Summary
Biodiversity is responsible for the provision of many ecosystem services; human well‐being is based on these services, and consequently on biodiversity. In soil, earthworms represent the ...largest component of the animal biomass and are commonly termed ‘ecosystem engineers’. This review considers the contribution of earthworms to ecosystem services through pedogenesis, development of soil structure, water regulation, nutrient cycling, primary production, climate regulation, pollution remediation and cultural services. Although there has been much research into the role of earthworms in soil ecology, this review demonstrates substantial gaps in our knowledge related in particular to difficulties in identifying the effects of species, land use and climate. The review aims to assist people involved in all aspects of land management, including conservation, agriculture, mining or other industries, to obtain a broad knowledge of earthworms and ecosystem services.
The importance of earthworms to ecosystem functioning has led to many studies on the impacts of metals on earthworms. Far less attention has been paid to the impact that earthworms have on soil ...metals both in terms of metal mobility and availability. In this review we consider which earthworms have been used in such studies, which soil components have been investigated, which types of soil have been used and what measures of mobility and availability applied. We proceed to review proposed reasons for effects: changes in microbial populations, pH, dissolved organic carbon and metal speciation. The balance of evidence suggests that earthworms increase metal mobility and availability but more studies are required to determine the precise mechanism for this.
We review the impact of earthworms on metal mobility and availability and suggest areas for further investigation.
Plastics fragment and threaten soil ecosystems. Degradation of soil structure is one of the risks. Despite this, data on impacts of different sized microplastics (MPs) on soil aggregates is lacking. ...This study systematically investigated the effects of pristine polyethylene powders of different sizes (< 35, < 125, < 500 µm) and concentrations (0, 0.1, 1.0, 10 wt%) on aggregate formation and their properties for two contrasting soils (woodland soil, WS; agricultural soil, AS). 75 day wet-dry cycles produced newly-formed aggregates in all treatments. MP size and concentration impacted the incorporation of MPs in aggregates and this varied with aggregate size; the size distribution of aggregates also varied with MP size and concentration. Aggregates produced in soil containing 10 wt% < 35 µm MPs had significantly lower MWDs (mean weight diameters) than controls. The wettability of aggregates (> 4 mm) reduced with increasing MP exposure concentration and decreasing MP exposure size. MP incorporation decreased the water stability of aggregates (1–2 mm) in WS but increased it in AS. The particle density of aggregates (> 4 mm) significantly decreased with increasing MP concentration, whereas MP size had no effect. As MPs breakdown, fragment and become smaller over time, their potential risk to the aggregated structure of soil increases.
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•Granular polyethylene microplastics (MPs) affect aggregate formation and properties.•Smaller MPs at higher concentrations increase MP incorporation into aggregates.•Aggregate mean weight diameter (MWD) and wettability decrease with reduced MP size.•Aggregate MWD, wettability and particle density decrease with MP concentration.•Influence of MPs on water stability varies with soil type.
Size distribution is a crucial characteristic of microplastics (MPs). A typical method for measuring this property is wet laser diffraction. However, when measuring size distributions of MPs, despite ...it being a poor dispersant for many MPs, water is commonly selected, potentially limiting the reliability of reported measurements. To evaluate dispersant suitability, different aqueous concentrations of ethanol (0, 10, 20, 30, 40, 50, 75, 100 wt%) and aqueous solutions of 0.001 wt% Triton X-100 and a mixture comprising 10 wt% sodium pyrophosphate and 10 wt% methanol were used as dispersants in a laser granulometer (Mastersizer 2000) to determine particle size distributions (PSDs) of granular polyethene MP35, MP125 and MP500 particles (nominally <35, < 125 and, < 500 μm in size). The reliability of the PSDs depended on the dispersant used and size of primary MPs. With increasing ethanol concentrations, PSD curves of MP35 particles shifted from multi-modal to mono-modal distributions. The measured size distribution reduced from 1588.7 to 4.5 μm in water to 39.9-0.1 μm in 100 wt% ethanol. Generally, as ethanol concentration increased uncertainty associated with the PSD parameters decreased. Although Triton X-100 and the mixed solution also showed better dispersion than water, measured particle sizes and COV (%) were notably larger than those for 100 wt% ethanol. Similar trends were observed for larger-sized MP125 and MP500 particles, but differences in PSD curves, PSD parameters, and COV (%) among dispersants were less pronounced. In all dispersants, the volume weighted mean diameters (VWMD) in 100 wt% ethanol (MP35: 14.1 μm, MP125: 102.5 μm, MP500: 300.0 μm) were smallest and close to diameters determined from microscope observations (MP35: 14.6 μm, MP125: 109.0 μm, MP500: 310.6 μm). Therefore, for accurate determinations of the PSDs of MP by wet laser diffraction, ethanol rather than water should be used as the dispersant.
