Academic literature on the topic 'Soil elutriate'

Mechanized excavation of tunnels with Earth Pressure Balance-Tunnel Boring Machines requires the use of foaming agents. The latter contain the anionic surfactant sodium lauryl ether sulphate (SLES) as the main compound. The re-use as a by-product of excavated soil containing foaming agents (spoil material) can pose a risk for soil and particularly for aquatic ecosystems if they are close to the spoil material final destination site. This work reports the chemical results (SLES residual concentrations) and ecotoxicological effects (battery of five tests) of 28 day-mesocosm studies performed at a tunnelling construction site. The soil mesocosms were set up with two different lithologies, which contained four different foaming agent products at the highest amounts used for excavation. The decrease in SLES concentrations and the ecotoxicological tests were performed in soil and its water extract (elutriate) at different times (0, 7, 14, 28 d). Elutriates were prepared in order to simulate a possible SLES leaching from soil to water. The results showed a decrease in SLES over time and different ecotoxicological responses depending not only on the initial amount of each product, but also on the soil lithology and organism tested (aquatic or terrestrial). This study showed how only site-specific ecotoxicological evaluations can ensure a safe management of the spoil material, making possible the re-use of soil and avoiding production of waste.

AbstractDiversity and nematode abundance were investigated in soils collected around the Gangue hill of Fushun West open-pit mine to evaluate soil pollution, due to heavy metals contents, using nematodes as bioindicators. Nematodes were collected from soil samples using elutriate-sievingflotation and centrifugation methods. The species richness and ecological indices were analyzed. On the base of chemical and nematological analysis, the results indicated that the area around the Gangue hill of Fushun West Openpit mine was polluted by heavy metal, but the degree of pollution was not very serious. According to the results obtained from single-factor analysis, cadmium soil content was ten times higher than the background; 29 genera of nematodes were identified and Acrobeloides, Cervidellus and Mesorhabtidis were the dominant genera in almost all sampling sites. The dominant genera were different as the distances to the Gangue hill changed. In particular, in the investigated areas bacterivores and plant-parasites nematodes were more diffuse than fungivores and omnivorepredators. Copper soil content was significantly correlated with plant parasitic trophic group and with total number of nematodes, thus suggesting that nematode communities studies are important scientific basis for understanding the healthy development of soil ecosystem.

The objective of the present study was to evaluate the bioremediation of soils artificially contaminated with atrazine, glyphosate and pendimethalin by fungal consortia in biodegradation processes in microcosms. Biodegradation was evaluated from microbial respiration over a period of 15 days and genotoxicity analysis in Allium cepa roots exposed to elutriate samples at zero and 50 μg mL-1 concentrations of the herbicides after the biodegradation process. The results were submitted to analysis of variance, the Tukey test and the Fischer test (p<0.05%) for comparison of means. The Aspergillus fumigatus - Penicillium citrinum consortium had a larger capacity to degrade atrazine but metabolism was inhibited in the presence of glyphosate and pendimethalin. There was a delay in the mitotic index in the meristematic cells of the Allium cepa roots exposed to the elutriates in the 50 μg mL-1 atrazine and pendimethalin concentration. There was a cellular alteration in the metaphase phase of the cells exposed to the elutriates at the 50 μg mL-1 concentration of the three herbicides. The changes occurred were low, indicating that there was degradation of part of the herbicides.

AbstractIn order to process large soil samples containing potato cyst nematodes, the Seinhorst (1964) cyst elutriator was scaled up to process both sandy and marine-clay soils in batches of up to 2.5 kg. Several modifications were implemented. To maintain the required upward current of 3.01 min−1, an inflow of 8.01 min−1 was necessary in the enlarged, 7.5 cm diam. sedimentation tube. Also water inflow is now regulated using a flow meter with pressuriser. Several experiments were undertaken, using artificial sandy soil and marine-clay soil, both naturally infested with potato cyst nematodes. In the final experiment, using the 8.01 min−1 inflow for 4 min, there was a loss of 0.65% and 0.74% of cysts, and eggs and juveniles, respectively. This indicates that the yield (99%) of the scaled-up elutriator matches that of the original Seinhorst elutriator and, therefore, is suitable for statutory and scientific research.

