Some adverse effects of soil amendment with organic Materials-The case of soils polluted by copper industry phytostabilized with red fescue

Effect of the direct use of biomass in agricultural soil on heavy metals __ activation or immobilization?

In recent years, the biomass was directly used extensively in agriculture due to its low cost and convenience. Increasingly serious soil pollution of heavy metals may pose threats and risks to human health. Directly addition of biomass to soil may affect the bioavailability and content of heavy metals. Here, we reviewed the impact of direct application of oil cake, manure, sewage sludge, straw and municipal waste to soil on the form and concentration of heavy metals in soil, and also emphasized the role of biomass in soil heavy metals remediation. Heavy metals can be activated in a short term by the content of heavy metals in biomass, the production of low-molecular-weight organic acids by biomass application, and the oxidation of sulfides (except for ammoniation). However, heavy metals in soil can be immobilized by humic substances. These can be produced by biomass during a long-term application to soil. Moreover, the degree of immobilization depended on the kind of biomass. Biomass contaminated by heavy metals cannot be returned to the field directly. Therefore, Mitigating the activation of heavy metals in the early stage of biomass application is meaningful, especially for application of these biomass such as straw, sewage sludge and municipal waste. Future researches should focus on the heavy metal control on direct use of biomass in agricultural.

Evaluating the environmental and economic impact of mining for post-mined land restoration and land-use: A review

Mining has been a long-standing key player in economic development, employment, infrastructure, and supply of essential raw materials for society. It has served as a viable route to economic transformation in resource-rich countries like Australia, Canada, the United States, and parts of Africa. In this review, the impact of mining has been conceptualized into economic, environmental, and social impacts. While it is clear that mining has transformed many economies, it has also impacted negatively on the environment and, to some extent, society. Some of the negative impacts of mining are loss of vegetation cover, mass destruction of water bodies, loss of biodiversity, land-use changes and food insecurity, increased social vices and conflicts, high cost of living, and air pollution. However, reclamation has been a viable way of reducing the negative impacts of abandoned mine lands and ensure productive and efficient utilization of mine wastelands. Compaction, low or high pH, low water holding capacity, gullies, bulk density, deficiency of micro, and macronutrients are the major factors limiting the productivity of mine wastelands. A combination of physical, chemical, and biological restoration practices is ideal for restoring the mine soil productivity. While the physical method deals with earth-battering, thus putting the land back to shape, the chemical and biological methods include various amendments such as biochar, compost, synthetic fertilizers, synthetic chelates, shrubs, and grasses, and nanoparticles. A combination of these three restoration methods restores soil fertility, stimulates microbial growth, and facilitates early ecological succession. However, before embarking on reclamation, the particular post-mined land use should be clearly stated, such as conservations, forestry, agriculture, construction, intensive recreation, non-intensive recreation, and lake or pool through land suitability and selection analyses. This review has guiding significance and recommendations for mining and post-mined rehabilitation.

Use of Brassica juncea and Dactylis glomerata for the phytostabilization of mine soils amended with compost or biochar

Phytostabilization of mine soils contaminated by potentially toxic elements (PTEs) requires plants tolerant to PTE toxicity and to the poor soil physico-chemical characteristics of these areas. A pot experiment was carried out to assess the phytostabilization potential of Brassica juncea and Dactylis glomerata in mine soils amended with compost and biochar. Furthermore, the Environmental Risk of the soils and the effects of the phytostabilization process on the microbiological population size and activity in the soils were also determined. According to the Ecological Risk Index (ERI) the soils studied presented "very high risk" and As, Cd and Pb were the target elements for phytostabilization. Both amendments improved soil conditions (e.g., increasing total-N and total organic-C concentrations) and contributed to PTE (Cd, Pb and Zn) immobilization in the soil. Compost showed a more marked effect on soil microbial biomass and nutrients release in soil, which led to higher B. juncea and D. glomerata biomass in compost treated soils. Biochar treatment showed a positive effect only on D. glomerata growth, despite it provoked strong PTE immobilization in both soils. The addition of both amendments resulted in an overall reduction of PTE concentration in the plants compared to the control treatment. In addition, both plant species showed higher accumulation of PTE in the roots than in the shoots (transfer factor<1) independently of the treatment received. Therefore, they can be considered as good candidates for the phytostabilization of PTE contaminated mine soils in combination with organic amendments like biochar and compost.

