Wariness is increasing about resident times of microplastics (MPs) in soils; however, limited knowledge is available on ultraviolet (UV) light exposure of MPs to soil fauna. This study investigated the effects of virgin and photoaged polyethylene microplastics (PE MPs) on soil mesofauna (enchytraeids and collembolans) at environmentally relevant concentrations in a microcosm incubation experiment. Ten individuals of each Enchytraeus crypticus and Folsomia candida and twenty Proisotoma minuta were exposed separately to virgin and photoaged PE MPs (40–48 μm) admixed in agricultural soil (0.2–2000 mg/kg) to evaluate reproduction and survival. After 28 d of exposure to photoaged PE MPs, there was a moderate survival reduction but reproduction promotion of E. crypticus. Contrastingly, F. candida exhibited an opposite trend, with survival enhancement and reproduction depression rates when exposed to both PE MP contaminated soils. However, P. minuta was the only species with significant apical endpoint changes after PE MP exposure; at 20 mg/kg photoaged and 2000 mg/kg virgin PE MP exposure, there was a 34% and 31% decrease in survival, respectively, and at 200 mg/kg photoaged PE MP exposure, an increase of 39% for reproduction. PE MPs had contrasting impacts on soil mesofauna species, which highlights the need to account for these variable results when understanding the repercussions of MP pollution on community assemblage and population dynamics in soils.

The impact of microplastics (MPs) on soil organisms is still a growing field, yet very little is known about the exposure of ultraviolet (UV) aging of MPs to soil organisms. In this study, we explored the response of the epigeic earthworm Eisenia andrei to pristine and UV-aged polyethylene (PE-MP) exposure at a wide range of environmentally relevant concentrations (0, 0.2, 2, 20, 200 and 2000 mg kg-1) in an organic farm soil for 56d and assessed changes in reproduction, ingestion, egestion and gut microbiome. Results showed that exposure to 20 mg kg- 1 pristine PE-MP significantly increased earthworm reproduction by 39 % but the same concentration decreased reproduction by 29 % when they were exposed to UV-aged PE-MP. Ingestion of PE was verified by staining the whole worm body and their casts after 48h of starvation. The amounts of PE-MP found in the body and the casts were positively correlated with PE-MP concentrations in the soil, however only significantly so with pristine PE-MP. A decline in E. andrei gut microbiome alpha diversity and a significantly different community composition were observed in UV-aged PE-MP exposures compared to pristine PE-MP. Relative to the control treatments, Proteobacteria increased up to 135 %, Actinobacteria increased up to 35 %, and Firmicutes decreased up to 38 % under UV-aged PE-MP exposure, whereas Cyanobacteria increased up to 19 times in the pristine PEMP treatments. These results confirm the negative effect of UV-aged PE-MP on earthworms even at low concentrations and could have important implications in the well-functioning of agricultural soils.

The persistent residence of microplastics (MPs) in soils is of increasing concern, yet very little is known about the exposure of ultraviolet (UV) aging of MPs to soil organisms. In this study, we explore the impacts of pristine and UV-aged polyethylene microplastics (PE-MP) at environmentally relevant concentrations on soil mesofauna (enchytraeids and collembolas) in a microcosm incubation experiment. We exposed 10 Enchytraeus crypticus, 10 Folsomia candida and 20 Proisotoma minuta separately to pristine and UV-aged PE-MP (40–48 μm) added to an organic farm soil at concentrations of 0, 0.2, 2, 20, 200 and 2000 mg/kg to assess their survival and reproduction. After 28d, we found a general a decrease in survival but an increase in reproduction of E. crypticus when exposed to UV-aged PE-MP. In contrast, F. candida showed the opposite trends, with increased survival and decreased reproduction rates when growing in both PE-MP contaminated soils. However, significant effects of PE-MP exposure were only observed for P. minuta, with a 34% and 31% decrease in survival rates at 20 mg/kg UV-aged and 2000 mg/kg pristine PE-MP, respectively, and increased reproduction rates of 39% at 200 mg/kg UV-aged PE. Our results suggest that PE-MP have contrasting effects on soil mesofauna species which need to be taken into account for understanding the effects of MP pollution on soil population dynamics and community structure.

