Energy reserves and metal-storage granules in the hepatopancreas of Oniscus asellus and Porcellio scaber (Isopoda) from a metal gradient at Avonmouth, UK

Detoxification and recovery after cadmium exposure in the freshwater crab Sinopotamon henanense

Cadmium (Cd) is a common pollutant in the aquatic environment, which puts the health and safety of aquatic organisms and humans at risk. In the present study, the freshwater crab Sinopotamon henanense was exposed to Cd (0, 50, 100, and 500 μg·L^-1) for 14 d (0-14th d), followed by 21 d (14-35th d) of depuration. The changes in Cd bioaccumulation, microstructure, biomacromolecules (polysaccharides, neutral lipids, DNA and total proteins), and biochemical parameters (SOD, CAT, GR, TrxR, MDA and AChE) in the gills and hepatopancreas were tested. The injured microstructure, activated antioxidant system, increased MDA, and inhibited AChE of the gills and hepatopancreas responded with progressive bioaccumulation of Cd. Meanwhile, the polysaccharides and neutral lipids in the hepatopancreas reduced and DNA synthesis enhanced. During depuration, more than 58.80 ± 8.53% and 13.84 ± 12.11% of Cd was excreted from the gills and hepatopancreas, respectively. Recovery of microstructure and biomacromolecules as well as alleviated oxidative damage and neurotoxicity were also found in these two organs. Additionally, based on PCA, I_his, GR and MDA were identified as the optimal biomarkers indicating the health status of crabs. In conclusion, S. henanense could resist Cd stress through antioxidant defence and self-detoxification.

The transfer of trace metals in the soil-plant-arthropod system

Essential and non-essential trace metals are capable of causing toxicity to organisms above a threshold concentration. Extensive research has assessed the behaviour of trace metals in biological and ecological systems, but has typically focused on single organisms within a trophic level and not on multi-trophic transfer through terrestrial food chains. This reinforces the notion of metal toxicity as a closed system, failing to consider one trophic level as a pollution source to another; therefore, obscuring the full extent of ecosystem effects. Given the relatively few studies on trophic transfer of metals, this review has taken a compartment-based approach, where transfer of metals through trophic pathways is considered as a series of linked compartments (soil-plant-arthropod herbivore-arthropod predator). In particular, we consider the mechanisms by which trace metals are taken up by organisms, the forms and transformations that can occur within the organism and the consequences for trace metal availability to the next trophic level. The review focuses on four of the most prevalent metal cations in soil which are labile in terrestrial food chains: Cd, Cu, Zn and Ni. Current knowledge of the processes and mechanisms by which these metals are transformed and moved within and between trophic levels in the soil-plant-arthropod system are evaluated. We demonstrate that the key factors controlling the transfer of trace metals through the soil-plant-arthropod system are the form and location in which the metal occurs in the lower trophic level and the physiological mechanisms of each organism in regulating uptake, transformation, detoxification and transfer. The magnitude of transfer varies considerably depending on the trace metal concerned, as does its toxicity, and we conclude that biomagnification is not a general property of plant-arthropod and arthropod-arthropod systems. To deliver a more holistic assessment of ecosystem toxicity, integrated studies across ecosystem compartments are needed to identify critical pathways that can result in secondary toxicity across terrestrial food-chains.

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.

Strategies for robust and accurate experimental approaches to quantify nanomaterial bioaccumulation across a broad range of organisms

One of the key components for environmental risk assessment of engineered nanomaterials (ENMs) is data on bioaccumulation potential. Accurately measuring bioaccumulation can be critical for regulatory decision making regarding material hazard and risk, and for understanding the mechanism of toxicity. This perspective provides expert guidance for performing ENM bioaccumulation measurements across a broad range of test organisms and species. To accomplish this aim, we critically evaluated ENM bioaccumulation within three categories of organisms: single-celled species, multicellular species excluding plants, and multicellular plants. For aqueous exposures of suspended single-celled and small multicellular species, it is critical to perform a robust procedure to separate suspended ENMs and small organisms to avoid overestimating bioaccumulation. For many multicellular organisms, it is essential to differentiate between the ENMs adsorbed to external surfaces or in the digestive tract and the amount absorbed across epithelial tissues. For multicellular plants, key considerations include how exposure route and the role of the rhizosphere may affect the quantitative measurement of uptake, and that the efficiency of washing procedures to remove loosely attached ENMs to the roots is not well understood. Within each organism category, case studies are provided to illustrate key methodological considerations for conducting robust bioaccumulation experiments for different species within each major group. The full scope of ENM bioaccumulation measurements and interpretations are discussed including conducting the organism exposure, separating organisms from the ENMs in the test media after exposure, analytical methods to quantify ENMs in the tissues or cells, and modeling the ENM bioaccumulation results. One key finding to improve bioaccumulation measurements was the critical need for further analytical method development to identify and quantify ENMs in complex matrices. Overall, the discussion, suggestions, and case studies described herein will help improve the robustness of ENM bioaccumulation studies.