Agronomic Approaches for Characterization, Remediation, and Monitoring of Contaminated Sites

With a view to conserving or improving soil ecosystem services, environment-friendly techniques, such as bio- and phytoremediation, can effectively be used for the characterization, risk assessment, and remediation of contaminated agricultural sites. Polyannual vegetation (meadows, poplar, and cane stands) is widely considered the most efficient tool for remediation (extraction of bioavailable fraction of contaminants), for undertaking safety measures (reducing the mobility of contaminants towards other environmental compartments), and for restoring the ecosystem services of contaminated agricultural sites (biomass production, groundwater protection, C storage, landscape quality improvement, and cultural and educational services). The roles of agronomic approaches will be reviewed by focusing on the various steps in the whole remediation process: (i) detailed environmental characterization; (ii) phytoremediation for reducing risks for the environment and human health; (iii) agronomic management for improving efficiency of phytoremediation; and (iv) biomass recycling in the win-win perspective of the circular economy.

Arsenic accumulation by red fescue (Festuca rubra) growing in mine affected soils - Findings from the field and greenhouse studies

Soils strongly enriched in arsenic in historical mining sites pose the environmental risk. Phytostabilization is a reasonable method for their remediation. A suitability of red fescue (Festuca rubra L.) for this purpose was examined. Plant and soil material was collected from four study objects: mine dumps in Złoty Stok and Czarnów and two areas formerly flooded by tailings. Total As in soils ranged 72-48900 mg/kg, while the shoots and roots of red fescue contained 1.5-65.5 and 2.3-824 mg/kg As, respectively. Bioaccumulation BAF and translocation TF factors were typical for excluders, however, in most cases, As in shoots exceeded 4 mg/kg, an EU threshold for As in fodder. A greenhouse experiment, that involved treatment with mineral fertilizers, manure, and forest litter, was performed to closer examine the factors governing As uptake by red fescue. A stress-resistant cultivar Leo-Pol was used as a test plant. Grass shoots were harvested after 6 and 12 weeks. Manure treatment increased strongly As extractability but did not increase As uptake by plants. Though, As concentrations in plants were in the pot experiment by manifold higher than those in the field. Particularly high (66.5-1580 mg/kg) was As in the second shoot harvest. Differences between the field and greenhouse data indicate that the populations of red fescue, that develop in As rich sites, are specifically As-tolerant. Possible mechanisms of tolerance are discussed. The conclusion is that the commercial cultivar, despite declared stress-resistance, cannot be used for phytostabilization of barren As-rich soils.

The effect of the selected remediation medium on the cadmium bioavailability in the selected ecosystem in the Southwestern locality of Slovakia

Soil is a sensitive ecological factor. Biodegradable materials from the environment can also be used to deal with serious ecological problems. Soil affecting by remediation medium - garden compost - was analysed for toxic cadmium (Cd) in terms of environmental protection. The objective of this research was to analyse soil and compost at foothill locality of the Tribeč Mountains (Southwestern Slovakia) in the years 2015−2017 to determine Cd contents in soil and compost, pH and to assess Cd bioavailability. The analyses were carried out using the Atomic Absorption Spectrometry with seven-step Selective Sequential Extraction methods. The results obtained were evaluated statistically using the SAS 9.4 software method by Spearman’s correlation coefficient. The results showed that Cd contents in soil had reached 2.96 mg kg−1 and soil with compost (the ratio 1:1) 2.71 mg kg−1 dry matter. Cd contents in the soil exceeded maximum allowed limit of 196%. And deceased by 25% after adding compost. The pH in soil with compost varied from 6.78 to 7.98. The pH prevented the mobility of Cd about 8.3% in average. Statistical dependence was high, which was demonstrated for relationship between Cd in soil, pH and compost. Available Cd forms in soil were 53.3% and soil with compost were 45% in average. The garden compost as a remediation medium reduced Cd bioavailability.

