Jana Najmanová

Mobility of arsenic and its compounds in soil and soil solution: the effect of soil pretreatment and extraction methods.

The effect of soil extraction procedures and/or sample pretreatment (drying, freezing of the soil sample) on the extractability of arsenic and its compounds was tested. In the first part, five extraction procedures were compared with following order of extractable arsenic portions: 2M HNO(3)>>0.43 M CH(3)COOH>or=0.05 M EDTA>or=Mehlich III (0.2M CH(3)COOH+0.25 M NH(4)NO(3)+0.013 M HNO(3)+0.015 M NH(4)F+0.001 M EDTA) extraction>>water). Additionally, two methods of soil solution sampling were compared, centrifugation of saturated soil and the use of suction cups. The results showed that different sample pretreatments including soil solution sampling could lead to different absolute values of mobile arsenic content in soils. However, the interpretation of the data can lead to similar conclusions as apparent from the comparison of the soil solution sampling methods (r=0.79). For determination of arsenic compounds mild extraction procedures (0.05 M (NH(4))(2)SO(4), 0.01 M CaCl(2), and water) and soil solution sampling using suction cups were compared. Regarding the real soil conditions the extraction of fresh samples and/or in situ collection of soil solution are preferred among the sample pretreatments and/or soil extraction procedures. However, chemical stabilization of the solutions should be allowed and included in the analytical procedures for determination of individual arsenic compounds.

The long-term variation of Cd and Zn hyperaccumulation by Noccaea spp and Arabidopsis halleri plants in both pot and field conditions

ABSTRACT Three Cd and Zn hyperaccumulating plant species Noccaea caerulescens Noccaea praecox and Arabidopsis halleri (Brassicacceae) were cultivated in seven subsequent vegetation seasons in both pot and field conditions in soil highly contaminated with Cd, Pb, and Zn. The results confirmed the hyperaccumulation ability of both plant species, although A. halleri showed lower Cd uptake compared to N. caerulescens. Conversely, Pb phytoextraction was negligible for both species in this case. Because of the high variability in plant yield and element contents in the aboveground biomass of plants, great variation in Cd and Zn accumulation was observed during the experiment. The extraction ability in field conditions varied in the case of Cd from 0.2 to 2.9 kg ha−1 (N. caerulescens) and up to 0.15 kg ha−1 (A. halleri), and in the case of Zn from 0.2 to 6.4 kg ha−1 (N. caerulescens) and up to 13.8 kg.ha−1 (A. halleri). Taking into account the 20 cm root zone of the soil, the plants were able to extract up to 4.1% Cd and 0.2% Zn in one season. However, cropping measures should be optimized to improve and stabilize the long-term phytoextraction potential of these plants.

The response of broccoli (Brassica oleracea convar. italica) varieties on foliar application of selenium: uptake, translocation, and speciation.

A model small-scale field experiment was set up to investigate selenium (Se) uptake by four different varieties of broccoli plants, as well as the effect of Se foliar application on the uptake of essential elements for plants calcium (Ca), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), manganese (Mn), phosphorus (P), sulfur (S), and zinc (Zn). Foliar application of sodium selenate (Na2SeO4) was carried out at two rates (25 and 50 g Se/ha), and an untreated control variant was included. Analyses of individual parts of broccoli were performed, whereby it was found that Se in the plant accumulates mainly in the flower heads and slightly less in the leaves, stems, and roots, regardless of the Se rate and broccoli variety. In most cases, there was a statistically significant increase of Se content in all parts of the plant, while there was no confirmed systematic influence of the addition of Se on the changing intake of other monitored elements. Selenization of broccoli leads to an effective increase in the Se content at a rate of 25 g/ha, whereas the higher rate did not result in a substantial increase of Se content compared to the lower rate in all varieties. Therefore, the rate of 25 g/ha can be recommended as effective to produce broccoli with an increased Se content suitable for consumption. Moreover, Se application resulted in an adequate increase of the main organic compounds of Se, such as selenocystine (SeCys2), selenomethionine (SeMet), and Se-methylselenocysteine (Se-MeSeCys).