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.

Terrestrial isopods as model organisms in soil ecotoxicology: a review

Isopods play an important role in the decomposition of leaf litter and therefore are making a significant contribution to nutrient cycling and soil ecosystem services. As a consequence, isopods are relevant models in soil ecotoxicology, both in laboratory toxicity tests and in field monitoring and bioindication studies. This paper aims at reviewing the use of isopods as test organisms in soil ecotoxicology. It provides an overview of the use of isopods in laboratory toxicity tests, with special focus on comparing different exposure methods, test durations, and ecotoxicological endpoints. A brief overview of toxicity data suggests that chemicals are more toxic to isopods when exposed through soil compared to food. The potential of isopods to be used in bioindication and biomonitoring is discussed. Based on the overview of toxicity data and test methods, recommendations are given for the use of isopods in standardized laboratory toxicity tests as well as in situ monitoring studies.

Urban Re-Greening: A Case Study in Multi-Trophic Biodiversity and Ecosystem Functioning in a Post-Industrial Landscape

The biodiversity of urban and post-industrial ecosystems is a highly relevant and growing new frontier in ecological research. Even so, the functionality of these ecosystems may not always be successfully predicted based on prior biodiversity and ecosystem functioning theory. Indeed, evidence suggests that the general biological impoverishment within the urban context envisioned thirty years ago was overstated. Many of the world’s urban centers support some degree of biodiversity that is indigenous, as well as a complex array of non-native species, resulting in highly functional, and often, novel communities. For over two decades, a multi-disciplinary team has examined the sub-lethal impact of soil metal contamination on the multi-trophic biodiversity and ecosystem functioning of a post-industrial brownfield in the New York City metropolitan area. We do this through examinations of photosynthesis, carbon allocation, and soil enzyme activity as well as multi-trophic metal translocation via the plant and rhizosphere. In this paper, we synthesize the findings of our research network and apply the results to a framework of functional diversity. Due to the unique constraints many post-industrial lands impose on communities, functional diversity may be more meaningful to ecosystem health than species richness.

Plastic bag and facial cleanser derived microplastic do not affect feeding behaviour and energy reserves of terrestrial isopods

Current data regarding the effects of microplastic (MP) on terrestrial organisms are very scarce. Isopods play an important role in plant litter decomposition processes and are commonly used test species in terrestrial ecotoxicity studies. Their altered feeding behaviour and energy reserves are established biomarkers of adverse effects upon stressor exposure. For this study we assessed the effects of MP derived from plastic bag film (mean size 183±93μm) and particles from a facial cleanser (mean size 137±51μm) on the terrestrial isopod, Porcellio scaber. Isopods were exposed to MP via feeding on food pellets (4mgg^-1 dry weight; 0.4% w w^-1) for 14days under laboratory conditions. A control group was exposed to food pellets with no MP added. In line with previously suggested modes of MP action on animal ingestion, we assessed the food ingestion rate, defecation rate, food assimilation rate and efficiency, body mass change, mortality and energy reserves (proteins, carbohydrates, and triglycerides) in the digestive glands (hepatopancreas) of individual isopods. Contrary to our expectations, no effects on either end-point were observed under the given exposure conditions. Further work should be carried out to investigate the potential longer-term effects of such exposure. We conclude that 14days exposure to plastic bag and facial cleanser MP is not severely hazardous to isopods.

