Research Items (31)
Performance of compost and biochar amendments for in situ risk mitigation of aged DDT, DDE and dieldrin residues in an old orchard soil was examined. The change in bioavailability of pesticide residues to Lumbricus terrestris L. relative to the unamended control soil was assessed using 4-L soil microcosms with and without plant cover in a 48-day experiment. The use of aged dairy manure compost and biosolids compost was found to be effective, especially in the planted treatments, at lowering the bioavailability factor (BAF) by 18-39%; however, BAF results for DDT in the unplanted soil treatments were unaffected or increased. The pine chip biochar utilized in this experiment was ineffective at lower the BAF of pesticides in the soil. The US EPA Soil Screening Level approach was used with our measured values. Addition of 10% of the aged dairy manure compost reduced the average hazard quotient values to below 1.0 for DDT + DDE and dieldrin. Results indicate this sustainable approach is appropriate to minimize risks to wildlife in areas of marginal organochlorine pesticide contamination. Application of this remediation approach has potential for use internationally in areas where historical pesticide contamination of soils remains a threat to wildlife populations.
One type of harsh environment for plants is metal- and metalloid-contaminated or mineralized soils: these exists in most countries due to geological formation or to a history of mining and/or smelting. Depending on soil pH and fertility, metal-rich soils may be barren and eroding into wider areas. Some elements present risk to humans, wildlife, livestock, plants, or soil organism and require remediation. The engineering approach of removing the contaminated soil is extremely expensive. Thus, alternative methods for in situ remediation of element-rich soils have been developed by the agricultural sciences. These methods include phytoextraction (growing plants which accumulate enough concentrations of an element in shoots for removal from the field) and phytostabilization (adding soil amendments which convert soil elements into forms with much lower phytoavailability and bioavailability so they no longer pose a risk to the environment). Phytomining is a variant of phytoextraction in which the element accumulated in plant shoots ave enough value to support farming a hyperaccumulator crop to produce a commercial bio-ore. This chapter reviews these valuable phytotechnologies which have been developed in the last few decades to reduce the costs of alleviating environment risks of contaminated soils.
Aims An improved understanding of the Ni root-to-shoot translocation mechanism in hyperaccumulators is necessary to increase Ni uptake efficiency for phytoextraction technologies. It has been presumed that an important aspect of Ni translocation and storage involves chelation with organic ligands. It has been reported that exposing several Ni hyperaccumulator species of Alyssum to Ni elicited a large increase in the histidine level of the xylem sap. In later studies it was shown that as time progressed the histidine:Ni ratio dropped considerably. Moreover, previous studies analyzed the relationship between Ni and ligands in plants that were exposed to Ni only for a few hours and therefore obtained results that are unlikely to represent field soils where plants are at steady-state Ni uptake. The aim of this study was to understand the quantitative relationship between Ni and organic ligands in the xylem sap of various Alyssum genotypes or species that reached steady-state Ni uptake after being exposed to Ni in either nutrient solution or serpentine soil for up to 6 weeks. Methods Total Ni concentration, 17 amino acids, 9 organic acids, and nicotianamine were measured in xylem sap of 100-day old plants of Alyssum. Results Results showed that the concentration of Ni in xylem sap of various Alyssum genotypes was 10–100 fold higher than the concentration of histidine, malate, citrate, and nicotianamine, which were the predominant Ni ligands measured in the sap. Conclusion When the physiology of the whole plant is taken into account, our results indicate that the concentration of organic chelators is too low to account for the complexation of all the Ni present in the xylem sap of Alyssum at steady-state Ni hyperaccumulation, and suggest that most of the Ni in xylem sap of this species is present as the hydrated cation.
