Growth and metal accumulation in Porcellio scaber exposed to poplar litter from Cd-, Pb-, and Zn-contaminated sites

First Insights Into Trace Element Accumulation by Philoscia affinis (Crustacea, Isopoda): a Novel Tracer to Assess Soil Contamination in Lowland Plains?

Isopods are terrestrial invertebrates that accumulate trace elements in large quantities, thus providing information on levels of soil contamination. However, the accumulation pattern seems to be species dependent. For this study, specimens of Philoscia affinis (Isopoda, Oniscidea) and soil samples were collected from both a protected area (site 1) and urban roadside (site 2) in the low plain of Friuli-Venezia Giulia (northeast Italy) to determine whether P. affinis could serve as a potential candidate for monitoring soil contamination. To do this, the following objectives were achieved: a) the level of trace elements (Al, Cd, Cu, Fe, Hg, Mn, Pb, Zn) were detected in soils and isopods; 2) the difference in trace elements accumulation was compared in the two sampling sites; 3) the bioaccumulation factor (BAF) was calculated for each element. With some exceptions, trace element concentrations were higher in both isopods and soil samples from the urban roadside compared to the protected area. Furthermore, except for Cd, Cu, and Zn, trace element levels were higher in the soil than in the isopod samples. The higher mean BAF values were recorded for Cd (6.169 and 6.974 for site 1 and 2, respectively), Cu (10.324 and 11.452 for site 1 and 2, respectively), and Zn (1.836 and 2: 1.943 for site 1 and 2, respectively), whereas BAF values <1 were recorded for the other elements. Philoscia affinis was found to be a potential candidate to monitor soil contamination as a macro-concentrator of Cu and Cd and a micro-concentrator of Zn.

Ecological Drawbacks of Nanomaterials Produced on an Industrial Scale: Collateral Effect on Human and Environmental Health

Currently, hundreds of different nanomaterials with a broad application in products that make daily lives a little bit easier, in every aspect, are being produced on an industrial scale at thousands of tons per year. However, several scientists, researchers, politics, and ordinary citizens have stated their concern regarding the life cycle, collateral effects, and final disposal of these cutting-edge materials. This review summarizes, describes, and discusses all manuscripts published in the Journal Citation Reports during the last 10 years, which studied the toxicity or the effects of nanomaterials on human and environmental health. It was observed that 23.62% of the manuscripts analyzed found no ecological or human risks; 54.39% showed that several nanomaterials have toxicological effects on the ecosystems, human, or environmental health. In comparison, only 21.97% stated the nanomaterials had a beneficial impact on those. Although only 54.39% of the manuscripts reported unfavorable effects of nanomaterials on ecosystems, human, or environmental health, it is relevant because the potential damage is invaluable. Therefore, it is imperative to make toxicological studies of nanomaterials with holistic focus under strictly controlled real conditions before their commercialization, to deliver to the market only innocuous and environmentally friendly products.

Changes in Morphometric Traits of Ground Beetles Along Urbanization Gradients

Urbanization has a significant impact on abiotic and biotic factors in nature. We examined the morphometric characters of four carabid species (Abax parallelepipedus, Carabus scheidleri, Carabus violaceus, and Pterostichus oblongopunctatus) along urbanization gradients in and around the cities of Vienna (Austria) and Debrecen (Hungary). We found significant differences among urban, suburban, and rural areas in the parameters of antennomers, the maxillary palpus, the labial palpus, and the length of the tibia and the elytra of the carabids studied. We also found significant differences between males and females based on the parameters of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. An interaction between urbanization and sex was found in the case of antennomers, the maxillary palpus, the labial palpus, the femur, and the elytra. Our findings suggested that in the cases of species from Carabini tribus the parameters of antennomers, the maxillary palpus, and the elytra could be useful for assessing the effects of urbanization because these morphometric characters responded sensitively to the environmental stress, whereas the most useful parameters are those of antennomers and the tibia for the species of Pterostichini tribus. Our findings also revealed that females are more sensitive to environmental stress than males.