The worldwide demand on bionematicides is in a growing trend, fueled by environmental concerns with potential negative impacts of synthetic products on ecosystems and non-target organisms, as well as by the need to provide solutions to organic farming management. As such, the main goal of the present study was to evaluate the impact of 1,4-naphthoquinone (NTQ), a nematicidal compound found in natural products such as walnut husk, on soil microbial community (non-target organisms), and determine ecotoxicological indicators in order to follow and quantify the effect of this compound. The effects on diversity and metabolic state of the microbial community were evaluated using a Phospholipid-derived Fatty Acid analysis (PLFA) method. Tests were conducted on a natural uncontaminated soil spiked with a range of NTQ concentrations (up to 768 mg/kg), as well as comparable control solutions containing solubilization enhancer Triton X-100 (TX100). NTQ impacted the soil microbial community, causing significant changes on global PLFA profile at 12 mg/kg, and significant changes on taxonomic biomarker balance at 96 mg/kg. TX100 also caused a significant effect on the global profile, but only at 192 mg/kg NTQ-equivalent. The modifications brought by either compounds were distinct, as different indicators were affected. The effects of NTQ on microbial community were quantifiable for several indicators by calculating half maximal effective concentrations (EC50). The method used proved to be suitable for the assessment of NTQ ecotoxicity in soils.

In the present contribution, the geochemical relationships of territorial units (landscapes), namely sewage sludge disposal sites and historical municipal solid waste landfills, that can be considered as chemical elements migration models and as dynamic components of ecological-geological systems (landfill site - adjacent area - recreation area)., is described. Since the study of pollutants migration in multicomponent systems is extremely time-consuming, the development of theoretical methods, able to simulate these processes, is of particular relevance. Therefore, in the present study, a geochemical model for substance migration in anthropogenically modified geoecological bodies and their surrounding was conceived, making use of complex mathematical processes and data analysis methodologies (parallel use of factor, cluster, canonical and discriminant analysis tools), and considering both geochemical specialization/composition of parent rocks and land use (functional geoecological zoning).

The use of organic wastes as soil amendments can be an important measure to improve soil quality and reduce waste accumulation and landfilling. However, the potential contaminant loads of such wastes, can be a source of environmental concern. Consequently, legislation has been developed to regulate the use of these wastes in agricultural soils. However, the regulations only consider chemical parameters, which are insufficient to establish the level of environmental risk. A possible solution is the use of species sensitivity distributions (SSDs), employing ecotoxicological data from test batteries that could be incorporated into legislation. In the present study, 2 different hazardous concentrations affecting 5 and 50% of the soil community (HC5 and HC50, respectively) were determined using ecotoxicological data (effect concentrations, 10 and 50% [EC10 and EC50, respectively]) for 5 different wastes. The results demonstrate that, as expected, current legislative thresholds do not translate to environmental risk/protection and that SSDs may be an important tool allowing the simple inclusion and interpretation of ecotoxicological data from test batteries in legislation. On the other hand, SSDs must be used with caution because there are still doubts about their actual value in risk prediction and about which estimates provide adequate protection. For instance, the use of HC50EC10 values is not recommended; these values overlap with the more conservative HC5EC50 data, highlighting the fact that the use of lower effect concentrations may not always provide the most protective approach. Also, hazardous concentrations need to be calibrated at the field or semifield level, to verify environmental protection in different soils/environments and the adequacy of standard test organisms. Environ Toxicol Chem 2019;38:1569–1576. © 2019 SETAC