This paper describes work carried out within the EU-funded FOOTPRINT project to characterize the diversity of European agricultural and environmental conditions with respect to parameters which most influence the environmental fate of pesticides. Pan-European datasets for soils, climate, land cover and cropping were intersected, using GIS, to identify the full range of unique combinations of climate, soil and crop types which characterize European agriculture. The resulting FOOTPRINT European agro-environmental dataset constitutes a large number of polygons (approximately 1,700,000) with attribute data files for i) area fractions of annual crops related to each arable-type polygon (as an indicator of its probability of occurrence); and, ii) area fractions of each soil type in each polygon (as an indicator of its probability of occurrence). A total of 25,044 unique combinations of climate zones, agricultural land cover classes, administrative units and soil map units were identified. The same soil/crop combinations occur in many polygons which have the same climate while the fractions of the soils and arable crops are different. The number of unique combinations of climate, soil and agricultural land cover class is therefore only 7961. 26-year daily meteorological data, soil profile characteristics and crop management features were associated with each unique combination. The agro-environmental scenarios developed can be used to underpin the parameterization of environmental fate models for pesticides and should also have relevance for other agricultural pollutants. The implications for the improvement and further development of risk assessment procedures for pesticides are discussed.
Duration: 48 months • Work package: WP7 • Work package leader: Bálint Balázs • Deliverable Title: Co-production of the policy assessment • Nature of deliverable: Report • Dissemination level: Public • Deliverable description: From the conceptual and methodological approach established in Task 7.1, we generated an analytical framework to determine how actual policies and governance solutions enable or limit legume production. The analysis was based on the assessment of a range of publications and interviews with key stakeholders at the EU, regional and national level. The policy document analysis was orchestrated by ESSRG and involved all partners in gathering data on regional and national level policies. Main interview themes covered the following questions: (i) what are the practical policy challenges?; (ii) what policy approaches already exist?; (iii) what is the most needed policy change?; (iv) how can different stakeholder interests be embedded in policy processes?; and, (v) what are the main learnings lessons for various policy communities? Co-production of research results were achieved by involving stakeholder groups in assessing existing policies via regional meetings of the European Legume Innovation Network workshops. • Contributors
- Oct 2018
BACKGROUND Sustainable agricultural practices are needed to face current threats to agricultural production in areas where water scarcity, recurrent droughts, and decreased soil quality are endangering productivity and food security. Deficit irrigation (DI) practices consist of reducing irrigation applied at levels below full crop evapotranspiration losses throughout the growing season or at specific phenological stages of the specific crop. The goal of our study was to evaluate the physiological response of table grapes subjected to DI relative to fruit quality. DI treatments were developed as a percentage of the grower practice (evapotranspiration losses are fully replenished by irrigation) on commercial fields of table grapes in Central California. DI practices began in 2011 and were continued throughout 2015. Grape berries were analyzed for mineral elements, berry weight, diameter and firmness, C and N content, pH, soluble solids, and total phenolic compounds. RESULTS In this study, DI practices in all treatments did not significantly increase or decrease nutraceutical compounds in grape berry and measured physiological responses to DI were mixed, with significant variation between years. CONCLUSIONS This study showed that DI practices could be safely used in dry areas for at least 4 years without affecting the nutritional quality of grape berry in ‘Crimson seedless’ and ‘Sugraone’. This article is protected by copyright. All rights reserved.
In arid regions, saline soils naturally rich in trace elements require identifying new crops and implementing management strategies for sustaining crop production and protecting water quality. Poor quality water produced from such soils can be utilized to grow specialty crops that are specifically selected for tolerance to high salt and B, such as pomegranates. The goal of this study was to evaluate the physiological responses related to nutritional quality in fruit from 1-year-old pomegranate trees irrigated for 3 years with typical poor quality water (i.e., that found in the western San Joaquin Valley, CA) containing high salinity (ranging from 3 to 9 dS m⁻¹), Se (0.25 mg Se L⁻¹) and B (4 mg B L⁻¹) in a micro-plot tile system where the root system was laterally confined. This study shows that the young pomegranate trees tolerated irrigation with poor water quality containing high salinity, Se and B for 3 years. Under these treatments and growing conditions, fruit were smaller but contained higher concentrations of phenolic compounds than the same variety of pomegranates grown under unconfined root system and irrigated with good quality water. The juice produced from fruit collected from these trees contained Se (up to 0.24 mg L⁻¹), as well as high concentrations of nutrients, including antioxidant phenolic compounds. The production of nutrient-enriched pomegranate fruit and juice may represent higher market value crop products using the poor quality water as a source of irrigation.