Physiological and histopathological responses of Porcellio laevis (Isopoda, Crustacea) as indicators of metal trace element contamination

This study was designed to assess the impact of the mixture of cadmium (Cd) and zinc (Zn) on the bioaccumulation and the ultrastructural changes in the hepatopancreas of Porcellio laevis (Latreille, 1804) after 4 weeks of exposure to contaminated Quercus leaves under laboratory conditions. For each metal, four concentrations were used with four replicates for each concentration. Metal concentrations in the hepatopancreas and the rest of the body were determined using atomic absorption spectrometry. From the first week until the end of the experiment, a weight gain in P. laevis was observed particularly between the first and the end of exposure from 93.3 ± 18.22 mg fw to 105.22 ± 16.16 mg fw and from 106.4 ± 22.67 mg fw to 125.9 ± 23.9 mg fw for Mix1 and Mix4, respectively. Additionally, the determined metal trace elements (MTE) concentrations in the hepatopancreas were considerably higher compared to those in the rest of the body and seem to be dose-dependent. Using transmission electron microscopy (TEM), some alterations were highlighted in the hepatopancreas. The main observed alterations were (a) the destruction of the microvilli border in a considerable portion of cells, (b) the increase of the lipid droplets with different shapes and sizes, (c) the increase in the number of the mitochondria, and (d) the appearance of TE in the form of B-type granules. The obtained results confirmed the ability of P. laevis to deal with high amounts of MTE, suggesting its possible use in future soil's biomonitoring programs.

The induced damage in the hepatopancreas of Orchestia species after exposure to a mixture of Cu/Zn-An ultrastructural study

The hepatopancreas of crustaceans species has been recognized as an essential target organ to assess trace elements' effects. Due to its dynamic and capability of detoxifying trace metal, this organ often indicates distinct pathological disturbances. In the present work, we intend to evaluate the bioaccumulation of trace metal in three Orchestia species (Orchestia montagui, Orchestia gammarellus, and Orchestia mediterranea) living in symmetry in the banks of Bizerte lagoon (37°13'8″N 09°55'1″E) after their exposure during 14 days to a mixture of copper and zinc, and to highlight the effect of these metals on their hepatopancreas ultrastructure using transmission electron microscopy. At the end of the experiment, results showed that the mortality and the body mass varied according to the used nominal concentrations. Significant alterations were noted in all the treatment groups. The degree of these alterations depends on the used concentration, and they are represented especially by the cells remoteness and the border lyses, the reduction of the nuclear volume, the increase in the cytoplasm density with the presence of trace metal in the nucleus as well as in the vacuole, the disorganization and the destruction of microvilli, the condensation of the majority of cellular organelles and mitochondria swelling. Through this study, Orchestia genus could be an attractive candidate for the biochemical study of trace metal toxicity in Tunisian wetlands.

Effects of Heavy Metals Artificial Contamination on Porcellio laevis (Latreille, 1804) (Crustacea: Isopoda: Oniscidea)

This study aimed at determining the competition of cadmium (Cd), lead (Pb), zinc (Zn) and copper (Cu) on their assimilation, on the food consumption and the growth of terrestrial isopod Porcellio laevis. Individuals were exposed to artificially contaminated litter of Quercus for 4 weeks and were weekly weighed. At the end of the experiment, the concentration of Cd, Pb, Zn and Cu in individuals were measured by atomic absorption spectrometry. Biological parameters such as growth, and bioaccumulation factor (BAF) were calculated and results from the various treatments were compared. Depending on metals, weight loss or gain were recorded for isopods during the four weeks of exposure. A weight loss was measured on individuals exposed to Cd-contaminated litter whereas a weight gain was highlighted for those exposed to the Zn-contaminated litter. BAF values revealed that P. laevis was macroconcentrator of Zn and Cu and deconcentrator of Cd and Pb.