Metallothioneins and heat shock proteins 70 in Armadillidium vulgare (Isopoda, Oniscidea) exposed to cadmium and lead

The heavy metals bioaccumulation capability in Armadillidium vulgare feeded with chestnut leaves contaminated with various sublethal concentrations of Cd and Pb, was evaluated under laboratory conditions. The metal concentration found in the hepatopancreas of treated animals, as measured by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), affected the expression and localization of MT and HSP70 as shown by immunohistochemical and western blotting analysis. The Cd content of the animals treated with the various concentrations of the metal has been always higher than that of chestnut leaves contaminated. The accumulation of Pb was, instead, always modest compared to the content of the chestnut leaves. The immunohistochemical investigation in hepatopancreas tissue of animals treated with increasing concentrations of Cd and Pb, by using the anti-MT and anti-HSP70 antibodies, has provided a response clearly positive even if differentiated in relation to the metal and concentration tested. In particular, a positive response to anti-MT antibody was detected in B and S cells nuclei and S cells cytoplasm; the localization of HSP70 was particularly intense at the cell surface. Western blotting analysis showed significant up-regulation of the expression (about 2.6 fold) of HSP70 proteins in the hepatopancreas of animals exposed to highest Pb concentrations respect to control. Moreover, samples exposed to higher Cd and Pb concentrations showed a higher expression of MT (3.2 fold and 4 fold respectively) compared to control. In summary, our data beyond to clearly demonstrate for the first time the expression of MT in terrestrial isopods, suggest that A. vulgare would be a suitable organism for assessing Cd and Pb exposure in environments threatened by metal pollution as suggested by the modulation of the biomarkers MT and HSP70.

Bioaccumulation of cadmium and lead and its effects on hepatopancreas morphology in three terrestrial isopod crustacean species

This study was designed to compare cadmium (Cd) and lead (Pb) bioaccumulation in three species of oniscidean isopods - Armadillidium granulatum Brandt, Armadillidium vulgare (Latreille) and Porcellio laevis Latreille which were exposed for three weeks to a contaminated diet, and to determine the morphological and ultrastructural changes in hepatopancreas. Metal accumulation, determined by Inductively Coupled Plasma Mass Spectrometry (ICP-MS), was linearly associated with the exposed concentration and was a function of the metal and the species tested. All three species accumulated lower levels of Pb than Cd. A. vulgare accumulated the largest concentration of Pb, especially at the higher doses, whereas P. laevis showed the greatest Cd accumulation, and the highest Cd concentration was lethal for all exposed species. The highest concentrations of Pb and Cd induced significant changes both in the general morphology of tubules and in the ultrastructural organization of epithelial cells in hepatopancreas. Some Pb/Cd induced alterations include: brush border disorganization; reduction of the basal labyrinth formed by the plasma membrane; condensation of some cytoplasm areas and of chromatin; rough endoplasmic reticulum and mitochondrial alterations; increase of secondary lysosomes and of type B granules in S cells. Some of the ultrastructural changes observed overlap with those induced by prolonged starvation, whereas others can be useful biomarkers of heavy metal toxicity. This study has confirmed that in terrestrial isopods, the accumulation of the different metals occurs in a species-specific manner; therefore ecological monitoring and assessment studies should consider each species individually. The research has confirmed that in the terrestrial isopods the accumulation of the different metals occurs in a species-specific way; therefore each species should first be evaluated in view of its employ in biomonitoring programs.

Is there a relationship between earthworm energy reserves and metal availability after exposure to field-contaminated soils?

Generic biomarkers are needed to assess environmental risks in metal polluted soils. We assessed the strength of the relationship between earthworm energy reserves and metal availability under conditions of cocktail of metals at low doses and large range of soil parameters. Aporrectodea caliginosa was exposed in laboratory to a panel of soils differing in Cd, Pb and Zn total and available (CaCl2 and EDTA-extractable) concentrations, and in soil texture, pH, CEC and organic-C. Glycogen, protein and lipid contents were recorded in exposed worms. Glycogen contents were not linked to the explaining variables considered. Variable selection identified CaCl2 extractable metals concentrations and soil texture as the main factors affecting protein and lipid contents. The results showed opposite effects of Pb and Zn, high inter-individual variability of biomarkers and weak relationships with easily extractable metals. Our results support the lack of genericity of energy reserves in earthworms exposed to field-contaminated soils.

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.