This study assessed potential bioaccumulation of various trace elements in grasses and earthworms as a consequence of soil incorporation of organic amendments for in situ remediation of an orchard field soil contaminated with organochlorine and Pb pesticide residues. In this experiment, four organic amendments of differing total organic carbon content and quality (two types of composted manure, composted biosolids, and biochar) were added to a contaminated orchard field soil, planted with two types of grasses, and tested for their ability to reduce bioaccumulation of organochlorine pesticides and metals in earthworms. The experiment was carried out in 4-L soil microcosms in a controlled environment for 90 days. After 45 days of orchardgrass or perennial ryegrass growth, Lumbricus terrestris L. were introduced to the microcosms and exposed to the experimental soils for 45 days before the experiment was ended. Total trace element concentrations in the added organic amendments were below recommended safe levels and their phytoavailablity and earthworm availability remained low during a 90-day bioremediation study. At the end of the experiment, total tissue concentrations of Cu, Cd, Mn, Pb, and Zn in earthworms and grasses were below recommended safe levels. Total concentrations of Pb in test soil were similar to maximum background levels of Pb recorded in soils in the Eastern USA (100 mg kg⁻¹ d.w.) because of previous application of orchard pesticides. Addition of aged dairy manure compost and presence of grasses was effective in reducing the accumulation of soil-derived Pb in earthworms, thus reducing the risk of soil Pb entry into wildlife food chains.
Trace elements (TEs) occur at minor concentration (>1 g kg−1) in the organisms, and some are essential nutrients (Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo, B, and Cl) for animals and plants. As a consequence of human activities such as industrial production, mining, transport, and agriculture, they are released in the environment at high concentrations. TEs can accumulate over time under specific environmental conditions, thus becoming environmental contaminants (Cs, Cr, W, U, Cd, Hg, Tl, Pb, Sn, As, Sb, Se). The environmental risk of TEs is associated with the mobility and bioavailability of the metals more than their total concentration. When they become environmentally mobile and move between media (i.e. soil to water), they can enter the food chain by being taken up by plants and animals. TEs cannot be degraded or broken down and at high concentration are toxic to organisms and tend to bioaccumulate in the environment. For example, selenium (Se) is a naturally occurring element with a wide distribution in almost all parent materials on Earth. At low concentration, Se is an essential nutrient but at high concentration is toxic. In the western side of the San Joaquin Valley in California, soils contain significant quantities of soluble mineral salts and trace elements such as Se and boron (B) that have been leached into shallow groundwater and/or drainage waters because of irrigation practices at Kesterson Reservoir in California. Soluble Se bioaccumulated in the avian food chain and resulted in an environmental disaster with high mortality and reproduction failure of migratory birds (Letey et al. 2002; Ohlendorf et al. 1986).
- Nov 2014
- American Phytopathological Society Abstracts
Selenium containing soil amendments might be beneficial to growers as selenium may increase resistance to certain plant pathogens and pests. Therefore, grapevines growing in soil with different amounts of selenium-laden amendment were evaluated for selenium effects on plant metabolism and susceptibility to Pierce’s disease (caused by the bacterium Xylella fastidiosa). The selenium amendments had few effects on grapevine amino acid and sugar levels. Levels of the phenolic compounds caftaric acid, procyanidin B2, epicatechin gallate, and catechin gallate were significantly greater in plants grown in soil with greatest selenium levels than those with less. However, phenolic levels were similar between grapevines grown with the most selenium and those grown with no added selenium. Grapevines with low and moderate levels of added selenium had greater amounts of the terpenoids camphene and linalool than grapevines grown with no added selenium. PD symptom severity was not significantly different among grapevines grown in soils with different levels of selenium. These results exhibit the ability of selenium soil amendments to change grapevine host metabolite levels. However, selenium soil amendment did not affect PD symptom progression.