The Effect of Urbanization on Trace Element Concentration and Symmetry of Woodlice (Armadillidium vulgare Latreille, 1804)

Woodlice are top consumers of a three-trophic system (soil, leaf litter, woodlice), and they are closely related to pollutant absorbing surfaces such as soil, leaf litter, and organic matter. We studied the effects of urbanization on trace element concentrations and fluctuating asymmetry of Armadillidium vulgare (Crustacea: Isopoda) individuals in and around Debrecen city, Hungary. Along an urbanization gradient (urban, suburban, and rural areas), trace element concentrations (Ba, Cu, Fe, Mn, Pb, and Zn) of woodlice and bioconcentration factor (BCF) were analyzed. Asymmetry was also measured in metric traits of woodlice: the length of three segments of antennae, the body length, and the width of the 3rd segment of pereon. We found significant differences in Ba and Cu concentration of A. vulgare individuals along the urbanization gradient. The highest Cu concentration was found in woodlice from the urban area and the highest Ba concentration was found in the individuals from the rural area. The Ba concentration was higher in females than in males. The BCF values of Cu indicated that A. vulgare accumulated this element from soil and leaf litter. There was no significant difference in symmetry of the bilateral traits of woodlice along the urbanization gradient based on FA levels. Our results showed that the urbanization had remarkable effect on the Ba and Cu concentration of woodlice which were originated from traffic pollution. At the same time, the anthropogenic activities did not affect the symmetry of the tested traits of A. vulgare individuals.

Ecotoxicological effects of trace element contamination in talitrid amphipod Orchestia montagui Audouin, 1826

This study deals with the evaluation of trace element bioaccumulation and histological alterations in the hepatopancreas of the supralittoral amphipod Orchestia montagui Audouin, 1826 due to the exposure to cadmium, copper, and zinc. Orchestia montagui individuals were maintained during 14 days in soils contaminated with different trace elements namely cadmium, copper, and zinc; a control was also prepared. Our results show that the mortality and the body mass vary according to the metal and the nominal concentration used. In general, the mortality increases from the seventh day. However, the body mass shows a decrease with cadmium exposure and an increase with copper and zinc exposures. Furthermore, the concentration factor highlights that this species is considered a macroconcentrator for copper and zinc. The hepatopancreas of unexposed and exposed animals were compared to detect histological changes. Our results show significant alterations in the hepatopancreas of the exposed animals after the experiment. The degree of these alterations was found to be dose-dependent. Among the histological changes in the hepatopancreas in O. montagui, a loss of cell structure was noted, especially cell remoteness and border lyses, the reduction of nuclear volume, an increase in the cytoplasm density with the presence of trace element deposits in both the nucleus and vacuoles, a disorganization and destruction of microvilli, and a condensation of the majority of cell organelles and mitochondria swelling. Through this study, we have confirmed that O. montagui can be a relevant model to assess trace metal element pollution in Tunisian coastal lagoons with the aim of using it in future biomonitoring programs.

Toxicity of Heavy Metals to Mongoloniscus sinensis (Dollfus, 1901) (Crustacea: Isopoda: Oniscidea)

The bioaccumulation of and resistance to different heavy metals in soil was tested using Mongoloniscus sinensis, a terrestrial isopod endemic to china, and results show that: (1) the median lethal concentration (LC₅₀) of Pb, Zn, Cd in the filter paper contact test after 48 h was 197.6, 503.7, 448.0 µg cm^- 2, LC₅₀ of Pb-Zn compounds was 173.8 and 440.8 µg cm^- 2 and after 14 days of soil contamination LC50 was 2917.0, 2977.9, 5048.4 mg kg^- 1, LC₅₀ of Pb-Zn compounds was 1219 and 1463 mg kg^- 1. Thus Zn turned out to be less toxic than Cd in the filter paper contact test, while their sequence of toxicity was reversed during the soil exposure test, which shows that M. sinensis can tolerate a dose of Zn and Cd. (2) analysis of body burdens showed that the sequence of internalized metal concentrations was Pb < Cd < Zn, which indicates that heavy metals in soil can be enriched and absorbed by M. sinensis, and that it is much more efficient at absorbing Zn and Cd than Pb.

