[show abstract][hide abstract] ABSTRACT: The applicability of a mature compost as a soil amendment to promote the growth of native species for the phytorestoration of a mine-affected soil from a semi-arid area (SE Spain), contaminated with trace elements (As, Cd, Cu, Mn, Pb and Zn), was evaluated in a 2-year field exper-iment. The effects of an inorganic fertiliser were also deter-mined for comparison. Bituminaria bituminosa was the se-lected native plant since it is a leguminous species adapted to the particular local pedoclimatic conditions. Compost addi-tion increased total organic-C concentrations in soil with respect to the control and fertiliser treatments, maintained elevated available P concentrations throughout the duration of the experiment and stimulated soil microbial biomass, while trace elements extractability in the soil was rather low due to the calcareous nature of the soil and almost unaltered in the different treatments. Tissue concentrations of P and K in B. bituminosa increased after the addition of compost, associated with growth stimulation. Leaf Cu con-centration was also increased by the amendments, although overall the trace elements concentrations can be considered non-toxic. In addition, the spontaneous colonisation of the plots by a total of 29 species of 15 different families at the end of the experiment produced a greater vegetation cover, especially in plots amended with compost. Therefore, the use of compost as a soil amendment appears to be useful for the promotion of a vegetation cover and the phytostabilisation of moderately contaminated soils under semi-arid conditions.
Environmental Science and Pollution Research 07/2013; · 2.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: Plants exposed to trace elements can suffer from oxidative stress, which is characterised by the accumulation of reactive oxygen species, alteration in the cellular antioxidant defence system and ultimately lipid peroxidation. We assessed the most-appropriate stress indexes to describe the response of two plant species, with different strategies for coping with trace elements (TEs), to particular contaminants. Noccaea caerulescens, a hyperaccumulator, and Lupinus albus, an excluder, were grown in three soils of differing pH: an acidic soil, a neutral soil (both contaminated mainly by Cu, Zn and As) and a control soil. Then, plant stress indicators were measured. As expected, N. caerulescens accumulated higher levels of Zn and Cd in shoots than L. albus, this effect being stronger in the acid soil, reflecting greater TE solubility in this soil. However, the shoot concentrations of Mn were higher in L. albus than in N. caerulescens, while the As concentration was similar in the two species. In L. albus, the phenolic content and lipid peroxidation were related with the Cu concentration, whereas the Zn and Cd concentrations in N. caerulescens were more closely related to glutathione content and lipid peroxidation. Interestingly, phytochelatins were only found in L. albus grown in polluted soils. Hence, the two species differed with respect to the TEs which provoked stress and the biochemical indicators of the stress, there being a close relationship between the accumulation of TEs and their associated stress indicators in the different plant organs.
Plant Physiology and Biochemistry 02/2013; 66C:47-55. · 2.78 Impact Factor
[show abstract][hide abstract] ABSTRACT: With a view to the selection of plants for the re-vegetation of contaminated, semi-arid land, two populations of the perennial
species Bituminaria bituminosa (Fabaceae) from the south of Spain were studied: one (“LA”) from a non-contaminated soil and the other (“C2”) from a similar
soil having elevated total levels of Pb and Zn (1,112 and 4,249μg g−1, respectively). For sand-cultured plants receiving nutrient solution, flow cytometry showed that heavy metals, at the concentrations
measured in aqueous extracts from contaminated soils, had only slight genotoxic effects on root tip cell nuclei. Both populations
were also grown in both soils, in two pot experiments. In the first, shoot biomass of LA and C2 in the contaminated soil was
decreased to similar extents, with respect to the “clean” soil. Tissue heavy metal concentrations were unlikely to have been
phytotoxic, except in the case of shoot Zn for population LA, but there were tissue deficiencies of P and K for populations
LA and C2, respectively. In the second pot assay, the stimulation of growth by NPK fertiliser confirmed that even though this
soil had high total heavy metal levels, nutrient availability was the principal factor limiting growth. The lesser transport
of heavy metals (Cd, Mn and Zn) to the shoot by the population from the contaminated site is a factor that should be considered
when selecting B. bituminosa lines for the phytostabilisation of such sites.