Recent studies have shown that application of phytohormones to shoots of Alyssum murale increased biomass production but did not increase Ni shoot concentration. Increased biomass and Ni phytoextraction efficiency is useful to achieve economically viable phytomining. The objective of this study was to evaluate the effect of two types of phytohormones on the Ni phytoextraction capacity of four Alyssum species. Two different commercially available phytohormones (Cytokin and Promalin) based on cytokinins and/or gibberellins were applied on shoot biomass of four Ni hyperaccumulating Alyssum species (A. corsicum, A. malacitanum, A. murale, and A. pintodasilvae). Cytokin was applied in two concentrations and promalin in one concentration. The application of phytohormones had no clear positive effect on biomass production, Ni accumulation and Ni phytoextraction efficiency in the studied Alyssum species. A. malacitanum was the only species in which a significantly negative effect of these treatments was observed (in Ni uptake). A slightly positive response to promalin treatment was observed in the biomass production and Ni phytoextraction efficiency of A. corsicum. Although this effect was not significant it does indicate a potential application of these approaches to improve phytoextraction ability. Further studies will be needed to identify the most adequate phytohormone treatment as well as the appropriate concentrations and application times.
Aims Past studies have demonstrated that hyperaccumulators absorb Ni from the same labile pools in soil as normal plant species. This study investigated whether the Ni hyperaccumulator plant Alyssum corsicum possesses distinct extraction mechanisms for different Ni species present in soils. Different Ni species have different solubilities and potential bioavailabilities to roots. Methods Uptake of Ni in shoots of A. corsicum was analyzed after four weeks of plant growth in nutrient solution with 17 different Ni compounds or soils. Results The results indicate that Ni uptake is related to Ni solubility and plant transpiration rate. The most soluble compounds had the highest Ni uptake, with the exception of Ni3(PO4)2, Ni phyllosilicate, Ni-acid birnessite which showed a low solubility but a relatively high plant uptake and transpiration rate. In serpentine soils and insoluble NiO plant transpiration rate was high but uptake was very low and statistically comparable to the control. Conclusions It appears that Ni uptake is driven by convection, which depends on the initial concentration of Ni in solution and the plant transpiration rate.
Hyperaccumulator species of the genera Alyssum can accumulate 100 times more Ni than normal crops and are therefore used for phytomining and phytoextraction of nickel contaminated soils. Basic studies on the physiology and metal uptake mechanisms of these plants are needed to increase efficiency and uptake capacity of Nickel (Ni) by hyperaccumulators. Recent attempts to disclose if those hyperaccumulator species require higher Ni level than normal plants failed because of the high Ni content in the seeds (7000-9000 microg g(-1)). In this study, we attempted to use chelator buffered nutrient solution to deplete Ni from the seed/seed coat and to obtain low Ni seedlings of Alyssum cultivars to be used in physiology studies. HEDTA-buffered nutrient solution did not deplete Ni from the seeds, perhaps because Ni was mainly localized within the seedling embryonic tissues with greatest Ni enrichment in the cotyledons and hypocotyls. We could not observe any positive correlation between seed fitness and germination capacity with seed Ni content. Investigation of nickel localization in Alyssum seeds using synchrotron X-ray microfluorescence (micro-SXRF) showed that nickel is localized in the embryonic tissues with greatest Ni enrichment observed in the cotyledons and hypocotyl.