Silver nanoparticles in sewage sludge: Bioavailability of sulfidized silver to the terrestrial isopod Porcellio scaber

Silver nanoparticles (AgNPs) are efficiently converted during the wastewater-treatment process into sparingly soluble Ag sulfides (Ag₂ S). In several countries, sewage sludge is used as a fertilizer in agriculture. The bioavailability of sulfidized Ag to the terrestrial isopod Porcellio scaber was investigated. Sewage sludge containing transformed AgNPs was obtained from a laboratory-scale sewage-treatment plant operated according to Organisation for Economic Co-operation and Development (OECD) guideline 303a. The results of transmission electron microscopy with energy dispersive X-ray of sludge samples suggest that AgNPs were completely transformed to Ag₂ S. Adult isopods were exposed to OECD 207 soil substrate amended with the AgNP spiked sludge for 14 d (uptake phase) followed by an elimination phase in unspiked soil of equal duration. Most of the Ag measured in P. scaber at the end of the uptake phase was found in the hindgut (71%), indicating that only a minor part of the estimated Ag content was actually assimilated by the isopods with 16.3 and 12.7% found in the carcass and hepatopancreas, respectively. As a result of this, the Ag content of the animals dropped following transition to unspiked sludge within 2 d to one-third of the previously measured Ag concentration and remained stable at this level until the end of the elimination period. The present study shows that Ag₂ S in sewage sludge is bioavailable to the terrestrial isopod P. scaber. Environ Toxicol Chem 2018;37:1606-1613. © 2018 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

Bioaccumulation of hexachlorobenzene in the terrestrial isopod Porcellio scaber

A test system to investigate the biomagnification of organic chemicals in the terrestrial isopod Porcellio scaber was developed and validated. Adult isopods were fed on alder leaf powder (Alnus glutinosa) spiked with [¹⁴ C]hexachlorobenzene (HCB). Test animals, sampled regularly during the uptake (16 d) and depuration phases (16 d), were analyzed, and the kinetics of tissue concentrations were determined. Uptake (k₁ ) and depuration rates (k₂ ) were calculated to estimate kinetic biomagnification factors (BMFs). In addition, the effect of coprophagy on the uptake and accumulation of HCB as well as the tissue distribution of HCB in P. scaber was investigated. The test system was shown to be suitable for investigations into the terrestrial bioaccumulation of chemicals. Coprophagy had no effect on the bioaccumulation of HCB in P. scaber. The hepatopancreas was identified as the main target tissue for HCB accumulation. The low BMF of 0.057 resulted from an assimilation efficiency (α) of 31.42%, a low uptake rate k₁ (0.009 d^-1 ), and a high depuration rate k₂ (0.164 d^-1 ). The results indicate that the terrestrial bioaccumulation of organic chemicals in P. scaber might not represent a worst-case scenario for biomagnification, limiting the value of the test system for the regulatory assessment of organic chemicals. Environ Toxicol Chem 2016;35:2867-2873. © 2016 The Authors. Environmental Toxicology and Chemistry Published by Wiley Periodicals, Inc. on behalf of SETAC.

Simulation of Invertebrate Aggregation Shows the Importance of Stable Personality over Diversity in Consensus Decision-Making

Aggregation of many species of invertebrate is an example of a consensus decision, the success of which is central to survival. Personality is a stable form of behavioural diversity which has been observed in the aggregation process, but neither the reasons for its stability nor its effects on consensus decisions are well understood. By using an agent-based model of invertebrate aggregation, it is found that diverse personalities have only limited benefits to the experimental consensus decision-making process, but may have a more valuable role in natural settings. Importantly, although certain personalities may ostensibly have potential drawbacks at the individual level, such as choosing to rest in unfavourable places, all individuals are likely to benefit from maintaining a constant personality, which promotes group stability. These findings help to improve understanding of consensus decision-making and the prevalence of stable personality.

Antioxidant defense gene analysis in Brassica oleracea and Trifolium repens exposed to Cd and/or Pb

This study focused on the expression analysis of antioxidant defense genes in Brassica oleracea and in Trifolium repens. Plants were exposed for 3, 10, and 56 days in microcosms to a field-collected suburban soil spiked by low concentrations of cadmium and/or lead. In both species, metal accumulations and expression levels of genes encoding proteins involved and/or related to antioxidant defense systems (glutathione transferases, peroxidases, catalases, metallothioneins) were quantified in leaves in order to better understand the detoxification processes involved following exposure to metals. It appeared that strongest gene expression variations in T. repens were observed when plants are exposed to Cd (metallothionein and ascorbate peroxidase upregulations) whereas strongest variations in B. oleracea were observed in case of Cd/Pb co-exposures (metallothionein, glutathione transferase, and peroxidase upregulations). Results also suggest that there is a benefit to use complementary species in order to better apprehend the biological effects in ecotoxicology.