Water Air and Soil Pollution 04/2012; 184(1):335-345. · 1.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: The halophytic shrub Atriplex halimus L. was used in a field phytoremediation experiment in a semi-arid area highly contaminated by trace elements (As, Cd, Cu, Mn, Pb and Zn) within the Sierra Minera of La Unión-Cartagena (SE Spain). The effects of compost and pig slurry on soil conditions and plant growth were determined. The amendments (particularly compost) only slightly affected trace element concentrations in soil pore water or their availability to the plants, increased soil nutrient and organic matter levels and favoured the development of a sustainable soil microbial biomass (effects that were enhanced by the presence of A. halimus) as well as, especially for slurry, increasing A. halimus biomass and ground cover. With regard to the minimisation of trace elements concentrations in the above-ground plant parts, the effectiveness of both amendments was greatest 12-16 months after their incorporation. The findings demonstrate the potential of A. halimus, particularly in combination with an organic amendment, for the challenging task of the phytostabilisation of contaminated soils in (semi-)arid areas and suggest the need for an ecotoxicological evaluation of the remediated soils. However, the ability of A. halimus to accumulate Zn and Cd in the shoot may limit its use to moderately-contaminated sites.
Journal of hazardous materials 04/2012; 223-224:63-71. · 4.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Chemical processes in the rhizosphere play a major role in the availability of metals to plants. The objective of this study
was to assess the potential of white lupin (Lupinus albus L.) for the phytoimmobilisation of heavy metals in a calcareous soil with high levels of Zn and Pb (2,058 and 2,947μg g−1, respectively) by evaluating the chemical changes in the rhizosphere, relative to bulk soil, which modify the solubility
of heavy metals. Plants were cultivated for 74days in specially designed pots (rhizopots) in which rhizosphere was sampled
easily under controlled conditions. White lupin accumulated high concentrations of Mn in the shoots (average of 4,960μg g−1), well above the normal concentration in plants (300μg g−1). But the metal concentrations found in shoots were not at toxic levels. Rhizosphere soil showed a significantly greater
redox potential (245mV) and water-soluble organic carbon content (34.6μg C g−1) than bulk soil (227mV; 27.6μg C g−1). Root activity decreased EDTA-extractable Pb, Zn and Fe and promoted their precipitation as insoluble compounds in the residual
fraction (acid digestion), hardly available to plants. These results indicate the suitability of this annual N2-fixing species for the initial phytoimmobilisation of heavy metals in contaminated soils.
Water Air and Soil Pollution 04/2012; 201(1):283-293. · 1.75 Impact Factor
[show abstract][hide abstract] ABSTRACT: The use of organic wastes as amendments in heavy metal-polluted soils is an ecological integrated option for their recycling. The potential use of alperujo (solid olive-mill waste) compost and pig slurry in phytoremediation strategies has been studied, evaluating their short-term effects on soil health. An aerobic incubation experiment was carried out using an acid mine spoil based soil and a low OM soil from the mining area of La Unión (Murcia, Spain). Arsenic and heavy metal solubility in amended and non-amended soils, and microbial parameters were evaluated and related to a phytotoxicity test. The organic amendments provoked an enlargement of the microbial community (compost increased biomass-C from non detected values to 35 μg g(-1) in the mine spoil soil, and doubled control values in the low OM soil) and an intensification of its activity (including a twofold increase in nitrification), and significantly enhanced seed germination (increased cress germination by 25% in the mine spoil soil). Organic amendments increased Zn and Pb EDTA-extractable concentrations, and raised As solubility due to the influence of factors such as pH changes, phosphate concentration, and the nature of the organic matter of the amendments. Compost, thanks to the greater persistence of its organic matter in soil, could be recommended for its use in (phyto)stabilisation strategies. However, pig slurry boosted inorganic N content and did not significantly enhance As extractability in soil, so its use could be specifically recommended in As polluted soils.
