Amendment with sewage sludge or biosolids can increase soil fertility but may also transfer biosolid-borne pollutants to the soil and the possible effects on the soil ecosystem are poorly understood, especially long-term effects. A long-term experiment was therefore established to assess the effects of repeated applications of different types of biosolids (fresh domestic, dried domestic and fresh industrial sludges) in field conditions. Nine years of sludge application led to changes in soil chemical and biological properties and generally contributed little to soil nutrient status. However, soil concentrations of potentially toxic elements (PTEs) were elevated by amendment, especially with industrial biosolids. Soil fauna are usually used to decipher the underlying effects of biosolid applications on the soil ecosystem. Here, collembolans (50.9%), nematodes (41.6%) and enchytraeid worms (7.50%) were collected and differentiated into different ecological and trophic groups and their body lengths and PTE concentrations in the body tissues were investigated. The animals showed different responses to the biosolids at population and individual levels. There were substantial changes in epigeic collembolan communities and bacterivorous nematodes increased significantly after biosolid amendment. Biosolid-borne PTEs were major factors and Redundancy (RDA) analysis indicates that collembolan communities were strongly influenced by zinc (Zn). The three groups of soil animals showed similar trends in accumulation of PTEs in the sequence cadmium (Cd) > Zn > copper (Cu), and the bioaccumulation factor (BAF) values of the PTEs were significantly higher in the industrial sludge treatment than in other two treatments with a similar trend of decreasing body length of nematodes. The results indicate that it is potentially risky to use industrial biosolids in the long term, and different species and ecological groups of collembolans and different trophic groups of nematodes should be examined when assessing soil health.

The toxicity of three biocides, esfenvalerate, picoxystrobin and triclosan, on adult survival and recruitment of juveniles was studied in the springtail Folsomia fimetaria, both in single and mixture experiments. Recruitment of juveniles was more sensitive to biocide exposure than adult survival. The concepts of concentration addition and independent action returned almost identical toxicity predictions, though both models failed to predict the observed toxicity due to synergistic deviations at high exposure concentrations. A comparison with a similar study on earthworms showed that response-patterns were species-specific. Consequently, there is no single reference concept which is applicable for all species of one ecosystem, which in turn questions the usefulness of such mixture prediction concepts in ecological risk assessment.

Anaerobically digested and composted sewage sludge (CSS) has been suggested to be a slow-release fertilizer in forestry and an alternative to quick-release inorganic fertilizers. The effects of CSS with or without added carbohydrate on inorganic nitrogen availability and on soil animals were tested in two Norway spruce plantations. Half of the seedlings were individually fertilized with CSS, and the rest were left as controls. Solid sucrose was added to half of the fertilized and untreated seedlings. Soil samples were taken in the autumn in the first and the second year after the treatments. CSS increased soil NH4–N (2100%), the proportion of soil NO3–N, and the N concentration of spruce needles. CSS greatly reduced the abundances of enchytraeids, tardigrades and collembolans, but increased the proportion and abundance of bacterial-feeding nematodes irrespective of carbohydrate addition. A better stabilization method needs to be developed before CSS can be used as a forest fertilizer.

Responses of Collembola to 7 years of CO2 enrichment (550 ppm) in a Swiss free-air CO2 enrichment (FACE) experiment in a forest with 80- to 120-year-old trees were investigated in this study. Contrary to our expectations, increased CO2 caused a significant decrease in Collembola numbers, including a significant decrease in euedaphic Collembola. Increased CO2, however, did not affect community group richness. Collembola biomass was not significantly changed by CO2 enrichment, regardless of whether it was considered in terms of the total community, life-strategy groups, or individual species (with an exception of Mesaphorura krausbaueri). The reason for this is that CO2 enrichment caused a general increase in individual body size, which compensated for reduced abundances. The results are consistent with the idea that the rhizosphere is important for soil fauna, and the combination of reduced fine root growth and increased soil moisture might trigger a reduction in Collembola abundance.

This study aimed at relating the abundance and diversity of invertebrate communities of urban soils to chemical and physical soil characteristics and to identify the taxa most sensitive or tolerant to soil stressors. The invertebrate community of five urban soils in Naples, Italy, was sampled. To assess soil quality invertebrate community indices (Shannon, Simpson, Menhinick and Pielou indices), Acarina/Collembola ratios, and the soil biological quality index (QBS) were calculated. The chemical and physical characteristics of the soils strongly differed. Abundance rather than taxa richness of invertebrates were more affected by soil characteristics. The community was more abundant and diverse in the soils with high organic matter and water content and low metal (Cu, Pb, Zn) concentrations. The taxa more resistant to the urban environment included Acarina, Enchytraeids, Collembola and Nematoda. Collembolans appeared particularly sensitive to changing soil properties. Among the investigated indices, QBS seems most appropriate for soil quality assessment.