The recently approved European Union (EU) Circular Economy Package intends to boost the production of fertilizing products, such as composts obtained from urban wastes (UWC) and the harmonization of their quality standards (certification), to avoid market rejection. UWC quality assessment frameworks in Europe, including the Portuguese and EU latest proposal on regulation of UWC production/commercialization are mostly based on physical-chemical and agronomical characterization. These do not provide any insight on the fraction of contaminant/mixture of contaminants bioavailable for non-target organisms, nor the existence of potential antagonistic and/or synergistic effects on them. The main objective of the present work if to evaluate the effects of UWC application on crop soils using seven standard ecotoxicological tests. Five UWC, two derived from source-separated organic wastes and three from mixed urban wastes were selected and tested using a battery of ISO guideline assays with plants and soil invertebrates. The tested doses intended to simulate over-use and repeated application scenarios, common practices among farmers. The results showed that the highest toxicity was observed for the UWC originated from source-separated organic wastes, when using concentrations slightly above the maximum annual doses. Excepting for this UWC, all the derived NOEC (No Observed Effect Concentration) were equal or higher than the maximum annual doses. The UWC toxicity for the tested species increased as follows: T. aestivum < L. sativa < E. crypticus < F. candida < E. andrei. UWC salinity, rather than the content of potentially toxic elements (PTEs), could explain the negative effects observed, considering that the composts are all equally stabilized. These results reinforce the need to include data from biological susceptibility of the receptors at risk on the existing regulation, to obtain a more realistic view of the potential risks and to adapt the UWC application practices, ultimately boosting the confidence of target-consumers.

The aims of this work was to investigate, in soil microcosms, the effects on soil microbial community structure and function of increasing concentrations of 4-Nonylphenol (NP). The lasts is a product of degradation of NPEOs (Nonylphenol polyethoxylates) with a known toxic and estrogenic capacity able to disrupt animal's hormonal systems. The effect of increasing concentrations of NP (0, 10, 30, 90, and 270 mg NP kg(-1) of dry soil) in soil microcosms in three sampling dates (28, 56, and 112 days) over soil microbial activity and function were assessed. Soil microbial activity was estimated by microbial ATP content, and both bacterial and fungal communities composition were estimated using the terminal restriction fragment length polymorphism technique (T-RFLP). Abundance of ammonia-oxidizing bacteria (AOB) was estimated by qPCR of gene encoding for the bacterial ammonia-monoxygenase (amoA). Changes in biologically mediated soil properties were also assessed, namely water-soluble NH4+, NO2- and NO3- content, the two last allowing the assessment of mineralization rates. NP-spiking had some unexpected impacts on microbial community structure and functions, since (i) impacted both bacterial and fungal communities structure at the highest NP concentration tested, bacterial communities were resistant to lower concentrations, while fungal communities were increasingly impacted until the end of the incubation at day 112; (ii) no community structure resilience was observed in bacteria at the highest NP concentration nor for fungi at any concentration; (iii) microbial activity decreased with NP after 28 and 56 d, but increased in the last sampling at the highest concentrations tests, coupled to an enrichment in AOB taxa after 56 and 112 days, that at least partly explain also explain the observed speed up of nitrification rates.

Despite the increasing use of pesticides in tropical countries, research and legislative efforts have focused on their temperate counterparts. This paper presents a review of the literature on environmental risk assessment of pesticides for tropical terrestrial agroecosystems. It aims at evaluating potential differences in pesticide risk between temperate and tropical regions as well as to highlight research needs in the latter. Peculiarities of pesticide risks in tropical terrestrial agroecosystems are discussed in subsections 1) agricultural practices; 2) research efforts; 3) fate and exposure; 4) toxicity testing methods; and 5) sensitivity. The intensive and often inadequate pesticide application practices in tropical areas are likely to result in a relatively greater pesticide exposure in edge-of-field water bodies. Since pesticide fate may be different under tropical conditions, tropical scenarios for models estimating predicted environmental pesticide concentrations should be developed. Sensitivity comparisons do not indicate a consistent similar, greater or lower relative sensitivity of tropical soil organisms as compared to temperate organisms. However, several methods and procedures for application in the tropics need to be developed, which include: 1) identifying and collecting natural soils to be used as reference test substrates in tests; 2) identifying and discerning the range of sensitivity of native test species to soil contaminants; 3) developing test guidelines applicable to tropical/subtropical conditions; and 4) developing methods and procedures for higher tier testing for full development and implementation of environmental risk assessment schemes.

