The Effect of Quinolones on Common Duckweed Lemna minor L., a Hydrophyte Bioindicator of Environmental Pollution.

Plant growth and the development of morphological traits in plants are inhibited under exposure to pharmaceuticals that are present in soil and water. The present study revealed that moxifloxacin (MOXI), nalidixic acid (NAL), levofloxacin (LVF) and pefloxacin (PEF) at concentrations of >0.29, >0.48, >0.62 and >1.45 mg × L-1, respectively, inhibited the growth (Ir) of duckweed plants and decreased their yield (Iy). In the current study, none of the tested quinolones (QNs) at any of the examined concentrations were lethal for common duckweed plants. However, at the highest concentration (12.8 mg × L-1), LVF increased Ir and Iy values by 82% on average and increased the values of NAL, PEF and MOXI by 62% on average. All tested QNs led to the loss of assimilation pigments. In consequence, all QNs, except for LVF, induced changes in chlorophyll fluorescence (Fv/Fm), without any effect on phaeophytinization quotient (PQ) values. The uptake of NAL, MOXI, LVF by Lemna minor during the 7-day chronic toxicity test was directly proportional to drug concentrations in the growth medium. Nalidixic acid was absorbed in the largest quantities, whereas in the group of fluoroquinolones (FQNs), MOXI, LVF and PEF were less effectively absorbed by common duckweed. This study demonstrated that biosorption by L. minor occurs regardless of the plants' condition. These findings indicate that L. minor can be used as an effective biological method to remove QNs from wastewater and water and that biosorption should be a mandatory process in conventional water and wastewater treatment.

Insight into metal immobilization and microbial community structure in soil from a steel disposal dump phytostabilized with composted, pyrolyzed or gasified wastes.

The soil system is a key component of the environment that can serve as a sink of pollutants. Using processed waste for aided phytostabilization of metals (HMs) in contaminated soils is an attractive phytoremediation technique that integrates waste utilization and recycling. In this study, we evaluated the effect of biologically and thermally processed wastes, i.e. sewage sludge compost (CSS), poultry feather ash (AGF) and willow chip biochar (BWC), on phytostabilization of contaminated soil from a steel disposal dump. Greenhouse experiments with Lupinus luteus L. and amendments (dosage: 3.0%, w/w) were conducted for 58 days. Soil toxicity was evaluated with Ostracodtoxkit and Phytotoxkit tests. At the end of the experiment, soil pH, plant biomass yield, and HM accumulation in plant tissues were determined. HM distribution, HM stability (reduced partition index) and potential environmental risk (mRI index) in the soil were assessed. During phytostabilization, changes in the diversity of the rhizospheric bacterial community were monitored. All amendments significantly increased soil pH and biomass yield and decreased soil phytotoxicity. AGF and BWC increased accumulation of individual HMs by L. luteus roots better than CSS (Cu and Cr, and Ni and Zn, respectively). The soil amendments did not improve Pb accumulation by the roots. Improvements in HM stability depended on amendment type: Ni and Pb stability were improved by all amendments; Zn stability, by AGF, and BWC; Cd stability, by AGF; and Cr stability, by BWC. AGF reduced the mRI most effectively. Microbial diversity in amended soils increased with time of phytostabilization and was up to 9% higher in CSS amended soil than in control soil. AGF application favored the abundance of the genera Arenimonas, Brevundimonas, Gemmatimonas and Variovorax, whose metabolic potential could have contributed to the better plant growth and lower mRI in that soil. In conclusion, AGF and BWC have great potential for restoring steel disposal dump areas, and the strategies researched here can contribute to achieving targets for sustainable development.

Successful Outcome of Phytostabilization in Cr(VI) Contaminated Soils Amended with Alkalizing Additives.

This study analysed the effect of three alkalizing soil amendments (limestone, dolomite chalcedonite) on aided phytostabilization with Festuca rubra L. depending on the hexavalent chromium (Cr(VI)) level in contaminated soil. Four different levels of Cr(VI) were added to the soil (0, 50, 100 and 150 mg/kg). The Cr contents in the plant roots and above-ground parts and the soil (total and extracted Cr by 0.01 M CaCl2) were determined with flame atomic absorption spectrometry. The phytotoxicity of the soil was also determined. Soil amended with chalcedonite significantly increased F. rubra biomass. Chalcedonite and limestone favored a considerable accumulation of Cr in the roots. The application of dolomite and limestone to soil contaminated with Cr(VI) contributed to a significant increase in pH values and was found to be the most effective in reducing total Cr and CaCl2-extracted Cr contents from the soil. F. rubra in combination with a chalcedonite amendment appears to be a promising solution for phytostabilization of Cr(VI)-contaminated areas. The use of this model can contribute to reducing human exposure to Cr(VI) and its associated health risks.