[show abstract][hide abstract] ABSTRACT: The use of waste materials as organic amendments in soil remediation can affect metal solubility; this interaction will vary with the characteristics of the organic matter that is added to the soil. A pot experiment was carried out in a calcareous, metal-polluted soil, using Beta maritima L. as an indicator species for the treatment effects on metal solubility. The treatments were: fresh solid olive husk, a mature compost, their respective water extracts (as the most reactive and biodegradable fraction) and an unamended, control soil. The compost reduced metal availability and plant uptake, while fresh olive husk favoured Mn bioavailability and produced phytotoxicity. The water-soluble extract from fresh solid olive husk also provoked elevated Mn solubility in soil, but did not increase Mn uptake by plants. The application of water-soluble organic matter obtained from compost did not affect heavy metal solubility significantly. Therefore, composted olive husk seems to be the most-appropriate material for the development of bioremediation strategies.
Journal of hazardous materials 02/2011; 186(2-3):1283-9. · 4.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: Nitrification is often negatively affected by heavy metal pollution in soils, this limiting land revegetation. Thus, the potential use of pig slurry as a nitrogen-rich organic amendment in different heavy metal contaminated soils has been evaluated; this also being a way of recycling this waste. In order to identify the factors affecting nitrification processes in heavy metal polluted soils (soil pH, heavy metal solubility and the N source), incubation experiments were run using two polluted soils with different pH values (5.0 and 7.1) and a non-contaminated soil (pH 8.2). Ammonium was added as pig slurry or as ammonium sulphate for comparison (both added at 150 mg NH(4)(+)-N kg(-1) of soil). Pig slurry provoked higher nitrification rates and N-immobilisation than ammonium sulphate, especially in the neutral-polluted soil, reflecting an improvement of the microbial activity in the soil. The microbial immobilisation of N led to an inverse relationship between the amount of N added and nitrate conversion in the neutral-polluted soil and in the non-contaminated soil amended with different pig slurry dosages (75, 150 and 225mg NH(4)(+)-N kg(-1) of soil). Low rates of nitrification and N-immobilisation were found in the acidic soil. Pig slurry addition to metal polluted soils enhanced soil nitrification, especially when metals were in low-solubility forms.
[show abstract][hide abstract] ABSTRACT: An incubation experiment was carried out to evaluate the rate of arsenic release from roots to soil during root mineralisation, in order to determine the viability of phytostabilisation of metal-polluted soil. Arsenic (As)-loaded roots were mixed with the soil, monitoring arsenic, phosphorus, copper and zinc solubility and pH. Arsenic dynamics in soil during root mineralisation depend on various factors such as mineralisation rate, pH and soil chemistry. After 56 days incubation, only the soil with T. gallica roots showed higher NH4(SO4)2-extractable As than soil without roots. Phosphorus release was positively correlated with extractable arsenic. Extractable Cu depended on root mineralisation but Zn solubility was controlled by soil pH. On the whole, species with high As accumulation in roots and a high mineralisation rate may release arsenic in soluble forms in the soil immediately after root addition, but the soil can partly retain arsenic subsequently. In this respect, the risk of As mobilisation due to root decomposition was found to be low, confirming the prospects for long-term phytomanagement and phytostabilisation of arsenic.
Journal of Environmental Monitoring 07/2009; 11(7):1375-80. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effects of a compost (produced from by-products of the olive oil industry) and a poultry manure on mineral ion solubility and exchangeability in a highly saline agricultural soil (electrical conductivity for a 1:5 soil:water extract=1.85 dS m(-1)) from Murcia (SE Spain) were studied. The organic amendments did not change significantly the soil electrical conductivity or the soluble Na(+), Ca(2+) or Mg(2+). Only soluble K(+) increased, due to the K(+) supplied by the amendments. The cation exchange capacity increased in treated soils, the exchange complex being mainly saturated with Ca(2+), Mg(2+) and K(+). However, Na(+) was not retained in the exchange sites, and the sodium absorption ratio remained low. The compost and manure increased markedly the shoot growth of the salt-tolerant Beta maritima L. (sea beet) and Beta vulgaris L. (sugar beet). For B. maritima, this seemed to be related to decreases in the shoot concentrations of Na(+) and Cl(-) and increases in K(+) and H(2)PO(4)(-). In the case of B. vulgaris, increases in shoot H(2)PO(4)(-) and B and, for manure-treated soil, a decrease in shoot Na(+) may have been involved. Cultivation of tomato (Lycopersicon esculentum Mill. cv. Moneymaker) in the soil used previously for B. vulgaris indicated that the effects of the manure on tissue cation concentrations were longer-lasting than those of the compost.