Using organic wastes, as soil amendments, is an important alternative to landfilling with benefits to soil structure, water retention, soil nutrient and organic matter concentrations. However, this practice should be monitored for its environmental risk due to the frequent presence, of noxious substances to soil organisms. To evaluate the potential of eight organic wastes with different origins, as soil amendments, reproduction tests with four soil invertebrate species (Folsomia candida, Enchytraeus crypticus, Hypoaspis aculeifer, Eisenia fetida) were performed using gradients of soil-waste mixtures. Results obtained demonstrated that contaminant concentrations required by current legislation might not be a protective measure for the soil ecosystem, as they do not properly translate the potential toxicity of wastes to soil invertebrates. Some wastes with contaminant loadings below thresholds showed higher toxicity than wastes with contaminants concentrations above legal limits. Also, test organism reproduction was differently sensitive to the selected wastes, which highlights the need to account for different organism sensitivities and routes of exposure when evaluating the toxicity of such complex mixtures. Finally this study shows that when combining chemical and ecotoxicological data, it is possible to postulate on potential sources of toxicity, contributing to better waste management practices and safer soil organic amendment products.

Soils from some Latin American countries support the highest biodiversity levels on the planet and simultaneously have some of the most serious environmental impacts attributed to both historical and current agricultural practices and industrial activities. Soil contamination has resulted from intensive use of pesticides, extensive mining and other industrial activities, and uncontrolled management of waste within inappropriate regulatory frameworks. The present study presents an overview of the scientific research on soil ecotoxicology conducted in Latin America, summarizing the recent advances and highlighting the needs for further refinements in this research field. Most of the contributions to the scientific literature have been from Brazil. The most investigated issue is the ecotoxicity of pesticides and earthworms, which were the organisms most frequently used as test species. Needs identified by Latin American researchers include methods and procedures for: 1) identifying and collecting natural soils to be used as reference test-substrates in tests, 2) identifying and discerning the range of sensitivities of native test species to soil contaminants, 3) developing environmental guidelines applicable to tropical/subtropical conditions, and 4) developing methods and procedures for higher tier testing for full development and implementation of environmental risk assessment schemes. The protection of Latin American soils, including provision of goods and services, is currently framed in legislation and other regulations, but implementation requires significant improvement and additional training programs. Environ Toxicol Chem 2017;36:1795-1810. © 2017 SETAC.

The present study is aimed at evaluating whether a gene expression assay with the microbial eukaryotic model Saccharomyces cerevisiae could be used as a suitable warning tool for the rapid preliminary screening of potential toxic effects on organisms due to scenarios of soil and water contamination with pyrimethanil. The assay consisted of measuring changes in the expression of the selected pyrimethanil-responsive genes ARG3 and ARG5,6 in a standardized yeast population. Evaluation was held by assessing the toxicity of surface runoff, a major route of pesticide exposure in aquatic systems due to non-point-source pollution, which was simulated with a pyrimethanil formulation at a semifield scale mimicking worst-case scenarios of soil contamination (e.g. accident or improper disposal). Yeast cells 2-h exposure to the runoff samples led to a significant 2-fold increase in the expression of both indicator genes. These results were compared with those from assays with organisms relevant for the aquatic and soil compartments, namely the nematode Caenorhabditis elegans (reproduction), the freshwater cladoceran Daphnia magna (survival and reproduction), the benthic midge Chironomus riparius (growth), and the soil invertebrates Folsomia candida and Enchytraeus crypticus (survival and reproduction). Under the experimental conditions used to simulate accidental discharges into soil, runoff waters were highly toxic to the standard test organisms, except for C. elegans. Overall, results point out the usefulness of the yeast assay to provide a rapid preview of the toxicity level in preliminary screenings of environmental samples in situations of inadvertent high pesticide contamination. Advantages and limitations of this novel method are discussed.