Water extraction kinetics of metals, arsenic and dissolved organic carbon from industrial contaminated poplar leaves

In industrial areas, tree leaves contaminated by metals and metalloids could constitute a secondary source of pollutants. In the present study, water extraction kinetics of inorganic elements (IE: Pb, Zn, Cd, As, Fe and Mn), dissolved organic carbon, pH and biological activity were studied for industrial contaminated poplar leaves. Moreover, the distribution of the IE through the size fractions of the associated top soil was measured. High quantities of Mn, Zn and As and polysaccharides were released in the solution from the strongly contaminated leaves. The kinetic of release varied with time and metal type. The solution pH decreased while dissolved organic contents increased with time after 30 days. Therefore, these contaminated leaves could constitute a source of more available organic metals and metalloids than the initial inorganic process particles. However, the distribution of the IE through the size fractions of the top soil suggested that a great part of the released IE was adsorbed, reducing in consequence their transfers and bioavailability. It's concluded that mobility/bioavailability and speciation of metals and metalloids released from the decomposition of polluted tree leaves depends on soil characteristics, pollutant type and litter composition, with consequences for environmental risk assessment.

Effects of heavy metal accumulation on some reproductive characters in Armadillidium granulatum Brandt (Crustacea, Isopoda, Oniscidea)

The impact of heavy metal bioaccumulation on reproduction of the isopod Armadillidium granulatum was studied by exposing the animals to food contaminated with various sub-lethal concentrations of cadmium, lead and zinc salts over a period of three weeks. The analysis carried out by atomic absorption spectrometry on whole body and on isolated female and male genital systems highlighted that, although metal's bioaccumulation was always concentration-dependent, it varies considerably depending on the metal (Cd>Zn>Pb) as pointed out by the respective values of the concentration factor. The heavy metals bioaccumulation has influenced in different ways the reproductive characters observed; while no significant difference was found with regard to the length of the incubation period and the number of broods--A. granulatum has an iteroparous reproductive strategy--the onset and the length of the reproductive season were negatively affected by the increase in concentration of the tested metals, in particular of Cd. The rate of gravid females, instead, was negatively affected by the bioaccumulation of Cd and Zn while in the groups treated with the highest concentrations of Pb all females produced at least one brood. The number of juveniles released from the brood pouch at the end of incubation resulted considerably higher and it was always positively correlated to the increase of the concentration of each metal, except for the highest Pb concentration. The explanation of this result, apparently anomalous, could be the object of a future research.

An in vivo invertebrate bioassay of Pb, Zn and Cd stabilization in contaminated soil

The terrestrial isopod (Porcellio scaber) was used to assess the remediation efficiency of limestone and a mixture of gravel sludge and red mud as stabilizing agents of Pb, Zn and Cd in industrially polluted soil, which contains 800, 540 and 7mgkg(-1) of Pb, Zn and Cd, respectively. The aim of our study was to compare and evaluate the results of the biological and non-biological assessment of metal bioavailability after soil remediation. Results of a 14d bioaccumulation test with P. scaber showed that that Pb and Zn stabilization were more successful with gravel sludge and red mud, while Cd was better stabilized and thus less bioavailable following limestone treatment. In vivo bioaccumulation tests confirmed the results of chemical bioaccessibility, however it was more sensitive. Biotesting with isopods is a relevant approach for fast screening of bioavailability of metals in soils which includes temporal and spatial components.

CAPSULE

Bioavailability assessed by P. scaber is a more relevant and sensitive measure of metal bioavailability than chemical bioaccessibility testing in remediated industrially polluted soil.