Exposure of Lemna minor L. to gentian violet or Congo red is associated with changes in the biosynthesis pathway of biogenic amines.

In the literature, there is a lack of data on the effect of gentian violet (GV) and congo red (CR) dyes on the biosynthesis pathway of biogenic amines (BAs) in Lemna minor L. (common duckweed). This plant species is an important link in the food chain. Both dyes inhibited growth, biomass yield and the biosynthesis of chlorophyll a in common duckweed. The predicted toxic units demonstrated that GV had a more toxic effect on the growth rate and biomass yield of common duckweed than CR. Decarboxylase activity in the biosynthesis of BAs in common duckweed is also a useful indicator for evaluating the toxicity of both dyes. Gentian violet also exerted more phytotoxic effects on the analyzed biochemical features of common duckweed because it changed the putrescine (Put) biosynthesis pathway, increased tyramine content 1.6 fold, inhibited the activity of S-adenosylmethionine decarboxylase by 40% and the activity of ornithine decarboxylase (ODC) by 80%. Tyrosine decarboxylase (TDC) was most active in plants exposed to the highest concentration of GV. Similarly to control plants, in common duckweed exposed to CR, Put was synthesized from ornithine; however, spermidine content was 86% higher, Put content was 51% lower, and ODC activity was 86% lower.

Assisted phytostabilization of soil from a former military area with mineral amendments.

Due to the presence of toxic pollutants, soils in former military areas need remedial actions with environmentally friendly methods. Greenhouse experiments were conducted to investigate the aided phytostabilization of multi-heavy metals (HMs), i.e. Cd, Cr, Cu, Ni, Pb, Zn, in post-military soil by Festuca rubra and three mineral amendments (diatomite, dolomite and halloysite). The amendments were applied at 0 and 3.0% to each pot filled with 5 kg of polluted soil. After seven weeks of the phytostabilization, selected soil properties, biomass yield of F. rubra and immobilization of HMs by their accumulation in plant and redistribution among individual fractions in soil were determined. In addition, ecotoxicology parameters of non-amended and amended soil were established using Phytotoxkit (Sinapsis alba) and Ostracodtoxkit (Heterocypris incongruens) tests. The addition of halloysite significantly increased F. rubra biomass. Diatomite significantly increased both the Cd, Cu, Pb and Cr concentrations in the roots and the pH of the soil. The application of halloysite significantly decreased the Cd and Zn contents of the soil after the completion of the experiment. Dolomite and halloysite were more effective in HM immobilization in soil by decreasing their content in an exchangeable fraction than diatomite. These soil amendments significantly differentiated the length of S. alba roots and had a positive effect on the development of H. incongruens.

Using Mosses as Bioindicators of Potentially Toxic Element Contamination in Ecologically Valuable Areas Located in the Vicinity of a Road: A Case Study.

This study analyzed the impact of road transportation on the concentration of Zn, Ni, Pb, Co, and Cd in moss (Pleurozium schreberi). The study was carried out over five years near a national road running from the north to the east (Poland) in the area of Natura 2000 sites. Samples were collected at three significantly different locations: (1) near a sharp bend, (2) near a straight section of the road in a woodless area, and (3) in a slightly wooded area. At each location, moss samples were collected from sites situated 2, 4, 6, 8, 10, 12, and 14 m from the road edge. The highest Zn and Cd contents in the moss were recorded 6 m from the road edge near a sharp bend (where vehicles brake sharply and accelerate suddenly). At the same location, at a distance of 2 m, the highest Pb concentration was noted, and at a distance of 4 m from the road, the highest Ni concentration was noted. The Co concentration in the moss was the highest near the woodless straight section at a distance of 2 and 12 m from the road. The concentrations of Zn, Pb, Ni, Co (only at the woodless location), and Cd (at all locations) were significantly and negatively correlated with distance from the road.

The combined effect of phytostabilization and different amendments on remediation of soils from post-military areas.