Chronic infection with Pseudomonas aeruginosa is associated with progressive deterioration in lung function in cystic fibrosis (CF) patients. The purpose of this trial was to assess the efficacy and ...safety of tobramycin nebuliser solution (TNS) and nebulised colistin in CF patients chronically infected with P. aeruginosa. One-hundred and fifteen patients, aged > or = 6 yrs, were randomised to receive either TNS or colistin, twice daily for 4 weeks. The primary end point was an evaluation of the relative change in lung function from baseline, as measured by forced expiratory volume in one second % predicted. Secondary end points included changes in sputum P. aeruginosa density, tobramycin/colistin minimum inhibitory concentrations and safety assessments. TNS produced a mean 6.7% improvement in lung function (p=0.006), whilst there was no significant improvement in the colistin-treated patients (mean change 0.37%). Both nebulised antibiotic regimens produced a significant decrease in the sputum P. aeruginosa density, and there was no development of highly resistant strains over the course of the study. The safety profile for both nebulised antibiotics was good. Tobramycin nebuliser solution significantly improved lung function of patients with cystic fibrosis chronically infected with Pseudomonas aeruginosa, but colistin did not, in this study of 1-month's duration. Both treatments reduced the bacterial load.
Background
This systematic review aimed to evaluate the impact of nutrition interventions on participant reported pain severity and intensity in populations with chronic pain.
Methods
Eight databases ...were systematically searched for studies that included adult populations with a chronic pain condition, a nutrition intervention and a measure of pain. Where possible, data were pooled using meta‐analysis. Seventy‐one studies were included, with 23 being eligible for meta‐analysis.
Results
Studies were categorised into four groups: (i) altered overall diet with 12 of 16 studies finding a significant reduction in participant reported pain; (ii) altered specific nutrients with two of five studies reporting a significant reduction in participant reported pain; (iii) supplement‐based interventions with 11 of 46 studies showing a significant reduction in pain; and (iv) fasting therapy with one of four studies reporting a significant reduction in pain. The meta‐analysis found that, overall, nutrition interventions had a significant effect on pain reduction with studies testing an altered overall diet or just one nutrient having the greatest effect.
Conclusions
This review highlights the importance and effectiveness of nutrition interventions for people who experience chronic pain.
The aim of this study is to test the stabilisation of metals in contaminated soils via the formation of low-solubility metal phosphates. Bone apatite, in the form of commercially available bone meal, ...was tested as a phosphate source on a mine waste contaminated made-ground with high levels of Pb, Zn and Cd. Triplicate leaching columns were set up at bone meal to soil ratios of 1:25 and 1:10, in addition to unamended controls, and were run for 18
months. The columns were irrigated daily with a synthetic rain solution at pH of 2, 3, and 4.4. After 100
days, the leachate Pb, Zn and Cd concentrations of all amended columns were significantly reduced. For 1:10 treatments, release of these metals was suppressed throughout the trial. For 1:25 treatments, Zn and Cd concentrations in the leachates began to increase after 300
days. DTPA and water extractions showed that Pb and Cd were more strongly held in the amended soils. This study concludes that the complexity of soil processes and the small quantities of metals sequestered precluded determination of a metal immobilisation mechanism.
An extended (18
months) leaching column study of metal (Pb, Zn, Cd) immobilisation using bone meal as a source of phosphate, demonstrating positive results.
Cystic fibrosis (CF) is the most common lethal hereditary disorder with autosomal recessive heredity in caucasians. The majority of CF patients suffer from chronic respiratory infection with the ...opportunistic bacterial pathogen Pseudomonas aeruginosa. No consensus among clinicians has been reached so far concerning antibiotic treatment against P. aeruginosa in CF patients. Consensus answers to 24 important questions in this context, based on current evidence, are presented, given by a panel of 34 European experts. Questions addressed and answered are: The diagnosis of P. aeruginosa lung colonization in CF; The impact of P. aeruginosa on the clinical state of CF patients; The assessment of P. aeruginosa susceptibility against antibiotics and the importance of these results for the clinician; The use of monotherapy versus combination therapy; The development of microbial resistance; The achievement of optimal airway concentrations; The effects of subinhibitory concentrations of antibiotics on P. aeruginosa; Statements on the pharmacokinetics of antibiotics in CF patients; Recommendations for doses and dosing intervals and length of treatment regimens; and Toxic side effects due to repeated antibiotic therapy was addressed. The expert panel answered further questions on the use of fluoroquinolones in children with CF, on the administration of nebulized antibiotics and whether prevention of P. aeruginosa lung colonization is possible in CF using antibiotic therapy. Problems of antibiotic therapy at home and in the hospital were addressed, a consensus statement on regular maintenance treatment, or treatment on demand, was given and different routes of administration of antibiotics were recommended for different clinical situations. Finally, the factors which determine the choice of the antibiotic, the dosage, and the duration of the treatment in cystic fibrosis patients were addressed and the design of future antibiotic studies in the context of Pseudomonas aeruginosa lung infection in cystic fibrosis patients were recommended.