A profile of arsenic species in different vegetables growing in arsenic-contaminated soils

ABSTRACT Six different vegetables (black radish, black salsify, lettuce, parsnip, Savoy cabbage and Swede turnip) were cultivated in model pot experiments. The soils used in the experiments originated from two mining and smelting sites in the Czech Republic – Příbram and Kutná Hora, respectively. These soils showed differences in physicochemical properties and/or total contents of arsenic, reaching 36.0 ± 1.0 and 473 ± 10 mg As kg−1, respectively. The four most common anionic arsenic compounds (arsenite As(III), arsenate As(V), dimethylarsinate (DMA), methylarsonate (MA)) were determined by high-performance liquid chromatography coupled to an inductively coupled plasma mass spectrometer. The concentration of arsenic species determined in edible plant parts decreased in the following order: Higher proportions of both DMA and MA were found in the aboveground edible parts (leaves) compared to the underground parts (tubers). The results indicate that the distribution of arsenic compounds differed predominantly according to individual plant species whereas almost no effect was observed due to the different soil properties. However, a higher arsenic concentration in soils resulted in more arsenic in the plant independently of the aboveground biomass (leaves) or the underground plant parts (tubers).

Content of Inorganic and Organic Pollutants and Their Mobility in Bottom Sediment from the Orlík Water Reservoir (Vltava River, Czech Republic)

ABSTRACT The content of both inorganic and organic pollutants, in sediment from the Orlík reservoir (Vltava river, Czech Republic), and the main tributaries, was determined to assess the total loads of the pollutants in the upper layer of sediment (0–30 cm), and the potential bioaccessibility and bioavailability of these pollutants. Organic pollutants showed non-hazardous levels of polycyclic aromatic hydrocarbons and polychlorinated biphenyls. Elevated phosphorus content indicated the possible eutrophization potential; however, significant correlation of phosphorus with iron and aluminum suggested a high immobilization rate of this element with iron and aluminum cations. Risk elements in the sediment were separated according to their potential environmental risk: (1) cobalt, nickel, copper, lead, vanadium, and chromium showed both low levels and relatively low mobility, i.e. low environmental risk; (2) the arsenic levels were significantly elevated (exceeding the maximum allowable limits for land application of sediment) but its mobility was low; (3) cadmium and zinc exceeded the limits and showed high mobility and bioaccessibility. These two elements also showed high bioavailability for the bivalves Unio tumidus and Anodonta anatina. The results showed differences in pollutant loads in sediment along the lake, and different input of pollutants via the individual tributaries.

An assessment of the risk of element contamination of urban and industrial areas using Taraxacum sect. Ruderalia as a bioindicator

Central Bohemia (Czech Republic) has highly developed industry and a dense rail network. Here, we aimed to determine the content of risk elements in dandelion plants (Taraxacum sect. Ruderalia) growing near train stations, industrial enterprises, and in the city parks of 16 cities in the Central Bohemian region. The highest element contents in the soils were found in industrial areas affected by the historical mining and smelting activities; contemporary industry showed no substantial effect on the soil element contents. The median values of element contents (As, Be, Cd, Co, Cr, Cu, Ni, Pb, and Zn) at the railway station sites were the highest among the monitored sites, where the differences between park and station sites were significant for Be, Co, and Zn. Although the intensity of the traffic at the individual stations differed, we found that long-term regular traffic enhanced the element contents in the soils and, subsequently, in the plants. For Cd, Co, Cr, Cu, Pb, V, and Zn, the highest median element contents were found in plant roots, regardless of the sampling site. For Cd and Zn, the contents in leaves were higher than in the inflorescences, and the opposite pattern was recorded for Co and Cu. As and Be were distributed equally among the plant parts. Among the sampling sites, the As, Be, Cd, Zn, and Pb contents in the plant roots tended to have higher median values at the station sites, confirming the results of our soil analyses. We detected a fairly good correlation between soil and plant content for cadmium, regardless of the sampling site, soil element content, or analyzed part of the plant. Thus, we propose that dandelion is a suitable bioindicator of cadmium pollution of soil.

Lead Accumulation Ability of Selected Plants of Noccaea spp.

