. The potential transport of microplastics due to a herd of 1000 sheep was estimated to be ~106 particlesâha-1ây-1. Further studies should focus on: assessing how much of the plastic found in faeces comes directly from plastic mulching, estimating the plastic degradation in the guts of sheep and understanding the potential effects of these plastic residues on the health of livestock.
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Plásticos , Suelo , Agricultura , Animales , Granjas , Heces , Microplásticos , Ovinos , España , VerdurasRESUMEN
The growing evidence of microplastic pollution in terrestrial ecosystems reveals adverse effects of microplastics on soil biota and plant growth. However, since large scale assessments are lacking, it is possible that the laboratory based experiments conducted have assumed unrealistic microplastic concentrations in soils. In this paper we present regional scale data on the presence of microplastics in soils under different land uses in the central valley of Chile, which is characterized by urbanization, agricultural, and mining operations. We identified microplastics in soils under four different land use systems having different management intensities (crop lands, pastures, rangelands, and natural grasslands), and all somewhat prone to accumulate microplastics from different sources. We analyzed 240 soil samples from Chile's central valley, trying to identify the most probable sources of the microplastics. Our hypothesis was that microplastics were ubiquitous in the environment and that their concentration peaks follow the intensity of fertilizer use (phosphorus), soil heavy metals concentrations derived from nearby mining operations (Zn and Cu), and distance to roads and urban areas. We did find evidence of microplastic pollution in crop lands and pastures (306 ± 360 and 184 ± 266 particles kg-1, respectively), but we did not observe pollution of rangelands and natural grasslands. Distance to mining operations, roads, or urban areas did not increase the microplastic particles count. Our observations contradict the common belief that microplastics are ubiquitous in the environment and relate the pollution problem more to agricultural activities. However, our data do not provide sufficient evidence to identify the pollution source. This is the first study that reports on microplastic occurrence in soils at a broad geographical scale. For greater insight on this topic more studies that contribute monitoring data about microplastics in soils are urgently needed.
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The impact of microplastic pollution on terrestrial biota is an emerging research area, and this is particularly so for soil biota. In this study, we addressed this knowledge gap by examining the impact of aged low-density polyethylene (LDPE) and polyester fibres (i.e. polyethylene terephthalate, PET) on a forest microbiome composition and activity. We also measured the corresponding physicochemical changes in the soil. We observed that bacteria community composition diverged in PET and LDPE treated soils from that of the control by day 42. These changes occurred at 0.2% and 0.4% (w/w) of PET and at 3% LDPE. Additionally, soil respiration was 8-fold higher in soil that received 3% LDPE compared to other treatments and control. There were no clear patterns linking these biological changes to physicochemical changes measured. Taken together, we concluded that microplastics aging in the environment may have evolutionary consequences for forest soil microbiome and there is immediate implication for climate change if the observed increase in soil respiration is reproducible in multiple ecosystems.
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Microbiota , Contaminantes del Suelo , Ecosistema , Bosques , Microplásticos , Plásticos/toxicidad , Suelo , Contaminantes del Suelo/análisis , Contaminantes del Suelo/toxicidadRESUMEN
The plastic mulch films used in agriculture are considered to be a major source of the plastic residues found in soil. Mulching with low-density polyethylene (LDPE) is widely practiced and the resulting macro- and microscopic plastic residues in agricultural soil have aroused concerns for years. Over the past decades, a variety of biodegradable (Bio) plastics have been developed in the hope of reducing plastic contamination of the terrestrial ecosystem. However, the impact of these Bio plastics in agroecosystems have not been sufficiently studied. Therefore, we investigated the impact of macro (around 5 mm) and micro (<1 mm) sized plastic debris from LDPE and one type of starch-based Bio mulch film on soil physicochemical and hydrological properties. We used environmentally relevant concentrations of plastics, ranging from 0 to 2% (w/w), identified by field studies and literature review. We studied the effects of the plastic residue on a sandy soil for one month in a laboratory experiment. The bulk density, porosity, saturated hydraulic conductivity, field capacity and soil water repellency were altered significantly in the presence of the four kinds of plastic debris, while pH, electrical conductivity and aggregate stability were not substantially affected. Overall, our research provides clear experimental evidence that microplastics affect soil properties. The type, size and content of plastic debris as well as the interactions between these three factors played complex roles in the variations of the measured soil parameters. Living in a plastic era, it is crucial to conduct further interdisciplinary studies in order to have a comprehensive understanding of plastic debris in soil and agroecosystems.
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Contaminantes del Suelo , Suelo , Agricultura , Ecosistema , Hidrología , PlásticosRESUMEN
Microplastic pollution is becoming a major challenge with the growing use of plastic. In recent years, research about microplastic pollution in the environment has become a field of study with increased interest, with ever expanding findings on sources, sinks and pathways of microplastics. Wastewater treatment plants effectively remove microplastics from wastewater and concentrate them in sewage sludge which is often used to fertilise agricultural fields. Despite this, quantification of microplastic pollution in agricultural fields through the application of sewage sludge is largely unknown. In light of this issue, four wastewater treatment plants and 16 agricultural fields (0-8 sewage sludge applications of 20-22 tons ha-1 per application), located in the east of Spain, were sampled. Microplastics were extracted using a floatation and filtration method, making a distinction between light density microplastics (ρ < 1 g cm-3) and heavy density microplastics (ρ > 1 g cm-3). Sewage sludge, on average, had a light density plastic load of 18,000 ± 15,940 microplastics kg-1 and a heavy density plastic load of 32,070 ± 19,080 microplastics kg-1. Soils without addition of sewage sludge had an average light density plastic load of 930 ± 740 microplastics kg-1 and a heavy density plastic load of 1100 ± 570 microplastics kg-1. Soils with addition of sewage sludge had an average light density plastic load of 2130 ± 950 microplastics kg-1 and a heavy density plastic load of 3060 ± 1680 microplastics kg-1. On average, soils' plastic loads increased by 280 light density microplastics kg-1 and 430 heavy density microplastics kg-1 with each successive application of sewage sludge, indicating that sewage sludge application results in accumulation of microplastics in agricultural soils.