Glyphosate-based herbicide (GBH) is the most widely used herbicide worldwide and has long been considered to have significantly low toxicity to non-target soil invertebrates based on short-term toxicity tests (<56 d). However, long-term GBH toxicity assessment is necessary as GBH is repeatedly applied in the same field annually because of the advent of glyphosate-resistant crops. In this study, a multigeneration test was conducted where Allonychiurus kimi (Collembola) was exposed to GBH for three generations (referred to as F₀, F₁, and F₂) to evaluate the long-term toxic effect. The endpoints used were adult survival and juvenile production for the individual level toxicity assessment. Phospholipid profile and population age structure were the endpoints used for sub-individual and population levels, respectively. GBH was observed to have no negative effects on adult survivals of all generations, but juvenile production was found to decrease in a concentration-dependent manner, with EC₅₀s being estimated as 572.5, 274.8, and 59.8 mg a.i. kg⁻¹ in the F₀, F₁, and F₂ generations, respectively. The age structure of A. kimi population produced in the test of all generations was altered by GBH exposure, mainly because of the decrease in the number of young juveniles. Further, differences between the phospholipid profiles of the control and GBH treatments became apparent over generations, with PA 16:0, PA 12:0, and PS 42:0 lipids not being detected at the highest concentration of 741 mg kg⁻¹ in F₂. Considering all our findings from sub-individual to population levels, repeated and long-term use of GBH could have significantly higher negative impacts on non-target soil organisms than expected.

Interaction between effects of hazardous chemicals in the environment and adverse climatic conditions is a problem that receives increased attention in the light of climate change. We studied interactive effects of phenanthrene and drought using a test system in which springtails (Folsomia candida Willem) were concurrently exposed to a sublethal phenanthrene level via passive dosing from silicone (chemical activity of 0.010), and sublethal drought from aqueous NaCl solutions (water activity of 0.988). Previous studies have shown that the combined effects of high levels of phenanthrene and drought, respectively, interact synergistically when using lethality as an end-point. Here, we hypothesized that phenanthrene interferes with physiological mechanisms involved in drought tolerance, and that drought influences detoxification of phenanthrene. However, this hypothesis was not supported by data since phenanthrene had no effect on drought-protective accumulation of myo-inositol, and normal water conserving mechanisms of F. candida were functioning despite the near-lethal concentrations of the toxicant. Further, detoxifying induction of cytochrome P450 and glutathione-S-transferase was not impeded by drought. Both phenanthrene and drought induced transcription of heat shock protein (hsp70) and the combined effect of the two stressors on hsp70 transcription was additive, suggesting that the cellular stress and lethality imposed by these levels of phenanthrene and drought were also additive.

To determine if long-term equilibration may alleviate molybdenum toxicity, earthworms, enchytraeids, collembolans and four plant species were exposed to three soils freshly spiked with Na₂MoO₄.2H₂O and equilibrated for 6 or 11 months in the field with free drainage. Total Mo concentrations in soil decreased by leaching, most (up to 98%) in sandy soil and less (54–62%) in silty and clayey soils. Changes in residual Mo toxicity with time were inconclusive in sandy soil. In the other two soils, toxicity of residual total Mo was significantly reduced after 11 months equilibration with a median 5.5-fold increase in ED50s. Mo fixation in soil, i.e. the decrease of soil solution Mo concentrations at equivalent residual total soil Mo, was maximally a factor of 2.1 only. This experiment shows natural attenuation of molybdate ecotoxicity under field conditions is related to leaching of excess Mo and other ions as well as to slow ageing reactions.

The present study tests the effect of antiparasitic compound ivermectin in a constructed food-web system, a soil multi-species (SMS) higher tier test system. Mutualism, competition and predation within the SMS system were introduced by the addition of five collembolan species, one enchytraeid and a predatory mite species. Bait lamina sticks were incorporated as a measure of functional toxicity, attempting to the integrated feeding activity of the invertebrates. The study showed that on the community level all treatments were significantly affecting the community abundance and composition and that the decrease in abundance corresponded well with increasing exposure concentration for all species. Since all concentrations had significant adverse effect on the community structure, the community-based no-effect-concentration is below the lowest test concentration of 0.25 mg kg⁻¹, whereas the EC10 for the individual species were as low as 0.05 mg kg⁻¹. The bait lamina respond was only affected at the highest exposure concentration.

The response of specific groups of organisms, like Collembola to atmospheric nitrogen (N) deposition is still scarcely known. We investigated the Collembola community in a subalpine forest (Alptal, Switzerland) as subjected for 12 years to an experimentally increased N deposition (+25 on top of ambient 12 kg N ha⁻¹ year⁻¹). In the 0-5 cm soil layer, there was a tendency of total Collembola densities to be lower in N-treated than in control plots. The density of Isotomiella minor, the most abundant species, was significantly reduced by the N addition. A tendency of lower Collembola group richness was observed in N-treated plots. The Density-Group index (dDG) showed a significant reduction of community diversity, but the Shannon-Wiener index (H') was not significantly affected by the N addition. The Collembola community can be considered as a bioindicator of N inputs exceeding the biological needs, namely, soil N saturation. Collembola community, which was significantly affected by a long-term N addition experiment, can be considered as a bioindicator of N saturation.