ABSTRACT Several species of the Noccaea genus are known for their hyperaccumulation ability especially in the case of Cd, Ni, and Zn. However, ambiguous observations were previously published concerning their accumulation properties for Pb. The Pb accumulation properties of Noccaea rotundifolia, Noccaea montana, and Noccaea jankae hungarica plants were tested in field and pot experiments in soils differing in the mobile pool of Pb, as well as in soilless hydroponic culture. The Pb content in the dry biomass of plant shoots reached up to 54 mg/kg in field conditions and 84 mg/kg in pots regardless of the bioavailable pool of Pb in the pots. The hydroponic experiment showed a stepwise increase in Pb content in plant biomass with increasing Pb concentration in the solution, but the predominant proportion of plant Pb was retained in the roots. Although the hyperaccumulation ability of some of the Noccaea species is widely discussed in the literature, our results are in agreement with those suggesting no Pb hyperaccumulation potential in these plants.

The effect of NPK fertilizer with different nitrogen solubility on growth, nutrient uptake and use by chrysanthemum

ABSTRACT The effect of nitrogen, phosphorus and potassium (NPK) fertilizer with different nitrogen forms on N, P, K use, uptake and growth of potted chrysanthemum plants during three vegetation phases was observed in two - years experiment. In the experiment, NPK fertilizer with slow soluble nutrients with different nitrogen forms: ureaform, (IBDU) isobutyledenediurea and melamin, was used. At control treatment the identical fertilizer was applied but the nitrogen was in ammonia and urea forms as usually used in horticulture. The experiment clearly showed the positive effect of NPK fertilizer containing half nitrogen amount in ureaform, on growth and plant nutrient uptake. This effect of nitrogen ureaform was confirmed by both the highest uptake of N, P, K and the highest yield of biomass. The NPK fertilizer with half nitrogen content in ureaform ensured optimal nutrient release according chrysanthemum nutrient requirement.

Distribution of arsenic compounds in Plantaginaceae and Cyperaceae plants growing in contaminated soil

ABSTRACT The ability of plant species to accumulate arsenic (As) species in the biomass from As-contaminated soils is variable. Among the plants widely grown at the As-contaminated locations, Plantaginaceae and Cyperaceae families belong to the frequent ones. In this study, the ability of Plantago lanceolata (Plantaginaceae) and three wetland plant species representing the family Cyperaceae (Carex praecox, Carex vesicaria, and Scirpus sylvaticus) naturally occurring in the soils with an elevated As in the Czech Republic were investigated. The plants were cultivated under controlled conditions in an As-contaminated soil reaching 735 mg kg−1 of the total As. The total As in plants reached up to 8.3 mg kg−1 in leaves, and up to 155 mg kg−1 in roots of C. praecox. Dominant As compounds were arsenite and arsenate with a small abundance of dimethylarsinic acid (DMA) in all the plant species. In Cyperaceae, small percentages of arsenobetaine (AB) and arsenocholine (AC) were detected, suggesting the ability of these plants to transform As into less toxic compounds. Moreover, the important role of As(V) sequestration on iron plaque on the root surface of Cyperaceae was confirmed. In this context, root washing with oxalic acid partially disrupted the iron plaque for the better release of arsenate.

The Contents of Selected Risk Elements and Organic Pollutants in Soil and Vegetation within a Former Military Area

The contents of selected risk elements (As, Ba, Be, Cd, Co, Cr, Cu, Fe, Ni, Pb, Sb, Ti, V, Zn), polycyclic aromatic hydrocarbons, and n-alkanes were determined in soils collected at the former military training base Milovice-Mladá (Czech Republic), where military activities were terminated in 1991. Seventeen soil samples were collected from the former tank shooting range called “Benátecký vrch” (area 16.2 ha) covered with herbaceous vegetation cover. No sample exceeding the threshold limits for maximum permissible limits of risk elements in soil was identified. The contents of organic pollutants in soil also did not pose a potential environmental risk. The risk element contents (especially Cu, Ni, Pb, and Zn) in aboveground biomass of Dactylis glomerata (Poaceae), Hypericum perforatum (Hypericaceae), Galium verum (Rubiaceae), and Plantago lanceolata (Plantaginaceae) sampled close to the soil sampling points indicated, however, potential environmental damage originating from the municipal landfill covering a substantial part of the area since 1995.