Soil metal contamination represents serious threats to plant ecosystem sustainability. Knowledge of metal distribution in plants and the effects of long-term exposure to high levels of metals on cytological stability in Deschampsia cespitosa and Populus tremuloides population is limited. The objective of the present study was to determine how D. cespitosa and P. tremuloides plants cope with soil metal contamination. The effects of high copper (Cu) and nickel (Ni) soil concentrations on cytological stability were also analyzed. The results provide strong evidence that D. cespitosa plants cope with metal contaminations by accumulating them in their root system with limited translocation to their aerial plant parts. Metal bioaccumulation factors were high with values of 5.53 (Cu), 35.19 (Fe), 151.21 (Mg), 24.38 (Ni), and 27.42 (Zn). On the other hand, the bioaccumulation factors in P. tremuloides were 0.42 (Cu), 1.67 (Fe), 4.77 (Mg), 0.94 (Ni), and 5.53 (Zn). The translocation factors (TFs) from roots to leaves for poplar (P. tremuloides) were high for Ni (8.38) and low for Cu (0.71). Cytological analysis clearly showed that long exposure of roots to high levels of metal contamination lead to significant mitotic disruption. Overall, 100 % of the plants from metal-contaminated sites showed a high level of mixoploidy compared to 17 % from the reference sites. Lagging chromosomes in mitotic anaphase were observed in most of the plants from metal-contaminated sites. These mitotic abnormalities appear to have no detectable effects on plant growth and survival.

In the European registration procedure for pesticides, microcosm and mesocosm studies are the highest aquatic experimental tier to assess their environmental effects. Evaluations of microcosm/mesocosm studies rely heavily on no observed effect concentrations (NOECs) calculated for different population-level endpoints. Ideally, a power analysis should be reported for the concentration–response relationships underlying these NOECs, as well as for measurement endpoints for which significant effects cannot be demonstrated. An indication of this statistical power can be provided a posteriori by calculated minimum detectable differences (MDDs). The MDD defines the difference between the means of a treatment and the control that must exist to detect a statistically significant effect. The aim of this paper is to expand on the Aquatic Guidance Document recently published by the European Food Safety Authority (EFSA) and to propose a procedure to report and evaluate NOECs and related MDDs in a harmonised way. In addition, decision schemes are provided on how MDDs can be used to assess the reliability of microcosm/mesocosm studies and for the derivation of effect classes used to derive regulatory acceptable concentrations. Furthermore, examples are presented to show how MDDs can be reduced by optimising experimental design and sampling techniques.

The efficiency of phytoextraction is limited because of the low growth exhibited by plants under the stress of heavy metals. Impatiens (Impatiens walleriana) cuttings were grown in soils artificially contaminated with cadmium (Cd) and modified with chemical fertilizer to study the relationship among the leaf area, transpiration rate, and Cd accumulation. The subcellular distribution of Cd in various impatiens organs was also measured. Experimental results showed that there were positive, linear relationships between the leaf area and the transpiration rate. A similar relationship was found between the transpiration rate and the Cd accumulation in the shoots. Suitable management practices can be conducted to increase the transpiration rate and thus the plant’s phytoextraction efficiency. In the roots and leaves, Cd was mainly compartmentalized in the soluble fraction and the cell wall fraction, respectively. The varied subcellular distribution of Cd in the different organs was responsible for the high accumulation capacity.

The carbon rich material obtained from pyrolysis process, i.e. biochar, has been widely discussed during the last decade due to its utilisation as a soil amendment. Furthermore, there is an unsolved question of biomass disposal from phytoremediation technologies. The idea of contaminated biomass pyrolysis has appeared, but there is lack of information about possible biochar utilisation obtained by this process. The aim of our study was to observe sorption properties of biochar prepared from contaminated biomass and release of contaminants from biochar back into the environment. The biomass of fast growing trees and maize was harvested on a site significantly damaged by risk element contamination (Cd, Pb and Zn). Plant biomass was pyrolysed and then the batch (de)sorption experiments were settled. The results confirmed no significant differences in metal sorption ability between biochars prepared from contaminated and uncontaminated biomass under the same conditions. The trend of maximum sorption capacity of observed matrices followed the order: wood biochar + soil (WB + soil) > wood uncontaminated biochar + soil (WUB + soil) > maize biochar + soil (MB + soil) > soil for cadmium, WB + soil > WUB + soil > soil for lead and MB + soil > WUB + soil > WB + soil > soil for zinc. Despite of increase of Zn desorption from wood biochars, maximum sorption capacity of the final WB + soil system was comparable to the WUB+soil sample. Our laboratory experiments showed high potential of biochar from contaminated plants as a soil amendment with sorption abilities and minimal risk of metal release.

The aim of this study was to describe the mechanisms that native Bacillus cereus M6 isolated from heavy crude oilᵒAPI gravity 11.5 uses to tolerate and/or resist toxic metals. Metal tolerance and removal of Pb(II), Cr(VI), and As(V) was determined. In addition, we evidenced the subcellular distribution of metals, the efflux pump kinetics, and morphological changes in metal-tolerant bacteria. B. cereus M6 exhibited strong tolerance and resistance to the metals evaluated and efficiently removed the metal content by operating efflux pumps and accumulating mainly in membrane fraction. Also, it was found that the model that best fit the efflux corresponds to an equation for resonant oscillations. B. cereus M6 uses mechanisms, including efflux pumps, intracellular and extracellular accumulation in parallel in order to maintain metal levels below a toxic threshold and overcome the effects of high concentrations. These findings are an approach of an energy-dependent efflux system to eliminate excessive amounts of crude oil-associated metals in Bacillus. B. cereus M6 may potentially be useful in designing improved strategies for the bioremediation of soils polluted with metals. Additionally, the prediction model developed would be useful for improving the monitoring of in vitro and in vivo bioremediation processes.

