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Neonicotinoid insecticides have come under increasing scrutiny for their impact on non-target organisms, especially pollinators. The current scientific literature is mainly focused on the impact of these insecticides on pollinators and some aquatic insects, leaving a knowledge gap concerning soil invertebrates. This study aimed at filling this gap, by determining the toxicity of imidacloprid and thiacloprid to five species of soil invertebrates: earthworms ( Eisenia andrei), enchytraeids ( Enchytraeus crypticus), Collembola ( Folsomia candida), oribatid mites ( Oppia nitens) and isopods ( Porcellio scaber). Tests focused on survival and reproduction or growth, after 3-5 weeks exposure in natural LUFA 2.2 standard soil. Imidacloprid was more toxic than thiacloprid for all species tested. F. candida and E. andrei were the most sensitive species, with LCs of 0.20-0.62 and 0.77 mg/kg dry soil for imidacloprid and 2.7-3.9 and 7.1 mg/kg dry soil for thiacloprid. ECs for effects on the reproduction of F. candida and E. andrei were 0.097-0.30 and 0.39 mg/kg dry soil for imidacloprid and 1.7-2.4 and 0.44 mg/kg dry soil for thiacloprid. The least sensitive species were O. nitens and P. scaber. Enchytraeids were a factor of 5-40 less sensitive than the taxonomically related earthworm, depending on the endpoint considered. Although not all the species showed high sensitivity to the neonicotinoids tested, these results raise awareness about the effects these insecticides can have on non-target soil invertebrates. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) have been used in numerous consumer products and may enter the soil through the land application of biosolids. However, little is known about the relationship between Ag NP exposure and their bioavailability for soil organisms. This study aims at comparing the uptake and elimination kinetics of Ag upon exposures to different Ag forms (NPs and ionic Ag (as AgNO)) in the isopod Porcellionides pruinosus. Isopods were exposed to contaminated Lufa 2.2 soil or alder leaves as food. Uptake and elimination rate constants for soil exposure did not significantly differ between Ag NPs and ionic Ag at 30 and 60 mg Ag/kg. For dietary exposure, the uptake rate constant was up to 5 times higher for Ag NPs than for AgNO, but this was related to feeding activity and exposure concentrations, while no difference in the elimination rate constants was found. When comparing both routes, dietary exposure resulted in lower Ag uptake rate constants but elimination rate constants did not differ. A fast Ag uptake was observed from both routes and most of the Ag taken up seemed not to be eliminated. Synchrotron X-ray fluorescence showed Ag in the S-cells of the hepatopancreas, thus supporting the observations from the kinetic experiment (i.e. low elimination). In addition, our results show that isopods have an extremely high Ag accumulation capacity, suggesting the presence of an efficient Ag storage compartment. [ABSTRACT FROM AUTHOR]

The woodlouse Porcellio dilatatus (Crustacea) is a suitable model organism as a biological indicator for the toxic effects evaluation induced by pollutants exposure in the environment. In this study, the influence of cadmium (Cd) species on survival and reproduction of isopods was investigated. Survival, growth and reproductive parameters (time to pregnancy, pregnancy duration, pregnancy and abortion occurrence, number of juveniles per female and juvenile weight) were recorded after isopods were exposed to two species of Cd deployed in food: Cd(Cys) and Cd(NO). There was a difference between survival rates of exposed males and females to both Cd species but in the case of Cd(NO) these differences were more accentuated, with females having higher survival rates. In the presence of both metal species a reduction in the number of pregnancies and pregnancy duration was observed, while in the case of Cd(Cys) all pregnancies were inconclusive. The number of juveniles delivered per female fed with Cd(NO) contaminated food was lower than in the control, whereas the juvenile weights were higher. To the best of our knowledge, the present study is the first toxicity test demonstrating that metal speciation affects reproduction in isopods. Cd(Cys) showed to be the most toxic of the contaminants tested in this long term exposure and capable of jeopardizing the reproduction efforts of isopods. [ABSTRACT FROM AUTHOR]

An achievable way to evaluate the bioavailability of a certain toxic in the environment is to measure the concentration inside soil organisms. Non-target saprotrophic organisms like isopods are often exposed to agrochemicals or other kind of persistent chemicals. In this study the isopod Porcellionides pruinosus was exposed to a constant concentration of Lindane (γ-HCH) via food. Using toxicokinetic models the bioaccumulation and fate of the pesticide by isopods was assessed and compared with previous studies, where an unexpected decrease in γ-HCH concentration was observed. Animal body burdens showed higher values, and a lower assimilation rate constant, although the elimination rate constant was twice the value previously observed. It was also observed that a significant amount of γ-HCH had an unknown fate. To discover its possible destiny, a factorial experiment was carried out using two types of CO2 traps and contaminated leaves in the presence and absence of isopods. It was concluded that isopod activity might have been responsible for a more rapid biotransformation of γ-HCH in leaves, since the amount of the pesticide is reduced in their presence. [ABSTRACT FROM AUTHOR]

In laboratory toxicity tests, woodlice (Oniscus asellus) exposed to a variety of different combinations of the metals cadmium, lead, and zinc exhibited a broad range in intensity of the induction of the 70 kDa stress protein (hsp70, stress-70). Using two-dimensional isobolograms and the ‘toxic unit’ concept, it could be shown that cadmium and lead as well as cadmium and zinc or lead and zinc act as synergists and cause superadditive effects on the stress response of these animals. Using a three- dimensional isobologram based on the stress-70 level in response to numerous combinations of all three tested metals, transfer to the field could be achieved: data obtained from O. asellus populations abundant at field sites, the soils of which are influenced mainly by different concentrations of these heavy metals, were found to fit this laboratory test-based model [ABSTRACT FROM AUTHOR]

The induction of stress-70 (hsp70) and stress-60 (hsp60, chaperonin 60) in the terrestrial woodlouse, Oniscus asellus, after exposure to various heavy metals and heavy metal combinations was investigated by means of standard Western-blot using monoclonal antibodies. The expression of stress-70 was found to react much more sensitively to metal contamination than that of stress-60. The general course of the stress-70 response to increasing metal concentration was found to be similar for all treatments. Based on the obtained results, this course could be divided into three zones: in the first zone, the expression of stress-70 proteins was only marginally increased by comparatively low metal concentrations; in the second zone, strong induction of stress-70 occurred and the ability of the heat shock system to react to increased metal concentrations reached its climax; and in the third, non-compensation zone, a further increase in heavy metal concentration resulted in a decline of stress-70 levels, which can be interpreted as a result of pathological tissue damage. Combinations of metals were found to increase the stress- 70 level more intensely than related concentrations of singularly applied metals. Based on these studies, a ranking scheme of increasing toxicological impact of a variety of heavy metal combinations was composed [ABSTRACT FROM AUTHOR]