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We investigated how different carbonized materials, or chars (olive mill pomace biochar (BC) and urban greens pruning residues hydrochar (HC)) affect an important member of soil fauna, the terrestrial isopod Porcellio scaber . The selection behavior of isopods towards chars after a 48 h exposure was studied in (i) soil-char amended tests with single and multiple choices, and (ii) tests with chars offered as pure material. Finally, we exposed the isopods to char-amended soils for a period of 14 days to follow the effect on food consumption, body mass and activities of enzymes that are commonly altered upon stressor exposure (acetylcholinesterase, AChE, and glutathione S-transferase, GST). We showed that isopods are able to select between char amended and un-amended soil and different forms of char amendments: a clear preference for BC, and avoidance of HC were evidenced. The preferences remained the same when the chars were sterilized leading to the conclusion that initial microorganism composition was not the reason for selection, but selection was governed by other chars’ physico-chemical properties. It remains to be elucidated which of these properties were the dominant reason for the selection. We also showed that isopods intentionally use BC as food at a similar rate to alder leaves. Medium-term exposure to HC resulted in adverse effects on isopods because it led to reduced feeding and growth, in addition to increasing GST activity, although no alterations in AChE activity were found. We suggest that behavioral tests with P. scaber could be used as a fast, reliable and economically feasible screening method for determining the safety of chars for the soil environment. Results represent significant contribution in the field of char toxicity testing, highlighting the importance of tests with isopods as important members of soil meso fauna, with the aim of influencing environmental policies and quality standards. [ABSTRACT FROM AUTHOR]

We investigated the effects of a commercial pigment grade rutile TiO 2 on the terrestrial isopod Porcellio scaber in three locations that differed in terms of abiotic and biotic conditions: the laboratory, open air, and the closed barn. Mortality and isopod energy reserves (digestive gland total proteins, lipids and carbohydrates) were not affected following 14 days exposure to up to 1000 mg TiO 2 per kg dry leaves (mg/kg) under any experimental scenario. However, in the field tests, isopods consumption of TiO 2 -coated leaves was reduced compared to that of uncoated leaves and the decrease was not dose-dependent. The highest reduction was in the closed barn (45–56%) rather than in the open-air (38–40%). In laboratory-based food choice tests, isopods neither preferred nor avoided leaves coated with TiO 2 , suggesting that rather than sensing the TiO 2 on the leaves directly, the isopods under open-air and barn exposure responded to altered attractiveness and/or palatability of the TiO 2 amended leaves. We propose that this could be due to altered microbial population on the leaves, a hypothesis that requires further investigation. Although short-term exposure to atmospheric deposition of up to 1000 mg/kg commercial TiO 2 is unlikely to pose an immediate threat to isopod mortality and energy balance, reduced leaf feeding may have implications for the decomposition of plant material. [ABSTRACT FROM AUTHOR]

Biomolecular profiling with Fourier-Transform InfraRed Microscopy was performed to distinguish the Zn2+-mediated effects on the crustacean (Porcellio scaber) digestive glands from the ones elicited by the ZnO nanoparticles (NPs). The exposure to ZnO NPs or ZnCl2(1500 and 4000 µg Zn/g of dry food) activated different types of metabolic pathways: some were found in the case of both substances, some only in the case of ZnCl2, and some only upon exposure to ZnO NPs. Both the ZnO NPs and the ZnCl2increased the protein (∼1312 cm−1; 1720–1485 cm−1/3000–2830 cm−1) and RNA concentration (∼1115 cm−1). At the highest exposure concentration of ZnCl2, where the effects occurred also at the organismal level, some additional changes were found that were not detected upon the ZnO NP exposure. These included changed carbohydrate (most likely glycogen) concentrations (∼1043 cm−1) and the desaturation of cell membrane lipids (∼3014 cm−1). The activation of novel metabolic pathways, as evidenced by changed proteins’ structure (at 1274 cm−1), was found only in the case of ZnO NPs. This proves that Zn2+are not the only inducers of the response to ZnO NPs. Low bioavailable fraction of Zn2+in the digestive glands exposed to ZnO NPs further supports the role of particles in the ZnO NP-generated effects. This study provides the evidence that ZnO NPs induce their own metabolic responses in the subtoxic range. [ABSTRACT FROM AUTHOR]

Salinization of soil as the main cause for soil degradation is a global issue. Despite this, the data concerning the effects of different salts on terrestrial organisms are still missing. Our aim was to address the effects of four different salts (NaCl, KCl, NaNO 3 , and KNO 3 ) on terrestrial isopods Porcellio scaber. Two types of experiments were performed. In the first experiment, the isopods were exposed to 1, 2, and 5 g salt/kg dry leaf for 14 days and afterwards animal mortality, feeding activity, moult and growth were monitored. In the second experiment, a 48-h soil selection tests was done to investigate their preference/avoidance to certain salts. The feeding rate and growth efficiency of isopods decreased in a dose-dependent manner after 14 days exposure to KNO 3 and NaNO 3 . We suggest that nitrate (NO 3 − ) may be the predominant reason for these effects, because (i) the effects were only observed in the case of NO 3 − -salts, and (ii) K + and Na + induced no effects in the case of Cl − -salts where the concentrations of these two cations were even higher as in the case of NO 3 − salts. 48-h soil selection test showed that isopods were able to choose between NaCl dosed and unamended soil: the isopods preferred to spend time on NaCl spiked soil (up to 5 g salt/kg dry soil). In the case of KNO 3 and NaNO 3 no significant soil selection by isopods was found. In these two exposures isopods spent approximately 50% of their visits on both sides of the soil. The survival of isopods decreased in a dose independent manner when exposed to NaNO 3 , KNO 3 , and KCl. We conclude that NaNO 3 , KCl, and KNO 3 affect the isopods, while no effects were caused by NaCl under the exposure conditions of this study. This study implies that also other salts besides commonly investigated NaCl should be tested when the potential hazard of soil salinization to terrestrial organisms is in question. [ABSTRACT FROM AUTHOR]