- Apr 2010
- Trace Elements in Soils
IntroductionThe Nature of Soil Contamination where Phytoextraction may be AppliedNeed for Metal-Tolerant Hyperaccumulators for Practical PhytoextractionPhytoremediation Strategies: Applications and LimitationsPhytostabilization of Zinc-Lead, Copper, or Nickel Mine Waste or Smelter-Contaminated SoilsRecovery of Elements from Phytoextraction BiomassRisks to Wildlife during Phytoextraction OperationsConclusions References
Nickel (Ni) is essential for all plants due to its role in urease activation. Demonstration of Ni essentiality has required exceptional effort to purify nutrient solutions to remove Ni; thus, an improved technique would make study of Ni deficiency more available to diverse researchers. As part of our research on Ni hyperaccumulation by plants, we developed chelator-buffered nutrient solutions with very low buffered activity of free Ni2+, and tested growth of Alyssum murale (Goldentuft Madwort), A. corsicum (Madwort), A. montanum (Mountain Alyssum) and Lycopersicon esculentum (Tomato). We used a modified Hoagland nutrient solution with 2 mM Mg and 1 mM Ca to simulate serpentine soil solutions. We could use hydroxyethyl-ethylene-diaminetriacetate (HEDTA) to achieve Ni2+ activity levels as low as 10-16 M, and cyclohexane-ethylenediamine-tetraacetate (CDTA) to supply higher activities of buffered Ni2+ compared with HEDTA; however, we were unable to obtain proof of induced Ni-deficiency, even with urea-N supply in a 6-week growth period, apparently because seeds supplied enough Ni for growth. Yields were somewhat reduced at lower Ni activity by the end of the test period, but strong deficiency symptoms did not occur, apparently due to the supply of Ni from hyperaccumulator species seeds (contained 7000–9000 mg Ni kg-1). Chelator buffering supplied controlled levels of Ni2+ for all test species; very low plant Ni levels were attained when seed Ni was low. Reaching clear and strong Ni deficiency appears to require longer growing periods, using seed with exceedingly low initial endogenous Ni, or species possessing higher Ni requirements.
To determine if the Ni-hyperaccumulator Alyssum corsicum can absorb Ni from the kinetically inert crystalline mineral NiO(s) (bunsenite). A. corsicum and A. montanum plants were grown for 30days in a serpentine Hoagland solution. NiO was provided at 0 or 0.1g L−1 (1.34mmol L−1) as reagent grade NiO particles <1 μm diameter, continuously mixed by aeration. A. corsicum and A. montanum shoots contained 19.4 and 5.2mg Ni kg−1 DW with NiO, and 3.0 and 1.1mg Ni kg−1 DW shoots, respectively in the control treatment. A. corsicum normally absorbs over 12,000mg Ni kg−1 shoots when supplied 300 μM soluble Ni. Roots were coated with the NiO particles and contained 3–5% Ni at harvest. Despite the small Ni accumulation in the NiO treatment above control, A. corsicum is not capable of dissolving and hyperaccumulating Ni from NiO.
The spatial and temporal heterogeneity of field soils influences the fate and behavior of strongly sorbing pollutants and their entry into the food chain. We studied the redistribution of surface-applied 54Mn, 65Zn, 57Co, and 134Cs in the soil profile and their recovery in the aerial parts of maize grown on an untilled agricultural soil during the growing season. Radionuclides were more concentrated in the preferential flow paths (PFP) than in the soil matrix and their concentration decreased with time. The recovery of 54Mn in the aerial plant parts increased between pollen shed and maturity, while the recovery of 65Zn and 57Co did not show any significant difference, and the recovery of 134Cs decreased with time. The amount and distribution of rainfall, and the chemical, physical, and microbiological soil characteristics are the major factors influencing the variation of radionuclide recovery with time.