Energy reserves and accumulation of metals in the ground beetle Pterostichus oblongopunctatus from two metal-polluted gradients

Living in an area chronically polluted with metals is usually associated with changes in the energy distribution in organisms due to increased energy expenses associated with detoxification and excretion processes. These expenses may be reflected in the available energy resources, such as lipids, carbohydrates, and proteins. In this context, the energy status of Pterostichus oblongopunctatus (Coleoptera: Carabidae) was studied in two metal pollution gradients near Olkusz and Miateczko Śląskie in southern Poland. Both regions are rich in metal ores, and the two largest Polish zinc smelters have been operating there since the 1970s. Beetles were collected from five sites at each gradient. Zinc and cadmium concentrations were measured in both the soil and the beetles. The possible reduction in energy reserves as a cost of detoxifying assimilated metals was evaluated biochemically by determining the total lipid, carbohydrates, and protein contents. At the most polluted sites, the Zn concentration in the soil organic layer reached 2,906 mg/kg, and the Cd concentration reached 55 mg/kg. Body Zn and Cd concentrations increased with increasing soil Zn and Cd concentrations (p = 0.003 and p = 0.0001, respectively). However, no relationship between pollution level and energetic reserves was found. The results suggest that populations of P. oblongopunctatus inhabiting highly metal-polluted sites are able to survive without any serious impact on their energy reserves, though they obviously have to cope with elevated body metal concentrations.

Enchytraeus albidus microarray: enrichment, design, annotation and database (EnchyBASE)

Enchytraeus albidus (Oligochaeta) is an ecologically relevant species used as standard test organisms for risk assessment. Effects of stressors in this species are commonly determined at the population level using reproduction and survival as endpoints. The assessment of transcriptomic responses can be very useful e.g. to understand underlying mechanisms of toxicity with gene expression fingerprinting. In the present paper the following is being addressed: 1) development of suppressive subtractive hybridization (SSH) libraries enriched for differentially expressed genes after metal and pesticide exposures; 2) sequencing and characterization of all generated cDNA inserts; 3) development of a publicly available genomic database on E. albidus. A total of 2100 Expressed Sequence Tags (ESTs) were isolated, sequenced and assembled into 1124 clusters (947 singletons and 177 contigs). From these sequences, 41% matched known proteins in GenBank (BLASTX, e-value ≤ 10(-5)) and 37% had at least one Gene Ontology (GO) term assigned. In total, 5.5% of the sequences were assigned to a metabolic pathway, based on KEGG. With this new sequencing information, an Agilent custom oligonucleotide microarray was designed, representing a potential tool for transcriptomic studies. EnchyBASE (http://bioinformatics.ua.pt/enchybase/) was developed as a web freely available database containing genomic information on E. albidus and will be further extended in the near future for other enchytraeid species. The database so far includes all ESTs generated for E. albidus from three cDNA libraries. This information can be downloaded and applied in functional genomics and transcription studies.

Sequestration of zinc from zinc oxide nanoparticles and life cycle effects in the sediment dweller amphipod Corophium volutator

We studied the effects of ZnO nanoparticles [ZnO NPs, primary particle size 35 ± 10 nm (circular diameter, TEM)], bulk [160 ± 81 nm (circular diameter, TEM)], and Zn ions (from ZnCl(2)) on mortality, growth, and reproductive endpoints in the sediment dwelling marine amphipod Corophium volutator over a complete lifecycle (100 days). ZnO NPs were characterized by size, aggregation, morphology, dissolution, and surface properties. ZnO NPs underwent aggregation and partial dissolution in the seawater exposure medium, resulting in a size distribution that ranged in size from discrete nanoparticles to the largest aggregate of several micrometers. Exposure via water to all forms of zinc in the range of 0.2-1.0 mg L(-1) delayed growth and affected the reproductive outcome of the exposed populations. STEM-EDX analysis was used to characterize insoluble zinc precipitates (sphaerites) of high sulfur content, which accumulated in the hepatopancreas following exposures. The elemental composition of the sphaerites did not differ for ZnO NP, Zn(2+), and bulk ZnO exposed organisms. These results provide an illustration of the comparable toxicity of Zn in bulk, soluble, and nanoscale forms on critical lifecycle parameters in a sediment dwelling organism.