Aggregation in woodlice: social interaction and density effects

Terrestrial isopods are known to be sensitive to humidity, brightness or temperature. Until now, aggregation was assumed to depend on these sensitivities as a result of individual preferences. In this paper, we show that the social component is also important in the isopod aggregation phenomenon. In experimental arenas with two identical shelters up to nearly 90% of woodlice aggregated under shelters. This aggregation was quick as in 10 minutes most of the animals aggregated, irrespective of their density. Nonetheless, 10-15% of the animals walked around the arena, rarely forming very small and short-lasting aggregates outside shelters. Woodlice aggregated preferably under one of the shelters in 77% of experiments. Indeed, almost 80% of the animals out of 40, 60 or 80 animals in the arena aggregated under one shelter. In arenas with 100 individuals the aggregations were proportionally smaller (70%). Our results revealed that 70 animals was a maximum number of woodlice in an aggregate. We concluded that the location of aggregates is strongly governed by individual preferences but the dynamics of aggregation and collective choice are controlled by social interaction between congeners. The tested densities of the animals in the arena did not impact the aggregation patterns.

Influence of compost addition on lead and arsenic bioavailability in reclaimed orchard soil assessed using Porcellio scaber bioaccumulation test

Long-term application of lead arsenate in orchards has led to a significant accumulation of Pb and As in the topsoil. Reclamation of old orchards for agricultural purposes entails the exposure of humans to Pb and As, which can be reduced by adequate remediation actions. In this study, we assessed the remediation efficiency of compost addition, commonly used as a sustainable agricultural practice, in decreasing the human exposure Pb and As by direct ingestion. The remediation was evaluated based on Pb and As bioavailability, assessed by means of a selective non-exhaustive chemical extraction (modified Morgan extraction, MME), with a physiologically based extraction test (PBET) for the assessment of Pb and As bioavailability in ingested soils and with a novel in vivo bioaccumulation test with isopods (Porcellio scaber). All the tests showed that compost addition consistently reduced Pb, but increased As potential bioavailability. The bioaccumulation test with P. scaber was sensitive to changes in Pb and As bioavailability in test soils. However, the results indicate that the bioavailability of As could be under- or overestimated using solely chemical extraction tests. Indirect assessment of trace metal bioavailability with bioaccumulation in isopods can be used as complementary source of data to the existing in vitro chemical extraction test approach for the estimation of human exposure to trace elements in polluted and remediated soil. This is the first report on the use of As accumulation in P. scaber as a tool for the assessment of As bioavailability in contaminated orchard soil.

Effects on survival and reproduction of Porcellio dilatatus exposed to different Cd species

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)(2) and Cd(NO(3))(2). There was a difference between survival rates of exposed males and females to both Cd species but in the case of Cd(NO(3))(2) 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)(2) all pregnancies were inconclusive. The number of juveniles delivered per female fed with Cd(NO(3))(2) 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)(2) showed to be the most toxic of the contaminants tested in this long term exposure and capable of jeopardizing the reproduction efforts of isopods.

Gene expression analysis of 4 biomarker candidates in Eisenia fetida exposed to an environmental metallic trace elements gradient: a microcosm study

Past activities of 2 smelters (Metaleurop Nord and Nyrstar) led to the accumulation of high amounts of Metal Trace Elements (TEs) in top soils of the Noyelles-Godault/Auby area, Northern France. Earthworms were exposed to polluted soils collected in this area to study and better understand the physiological changes, the mechanisms of acclimation, and detoxification resulting from TE exposure. Previously we have cloned and transcriptionally characterized potential biomarkers from immune cells of the ecotoxicologically important earthworm species Eisenia fetida exposed in vivo to TE-spiked standard soils. In the present study, analysis of expression kinetics of four candidate indicator genes (Cadmium-metallothionein, coactosin like protein, phytochelatin synthase and lysenin) was performed in E. fetida after microcosm exposures to natural soils exhibiting an environmental cadmium (Cd) gradient in a kinetic manner. TE body burdens were also measured. This microcosm study provided insights into: (1) the ability of the 4 tested genes to serve as expression biomarkers, (2) detoxification processes through the expression analysis of selected genes, and (3) influence of land uses on the response of potential biomarkers (gene expression or TE uptake).