Maria Manuela Abreu

Inter-population variation on the accumulation and translocation of potentially harmful chemical elements in Cistus ladanifer L. from Brancanes, Caveira, Chança, Lousal, Neves Corvo and São Domingos mines in the Portuguese Iberian Pyrite Belt

PurposeThis study aimed to compare the variation on the accumulation and translocation of potentially harmful chemical elements and nutrients (As, Ca, Cu, Fe, K, Mg, Mn, Ni, Pb and Zn) in Cistus ladanifer L. belonging to populations growing in different mine areas from the Portuguese Iberian Pyrite Belt (Brancanes, Caveira, Chança, Lousal, Neves Corvo, São Domingos). These mines are abandoned (except Neves Corvo that is still operating) and have different contamination levels.Materials and methodsComposite samples of soils (n = 31), developed on different mine wastes and/or host rock, and C. ladanifer plants (roots and shoots) were collected in the mine areas. Soils were characterized for pH, NPK and organic C, by classical methodologies. Soils (total fraction—four acid digestion, and available fraction—extracted with aqueous solution of diluted organic acids, simulating rizosphere conditions) and plants (ashing followed by acid digestion) elemental concentrations were determined by ICP. Soil–plant transfer and translocation coefficients were calculated. Principal components analysis in both ways, the classical method and a second approach with adaptations used mostly in multivariate statistical processes control data, were done in order to compare the plants populations.Results and discussionSoils had large heterogeneity in their characteristics. Caveira, Lousal, Neves Corvo and São Domingos soils showed the highest total concentrations of As, Cu, Pb and Zn. Independently of the mine, available fractions of elements were low. Intra- and inter-population variations in accumulation and translocation of elements were evaluated. Plants were not accumulators of the majority of the analysed elements. Nutrients were mainly translocated from roots to shoots, while trace elements were stored in roots (except in Neves Corvo for As and Pb, and São Domingos for As). Elements concentrations in plant populations from Lousal, Chança and São Domingos did not present much variation. Brancanes soils and plants presented strong differences compared to other areas.ConclusionsCistus ladanifer plants are able to survive in mining areas with polymetallic contamination at different elements concentrations in total and available fraction. This species presented variations inter- and intra-populations in accumulation and translocation of chemical elements; however, all studied populations, except Brancanes, can belong to the same population cluster.

A methodology for creating greenways through multidisciplinary sustainable landscape planning

This research proposes a methodology for defining greenways via sustainable planning. This approach includes the analysis and discussion of culture and natural processes that occur in the landscape. The proposed methodology is structured in three phases: eco-cultural analysis; synthesis and diagnosis; and proposal. An interdisciplinary approach provides an assessment of the relationships between landscape structure and landscape dynamics, which are essential to any landscape management or land use. The landscape eco-cultural analysis provides a biophysical, dynamic (geomorphologic rate), vegetation (habitats from directive 92/43/EEC) and cultural characterisation. The knowledge obtained by this analysis then supports the definition of priority actions to stabilise the landscape and the management measures for the habitats. After the analysis and diagnosis phases, a proposal for the development of sustainable greenways can be achieved. This methodology was applied to a study area of the Azambuja Municipality in the Lisbon Metropolitan Area (Portugal). The application of the proposed methodology to the study area shows that landscape stability is crucial for greenway users in order to appreciate the landscape and its natural and cultural elements in a sustainable and healthy way, both by cycling or by foot. A balanced landscape will increase the value of greenways and in return, they can develop socio-economic activities with benefits for rural communities.

Enzymatic Activity of a Mine Soil Varies According to Vegetation Cover and Level of Compost Applied

We applied three doses of compost from mixed municipal solid waste (0, 15, and 30 g kg−1 of soil) to a soil developed on pyrite mine wastes. Part of the soil was planted with young Erica australis L. collected at the mine; part was fertilized with N-P-K-Mg and sown with Dactylis glomerata L. Bare soil without mineral fertilization was included in the experiment, as well. Compost application to bare soil increased pH, provided plant nutrients, and enhanced the activity of the six soil enzymes tested. Growth of D. glomerata, and E. australis was stimulated in compost-amended soil compared with unamended controls. The presence of D. glomerata led to the greatest activities of soil acid phosphatase, β-glucosidase, and cellulase compared with bare soil or with soil with E. australis. The presence of E. australis increased the activities of protease and cellulase in amended soil, compared with control, but it impaired dehydrogenase, β-glucosidase, and acid phosphatase activities. These negative impacts probably derived from phenolic compounds known to be released from roots of this species. The survival strategy of this species seems to include a small need for P in the shoots, and the release of exudates that impair microbial activity and P cycling.

