Biosolids, mycorrhizal fungi and Eucalypts for phytostabilization purposes of sulphidic mine tailings

11 pages, 4 figures, 5 tables, 33 references.In mine tailings facilities, phytostabilisation is an attractive technology for long-term remediation. We tested the effect of the addition of biosolids combined with a native arbuscular mycorrhizal inoculum (AMF) on growth of a eucalypt (E. cladocalyx), and on trace element stabilization of sulphidic gold mine tailings. A glasshouse trial was established using four substrates: tailings (T); tailings with a layer of 5 cm topsoil (TS); tailings amended with 100 dry t ha-1 biosolids (LB), and tailings amended with 500 dry t ha-1 biosolids (HB). Half pots were inoculated with a mixture of Glomus sp. (WUM51 - 9227), Scutelaspora aurigloba (WUM51 - 53) and Acaulospora levis (WUM46) culture mix, and others were uninoculated controls. Two seeds per pot were sown in the pots and after 30 days all pots were uniformly thinned to 1 plant/pot. Plants were destructively harvested at 150 days after the sowing. Leaf and stem weights, leaf area and plant height were measured for each plant. Nutrients and trace element concentrations in leaves and stems were also determined. Addition of biosolids significantly increased mycorrhizal colonization (both ectomycorrhizal (ECM) and arbuscular mycorrhizal) in roots compared with the other treatments. Biosolids clearly improved the establishment and growth of the eucalypts. At low biosolid doses, mycorrhizal inoculum increased plant biomass production and the effectiveness of nutrient uptake. Trace element concentrations in trees of the biosolid-amended pots were in general high. It is therefore important to reduce the uptake of toxic elements by plants, which can be done successfully by adjusting amendment addition and the use of mycorrhizal inoculation, and then monitoring trace element contents of different taxa growing in the affected area.Dr. E. Madejón received financial support for her work at The University of Melbourne (Australia) from Program Salvador de Madariaga of the Spanish MEC. P Madejón thanks her Ramon y Cajal Contract financed by the Spanish Ministry of Innovation and Science.Peer reviewe

Carbon fractions and enzymatic activities in two cultivated dryland soils under conservation tillage

Abstract Long-term soil management experiments are expected to provide important information regarding sustainable crop production systems. In this study we evaluated the long-term effect of conservation tillage (CT) on biological properties in two different textured soils [Entiso

An Assessment of Contaminants in UK Road-Verge Biomass and the Implications for Use as Anaerobic Digestion Feedstock

Biomass from harvested road-verge herbage has potential value as a feedstock for anaerobic digestion (AD) energy plants. However, the proximity to road traffic related pollution sources introduces the possibility of contamination by potentially toxic elements and polycyclic aromatic hydrocarbons. Potential sources of pollution from road traffic emissions are identified and the consequent likelihood of certain contaminants being present at elevated levels is assessed. Samples of road verge biomass harvested from selected locations in Lincolnshire UK for use in AD plants were analysed to produce a set of measurements for the presence of the contaminants of interest. The measured levels of these contaminants are compared to reported background levels in UK herbage and soils to assess if there is significant increased concentration in road-verge biomass. Samples of digestate from an AD plant using the road-verge biomass as feedstock were also analysed to determine if there is notable risk of transfer and concentration of contaminants into agricultural land where the digestate may be used for fertilisation. While elevated levels of contaminants were detected, they were not found in concentrations on road verge biomass at high enough levels to cause adverse effects or concerns for its safe use as an AD feedstock

Deep-sequencing reveals broad subtype-specific HCV resistance mutations associated with treatment failure

A percentage of hepatitis C virus (HCV)-infected patients fail direct acting antiviral (DAA)-based treatment regimens, often because of drug resistance-associated substitutions (RAS). The aim of this study was to characterize the resistance profile of a large cohort of patients failing DAA-based treatments, and investigate the relationship between HCV subtype and failure, as an aid to optimizing management of these patients. A new, standardized HCV-RAS testing protocol based on deep sequencing was designed and applied to 220 previously subtyped samples from patients failing DAA treatment, collected in 39 Spanish hospitals. The majority had received DAA-based interferon (IFN) a-free regimens; 79% had failed sofosbuvir-containing therapy. Genomic regions encoding the nonstructural protein (NS) 3, NS5A, and NS5B (DAA target regions) were analyzed using subtype-specific primers. Viral subtype distribution was as follows: genotype (G) 1, 62.7%; G3a, 21.4%; G4d, 12.3%; G2, 1.8%; and mixed infections 1.8%. Overall, 88.6% of patients carried at least 1 RAS, and 19% carried RAS at frequencies below 20% in the mutant spectrum. There were no differences in RAS selection between treatments with and without ribavirin. Regardless of the treatment received, each HCV subtype showed specific types of RAS. Of note, no RAS were detected in the target proteins of 18.6% of patients failing treatment, and 30.4% of patients had RAS in proteins that were not targets of the inhibitors they received. HCV patients failing DAA therapy showed a high diversity of RAS. Ribavirin use did not influence the type or number of RAS at failure. The subtype-specific pattern of RAS emergence underscores the importance of accurate HCV subtyping. The frequency of “extra-target” RAS suggests the need for RAS screening in all three DAA target regions

Phytostabilization of mine tailings using compost-assisted direct planting: Translating greenhouse results to the field

Standard practice in reclamation of mine tailings is the emplacement of a 15 to 90 cm soil/gravel/rock cap which is then hydro-seeded. In this study we investigate compost-assisted direct planting phytostabilization technology as an alternative to standard cap and plant practices. In phytostabilization the goal is to establish a vegetative cap using native plants that stabilize metals in the root zone with little to no shoot accumulation. The study site is a barren 62-hectare tailings pile characterized by extremely acidic pH as well as lead, arsenic, and zinc each exceeding 2000 mg kg(-1). The study objective is to evaluate whether successful greenhouse phytostabilization results are scalable to the field. In May 2010, a 0.27 ha study area was established on the Iron King Mine and Humboldt Smelter Superfund (IKMHSS) site with six irrigated treatments; tailings amended with 10, 15, or 20% (w/w) compost seeded with amix of native plants (buffalo grass, arizona fescue, quailbush, mountain mahogany, mesquite, and catclaw acacia) and controls including composted (15 and 20%) unseeded treatments and an uncomposted unseeded treatment. Canopy cover ranging from 21 to 61% developed after 41 months in the compost-amended planted treatments, a canopy cover similar to that found in the surrounding region. No plants grew on unamended tailings. Neutrophilic heterotrophic bacterial counts were 1.5 to 4 orders of magnitude higher after 41 months in planted versus unamended control plots. Shoot tissue accumulation of various metal(loids) was at or below Domestic Animal Toxicity Limits, with some plant specific exceptions in treatments receiving less compost. Parameters including % canopy cover, neutrophilic heterotrophic bacteria counts, and shoot uptake of metal(loids) are promising criteria to use in evaluating reclamation success. In summary, compost amendment and seeding, guided by preliminary greenhouse studies, allowed plant establishment and sustained growth over 4 years demonstrating feasibility for this phytostabilization technology. (C) 2016 Elsevier B.V. All rights reserved.NIEHS Superfund Research Program [2 P42 ES04940]24 month embargo; published online: 13 May 2016This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]