Army bases and battle fields are areas of high pollution due to the chemicals released there. Soils in these areas suffer from these uses of the land, and ecosystem services are affected. Although, in the 20th century, the production of bombs and the locations of battle fields and army bases were widespread, there is little research on the impact of war on nature. Moreover, there is a need to rehabilitate the disturbed soils. The contents and ecological risks of Cu, Ni, Cd, Pb, Zn, and Cr in the topsoil from a post-military area (north-eastern Poland) were investigated. In addition, a vegetation experiment was performed with the technique of aided phytostabilization on soils from the study area. The novelty of this study is the assessment of the usefulness of soil amendments (chalcedonite, limestone, activated carbon) in heavy metal (HM) phytostabilization in contaminated soils from post-military areas. Soil samples were also examined for pollution quantification indicators, including the index of geoaccumulation (Igeo), contamination factor (CF), and degree of contamination, and subjected to the Ostracodtoxkit test. The mean contents of the tested HMs were higher than those stipulated in soil environmental quality standards. The highest Igeo (7.38) and CF (346) values were those of Cr and Zn, respectively. The highest increase in soil pH was observed after the application of limestone to the soil. The greatest reduction in Cu, Ni, and Cd contents was caused by addition of limestone. The contents of HMs in Festuca rubra were higher in its roots than in its above-ground parts.

The applicability of compost, zeolite and calcium oxide in assisted remediation of acidic soil contaminated with Cr(III) and Cr(VI).

The effect of soil amendments, i.e., compost, zeolite, and calcium oxide, on the chemical properties of soil contaminated with Cr(III) and Cr(VI) and the uptake of selected heavy metals by spring barley (Hordeum vulgare L.) and maize (Zea mays L.) was determined in a pot experiment. The content of all investigated heavy metals in the tested plants varied significantly in response to the tested soil amendments and increasing concentrations of Cr(III) and Cr(VI). Compost, zeolite, and calcium oxide contributed to an increase in the average yield of the aerial parts of maize plants only in treatments contaminated with Cr(III). The concentrations of Cr, Zn, and Ni in the aerial parts of spring barley and maize were higher in treatments contaminated with Cr(III) than in treatments contaminated with Cr(VI). Calcium oxide induced a significant increase in soil pH relative to the control treatment. In treatments without soil amendments, the average Cr content of soil was higher in pots contaminated with Cr(VI). The concentrations of Zn and Cu in non-amended treatments were negatively correlated with increasing doses of Cr(III) and Cr(VI). Calcium oxide decreased the average content of Cr, Cu, and Ni in all experimental variants. Compost increased the average content of Zn in treatments contaminated with Cr(III) and Cr(IV) relative to non-amended soil.

The effects of glyphosate-based herbicide formulations on Lemna minor, a non-target species.

Research into plants plays an important role in evaluations of water pollution with pesticides. Lemna minor (common duckweed) is widely used as an indicator organism in environmental risk assessments. The aim of this study was to determine by biological Lemna test and chemical methods the effect of glyphosate (GlyPh) concentrations of 0-40 µM on duckweed, an important link in the food chain. There are no published data on glyphosate's effects on the activity of enzymes of the amine biosynthesis pathway: ornithine decarboxylase, S-adenosylmethionine decarboxylase, tyrosine decarboxylase, lysine decarboxylase and arginine decarboxylase, and the content of shikimic acid and glyphosate residues in the tissues of common duckweed. It was found that glyphosate was taken up by duckweed. In plants exposed to 3 µM of glyphosate for 7 days, glyphosate content exceeded the acceptable Maximum Residue Level (MRL) 10-fold. Glyphosate accumulation in plant tissues exerted toxic effects on duckweed by decreasing its growth and yield, inhibiting the synthesis of chlorophyll a and b and carotenoids, and decreasing the photochemical activity of photosystem II (PSII). However, glyphosate increased the concentration of shikimic acid in the tested plants. The activity of ornithine decarboxylase increased 4-fold in plants exposed to 20 µM of the herbicide. As a water pollutant, glyphosate increased the content of biogenic amines tyramine, putrescine, cadaverine, spermidine and spermine. The activity of peroxidase and catalase was highest in duckweed exposed to 20 µM and 7 µM of the herbicide, respectively. The predicted toxic units were calculated based on glyphosate content and the computed EC values. The mean effective concentration calculated for all morphological and biochemical parameters of duckweed was determined at EC10 = 1.55, EC25 = 3.36, EC50 = 6.62 and EC90 = 14.08 µM of glyphosate. The study demonstrated that glyphosate, the active ingredient of Roundup Ultra 360 SL herbicide, induces morphological and biochemical changes in non-target plants and exerts toxic effects on aquatic ecosystems even during short-term exposure.

