The effect of different sewage concentrations (0, 20, 60 and 100%), vegetation (Bare, Avicennia marina or Rhizophora mucronata) and immersion periods (immersion/emersion period of 12/12 h or 3/3 days just for 100%) conditions were studied for 6 months on survival and growth rates of Terebralia palustris (Linnaeus, 1767). Gastropods' activity and ecosystem engineering preformed at bare and A. marina planted cells and 3 sewage conditions (0, 20 and 60%) were determined. Survival rates were higher than 70% in all treatments. Growth rate decreased significantly with increasing sewage concentrations (mainly at unplanted conditions) and longer immersion periods. A complete shift (from immersion to emersion periods) and a significant decrease in mobility and consequently its engineer potential, due to sewage contamination, lead to a 3–4 fold decrease in the amount of sediment disturbed. Sewage contamination, primary producers' abundance and environmental conditions may have influenced the gastropods survival, growth and its ecosystem engineering potential. Terebralia palustris high ecosystem engineering potential in constructed mangrove wetlands.

The effects of experimentally elevated O3 on soil respiration rates, standing fine-root biomass, fine-root production and δ13C signature of newly produced fine roots were investigated in an adult European beech/Norway spruce forest in Germany during two subsequent years with contrasting rainfall patterns. During humid 2002, soil respiration rate was enhanced under elevated O3 under beech and spruce, and was related to O3-stimulated fine-root production only in beech. During dry 2003, the stimulating effect of O3 on soil respiration rate vanished under spruce, which was correlated with decreased fine-root production in spruce under drought, irrespective of the O3 regime. δ13C signature of newly formed fine-roots was consistent with the differing gs of beech and spruce, and indicated stomatal limitation by O3 in beech and by drought in spruce. Our study showed that drought can override the stimulating O3 effects on fine-root dynamics and soil respiration in mature beech and spruce forests. Drought has the capacity to override the stimulating ozone effect on soil respiration in adult European beech/Norway spruce forest.

There is currently a lack of ecotoxicity tests adapted to earthworm species of higher ecological relevance and whose endpoints could be directly related to their ecological role in the soil. We propose a new and relatively simple ecotoxicity test based on the estimation of cast production (CP) by Lumbricus terrestris under laboratory conditions. CP was found to be linearly correlated to earthworm biomass and to be greatly influenced by soil water content. Azinphos-methyl had no effect on CP at all the concentrations tested. Significant decreases were observed at the normal application rate for other pesticides with (imidacloprid, carbaryl, methomyl) or without (ethyl-parathion and chlorpyrifos-ethyl) a clear concentration–effect response. For the highest concentration tested, reduction in CP varied between 35 and 67%. CP is straightforward and rapidly measured and ecologically meaningful. We thus believe it to be of great use as an endpoint in ecotoxicity testing. Cast production of Lumbricus terrestris is affected by pesticides under laboratory conditions.

The metabolite 2,6-dichlorobenzamide (BAM) is a frequent groundwater pollutant produced during degradation of the herbicide 2,6-dichlorobenzonitrile (dichlobenile). Spatial variability of BAM mineralisation is uncharacterized in surface soil, however, and factors controlling the heterogeneity remain unknown. We addressed these issues by sample-to-sample comparisons of BAM mineralisation rates and a range of soil characteristics at spatial scales ranging from meters to centimetres. For mineralisation assays nano-molar concentrations of labelled BAM were added to determine mineralisation rates under realistic conditions. We found a significant variability of BAM mineralisation which increased with decreasing spatial scale. BAM mineralisation rates were correlated to the density of BAM-degrading bacteria but not to water content, TOC, NH4+, NO3−, or pH. The genus Aminobacter, which contains the only BAM degraders known, was detected in MPN samples of BAM degraders by a specific PCR assay targeting the 16S rRNA gene, confirming a role of Aminobacter in BAM mineralisation. Density of degrader bacteria is the main factor in BAM mineralisation when considering realistic low concentrations in soil.

Chemical methods to predict the bioavailable fraction of organic contaminants are usually validated in the literature by comparison with established bioassays. A soil spiked with polycyclic aromatic hydrocarbons (PAHs) was aged over six months and subjected to butanol, cyclodextrin and tenax extractions as well as an exhaustive extraction to determine total PAH concentrations at several time points. Earthworm (Eisenia fetida) and rye grass root (Lolium multiflorum) accumulation bioassays were conducted in parallel. Butanol extractions gave the best relationship with earthworm accumulation (r2 ≤ 0.54, p ≤ 0.01); cyclodextrin, butanol and acetone–hexane extractions all gave good predictions of accumulation in rye grass roots (r2 ≤ 0.86, p ≤ 0.01). However, the profile of the PAHs extracted by the different chemical methods was significantly different (p < 0.01) to that accumulated in the organisms. Biota accumulated a higher proportion of the heavier 4-ringed PAHs. It is concluded that bioaccumulation is a complex process that cannot be predicted by measuring the bioavailable fraction alone. The ability of chemical methods to predict PAH accumulation in Eisenia fetida and Lolium multiflorum was hindered by the varied metabolic fate of the different PAHs within the organisms.

Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH2N-C(N-NO2)-CHN-CHO or its isomer N(NO2)CH-CHN-CO-CHNH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil. Two key intermediates of CL-20 degradation are potential markers of its natural attenuation in soil.

Despite numerous reviews suggesting that microbial biosensors could be used in many environmental applications, in reality they have failed to be used for which they were designed. In part this is because most of these sensors perform in an aqueous phase and a buffered medium, which is in contrast to the nature of genuine environmental systems. In this study, a range of non-exhaustive extraction techniques (NEETs) were assessed for (i) compatibility with a naphthalene responsive biosensor and (ii) correlation with naphthalene biodegradation. The NEETs removed a portion of the total soil naphthalene in the order of methanol > HPCD > βCD > water. To place the biosensor performance to NEETs in context, a biodegradation experiment was carried out using historically contaminated soils. By coupling the HPCD extraction with the biosensor, it was possible to assess the fraction of the naphthalene capable of undergoing microbial degradation in soil. Exposure of microbial biosensors to cyclodextrin solutions allows the assessment of the degradable fraction of contaminants in soil.

The earthworm Lumbricus rubellus (Hoffmeister, 1843) is a terrestrial pollution sentinel. Enzyme activity and transcription of phase II detoxification superfamily glutathione transferases (GST) is known to respond in earthworms after soil toxin exposure, suggesting GST as a candidate molecular-based pollution biomarker. This study combined sub-proteomics, bioinformatics and biochemical assay to characterise the L. rubellus GST complement as pre-requisite to initialise assessment of the applicability of GST as a biomarker. L. rubellus possesses a range of GSTs related to known classes, with evidence of tissue-specific synthesis. Two affinity-purified GSTs dominating GST protein synthesis (Sigma and Pi class) were cloned, expressed and characterised for enzyme activity with various substrates. Electrospray ionisation mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) following SDS-PAGE were superior in retaining subunit stability relative to two-dimensional gel electrophoresis (2-DE). This study provides greater understanding of Phase II detoxification GST superfamily status of an important environmental pollution sentinel organism. This study currently provides the most comprehensive view of the Phase II detoxification enzyme superfamily of glutathione transferases within the important environmental pollution sentinel earthworm Lumbricus rubellus.

Two birch clones originating from metal-contaminated sites were exposed for 3 months to soils (sand-peat ratio 1:1 or 4:1) spiked with a mixture of polyaromatic hydrocarbons (PAHs; anthracene, fluoranthene, phenanthrene, pyrene). PAH degradation differed between the two birch clones and also by the soil type. The statistically most significant elimination (p <= 0.01), i.e. 88% of total PAHs, was observed in the more sandy soil planted with birch, the clearest positive effect being found with Betula pubescens clone on phenanthrene. PAHs and soil composition had rather small effects on birch protein complement. Three proteins with clonal differences were identified: ferritin-like protein, auxin-induced protein and peroxidase. Differences in planted and non-planted soils were detected in bacterial communities by 16S rRNA T-RFLP, and the overall bacterial community structures were diverse. Even though both represent complex systems, trees and rhizoidal microbes in combination can provide interesting possibilities for bioremediation of PAH-polluted soils. Birch can enhance degradation of PAH compounds in the rhizosphere.

The effects on the growth of tomato seedlings and cadmium accumulation of earthworm mucus and a solution of amino acids matching those in earthworm mucus was studied through a hydroponic experiment. The experiment included four treatments: 5 mg Cd L⁻¹ (CC), 5 mg Cd L⁻¹ þ 100 mL L⁻¹ earthworm mucus (CE), 5 mg Cd L⁻¹ þ 100 mL L⁻¹ amino acids solution (CA) and the control (CK). Results showed that, compared with CC treatment, either earthworm mucus or amino acids significantly increased tomato seedling growth and Cd accumulation but the increase was much higher in the CE treatment compared with the CA treatment. This may be due to earthworm mucus and amino acids significantly increasing the chlorophyll content, antioxidative enzyme activities, and essential microelement uptake and transport in the tomato seedlings. The much greater increase in the effect of earthworm mucus compared with amino acid treatments may be due to IAA-like substances in earthworm mucus.