The evidence on the degradation processes in the midgut epithelial cells of the larval antlion Euroleon nostras (Geoffroy in Fourcroy, 1785) (Myrmeleontidae, Neuroptera)

We analysed structural differences between midgut epithelial cells of fed instar antlions' larvae Euroleon nostras and starved ones. In starved larvae the presence of autophagolysosome-like structures was observed, which are characteristic structures associated with autophagy. The results presented here provide insight supporting the role of autophagy as a cell survival mechanism for the periods of food deprivation. Additional structural changes in the cytoplasm were seen in the spherites. The ultrastructure and chemical composition of spherites in the midgut epithelial cells of first, second and third instar larvae were observed with light microscopy and transmission electron microscopy (TEM). A detailed characterization of the elemental composition of the spherites was studied using analytical electron microscopy; a combination of energy dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS) and energy filtering TEM (EFTEM) was applied. The structure and elemental composition of the spherites changed during the period of larval life. Moreover, changes in chemical composition were found between spherites from fed and starved E. nostras. In fed first instar larvae, the spherites contained an organic matrix, composed of C, N and O. In this matrix, P, Cl, Ca and Fe were detected. In starved first instar larvae, only C, N and P were present. The spherites of fed second instar larvae were rich in organic and inorganic elements and were composed of C, N, O, Na, Mg, P, S, Cl, K, Ca, Mn, Fe and Zn. In starved second instar larvae, the chemical elements N, O, P, Ca and Fe were found. In fed third instar larvae, the spherites contained C, N, O, Na, Mg, P, Cl, K, Ca, Mn, Fe, Co and Zn. In starved third larvae, C, O, Si, Ca, and Fe were detected. Generally, the spherites are exploited in starved larvae. These results suggest that the elemental supply of spherites may provide crucial support for physiological processes during starvation periods amongst E. nostras instar larvae. In some cases in fed second and fed third instar larvae, spherites were seen in the lumen of the midgut. Such spherites could serve as reservoirs for nontoxic waste material that cannot be metabolized.

Application of analytical electron microscopic methods to investigate the function of spherites in the midgut of the larval antlion Euroleon nostras (Neuroptera: Myrmeleontidae)

This study presents an application of analytical electron microscopy in biology to investigate the chemical composition of the spherites and to elucidate the importance of these methods in the life sciences. The structure of the spherites in the midgut cells of first, second, and third instar larvae Euroleon nostras was investigated by a combination of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDXS), electron energy-loss spectroscopy (EELS), and energy filtering TEM (EFTEM). The structure and chemical composition of the spherites changed during the metamorphosis. In first larvae, the spherites are composed of amorphous, flocculent material, containing C, N, and O. In second larvae and third ones, the spherites have concentric layers of alternating electron-dense and electron-lucent material. In second larvae, Si, P, Ca, and Fe are accumulated in the spherite organic matrix, composed of C, N, and O. In the spherites of third larvae, additionally Al was found. Therefore, the spherites are thought to store organic compounds in all three larval stages of E. nostras and additionally inorganic compounds in second and third ones. In first larvae, spherites are present in the midgut cells; in second and third larvae, they are present in the cells of the midgut and in its lumen. It could be suggested that the spherites might be involved in the regulation of the appropriate mineral composition of the internal environment and could serve as the accumulation site of nontoxic waste materials that cannot be metabolized.

Quantitative immunodetection of metallothioneins in relation to metals concentration in spiders from variously polluted areas

Spiders inhabiting post industrial environments, such as waste heaps or ore-bearing areas, are exposed to high concentrations of metals, accumulated in the body of their prey and transferred along food chains. Therefore spiders are pressed to develop metal-neutralization strategies. Low-molecular, multifunction proteins: metallothioneins (MTs), often postulated as biomarkers of metal exposure, are known to bind metals and thus protect organisms against their toxic effects. Yet the proteins are still not well recognized in spiders. The aim of this study was to assess, by immunodetection method, ELISA, the concentration of metallothioneins in adult females of three web building spider species: Araneus diadematus (Araneidae), Agelena labyrinthica (Agelenidae) and Linyphia triangularis (Linyphiidae) from three variously polluted areas in southern Poland: Olkusz, ore-bearing post industrial site; Katowice-WeŁnowiec: post metallurgic waste heap, Pilica: the reference, rural, area. The concentration of metallothioneins has been analyzed in relation to the metal concentration in spiders body. The study gives the evidence that metallothioneins are reliably detectable by means of ELISA technique. The analysis of results obtained shows a strong species-dependence of the MTs level. Positive correlations between MTs concentration and metal body burden (mainly Zn and Pb) were found. This suggests that the proteins play an important role in the neutralization and regulation of metal ions in spiders. The same correlation indicate the possibility to consider MTs in spiders as biomarkers of metal exposure and effects. However, the species specificity as well as metal characteristics should be taken under account.