Structure-induced non-uniform water flow induces a heterogeneous distribution of surface-applied radionuclides in the soil profile. This study was conducted to assess the amount of 134Cs which can be taken up by a single root growing in an area enriched in 134Cs relative to the total amount of 134Cs that can be taken up by the whole root system growing in an area homogeneously contaminated with 134Cs. A split-root experiment was used to simulate the heterogeneous distribution of 134Cs and roots. Seedlings of maize (Zea mays L. cv Corso) were grown for 14days in solution culture and then transferred to a two-compartment pot system, where a single root was grown in a 134Cs contaminated compartment while the rest of the root system was grown in an uncontaminated compartment. Plants with the whole root system growing in a solution contaminated with 134Cs were used as control. We tested the effect of the competition between Cs and K on the uptake and translocation of 134Cs by using two K concentrations, 0.2 and 1.05mM. At the K concentration of the nutrient solution of 0.2mM the single root representing 21% of the total root weight was able to take up 47% of the 134Cs taken up by the entire root system, while at 1.05mM the single root, representing 15% of the total root weight, took up 15% of the 134Cs taken up by the entire root system. The translocation of 134Cs from the root to the shoots did not depend on the external K concentration in the nutrient solution, but it was lower in the split root treatment than in the control treatment at both K concentrations.
The radiological impact of radionuclides released to the terrestrial environment is usually predicted with mathematical models in which the transfer of radionuclides from soil to the plant is described with the transfer factor (TF). This paper questions the validity of the protocols proposed by the International Atomic Energy Agency to measure TF in the field and in greenhouses conditions. We grew maize (Zea mays L.) both in the field after a surface application of radionuclides ((54)Mn, (57)Co, (65)Zn, and (134)Cs) and in a greenhouse with the same soil that has received the same fertilization and that had been previously sieved and homogeneously labeled with the same radionuclides before being repacked in pots. The analysis of the displacement of radionuclides in the field soil profile showed a higher concentration of the surface-applied radionuclides in the preferential flow path (PFP) in comparison to the soil matrix indicating that they infiltrated heterogeneously in the soil profile due to the structure-induced non-uniform water flow. A significantly higher recovery of (57)Co and (134)Cs was observed in the plants grown in the field soil, whereas no differences in the recovery of (54)Mn and (65)Zn between the two experiments were detected. These results suggest that (i) under field conditions the soil-to-plant transfer of radionuclides that co-exist as stable elements present at low concentrations in the soil and in the plant is higher than that measured under greenhouse conditions and (ii) the implicit assumption made when calculating the TF (that radionuclides are homogeneously distributed in the soil profile) is not valid, thereby preventing the calculation of an average concentration to obtain the TF parameter.
- Jan 2002
- EGS General Assembly Conference Abstracts
To investigate the persistence and transport efficiency of flow paths in structured soils, two radiotracer experiments have been performed in unsaturated, untilled agricultural loams (eutric cambisol above glacial moraine). In both experiments, four radioactive tracers (54Mn, 57Co, 65Zn, and 134Cs) and a Brilliant Blue dye solution were applied prior to excavation and sampling, and radionuclides were consistently found to be enriched in regions of preferential flow relative to the soil matrix. However, the introduction of maize and five-weeks of additional infiltration time in one of the experiments did allow some diffusion between matrix and flow paths: the average flowpath enrichment factor was 5.4(0.5) for samples at 0-10cm depth, 6.8(2.2) at 10-20cm, and 9.8(1.7) at 20-30cm. Batch experiments in homogenized soil indicated that 65Zn and 134Cs were less mobile than 54 Mn and 57Co, yet in the field the sampled radionuclide ratios were equivalent to the ratio in the application solution. This similarity suggests that flow was either too rapid or the flow path kinetics too slow to attenuate the transport of less mobile species. Since there was little difference in radiotracer distribution after five days or six weeks of infiltration, it is thought that flow paths persist for months at minimum. Path structure is not likely to remain stable for more than 16 years however, considering the even distribution of 137Cs (deposited in 1986) on the lateral scale. Information on the short-term stability of flow paths is important for dual porosity models of solute transport in agricultural soils and for risk assessment of soil leaching and groundwater contamination.
- Jan 2001
New programs for the development of forestry and fruit crop production needs to be focused to the increase of biological and genetic resources. Therefore, a priority aspect is the identification of the origin and characteristics of the propagation material. Particularly in protected areas, the sanitary and genetic controls of the propagation material are requested with the highest guarantee.