The widespread use of detergents increases the concentration of surfactant in lakes and reservoirs. High surfactant loads produces toxicity to algae; however, the influence of the increasing surfactant on the competition between algae is not clear. In this paper, different amounts of linear alkylbenzene sulfonate (LAS) were added to test the effects of LAS on the competition between Microcystis aeruginosa and Scenedesmus obliquus under eutrophic condition. In single culture, the growth of S. obliquus was promoted under lower LAS concentrations (1 and 20 mg L⁻¹), but cell density of S. obliquus reduced when treated with higher LAS concentration (100 mg L⁻¹). The growth of M. aeruginosa was inhibited markedly with 20 and 100 mg L⁻¹ LAS. Compared with single culture, the result was opposite in co-cultures and the cell density of S. obliquus increased significantly when treated with LAS of 1, 20, and 100 mg L⁻¹. The specific growth rates of S. obliquus and M. aeruginosa in both cultures were 0.4–0.5 day⁻¹ and 0.6–0.7 day⁻¹, respectively, except that the specific growth rate of M. aeruginosa in both cultures treated with 100 mg L⁻¹ LAS was about 0.2 day⁻¹. M. aeruginosa dominated over S. obliquus in the co-culture without LAS, while the competition was completely opposite with the addition of 20 mg L⁻¹ LAS. The growth of S. obliquus treated with 20 mg L⁻¹ LAS was not affected significantly in single culture but was promoted by 75 % in co-culture. Moreover, the growth of S. obliquus in co-culture treated with 100 mg L⁻¹ LAS was promoted by more than 97 %. These results suggested that the increasing LAS would overturn the competition of algae in freshwater ecosystems.

Environmental contamination caused by mercury is a serious problem worldwide. The study was conducted in order to identify Hg contamination in soil, technosoil from dumps, groundwater, and surface water in the surroundings of the abandoned Hg deposit of Malachov in Central Slovakia. Soil from the Malachovský brook valley was classified as cambi-soil (rendzina). The highest Hg concentrations (44.24 mg kg⁻¹) were described in the soil from the mining area at the Veľká Studňa locality. In the groundwater, the maximal Hg content is 0.84 μg L⁻¹, and in the surface water it is 394 μg L⁻¹. The speciation study proved that in most samples, Hg occurs in the form of cinnabarite. The release of Hg into the environment as a consequence of weathering is limited.

The purpose of the paper is to assess the groundwater quality near the landfill sites using landfill water pollution index (LWPI). In order to investigate the scale of groundwater contamination, three landfills (E, H and S) in different stages of their operation were taken into analysis. Samples of groundwater in the vicinity of studied landfills were collected four times each year in the period from 2004 to 2014. A total of over 300 groundwater samples were analysed for pH, EC, PAH, TOC, Cr, Hg, Zn, Pb, Cd, Cu, as required by the UE legal acts for landfill monitoring system. The calculated values of the LWPI allowed the quantification of the overall water quality near the landfill sites. The obtained results indicated that the most negative impact on groundwater quality is observed near the old Landfill H. Improper location of piezometer at the Landfill S favoured infiltration of run-off from road pavement into the soil-water environment. Deep deposition of the groundwater level at Landfill S area reduced the landfill impact on the water quality. Conducted analyses revealed that the LWPI can be used for evaluation of water pollution near a landfill, for assessment of the variability of water pollution with time and for comparison of water quality from different piezometers, landfills or time periods. The applied WQI (Water Quality Index) can also be an important information tool for landfill policy makers and the public about the groundwater pollution threat from landfill.