•We model Eisenia fetida populations using an agent-based framework.•Individual energy budgets follow the basic principles of physiological ecology.•Methods are developed to show how chemicals ...achieve their physiological effects.•The model realistically captures sublethal effects under variable feeding conditions.•Energy budget ABMs have potential for refining chemical risk assessment.
Earthworms are important organisms in soil communities and so are used as model organisms in environmental risk assessments of chemicals. However current risk assessments of soil invertebrates are based on short-term laboratory studies, of limited ecological relevance, supplemented if necessary by site-specific field trials, which sometimes are challenging to apply across the whole agricultural landscape. Here, we investigate whether population responses to environmental stressors and pesticide exposure can be accurately predicted by combining energy budget and agent-based models (ABMs), based on knowledge of how individuals respond to their local circumstances. A simple energy budget model was implemented within each earthworm Eisenia fetida in the ABM, based on a priori parameter estimates. From broadly accepted physiological principles, simple algorithms specify how energy acquisition and expenditure drive life cycle processes. Each individual allocates energy between maintenance, growth and/or reproduction under varying conditions of food density, soil temperature and soil moisture. When simulating published experiments, good model fits were obtained to experimental data on individual growth, reproduction and starvation. Using the energy budget model as a platform we developed methods to identify which of the physiological parameters in the energy budget model (rates of ingestion, maintenance, growth or reproduction) are primarily affected by pesticide applications, producing four hypotheses about how toxicity acts. We tested these hypotheses by comparing model outputs with published toxicity data on the effects of copper oxychloride and chlorpyrifos on E. fetida. Both growth and reproduction were directly affected in experiments in which sufficient food was provided, whilst maintenance was targeted under food limitation. Although we only incorporate toxic effects at the individual level we show how ABMs can readily extrapolate to larger scales by providing good model fits to field population data. The ability of the presented model to fit the available field and laboratory data for E. fetida demonstrates the promise of the agent-based approach in ecology, by showing how biological knowledge can be used to make ecological inferences. Further work is required to extend the approach to populations of more ecologically relevant species studied at the field scale. Such a model could help extrapolate from laboratory to field conditions and from one set of field conditions to another or from species to species.
There is significant current interest in the application of magnetic (magnetite or maghemite) nanoparticles functionalised with chelating agents for the environmental remediation of metal ...contaminated waters and solutions. Whilst there is a body of knowledge about the potential remediation efficacy of such engineered nanoparticles from studies involving synthetic solutions of single metals, there is relatively little data involving mixed-metal solutions and virtually no studies about nanoparticle performance in chemically complex environmental solutions representing those to which a scaled-up nanoremediation process might eventually be applied. Therefore, we investigated the ability of diethylenetriaminepentaacetic acid (DTPA)-functionalised, silica-coated maghemite nanoparticles to extract potentially toxic (Cd, Co, Cu) and “non-toxic” (Ca, Mg) metals from solution (initial metal = 10 mg L−1; pH range: 2–8) and to extract a wider range of elements (As, Ca, Cd, Co, Cr, Cu, Mg, Na, Pb, Zn) from leachate obtained from 10 different contaminated soils with variable initial pH, (semi-)metal and dissolved organic carbon (DOC) concentrations. The functionalised nanoparticles could extract the potentially toxic metals with high efficiency (in general >70%) from single metal solutions and with efficiencies that were either unaffected or reduced from the soil leachates. Kd values remained high (>500 L kg−1), even for the soil leachate extractions. Our findings show that DOC and relatively high concentrations of non-toxic elements do not necessarily reduce the efficiency of metal contaminant removal by DTPA-functionalised magnetic nanoparticles and thus demonstrate the remediation potential of such particles when added to chemically complex soil-derived contaminated solutions.
•DTPA-functionalised magnetic nanoparticles can remove Cd, Co and Cu from solution at a range of pHs.•Ca and Mg have far lower removal efficiencies.•Metal extraction from soil leachates is similar or reduced compared to single metal solutions.•The nanoparticles have potential for remediating metal-contaminated water and solutions generated by soil washing.
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