No costs on freeze tolerance in genetically copper adapted earthworm populations (Dendrobaena octaedra)

For nearly three centuries the area around Gusum, in south-east Sweden, has been highly polluted with copper. An earlier study in this area showed that populations of the freeze-tolerant earthworm Dendrobaena octaedra were genetically adapted to copper. Apparently, no life-history costs to reproduction or growth were imposed by this adaptation. In the present paper we therefore investigated how laboratory raised F1-generations of these populations coped when exposed to increased copper concentrations in the soil and to sub-zero temperatures. We found that D. octaedra from polluted sites accumulated the same amount of copper as reference worms. Furthermore, earthworms from polluted sites survived equally to reference worms when exposed to freezing temperatures (-8 or -12°C). However, when simultaneously exposed to the lowest temperature and copper, the worms from polluted sites survived significantly better than reference worms. The overall conclusion of this study is that worms from polluted sites seem to be better at handling copper and accrue no costs in terms of reduced cold tolerance in connection to genetic adaptation in these populations.

Body metal concentrations and glycogen reserves in earthworms (Dendrobaena octaedra) from contaminated and uncontaminated forest soil

Stress originating from toxicants such as heavy metals can induce compensatory changes in the energy metabolism of organisms due to increased energy expenses associated with detoxification and excretion processes. These energy expenses may be reflected in the available energy reserves such as glycogen. In a field study the earthworm, Dendrobaena octaedra, was collected from polluted areas, and from unpolluted reference areas. If present in the environment, cadmium, lead and copper accumulated to high concentrations in D. octaedra. In contrast, other toxic metals such as aluminium, nickel and zinc appeared to be regulated and kept at low internal concentrations compared to soil concentrations. Lead, cadmium and copper accumulation did not correlate with glycogen reserves of individual worms. In contrast, aluminium, nickel and zinc were negatively correlated with glycogen reserves. These results suggest that coping with different metals in earthworms is associated with differential energy demands depending on the associated detoxification strategy.

Biomonitoring the environmental impact of atmospheric emissions from the Avonmouth zinc smelter, United Kingdom

This paper examines the impact of an industrial point-source atmospheric emission on the feeding of early life stages of a terrestrial invertebrate. Larvae of a bagworm moth, Luffia ferchaultella [Stephens], were fed terrestrial epiphytic algae (Desmococcus viridis [Menegh]) collected from five sites located along a 16 km transect around the Avonmouth zinc smelter. After 10 days of exposure symptoms of lethal and sublethal toxicity (mortality and paralysis) were observed. Reductions in the amount of faecal material (frass) produced were also identified, and these correlated with distance downwind of the smelter. The elevated concentrations of lead, mercury, arsenic, antimony, copper, cadmium, lead and nickel present in the algae could account for these symptoms of toxicity. Similar symptoms were observed when larvae were fed algae spiked with inorganic mercury. These results are consistent with other studies of soil toxicity conducted around the Avonmouth smelter. However, the current study suggests that the impacted area exceeds this 16 km transect and demonstrates the value of bagmoth larvae as sensitive biomonitors of metallic atmospheric pollutants above the rhizosphere.