Transfer of U, Al and Mn in the water–soil–plant (Solanum tuberosum L.) system near a former uranium mining area (Cunha Baixa, Portugal) and implications to human health

Knowledge about metals in crops, grown in contaminated soils around mine sites, is limited and concerns about exposure to hazardous elements through the consumption of contaminated foodstuff, are high. In this study a field experiment was carried out in two agricultural soils located near a former uranium mine area (Cunha Baixa, Portugal). The purpose of the study was to assess the effect of irrigation water quality on soil-potato (Solanum tuberosum L.) crop system and to evaluate if the consumption of the crop represents health risk to the local villagers. The soils were divided in two plots: one irrigated with contaminated water (U: 1.03-1.04mg/L; Al: 7.5-8.00mg/L; Mn: 4.52mg/L) and the other with uncontaminated water (U: 14-10μg/L; Al: 17-23μg/L; Mn: 2.4-5.7μg/L). After irrigation and potato growth, only soil characteristics, as salinity and total U and Mn concentrations were significantly different from those measured at the beginning of the experiment. Within the potato plants, elements were mostly translocated and concentrated in the aerial part: stems and leaves (U: 73-87%; Al: 85-96%; Mn: 85-94%), which minimize the risk of contamination of the edible tissue. In potato tubers, the highest average concentrations (121-590μg U/kg; 25-64mg Al/kg; 12-13mg Mn/kg dry weight) were registered at soil plots irrigated with contaminated water. Uranium and Al were mostly concentrated in the potato peel (88-96 and 76-85%, respectively), and Mn (67-78%) in the pulp, which reinforces the importance of removing peel to minimize human exposure. The risk analysis calculated for non-cancer health effects (hazard quotient), related only to the exposure through the consumption of this basic foodstuff, revealed safety for Cunha Baixa village residents (adults and children) even when potato crop was grown on U enriched soils and irrigated with contaminated water.

Effect of liming and cadmium application in an acid soil on cadmium availability to sudangrass

Abstract A greenhouse pot experiment was conducted, using an acid sandy loam Dystric Cambisol derived from schist, in order to evaluate the effect of liming and cadmium (Cd) application on Cd availability to sudangrass (Sorghum sudanense cv.Tama). The soil was incubated with four levels of lime and three levels of Cd. After soil incubation, sudangrass was then sown. During the experiment the pots were maintained at 70% of field moisture capacity. After harvest, the air‐dried soil samples were analyzed for extractable Cd using 0.01 mol L‐1 CaCl2, 0.43 mol L‐1 HNO3, and 1 mol L1 AcNH, pH 7 reagents. Although liming increased soil pH from 4.3 to 6.6, the effect of liming on soil pH was dependent on Cd level (p=0.05). Soil exchangeable calcium (Ca) increased due, not only to CaCO3 addition, but also to the exchange sites created by Al3+ desorption. However, a significant decrease of exchangeable Ca with added Cd was observed mainly for the first CaCO3 level. Liming significantly lowered exchangeable magnesium...

Application of chromium to soils at different rates and oxidation states. I. Effect on dry matter yield and chromium uptake by radish

An experiment was carried out to study plant responses to the addition of chromium (Cr) both in hexavalent and trivalent oxidation states to soil. A pot experiment with two soils, Ferric Lixisol (LXf) and Stagnic Luvisol (LVj), was conducted in the greenhouse. Chromium was added at four rates (0, 10, 50, and 100 mg kg−1), and radish (Raphanus sativus) was used as plant test. Radish was sown after 25 days of incubating the soil with Cr. In LVj dry matter yield showed greater values for both Cr oxidation states, except when 100 mg kg−1 of Cr(VI) was applied. The increase of Cr concentration in the plant, in both soils, did not always correspond to yield decreasing. With few exceptions [especially in the case of LVj soil and Cr(VI)] the content of Cr in shoots was higher than in roots. Content for both oxidation states of Cr was always higher in the LVj soil. This is probability due to the presence of Mn oxides [which induce Cr(III) oxidation], smectites and to the low contents of iron oxides in the soil. These soil characteristics caused a decrease on Cr(VI) adsorption, thereby increasing its mobility and availability. On the other hand, in the LXf soil iron oxides and kaolinites acted as a sink for Cr(VI).

Remediation of Potentially Toxic Elements in Contaminated Soils

This chapter aims to offer an overview of the main remediation methods of potentially toxic elements in contaminated soils, mainly heavy metals, metalloids and radionuclides, focusing on their essential characteristics, advantages and limitations. It consists of two main groups of technologies: the first group dealing with containment and confinement, minimizing their toxicity, mobility and bioavailability. Containment measures include covering, sealing, encapsulation and immobilization through solidification (cement-based, polyethylene and resine binders, bituminization or asphalt batching and vitrification or glassification) and stabilization with inorganic and organic amendments. The second group, remediation with decontamination is based on the remotion, clean up and/or destruction of contaminants. This group includes mechanical procedures (excavation, transport and disposal to landfills), physical separations, chemical technologies such as soil washing with leaching or precipitation of potentially toxic elements, soil flushing, thermal treatments (desorption, pyrometallurgical processes and incineration) and electrokinetic technologies (electromigration, electroosmosis, electrophoresis and combinations of electrokinetics with other techniques). There are also two approaches of biological nature: bioremediation (biosorption, bioreduction, biomineralization and bioleaching-with some examples from Korea) and phytoremediation (phytoextraction, including chelate-assisted phytoextraction, phytostabilization, phytoremediation in mining activities -with examples from Portugal, Spain, Ecuador, Peru and Chile mainly-, phytovolatilisation and phytomining).