Integrated Management of Pig Residues and Copper Mine Tailings for Aided Phytostabilization

There is high demand for identifying socio-environmentally sound ways to dispose of large quantities of offensive odor-generating organic residues produced by intensive livestock farming. The use of these residues as amendments at large-scale mine tailings storage facilities for in situ plant-based reclamation may be a useful alternative. We performed a greenhouse assay to evaluate effectiveness of pig slurries and the solid organic fraction of aerobic-aerated pig slurries, both treated and not treated for odor emission, as amendments for copper tailings. Different doses of slurries or the solid organic fraction of the slurries, untreated and treated with either ozone or a commercial product used to manage strong odors (Just a Drop), were incorporated into tailings and stabilized (15 d) under greenhouse conditions. L. (ryegrass) was used as bioindicator for Cu and Zn toxicity. Plant performance (shoot and root dry biomass, Cu and Zn content in leaves) and general physicochemical characteristics of substrates were evaluated. Our results showed that odor management of pig residues was possible with commercial products, and their incorporation into tailings rapidly and effectively reduced odor emission. The solid organic fraction of the slurries neutralized acidic tailings, and both pig residues increased organic matter and nutrient content in tailings while reducing extractable Cu. As a result, ryegrass productivity was significantly improved by incorporation of either slurries or their solid organic fraction into tailings in a dose-dependent form. Foliar Cu content in ryegrass was not affected but foliar Zn content increased; however, Zn remained within acceptable ranges. Both the pig slurries and their soil organic fractions proved to be valuable residues for tailings reclamation.

High copper levels in follicular fluid affect follicle development in polycystic ovary syndrome patients: Population-based and in vitro studies

Although the adverse effects of copper overexposure on the liver, kidney, spleen and intestinal organs are well known, information about the impact of copper toxicity on human reproduction is limited. A total of 348 infertile patients were enrolled in our present study, including 89 with polycystic ovary syndrome (PCOS), 145 with fallopian tube obstruction and 114 controls. The follicular fluid concentrations of 22 trace elements were measured by inductively coupled plasma mass spectrometry (ICP-MS). Principal component analysis was used to identify trace element profile alterations in different groups. The mRNA levels of steroidogenesis-related genes were measured by real-time PCR. Our results showed that the trace element profile in follicular fluid was obviously altered in PCOS patients. Copper concentrations were significantly (p < .05) higher in the PCOS group than in the other two groups. Increased copper levels in follicular fluid were associated with a higher number of retrievable oocytes in the PCOS group (B = 1.785, p = .001) but a lower rate of high-quality embryos (B = -6.360, p = .050). Moreover, follicular fluid copper levels were positively correlated with follicular fluid progesterone levels (r = 0.275, p = .010) and testosterone levels (r = 0.250, p = .022). Cultured human granulosa cells overexposed to copper showed significantly (p < .05) increased estradiol secretion and decreased testosterone levels. Real-time quantitative PCR revealed a significant (p < .05) increase in CYP19A1 and HSD3b mRNA expression. Our results indicate that increased copper levels in follicular fluid could affect follicle development in PCOS patients, and the mechanism may be related to copper-induced abnormalities in steroidogenesis.

Effectiveness of pig sludge as organic amendment of different textural class mine tailings with different periods of amendment-contact time

The present study assesses the effect of tailing texture (loamy sand (LT) and sandy loam (ST)), dose of pig sludge (0, 50, 100 and 200 t ha^-1) and amendment-contact time (14, 28 and 42 days) on physicochemical quality of amended substrate using Lolium perenne var Nui as a bioindicator. The main properties of LT differed of ST in levels of total organic carbon (0.19 and 0.58%), in pH (4.6 and 8.5), total Cu (202 and 1647 mg kg^-1) and Zn content (31 and 137 mg kg^-1). Soil pore water of experimental substrates was characterized for pH, electrical conductivity (EC) and Cu²⁺ ion activity (pCu²⁺) while ammonium nitrogen (NH₄⁺-N), infiltration rate and general physicochemical characteristics were measured in substrates. Shoot biomass (SB), root biomass (RB) and the RB:SB ratio was calculated for L. perenne. The results showed there to be a significant interaction (p < 0.05) between tailing texture, sludge dose and amendment-contact time for pCu²⁺, infiltration rate, SB, RB, and RB: SB ratio, but not for pH, EC, or NH₄⁺-N. However, sludge dose and amendment-contact time significantly affected all variables. By increasing dosages of pig sludge, pore water pH increased, and this was associated with decreases in pCu²⁺ and the infiltration rate. High doses of pig sludge (100 and 200 t ha^-1) impaired growth of L. perenne irrespective of tailing texture and amendment-contact time, likely because of the rise of EC (up to 14 mS cm^-1). For both tailing textures, the highest biomass was obtained after incorporation of 50 t ha^-1 of pig sludge, with increasing values as amendment-contact time rose. In conclusion, effective management of pig sludge for tailing reclamation should guarantee doses <50 t ha^-1 and amendment-contact time >28 days, irrespective of tailing texture.