A wide use of foaming agents as lubricants is required in mechanized tunneling. Their main component, the anionic surfactant sodium lauryl ether sulphate (SLES), can remain in residual concentrations in soil debris, influencing their potential reuse as by-product. This study aimed at evaluating the environmental fate and effects of a foaming product used for conditioning soils collected from real excavation sites, in the presence/absence of an anti-clogging polymer, both containing SLES. Soil microcosm experiments were set-up and incubated for 28 days. Over time, soils and their water extracts (elutriates) were collected to perform both ecotoxicological tests (Vibrio fischeri, Lepidium sativum, Eisenia foetida, Hetereocypris incongruens, Danio rerio) and SLES analysis. The results showed that, just after conditioning, SLES did not exert any hazardous effect on the organisms tested except for the bacterium V. fischeri, which was the most sensitive to its presence. However, from day seven the toxic effect on the bacterium was never observed thanks to the SLES decrease in the elutriates (<2 mg/L). SLES degraded in soils (half-lives from 9 to 25 days) with higher disappearance rates corresponding to higher values of microbial abundances. This study highlights the importance of site-specific studies for assessing the environmental reuse of spoil materials.

A soil sampler, elutriator, and associated sample flushing device were designed and constructed for an intensive study of weed seedbanks. This equipment was used in 1993 to collect and process 4980 soil samples. The sampler was durable, core size was consistent, and sampling was efficient. Cores were approximately 200 cm3and two people could take 120 cores/h. The elutriator separated weed seeds from 36 of these cores at a time. Washing required 60 to 75 min depending on soil texture. Seeds as small as 0.3 mm in diam were recovered and almost 100% of the seeds were recovered from samples spiked with barnyardgrass, redroot pigweed, velvetleaf, and witchgrass. The flushing device was used to transfer sample contents from strainers of the elutriator to propyltex bags for drying and storing. Equipment like this, plus improved technology for identifying and counting seeds, is needed to make weed seedbank studies more feasible.

Vermicompost, the digestion product of organic material by earthworms, has been widely reported to have a more positive effect on plant growth and plant health than conventional compost. A study was conducted to investigate the effects of different vermicompost elutriates (aerated compost teas) on soils and plant growth. The teas were analyzed by chemical, microbiological, and molecular methods accompanied by plant growth tests at laboratory and field scale. The number of microorganisms in the teas increased during the extraction process and was affected by substrate addition. The vermicompost tea found to increase plant growth best under laboratory tests was applied to cereals (wheat and barley) and vegetables ( Raphanus sativus , Rucola selvatica , and Pisum sativum ) in a field study. The results revealed no effects of tea application on plant yield; however, sensoric tests indicated an improvement in crop quality. The soils from laboratory and field studies were investigated to detect possible microbial or chemical changes. The results indicated that minor changes to the soil microbial community occurred following tea application by foliar spray in both the laboratory-scale and field-scale experiments.