The protection of landscape as a resource: case study - Monte da Guia protected area (Faial-Azores).

The evolution of the concept of landscape to incorporate components like cultural and socio‐economic factors, in addition to the natural and aesthetic features, influenced the perception of landscape as a resource. On the other hand, the relationships between territorial features as well as the understanding of their temporal dynamics determine the significance of these features for the quality of a landscape and, consequently, for its conservation. This implies that all components – natural and physical, but also cultural and visual – upon which landscape quality is assessed, ought to be considered and studied globally. Natural resources and cultural heritage, however, are usually considered independently when developing protected areas management plans. Here, we present a methodology developed for the Monte da Guia management plan, which allows the interrelated analysis of landscape factors such as geology, geomorphology, pedology, flora and vegetation cover as well as the cultural and visual characters. Using the concepts of biophysical sensitivity and visual quality, we evaluated the relevance of these various factors for the determination of the state of equilibrium/degradation of a landscape, and hence for its conservation value. This methodology may contribute to the development of improved zoning maps and management guidelines determining land use and management strategies for the conservation of individual resources that, together, determine landscape quality.

The physiological mechanisms underlying the ability of Cistus monspeliensis L. from São Domingos mine to withstand high Zn concentrations in soils

Cistus monspeliensis L. is a species that grows spontaneously in contaminated mining areas from the Iberian Pyrite Belt. This species can have high concentrations of Zn in the shoots without visible signs of phytotoxicity. In order to understand the physiological mechanisms underlying this tolerance, C. monspeliensis was grown at several concentrations of Zn(2+) (0, 500, 1000, 1500, 2000µM) and the effects of this metal on plant development and on the defence mechanisms against oxidative stress were evaluated. Independently of the treatment, Zn was mainly retained in the roots. The plants with the highest concentrations of Zn showed toxicity symptoms such as chlorosis, low leaf size and decrease in biomass production. At 2000µM of Zn, the dry biomass of the shoots decreased significantly. High concentrations of Zn in shoots did not induce deficiencies of other nutrients, except Cu. Plants with high concentrations of Zn had low amounts of chlorophyll, anthocyanins and glutathione and high contents of H2O2. The highest concentrations of Zn in shoots of C. monspeliensis triggered defence mechanisms against oxidative stress, namely by triggering antioxidative enzyme activity and by direct reactive oxygen species (ROS) scavenging through carotenoids, that are unaffected by stress due to stabilisation by ascorbic acid.

Evaluation of chemical parameters and ecotoxicity of a soil developed on gossan following application of polyacrylates and growth of Spergularia purpurea.

The aim of this study was to evaluate the chemical characteristics and ecotoxicity of a mine soil developed on gossan materials and amended with hydrophilic polyacrylate polymers after a growth cycle of Spergularia purpurea. Different acute bioassays (Daphnia magna immobilization; microalgae growth inhibition; germination and growth of lettuce and oat) were carried out with simulated leachates, pore water and soil samples. The germination and growth of native shrubs (Cistus ladanifer and Lavandula sampaioana) were also evaluated in the lysimeters where S. purpurea had grown. The soil had high total concentrations (g/kg) of Al (3.50-8.60), As (2.55-2.73), Cu (0.13-0.91) and Pb (4.48-6.16). However, the percentages of elements in aqueous extracts (simulating leachates, pore water, and the conditions of the rhizosphere soil) were small when compared to their total soil concentrations (less than 9% except for Na in leachates). Growth of S. purpurea and other natural colonization of plant species (Poaceae, Fabaceae and Asteraceae families) improved chemical characteristics but the application of the polyacrylate polymers contributed to a further improvement of soil quality. However, this was not sufficient to ensure the growth of a large number of shrubs despite a great germination rate. Among the several species used on the ecotoxicological assessment, the D. magna test was the only bioassay that showed a clear toxicity of soil leachates, suggesting the importance of using several ecotoxicological tests to assess the environmental risk of soil contamination and its rehabilitation. Although the studied soil can be considered contaminated taking into account the total soil concentrations of Al, As, Cu and Pb, the low concentrations of the same chemical elements in extractable solutions, that simulated the fractions really available for organisms, did not demonstrate a substantial toxic effects in the organisms and, consequently, negative impact on the environment.