Current risk assessment methods for measuring the toxicity of plant protection products (PPPs) on soil invertebrates use standardized laboratory conditions to determine acute effects on mortality and sublethal effects on reproduction. If an unacceptable risk is identified at the lower tier, population-level effects are assessed using semifield and field trials at a higher tier because modeling methods for extrapolating available lower-tier information to population effects have not yet been implemented. Field trials are expensive, time consuming, and cannot be applied to variable landscape scenarios. Mechanistic modeling of the toxicological effects of PPPs on individuals and their responses combined with simulation of population-level response shows great potential in fulfilling such a need, aiding ecologically informed extrapolation. Here, we introduce and demonstrate the potential of 2 population models for ubiquitous soil invertebrates (collembolans and earthworms) as refinement options in current risk assessment. Both are spatially explicit agent-based models (ABMs), incorporating individual and landscape variability. The models were used to provide refined risk assessments for different application scenarios of a hypothetical pesticide applied to potato crops (full-field spray onto the soil surface [termed "overall"], in-furrow, and soil-incorporated pesticide applications). In the refined risk assessment, the population models suggest that soil invertebrate populations would likely recover within 1 year after pesticide application, regardless of application method. The population modeling for both soil organisms also illustrated that a lower predicted average environmental concentration in soil (PECsoil) could potentially lead to greater effects at the population level, depending on the spatial heterogeneity of the pesticide and the behavior of the soil organisms. Population-level effects of spatial-temporal variations in exposure were elucidated in the refined risk assessment, using ABMs and population-level endpoints while yielding outputs that directly address the protection goals. We recommend choosing model outputs that are closely related to specific protection goals, using available toxicity data and accepted fate models to the extent possible in parameterizing models to minimize additional data needs and testing, evaluating, and documenting models following recent guidance.

In the present study, a new complementary approach combining the use of the natural soil microarthropod community and conventional test methods was used. The effects of soil contamination with the insecticide carbofuran on two geographically distinct microarthropod communities (Mediterranean and Tropical) were evaluated in their soils of origin under controlled laboratory conditions. After contamination of two agricultural soils from Portugal and Brazil, a gradient of concentrations was prepared. Soil cores were taken from the respective uncontaminated surrounding areas and the mesofauna of three cores was extracted directly to the test soil.After extracting the microarthropod communities to the test soil, these were incubated under laboratory conditions for 4 weeks, after which the mesofauna was extracted again. The organisms were assorted into higher taxonomic groups and Acari and Collembola were respectively assorted into order/sub-order/cohort and family. Collembolans were still classified according to morphological traits and used as a case-study of trait based risk assessment (TERA; Band et al 2008) of pesticides.The exposure to insecticide contamination caused the impoverishment of the taxonomic diversity in both communities. Significant shifts in the microarthropod community structure in the different carbofuran treatments were found for both soils, although effects were more pronounced in the assay performed with the soil from Brazil. Collembolans were the most affected group with a strong decline in their abundance. A dose-response relationship was observed, showing a consistent decline on the relative abundance of Isotomidae, closely followed by an increase of Entomobryidae. Contrastingly, Acari (especially Oribatida) tended to increase their numbers with higher concentrations.Trait based analysis of Collembola data suggested that a shift in the functional composition of the communities occurred due to carbofuran soil contamination and that species adapted to deeper soil layers were more vulnerable to insecticide toxicity. (C) 2013 Elsevier B.V. All rights reserved.

The main objective of the present study was to evaluate the toxicity of two reference chemicals, Carbendazim and Phenmedipham, for the compostworm Eisenia andrei (effects of Carbendazim) and the potworm Enchytraeus crypticus (effects of Phenmedipham) in 12 Mediterranean soils with contrasting soil properties. The observed toxicity was also compared to that obtained for OECD standard soil, used as a control.The soils were selected to be representative for the Mediterranean region and to cover a broad range of soil properties. The evaluated endpoints were avoidance behavior and reproduction. Soils were also assembled in two groups according to their pedological properties.Toxicity benchmarks (AC50s) obtained for E. andrei avoidance behavior in carbendazim-contaminated soils were generally higher for sandy soils with low pH. The toxic effects on the reproduction of the compostworms were similar in the six tested soils, indicating a low influence of soil properties. The avoidance response of E. crypticus towards Phenmedipham was generally highly variable in all tested soils. Even though, a higher toxicity was observed for more acidic soils. The EC50s for reproduction of the latter species varied by a factor of 9 and Phenmedipham toxicity also tended to be increasing in soils with lower pH, except for the soils with extreme organic matter content (0.6 and 5.8%).A soil effect on chemical toxicity was clearly confirmed, highlighting the influence that test soils can have in site-specific ecological risk assessment. Despite some relationships between soil properties and toxicity were outlined, a clear and statistically significant prediction of chemical toxicity could not be established. The range of soil properties was probably narrow to give clearer and more consistent insights on their influence. For the four groups of tests, the toxicity observed for OECD soil was either similar, lower, or generally higher if compared with Mediterranean soils. Moreover, it did represent neither the organic matter content found in Mediterranean soils nor their textural classes.