Recent developments on environmental fate models indicate that as nano waste, engineered nanomaterials/nanoparticles (ENM/Ps) could reach terrestrial ecosystems thus potentially affecting environmental and human health. Plants can be therefore exposed to ENM/Ps but controversial data in terms of fate and toxicity are currently available. Furthermore, there is a current lack of information on complex interactions/transformations to which ENM/Ps undergo in the natural environment as for instance with existing toxic compounds. The main aim of current study is to evaluate potential toxicological risks due to the exposure of plants to ENM/Ps in their natural environment, and investigating different routes of exposure (i.e. water and soil). The aim of the first study reported in chapter 1 was to asses behavior and biological effects of titanium dioxide nanoparticles (n- TiO2) (Aeroxide P25, Degussa Evonik) and its interaction with cadmium (CdCl2) in plants using radish seeds (Raphanus sativus parvus) as model species. Radish seeds were exposed to different concentrations of n-TiO2 (range 1-1000 mg/L) and CdCl2 ( range 1-250 mg/L) alone and in combination using a seed germination and seedling growth toxicity test OECD 208. Percentages of seed germination, germination index (GI) and root elongation were calculated. Cell morphology and oxidative stress parameters as glutathione-S-transferase (GST) and catalase activities (CAT) were measured in radish seeds after 5 days of exposure. Z-Average, PdI and Z-potential of n-TiO2 in Milli-Q water as exposure medium were also determined. DLS analysis showed small aggregates of n-TiO2, negative Z-potential and stable PdI in seed’s exposure media. Germination percentage, GI and root length resulted affected by n-TiO2 exposure compared to controls. Exposure of CdCl2 significantly abolished germination % and GI compared to control seeds and a concentration dependent decrease on root elongation was observed against controls (p<0.05). As well, significant decrease of germination %, GI and root elongation was observed in seeds co-exposed to n-TiO2 and CdCl2 at the highest concentrations (1000mg/L n-TiO2 and 250 mg/L CdCl2) compared to co-exposed seeds at low concentration (1mg/L n-TiO2 and 1 mg/L CdCl2) and controls (p<0.05). Root elongation significantly increase compared to controls at the lowest co-exposure concentration (p<0.05). Similarly at intermediate concentrations of 10 and 100 mg/L in co-exposure conditions, n-TiO2 did not affect CdCl2 toxicity. Concerning antioxidant enzymes, a significant increase of CAT activity in seeds exposed to single high n-TiO2 concentration (1000 mg/L) was observed while n-TiO2 (1 mg/ L), CdCl2 (1 and 250 mg/L) and co-exposure resulted significantly decreased compared to controls (p<0.05). Regarding GST activity, a slight increase in seeds exposed to 1000 mg/L n-TiO2 but no significantly was observed, however both n-TiO2 and CdCl2 alone (1 and 250 mg/L, respectively) or in combinations caused a significant decrease in GST activity (p<0.05). Therefore, overall data support the hypothesis that the presence of n-TiO2 do not affect the toxicity of CdCl2 at least at the highest concentration (100 and 250 mg/L) in radish seeds. Morphological alterations in nuclei, vacuoles and shape of radish root cells were observed upon single Cd exposure and not abolished in the presence of n-TiO2. Nevertheless, although n-TiO2 seems not to reduce Cd toxicity at high concentration (up to 250 mg/L), interactions cannot be excluded based on obtained results. The aim of the second study reported in chapter 2 was to assess if the presence of n-TiO2 might affect elutriate toxicity to radish seeds (R. sativus parvus) seeds as a model species. Radish seeds were exposed to 11 soils (elutriates) alone and in combination with 1 mg/L of n-TiO2 collected from an industrial site located in Taranto area (South East of Italy). Exposure of seeds was performed according to OECD (208) guideline. Then, root elongation, percentages of seed germination and germination index% (GI) were analyzed. In addition, levels of several trace elements were also determined in soils in order to assess their level of contamination and effects on root elongation, seed germination and GI% further discussed. Main results revealed that the presence of n-TiO2 seems not affecting root length, GI % and germination% of seeds compared to seeds exposed to elutriates alone with the exception of only 2 sites. Moreover, the absence of any clear relationship between effects of elutriate on radish seed germination and trace elements levels was observed. Only slight but not significant changes based on levels of trace elements present in soil were observed in growth parameters. In particular levels of Co, Ni, Zn, Cu, Ti and Sn seem to affect radish seeds germination more than others. Regarding co-exposed seeds, the presence of n-TiO2 caused 100% of germination of radish seeds. Furthermore, in comparison to exposed seeds to elutriates alone, root length and GI % resulted more stimulated. Only slight effects on GI% and root length were observed which might be linked to interaction of these elements