This study investigates the use of sericite beads and microalgae for the removal of heavy metals from acid mine drainage (AMD) and the simultaneous enhancement of biomass productivity. The experiment was conducted over a period of 6 days in a hybrid system containing sericite beads and microalgae Chlorella sp. The results show that the biomass production increased to ~8.04 times its initial concentration of 0.367 g/L as measured by an optical panel photobioreactor (OPPBR) and had a light transmittance of 95 % at a 305-mm depth. Simultaneous percent removal of Fe, Cu, Zn, Mn, As, and Cd from the AMD effluent was found to be 97.78 to 99.26 %. Biomass production was significantly enhanced by removal of heavy metal ions. We thus found that our hybrid system of sericite beads and microalgae was highly effective in removing heavy metal and in enhancing biomass production and could be a useful alternative treatment of AMD.

The effluent of the ornamental rock industry is characterized by presenting great concentrations of total solids, high contents of iron, and elevated pH, all responsible for the contamination of the superficial and ground waters, destruction of the soil, the vegetation, and the silting of the rivers. The purpose of this study is to assess the cytotoxic and genotoxic effects and the anatomical changes caused by the effluents arising from the ornamental rock polishing industry in root apex cells of Allium cepa L. (Amaryllidaceae). The samples of the effluent were collected in a polishing industry located in Nova Venécia, State of Espírito Santo, and were analyzed by mass spectrometry and atomic emission. Bulbs of A. cepa were exposed to the effluent at 12.5, 25, 37.5, 50, 75, and 100 % concentrations (residue in raw form) (v/v) for a period of 20 days. For the positive control, metilmethanesulfonate (MMS) at 4 × 10⁻⁴-M concentration was used, and distilled water was used for the negative control. The experiment was assessed taking into consideration the following parameters: mitotic index, frequency of chromosomal and nuclear abnormalities in the root apical meristem, and root anatomy. The mitotic index suffered a decrease proportional to the increase in the concentration of effluent. All the concentrations of the effluent led to chromosomal and nuclear abnormalities being stickiness and nuclear shoots the most frequent. The root apex evidenced changes that reflected on the decrease of the percentage area of the protoderm and the fundamental meristem and the increase in the areas of the cap and quiescent center. The symptoms of toxicity are related to the high frequency of cell in cellular death process observed in the roots exposed to the higher concentrations and to the decrease in the mitotic index of the apical root meristem.

We investigated a peat profile from the Izery Mountains, located within the so-called Black Triangle, the border area of Poland, Czech Republic, and Germany. This peatland suffered from an extreme atmospheric pollution during the last 50 years, which created an exceptional natural experiment to examine the impact of pollution on peatland microbes. Testate amoebae (TA), Centropyxis aerophila and Phryganella acropodia, were distinguished as a proxy of atmospheric pollution caused by extensive brown coal combustion. We recorded a decline of mixotrophic TA and development of agglutinated taxa as a response for the extreme concentration of Al (30 g kg⁻¹) and Cu (96 mg kg⁻¹) as well as the extreme amount of fly ash particles determined by scanning electron microscopy (SEM) analysis, which were used by TA for shell construction. Titanium (5.9 %), aluminum (4.7 %), and chromium (4.2 %) significantly explained the highest percentage of the variance in TA data. Elements such as Al, Ti, Cr, Ni, and Cu were highly correlated (r > 0.7, p < 0.01) with pseudostome position/body size ratio and pseudostome position. Changes in the community structure, functional diversity, and mechanisms of shell construction were recognized as the indicators of dust pollution. We strengthen the importance of the TA as the bioindicators of the recent atmospheric pollution.

In this study, BiVO₄ powder is prepared and used as a visible-light catalyst for the photocatalytic degradation of alachlor. The as-prepared BiVO₄ photocatalyst is characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–vis diffuse reflectance spectra (DRS), and BET surface area analysis. Alachlor could be successfully degraded in the presence of both H₂O₂ and BiVO₄ catalyst under visible-light irradiation. With optimal operating parameters, its degradation efficiency could reach 97 % in 6 h. Factors such as solution pH, catalyst dosage, and the presence of anions are found to influence the degradation rate. To scrutinize the mechanistic details of the alachlor photodegradation, the intermediates of the process are separated, identified, and characterized by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Results suggest that possible transformation pathways may include oxidation of the arylethyl group, cleavage of the N-methoxymethyl group, and N-chloroacetyl moiety.

Stir bar sorptive extraction (SBSE) and solid phase microextraction (SPME) are well-established sample preparation methods for the analysis of polycyclic aromatic hydrocarbons in aqueous samples. However, complex matrices especially characterized by slurry particles and dissolved organic matter (DOM) can hamper the extraction of PAH with both SBSE and SPME and lead to different results. Thus, we produced aqueous eluates from PAH-contaminated soils differing in particle size distribution and organic matter content and determined the PAH concentration in the eluates with both SBSE and SPME. Furthermore, we tested the influence of filtration on the PAH analysis. The excess finding of PAH with SBSE compared to SPME ranged from −16.6 to 24.5 %. The differences increased after filtration. We found a strong positive correlation of the excess finding to the total organic carbon content (TOC) and a negative one to the pH value. The results indicate that SBSE is less affected by complex matrices than SPME.