[show abstract][hide abstract] ABSTRACT: To explore in a multiethnic primary care population the impact of child gender and of race/ethnicity on parent and child reports of school-age anxiety and on the factor structure of the Screen for Childhood Anxiety and Related Emotional Disorders (SCARED).
A consecutive sample of 515 children (8 to <13 years) and their parent presenting for primary care completed self-report (C) and parent-report (P) versions of the SCARED-41.
Neither SCARED scores nor parent-child difference varied significantly with race/ethnicity. Predictors of higher SCARED scores were less parental education, younger child age and female gender. Exploratory factor analysis conducted separately for SCARED-C and SCARED-P yielded four factors. There was large variation in factor structure between SCARED-C and SCARED-P and across ethnic and gender subgroups, greatest for somatic/panic/generalized anxiety and Hispanic children.
Primary care triage of anxious children requires data from both the parent and child and must go beyond cross-sectional symptom inventories. Clinicians must elicit from each family their perhaps culturally bound interpretation of the child's somatic and psychological symptoms.
Journal of the American Academy of Child & Adolescent Psychiatry 03/2007; 46(3):332-40. · 6.97 Impact Factor
[show abstract][hide abstract] ABSTRACT: Objective
To explore in a multiethnic primary care population the impact of child gender and of race/ethnicity on parent and child reports of school-age anxiety and on the factor structure of the Screen for Childhood Anxiety and Related Emotional Disorders (SCARED).
Journal of The American Academy of Child and Adolescent Psychiatry - J AMER ACAD CHILD ADOLESC PSY. 01/2007; 46(3):332-340.
[show abstract][hide abstract] ABSTRACT: Degradation of organic matter (OM) from organic amendments used in the remediation of metal contaminated soils leads to changes in soil chemical properties shortly after their addition, which may affect the soil metal distribution. The effects of two differing organic amendments on OM mineralisation and fractionation of heavy metals in a contaminated soil were investigated in an incubation experiment. The treatments were: control unamended soil, soil amended with fresh cow manure, and soil amended with a compost having a high maturity degree. The soil used was characteristic of the mining area at La Unión (Murcia, Spain) with 28% CaCO(3) and sandy-loam texture (pH 7.7; 2602 mg kg(-1)Zn; 1572 mg kg(-1)Pb). Manure and compost C-mineralisation after 56 days (24% and 3.8%, respectively) were below values reported previously for uncontaminated soils. Both amendments favoured Zn and Pb fixation, particularly the manure. Mn solubility increased at the beginning of the experiment due to a pH effect, and only Cu solubility increased through organic matter chelation in both amended soils.
[show abstract][hide abstract] ABSTRACT: Phytoremediation of metal-polluted soils can be promoted by the proper use of soil amendments and agricultural practices. A 4-year phytoremediation programme was applied to a site affected by the toxic spill of pyrite residue at Aznalcóllar (Spain) in 1998, contaminated with heavy metals (Zn, Cu, Pb, Cd) and arsenic. This consisted of active phytoremediation, using organic amendments (cow manure and compost) and lime and growing two successive crops of Brassica juncea (L.) Czern., followed by natural attenuation without further intervention. Changes in soil pH, extractable metal and As concentrations, organic carbon content and microbial biomass was evaluated. The initial oxidation of metal sulphides from pyrite residues released soluble metals and reduced soil pH to extremely acidic values (mean 4.1, range 2.0-7.0). The addition of lime (up to 64 t ha(-1)) increased soil pH to adequate values for plant growth, resulting in a significant decrease in DTPA-extractable metal concentrations in all plots. The natural attenuation phase showed also a decrease in extractable metals. Organic treatments increased the soil total organic carbon, which led to higher values of microbial biomass (11.6, 15.2 and 14.9 g kg(-1) TOC and 123, 170 and 275 microg g(-1) biomass-C in control, compost and manure plots, respectively). Active phytoremediation followed by natural attenuation, was effective for remediation of this pyrite-polluted soil.