with n-TiO2. Likewise, it seemed that Co, Se, Sb and As in presence of n-TiO2 are responsible for changes on growth parameters. According on the overall results, soil elutriates alone could not be able to show real toxicity of a contaminated soil on seeds germination and future study should be performed in order to assess their suitability in real exposure scenarios. Therefore, based on observed data further investigations are required in order to assess real environmental scenarios where such particles could be present in soils together with existing contaminants such trace elements. The purpose of third study reported in chapter 3 chapter was to assess the impact of n-TiO2 alone and in combination with CdCl2 on germination and growth of radish seeds (R. sativus) exposed in vitro (experiment 1) and in vivo (directly into soils) (experiment 2). In experiment 1(in vitro) radish seeds were exposed to n-TiO2 (1 and 1000 mg/L and CdCl2) and CdCl2 (1 and 250 mg/L) alone and in combination (n-TiO2 1, 10, 100, 1000 mg/L and CdCl2 1, 10, 100, 250 mg/L) using a seed germination and seedling growth toxicity test OECD 208. In experiment 2 (in vivo), radish exposed only to water and then seedling transferred to soils contaminated with n-TiO2 (1 and 1000 mg/L and CdCl2) and CdCl2 (1 and 250 mg/L) alone and in combination (n-TiO2 1, 10, 100, 1000 mg/L and CdCl2 1, 10, 100, 250 mg/L), still following OECD 208 test conditions. Root length, shoot length and numbers of secondary leaves of all plants from the two experiments (1 and 2) were recorded at day 10 and day 21. Growth parameters of radish at both day 10 and day 21 showed that plants from seeds exposed during germination (experiment 1) resulted more affected by single and co-exposure to n-TiO2 and CdCl2 than those exposed directly in soil (experiment 2). Furthermore, presence of CdCl2 at 250 mg/L alone and in combination with 1000 mg/L of n-TiO2 seemed affect the root and shoot length in both experiments 1and 2 at day 10 and day 21. Growth parameter analysis of single and co-exposed groups in experiment 1 at day 10, showed a decrease in root length in all tested plants with exception of those exposed to n-TiO2 (1mg/L), co-exposed to n-TiO2 and CdCl2 (1mg/L and 1mg/L), (10 mg/L and 10 mg/L) and (100 mg/L and 10 mg/L) which showed slight increase compared to control. In experiment 2 at day10 only exposed plants to 1000 mg/kg of n-TiO2 revealed significant increase of root length while other all single and co-exposure groups showed a decrease of root length respect to control. Shoot length in exposed plants to all single and co-exposure groups in both experiments 1 and 2 at day 10 showed a decrease compared to control except plants exposed to n-TiO2 and CdCl2 (100 mg/kg and 10 mg/kg) in experiment 2 which showed an increase. Obtained results on day 21 showed a decrease of root length respect to control on tested plants to all single and co-exposure groups in both experiments 1 and 2 with exception of exposed radish to 1 mg/L of CdCl2 in experiment 1. Shoot length of all tested single and co-exposure groups in experiments 1 and 2 showed a decrease compared to control except radish exposed to 1000 mg/kg of n-TiO2 which revealed an increase in experiment 2. Regarding secondary leaves, in both experiments 1and 2 at day 10 no leaves were shown. On the opposite, (2 leaves) were present at day 21 in most plants exposed to single and in combination, while those exposed to CdCl2 (250 mg/kg), n-TiO2 and CdCl2 (10 and 100 mg/L) and (1000 mg/kg and 250 mg/kg) in experiment 1 showed no leaves. Likewise, exposure n-TiO2 (1000 mg/kg) and co-exposure of n-TiO2 and CdCl2 (10 mg/kg and 100) showed only one secondary leaf in experiment 2 at day 21.

Public gardens and park zones are an important and widely visited component of urban spaces worldwide, however they can be polluted and even dangerous for humans and animals visiting them. The simplest way to screen the level of pollution of those green zones is to assess their ecological toxicity. In the present study, to assess the ecotoxicity of soil and ground samples obtained in 15 parks and public gardens in the city of Kazan (Russia) with 1 Mio citizens were investigated. Two elutriate assays with Ceriodaphnia affinis and Chlorella vulgaris and one contact assay with Bacillus pumilus were used in order to estimate the ecotoxicity of the samples. It was revealed that B. pumilus was less sensitive to the components present in ground samples from the green zones. Thus, the lowest toxicity of the undiluted sample was estimated to be 3.33% (sample Gorkiy Central Park of Culture and Leisure) and the highest � 27% (�Dubovyj kordon� public garden). For C. affinis, we managed to assess the toxicity without dilution step for 7 samples out of 15. For the other 8 samples, the additional dilution series was prepared, and the LID10 index was calculated. Thus, the LID10 index these samples for C.affinis ranged from 34 to 40, for Chl. vulgaris varied from 13 to 50. It should be noted that samples with the highest toxicity (revealed for at least one test object) were obtained from the parks that visually looked less clean and organized.