Structure of the Malpighian tubule cells and annual changes in the structure and chemical composition of their spherites in the cave cricket Troglophilus neglectus Krauss, 1878 (Rhaphidophoridae, Saltatoria)

Periodical changes in the structure of spherites in the Malpighian tubule cells of the cave cricket Troglophilus neglectus were studied to elucidate their role during the cricket's life cycle in natural circumstances. Special interest was given to the dormant overwintering period when we hypothesized that the primary role of spherites is to supply minerals for basic vital processes. The investigation was carried out by light and transmission electron microscopy, energy dispersive X-ray spectroscopy, electron energy-loss spectroscopy and energy-filtering TEM. Spherites are present only in the middle Malpighian tubule segment, consisting of Type 1 cells, characterized, among other features, by a round, apically placed nucleus and numerous spherites, and a few Type 2 cells with an elongated nucleus in the centre and sparse spherites. At the beginning of dormancy in November juveniles, minerals are accumulated in spherites and then decline until March. In one-year-old May larvae, spherites are commonly rich in minerals, and from July onwards they are progressively exploited in the adults. Spherite destruction starts with apoptosis in senile October individuals. The findings suggest that the mineral supply of spherites in Malpighian tubules is crucial to supporting vital processes throughout the life cycle of T. neglectus.

Critical analysis of soil invertebrate biomarkers: a field case study in Avonmouth, UK

During the period 1996-1999 a joint field research programme (BIOPRINT-II) funded by the European Union was undertaken. The main objective of this project was the deployment of biochemical fingerprint techniques of soil invertebrate biomarkers for assessing the exposure and effect of toxicants on soil invertebrates in the field. The aim was to apply these techniques in the field focusing on a a chronically polluted field near a lead and zinc smelter in Avonmouth (UK). Therefore six sites were selected from which organisms were either sampled or transplanted to or from the laboratory. The project has provided a unique opportunity to apply a series of biological test methodologies in order to determine the hazard posed to soil sustainability and by inference soil biodiversity and function. This work has attempted to understand the linkage between effects measured at the molecular or cellular level and relate these to changes at higher levels of biological organisation. Here we evaluated the links between biomarkers and soil function parameters. The paper aims to summarize and explore the necessary caveats that must be understood before soil biomarker test systems may be used to strengthen the risk assessment process.

Stress proteins (hsp70, hsp60) induced in isopods and nematodes by field exposure to metals in a gradient near Avonmouth, UK

Heat shock proteins (hsps) are potential biomarkers for monitoring environmental pollution. In this study, the use of hsps as biomarkers in field bioassays was evaluated in terrestrial invertebrates exposed to a metal gradient near Avonmouth, UK. We investigated the hsp70 response in resident and transplanted isopods of the species Oniscus asellus and Porcellio scaber and the hsp60 response in transplanted nematodes of the species Plectus acuminatus in six field sites along the metal gradient. Considerable differences were detected in the stress responses between nematodes and isopods (isopods responded in a gradient-specific manner, nematodes did not), the two isopod species and the transplanted and resident specimens of each isopod species: in the sites closest to the smelter, O. asellus residents showed high hsp70 levels while O. asellus transplanted from an unpolluted site displayed comparatively low hsp70 levels. For P. scaber, it was just the opposite. In resident isopod populations of both species, tolerant phenotypes were revealed in the most contaminated field sites. The hsp70 level in both isopod species was a suitable biomarker of effect (but of exposure only in non-tolerant individuals) even in long-term metal-contaminated field sites. The hsp60 response in the nematode alone was not a suitable biomarker for heavily contaminated soils. However, it had indicative value when related to the hsp70 response in the isopods and could be a suitable biomarker for less heavily contaminated soils.

Does the environment or the source of the population define stress status and energy supply in the freshwater amphipod, Gammarus fossarum?

To investigate the effects of acclimation and/or adaptation on the stress protein (hsc/hsp70) response, adenylate energy charge (ACE), ATP/ADP ratio and both lipid and glycogen supply, specimens of four different populations of the freshwater amphipod Gammarus fossarum (Koch, 1835) were transplanted and exposed at sites with various levels of pollution. Induction of the stress protein response was highest in those gammarids transplanted from nearly unpolluted or just moderately polluted sites to severely polluted stream portions. The lowest hsc/hsp70 levels were found in animals transplanted from the polluted sites to the less polluted sites. In all cases the adenylic energy charge (AEC) and ATP/ADP ratio did not show any deficiency in the cellular energy supply. The amount of energy storage substrates, lipid droplets and glycogen in the hepatopancreas, the main metabolic tissue, was similar in all resident populations. In all these amphipod populations, tolerant phenotypes which had diverged genetically were not revealed; rather, the stress and recovery effects derived from the physiologically regulated, cellular stress response.