[show abstract][hide abstract] ABSTRACT: The influence of pig slurry applications on the nutrient composition of three horticultural crops (pepper, tomato and lettuce) grown on two calcareous soils under irrigated conditions was studied. The optimum dose of pig slurry for nitrogen nutrition of the crops was found to be 100 m3 ha−1 and was independent of the number of previous applications. Soil characteristics had a great influence on the amount of phosphorus taken up by the plants. This is due to the large amount of phosphorus added in the slurry which remained in the soil in a plant-available form. As the number of applications increased, the amount of slurry required to satisfy the phosphorus requirement of the crops decreased. Amounts of slurry within 100-150 m3 ha−1 were required for adequate potassium plant nutrition. However, soil characteristics, particularly the amount of clay and thus its exchange capacity, had a significant influence on the plant potassium uptake.
Journal of the Science of Food and Agriculture 09/2006; 62(2):129 - 135. · 1.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: The effects of humic acids (HAs) extracted from two different organic materials on the distribution of heavy metals and on organic-C mineralisation in two contaminated soils were studied in incubation experiments. Humic acids isolated from a mature compost (HAC) and a commercial Spaghnum peat (HAP) were added to an acid soil (pH 3.4; 966 mg kg(-1) Zn and 9,229 mg kg(-1) Pb as main contaminants) and to a calcareous soil (pH 7.7; 2,602 mg kg(-1) Zn and 1,572 mg kg(-1) Pb as main contaminants) at a rate of 1.1g organic-C added per 100g soil. The mineralisation of organic-C was determined by the CO(2) released during the experiment. After 2, 8 and 28 weeks of incubation the heavy metals of the soils were fractionated by a sequential extraction procedure. After 28 weeks of incubation, the mineralisation of the organic-C added was rather low in the soils studied (<8% of TOC in the acid soil; <10% of TOC in the calcareous soil). Both humic acids caused significant Zn and Pb immobilisation (increased proportion of the residual fraction, extractable only with aqua regia) in the acid soil, while Cu and Fe were slightly mobilised (increased concentrations extractable with 0.1M CaCl(2) and/or 0.5M NaOH). In the calcareous soil there were lesser effects, and at the end of the experiment only the fraction mainly related to carbonates (EDTA-extractable) was significantly increased for Zn and decreased for Fe in the humic acids treated samples. However, HA-metal interactions provoked the flocculation of these substances, as suggested by the association of the humic acids with the sand fraction of the soil. These results indicate that humic acid-rich materials can be useful amendments for soil remediation involving stabilisation, although a concomitant slight mobilisation of Zn, Pb and Cu can be provoked in acid soils.
[show abstract][hide abstract] ABSTRACT: Cultivation of crops in or close to contaminated sites may result in both growth inhibition and tissue accumulation of heavy metals, with resulting possible risks to humans or livestock health if these tissues are ingested. In this work, growth inhibition and accumulation of Cd, Cu, Pb and Zn for three Brassica crop species (B. oleracea L., B. carinata A. Br. and B. juncea (L.) Czern.) and the autochthonous Cu-accumulating species Hirschfeldia incana (L.) Lagrèze-Fossat were studied, in two contaminated soils from the Murcia region of Spain and one from Valencia, over a 80-day period (40 days for H. incana) in pot experiments.Growth parameters indicated a tolerance index averaged for the two contaminated soils (relative to non-contaminated substrate) of the Brassica species in the order: B. juncea (mean value 97.6%) > B. carinata cv. 117 (74.2%) > B. carinata cv. 2920 (66.5%) ≈ B. oleracea (65.6%), with an average of 72% for H. incana. Above-ground tissue metal concentrations indicated a possible risk to human and livestock health from Cd and Pb for B. oleracea and H. incana. H. incana did not show a marked shoot accumulation of Cu, possibly due to inhibition of Cu uptake by the high soil levels of Zn and Pb. Its shoot tissue concentrations of Pb and Zn were related more closely to the total soil metal concentrations than to the DTPA-extractable, concentrations of these elements.