Long-term responses of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) to the contamination of light soils with diesel oil.

Research into trees plays a very important role in evaluations of soil contamination with diesel oil. Trees are ideal for reclaiming contaminated soils because their large biomass renders them more resistant to higher concentrations of pollutants. In the literature, there is a general scarcity of long-term studies performed on trees, in particular European beeches. The aim of this study was to evaluate the responses of Scots pines and European beeches grown for 8 years on soil contaminated with diesel oil. Selected morphological and physiological parameters of trees were analyzed. The biomass yield of Scots pines was not significantly correlated with increasing concentrations of diesel oil, but it was more than 700% higher than in European beeches. Scots pines were taller and had a larger stem diameter than European beeches during the 8-year study. The diameter of trees grown on the most contaminated soil was reduced 1.5-fold in Scots pines and more than twofold in European beeches. The length of Scots pine needles from the most contaminated treatment decreased by 50% relative to control needles. The shortest needles were heaviest. The fluctuating asymmetry (FA) of needle length was highest in Scots pines grown on the most contaminated soil, whereas the reverse was noted in the FA of needle weight. Diesel oil decreased the concentrations of chlorophylls a and b, total chlorophyll, and carotenoids. The Fv/Fm ratio of needles and leaves was influenced by the tested concentrations of diesel oil. The results of the study indicate that the Scots pine better adapts (grows more rapidly and produces higher biomass) to long-term soil contamination with diesel oil than the European beech. In European beeches, growth inhibition and leaf discoloration (a decrease in chlorophyll content) were observed already after the first year of the experiment, which indicates that 1-year-old seedlings of European beech are robust bioindicators of soil contamination with diesel oil.

Atmospheric Factors Affecting a Decrease in the Night-Time Concentrations of Tropospheric Ozone in a Low-Polluted Urban Area.

Ozone (O3) decomposition in the troposphere is a very important process which prevents excessive O3 accumulation in the air. It is particularly significant on warm summer days which are marked by a high risk of photochemical smog. We used Spearman's rank correlation test to determine relationships between the drop in O3 concentrations over time (-ΔO3), nitrogen oxide (NO), nitrogen dioxide (NO2), and total nitrogen oxide (NOx) concentrations and meteorological factors (1-h average) in low-polluted urban area in Olsztyn (north-eastern Poland). Nitrogen oxide concentrations were measured continuously by the chemiluminescence method, and O3 concentrations were determined by the UV photometric method. The obtained results suggest that the rate of decomposition of tropospheric O3 is affected mostly by the presence of NOx, high temperature, and air humidity (positive correlation) as well as by wind speed (negative correlation). Maximum correlation coefficient values were reported between -ΔO3 and air temperature, -ΔO3 and absolute air humidity when NOx concentrations were low (below 1.0 microgram per cubic meter), reaching 0.271 and 0.243, respectively. These results indicate that O3 also reacted with air components other than NO and NO2. Precipitation at average temperature of < 0 °C did not significantly contribute to a drop in O3 concentrations at night-time. In the warm season, precipitation slowed down the rate of O3 decomposition, mostly because NOx were scrubbed by rain. An analysis of seasonal and daily -ΔO3 fluctuations revealed that -ΔO3 values were highest in the summer and shortly after sunset in the diurnal cycle.

Uptake and reaction to roundup ultra 360 SL in soybean seedlings.

Due to the widespread and frequent use of Roundup Ultra 360 SL in crops production, the active substance glyphosate is often present (in the soil or in post-harvest remnants) and may be toxic to plants, including the non-target species. The aim of the current study was to determine the sensitivity of young soybean seedlings to glyphosate in concentrations ranging from 0 to 10 µM. It was demonstrated that the seedlings take small quantities of soil glyphosate up. More of the active substance was found in the shoots than in the roots. From the doses applied, the plant absorbs up to 4% of soil glyphosate, while over 96% remains in the soil. This suggests that only 4% of glyphosate taken up from the soil affects plant seedling development and water management. It modifies the contents of the biogenic amines cadaverine and putrescine as well as the activity of enzymes involved in their biosynthesis, i.e. ornithine decarboxylase and lysine decarboxylase. The free radical content of the roots increased with increasing herbicide doses and time of exposure. The main enzyme involved in the rapid removal of free radicals was superoxide peroxidase, activated by the herbicide treatment, while catalase was not significantly stimulated.