Enzymes immobilization is a useful way to allow enzyme reuse and increase their stability. A high redox potential laccase from Trametes versicolor (TvL) and a low redox potential, but commercially available low-cost laccase from Myceliophthora thermophila (MtL), were successfully immobilized and co-immobilized onto fumed silica nanoparticles (fsNP). Enzyme loads of 1.78 ± 0.07, 0.69 ± 0.03, and 1.10 ± 0.01 U/mg fsNP were attained for the optimal doses of TvL, MtL, and co-immobilized laccases, respectively. In general, the laccase-fsNP conjugates showed a higher resistance against an acidic pH value (i.e., pH 3), and a higher storage stability than free enzymes. In addition, immobilized enzymes exhibited a superior long-term stability than free laccases when incubated in a secondary effluent from a municipal wastewater treatment plant (WWTP). For instance, the residual activity after 2 weeks for the co-immobilized laccases and the mixture of free laccases were 40.2 ± 2.5 % and 16.8 ± 1.0 %, respectively. The ability of the laccase-fsNP to remove a mixture of ¹⁴C-bisphenol A (BPA) and ¹⁴C-sodium diclofenac (DCF) from spiked secondary effluents was assessed in batch experiments. The catalytic efficiency was highly dependent on both the microbial source and state of the biocatalyst. The high redox potential TvL in free form attained a four-fold higher percentage of BPA transformation than the free MtL. Compared to free laccases, immobilized enzymes led to much slower rates of BPA transformation. For instance, after 24 h, the percentages of BPA transformation by 1000 U/L of a mixture of free laccases or co-immobilized enzymes were 67.8 ± 5.2 and 27.0 ± 3.9 %, respectively. Nevertheless, the use of 8000 U/L of co-immobilized laccase led to a nearly complete removal of BPA, despite the unfavorable conditions for laccase catalysis (pH ~ 8.4). DCF transformation was not observed for any of the enzymatic systems, showing that this compound is highly recalcitrant toward laccase oxidation under realistic conditions.

The objectives of the present field study were to examine the soil enzyme activities in the soil root zones of Plantago lanceolata and Plantago major in different heavy metal contaminated stands. Moreover, the investigations concerned the intensity of root endophytic colonization and metal bioaccumulation in roots and shoots. The investigated Plantago species exhibited an excluder strategy, accumulating higher metal content in the roots than in the shoots. The heavy metal accumulation levels found in the two plantain species in this study were comparable to other plants suggested as phytostabilizers; therefore, the selected Plantago species may be applied in the phytostabilization of heavy metal contaminated areas. The lower level of soil enzymes (dehydrogenase, urease, acid, and alkaline phosphatase) as well as the higher bioavailability of metals in the root zone soil of the two plantain species were found in an area affected by smelting activity, where organic matter content in the soil was also the smallest. Mycorrhizal colonization on both species in the contaminated area was similar to colonization in non-contaminated stands. However, the lowest arbuscule occurrence and an absence of dark septate endophytes were found in the area affected by the smelting activity. It corresponded with the lowest plant cover observed in this stand. The assessment of enzyme activity, mycorrhizal colonization, and the chemical and physical properties of soils proved to be sensitive to differences between sites and between Plantago species.

Plant growth-promoting yeasts are often over looked as a mechanism to improve phytoremediation of heavy metals. In this study, Cryptococcus sp. NSE1, a Cd-tolerant yeast with plant growth capabilities, was isolated from the rhizosphere of the heavy metal hyperaccumulator Sedum plumbizincicola. The yeast exhibited strong tolerance to a range of heavy metals including Cd, Cu, and Zn on plate assays. The adsorption rate Cd, Cu, Zn by NSE1 was 26.1, 13.2, and 25.2 %, respectively. Irregular spines were formed on the surface of NSE1 when grown in MSM medium supplemented with 200 mg L⁻¹ Cd. NSE1 was capable of utilizing 1-aminocyclopropane-1-carboxylate (ACC) as a sole nitrogen source and was capable of solubilization of inorganic phosphate at rates of 195.2 mg L⁻¹. Field experiments demonstrated that NSE1 increased phytoremediation by increasing the biomass of Cd hyperaccumulator S. plumbizincicola (46 %, p < 0.05) during phytoremediation. Overall, Cd accumulation by S. plumbizincicola was increased from 19.6 to 31.1 mg m⁻² though no difference in the concentration of Cd in the shoot biomass was observed between NSE1 and control. A Cd accumulation ratio of 38.0 % for NSE1 and 17.2 % for control was observed. The HCl-extractable Cd and CaCl₂-extractable Cd concentration in the soil of the NSE1 treatment were reduced by 39.2 and 29.5 %, respectively. Community-level physiology profiling, assessed using Biolog Eco plates, indicated functional changes to the rhizosphere community inoculated with NSE1 by average well color development (AWCD) and measurement of richness (diversity). Values of Shannon-Weiner index, Simpson index, and McIntosh index showed a slight but no significant increases. These results indicate that inoculation of NSE1 could increase the shoot biomass of S. plumbizincicola, enhance the Cd accumulation in S. plumbizincicola, and decrease the available heavy metal content in soils significantly without overall significant changes to the microbial community.