[show abstract][hide abstract] ABSTRACT: Two crops of Brassica juncea (L.) Czern. were grown in a field experiment, at the site affected by the toxic spillage of acidic, metal-rich waste in Aznalcóllar (Seville, Spain), to study its metal accumulation and the feasibility of its use for metal phytoextraction. The effects of organic soil amendments (cow manure and mature compost) and lime on biomass production and plant survival were also assessed; plots without organic amendment and without lime were used as controls. Plots, with or without organic amendment, having pH < 5 were limed for the second crop. Soil acidification conditioned plant growth and metal accumulation. The addition of lime and the organic amendments achieved higher plant biomass production, although effects concerning metal bioavailability and accumulation were masked somewhat by pH variability with time and between and within plots. Tissue metal concentrations of B. juncea were elevated for Zn, Cu and Pb, especially in leaves of plants from plots with low pH values (maxima of 2029, 71 and 55 microg g(-1), respectively). The total uptake of heavy metals in the plants was relatively low, emphasising the problems faced when attempting to employ phytoextraction for clean-up of pluri-contaminated sites.
[show abstract][hide abstract] ABSTRACT: Chenopodium album L. was found to be one of the initial plant species colonising a heavy metal-contaminated site, polluted by pyritic (sulphide-rich) waste from the Aznalcóllar mine spill (South-western Spain). This indicates its importance in the re-vegetation of this soil. In a pot experiment, C. album was sown in soil collected from the contaminated site, either non-amended or amended with cow manure or compost produced from olive leaves and olive mill wastewater, in order to study the effect on heavy metal bioavailability and soil pH. In non-amended and compost-amended soils, soil acidification, probably resulting from oxidation and hydrolysis of sulphide, led to increases in the concentrations of soluble sulphate and plant-available Cu, Zn and Mn in the soil (extractable with 0.1 M CaCl(2)). Under these conditions, shoot growth of C. album was negligible and shoot concentrations of Zn (2,420-5,585 microg g(-1)) and Mn (5,513-8,994 microg g(-1)) were phytotoxic. Manure application greatly increased shoot growth and reduced the shoot concentrations of Cu, Zn, and Mn, and their plant-available concentrations in the soil. These effects appeared to be related to an increase of soil pH, due to an inhibition of sulphide oxidation/hydrolysis, relative to the non-amended soil. For metal sulphides-contaminated soil, liable to acidification, manure application appears to be able to enhance the initial stages of re-vegetation, by species such as C. album.
[show abstract][hide abstract] ABSTRACT: This work describes the effects of a poultry manure and a compost (prepared from olive mill and cotton wastes) on soil conditions and plant nutrient status and growth in a saline soil from Mediterranean Spain, having an electrical conductivity for a 1:5 aqueous extract of 1.51 dS m. Two Brassica spp. (B. carinata A. Br. and B. oleracea L.) were selected from a hydroponic screening with two salinity levels, in which the greater tolerance of B. oleracea seemed to be related to maintenance of shoot K and restriction of Na and Cl, behavior shown also by B. carinata at the lower salinity level. Brassica carinata and B. oleracea were grown in the soil after incorporation of the organic materials. The amendments increased the cation exchange capacity of the soil and the concentrations of exchangeable K and Mg. A significant proportion of the K added by the amendments was retained in the exchange complex. The equilibrium between soluble and exchangeable K tended toward the exchangeable forms, whereas Na remained mainly in the soil solution. Addition of manure significantly increased shoot growth for both Brassica species, while compost markedly improved B. oleracea shoot growth. These effects may have been related to increased shoot tissue K:Na ratios and total phosphorus (P) concentrations, reflecting the K and P contents of the amendments. When tomato (Lycopersicon esculentum Mill.) was grown in the amended soils used for B. oleracea, its growth was not significantly greater than in the control. Although the organic amendments raised the water-extractable boron (B) concentration of the soil, plant tissue B concentrations were unaffected, possibly due to the elevated concentration of soluble in the soil.
COMMUNICATIONS IN SOIL SCIENCE AND PLANT ANALYSIS Vol. 35. 01/2004; Nos. 17 & 18(pp. 2495–2514):2495-2514.