Soil properties are the main explanation to the different toxicities obtained in different soils due to their influence on chemical bioavailability and the test species performance itself. However, most prediction studies are centred on a few soil properties influencing bioavailability, while their direct effects on test species performance are usually neglected. In our study, we develop prediction models for the toxicity values obtained in a set of soils taking into account both the chemical concentration and their soil properties.

The present study evaluated the bioremediation efficacy of a cleanup tool for atrazine-contaminated soils (Pseudomonas sp. ADP plus citrate [P. ADP?+?CIT]) at a semifield scale, combining chemical and ecotoxicological information. Three experiments representing worst-case scenarios of atrazine contamination for soil, surface water (due to runoff), and groundwater (due to leaching) were performed in laboratory simulators (100 x 40 x 20?cm). For each experiment, three treatments were set up: bioremediated, nonbioremediated, and a control. In the first, the soil was sprayed with 10 times the recommended dose (RD) for corn of Atrazerba and with P. ADP?+?CIT at day 0 and a similar amount of P. ADP at day 2. The nonbioremediated treatment consisted of soil spraying with 10 times the RD of Atrazerba (day 0). After 7 d of treatment, samples of soil (and eluates), runoff, and leachate were collected for ecotoxicological tests with plants (Avena sativa and Brassica napus) and microalgae (Pseudokirchneriella subcapitata) species. In the nonbioremediated soils, atrazine was very toxic to both plants, with more pronounced effects on plant growth than on seed emergence. The bioremediation tool annulled atrazine toxicity to A. sativa (86 and 100% efficacy, respectively, for seed emergence and plant growth). For B. napus, results point to incomplete bioremediation. For the microalgae, eluate and runoff samples from the nonbioremediated soils were extremely toxic; a slight toxicity was registered for leachates. After only 7 d, the ecotoxicological risk for the aquatic compartments seemed to be diminished with the application of P. ADP?+?CIT. In aqueous samples obtained from the bioremediated soils, the microalgal growth was similar to the control for runoff samples and slightly lower than control (by 11%) for eluates. Environ. Toxicol. Chem. 2012; 31: 15641572. (C) 2012 SETAC

A current challenge in soil ecotoxicology is the use of natural soils as test substrates to increase ecological relevance of data. Despite the existence of six natural reference soils (the Euro‐soils), some parallel projects showed that these soils do not accurately represent the diversity of European soils. Particularly, Mediterranean soils are not properly represented. To fill this gap, 12 natural soils from the Mediterranean regions of Alentejo, Portugal; Cataluña, Spain; and Liguria, Italy, were selected and used in reproduction and avoidance tests to evaluate the soil habitat function for earthworms (Eisenia andrei) and enchytraeids (Enchytraeus crypticus). Predictive models on the influence of soil properties on the responses of these organisms were developed using generalized linear models. Results indicate that the selected soils can impact reproduction and avoidance behavior of both Oligochaete species. Reproduction of enchytraeids was affected by different soil properties, but the test validity criteria were fulfilled. The avoidance response of enchytraeids was highly variable, but significant effects of texture and pH were found. Earthworms were more sensitive to soil properties. They did not reproduce successfully in three of the 10 soils, and a positive influence of moisture, fine sand, pH, and organic matter and a negative influence of clay were found. Moreover, they strongly avoided soils with extreme textures. Despite these limitations, most of the selected soils are suitable substrates for ecotoxicological evaluations. Environ. Toxicol. Chem. 2011; 30:1050–1058. © 2011 SETAC