Wet deposition fluxes of organochlorine pesticides (OCPs) were determined for rain samples collected in a coastal area of Turkey. Seventeen precipitation samples were collected over a 1-year period from 2008 to 2009. Rainwater was accumulated at the beginning of rain events using real time monitoring. Atmospheric concentrations were also measured in parallel with deposition samples. Both atmospheric concentrations and deposition fluxes were determined as particle and gas phases. The particle phase and dissolved phase deposition fluxes were 794.26 ± 756.70 ngm⁻² day⁻¹ and 800.77 ± 672.63 ngm⁻² day⁻¹, respectively. The washout ratios for OCP compounds were calculated separately for the particle and dissolved phases using the atmospheric concentrations and rain concentrations. The minimum washout ratio for the particle phase was 2339.47 for Endrin aldehyde, whereas the maximum washout ratio was 497593.34 for Methoxychlor. The maximum washout ratio for the dissolved phase was 247523.89 for Endosulfan beta, whereas the minimum washout ratio was 10169.69 for p,p′-DDT. The dry deposition velocities ranged from 0.01 to 1.67 cms⁻¹. The partitioning of wet deposition between the particle and dissolved phases was 50 % in terms of total OCP deposition.

Organochlorine pesticides (OCPs) have attracted widespread concern because of their environmental persistence and toxicity. The historical influence of different agricultural land use types on soil concentrations of OCP residues was investigated by collecting a total of 52 surface soil samples from long-term cotton fields and fields with other crops in Lvdian township, Henan province, eastern central China. The concentration, composition, and possible sources of 16 OCPs were determined and a health risk assessment of these soils was conducted. Hexachlorocyclohexane (HCH), heptachlor, chlordane, and dichloro diphenyl trichloroethane plus its main metabolites (DDTs) were the most frequently detected OCPs with concentrations of 2.9–56.4 ng g⁻¹, 4.3–14.0 ng g⁻¹, 18.0–1254.4 ng g⁻¹, and below detection limit (BDL) −206.1 ng g⁻¹, respectively. Analysis of variance of p,p-DDE shows significant (P < 0.05) differences while other OCPs show no significant differences between historical cotton fields and fields containing other crops. Compositional analysis suggests that the HCH is derived mainly from the use of lindane and that there are recent inputs. Analysis of variance and compositional analysis indicate that the p,p-DDE in surface soil from long-term cotton fields is derived mainly from the aerobic biodegradation of historical residues. The sum of carcinogenic risk values of OCPs for soil samples were found to be 1.58 × 10⁻⁶, posing a low cancer risk to the inhabitants of the region studied.

Well-positioned and configured vegetation barriers (VBs) have been suggested as one of the green infrastructures that could improve near-road (local) air quality. This is because of their influence on the underlying mechanisms: dispersion and mass removal (by deposition). Some studies have investigated air quality improvement by near-road vegetation barrier using the dispersion-related method while few studies have done the same using the deposition-related method. However, decision making on vegetation barrier’s configuration and placement for need-based maximum benefit requires a combined assessment with both methods which are not commonly found in a single study. In the present study, we employed a computational fluid dynamics model, ENVI-met, to evaluate the air quality benefit of near-road vegetation barrier using an integrated dispersion–deposition approach. A technique based on distance between source (road) and point of peak concentration before dwindling concentration downwind begins referred to as “distance to maximum concentration (DMC)” has been proposed to determine optimum position from source and thickness of vegetation barrier for improved dispersion and deposition-based benefit, respectively. Generally, a higher volume of vegetation barrier increases the overall mass removal while it weakens dispersion of pollutant within the same domain. Hence, the benefit of roadside vegetation barrier is need-based and can be expressed as either higher mass deposition or higher mass dispersion. Finally, recommendations on applications of our findings were presented.