Rosanna Ginocchio

Phytostabilization of copper mine tailings with biosolids: Implications for metal uptake and productivity of Lolium perenne

A greenhouse pot experiment was conducted to evaluate the feasibility of using biosolids and Lolium perenne for the phytostabilization of copper mine tailings and to evaluate the patterns of metal accumulation and translocation in plants. Biosolids were applied either on the surface or mixed with the tailings at rates of 0, 6, and 12% w/w. All pots were seeded with L. perenne and after six months, the plants were harvested and separated into roots and shoots for metal concentrations analyses as well as some physiological characteristics of the plants. In order to correlate the metal content in plant tissues with some chemical properties, the pore-water of the substrates was analyzed for metals, pH and dissolved organic carbon. Results showed that biosolids application increased the dry biomass production of L. perenne and the shoot concentrations of N and chlorophyll. On the other hand, biosolids increased the concentration of Cu and Zn in the pore-water and in plant tissues. Despite this, there were no evident symptoms of phytotoxicity and the concentration of metals was within the normal ranges described for plants and below the maximum tolerable level for animals. In addition, plant tissue analysis showed that the application of biosolids could significantly reduce Mo uptake and shoot accumulation in plants. The metals were taken up by plants in the following order: Cu>Zn>Mo>Cd. The distribution patterns of metals in plants showed that metals were mainly accumulated in the roots and only a small amount of them were transported to the shoots. These results suggest that mixed application of biosolids (6%) and the use of L. perenne could be appropriate for use in programs of phytostabilization of copper mine tailings. However, these results should be tested under field conditions in order to confirm their efficacy under semi-arid Mediterranean climate conditions.

Metallophytes: The unique biological resource, its ecology and conservational status in Europe, central Africa and Latin America

Metalliferous soils provide very restrictive habitats for plants due to phytotoxicity, resulting in severe selection pressures. Species comprising heavy-metal plant communities are genetically altered ecotypes with specific tolerances to eg., cadmium, copper, lead, nickel, zinc and arsenic, adapted through micro-evolutionary processes. [introduction extract]

Fire regimes and vegetation responses in two Mediterranean-climate regions

Los incendios forestales originados por tormentas estivales son una caracteristica comun en la mayoria de las regiones con clima Mediterraneo, tal como el sur de California, y han jugado un rol importante en la ecologia y evolucion de su flora. Las regiones con clima Mediterraneo han sido, ademas, centros importantes para el establecimiento de poblaciones humanas, las que al alterar los regimenes de incendios podrian producir efectos negativos importantes en este tipo de formaciones vegetales. Sin embargo, los efectos antropicos sobre el regimen de incendios podrian tener impactos distintos en ecosistemas Mediterraneos cuya vegetacion ha evolucionado naturalmente con este tipo de perturbacion. Asi, en este trabajo comparamos los regimenes de incendios y la capacidad de respuesta de la vegetacion de dos regiones con clima Mediterraneo que han tenido historias distintas en cuanto a la ocurrencia natural de incendios forestales y de ocupacion humana, tales como la zona central de Chile (matorral) y el sur de California (chaparral). En Chile, casi todos los incendios forestales son el resultado de actividades antropicas, mientras que en California los incendios producidos por el hombre se suman a los producidos por tormentas estivales. En ambas regiones, los incendios son mas frecuentes en verano debido a la acumulacion de biomasa vegetal seca altamente combustible. El hombre ha incrementado significativamente la frecuencia de incendios tanto en el matorral como en el chaparral en las ultimas decadas, pero la extension de los incendios no se ha incrementado en forma importante, probablemente debido a mejores sistemas de supresion del fuego y a la menor acumulacion de biomasa vegetal seca por el aumento de la fragmentacion del paisaje con desarrollos urbanos y agricolas con menor potencial de combustion. Como se esperaba, las respuestas de regeneracion de las plantas despues de los incendios son distintas en el matorral y en el chaparral. Las plantas del matorral muestran un rango de respuestas regenerativas mayor, las que van desde el rebrote basal, al rebrote desde el lignotuber y a la germinacion y floracion estimuladas por el fuego, con estimulos fuego-especificos tales como shock termico, quimicos presentes en el humo y en la madera quemada. Las plantas del matorral tienen cierta capacidad de regeneracion despues del fuego, pero estas probablemente evolucionaron como consecuencia de otras presiones ambientales, tales como las severas y largas sequias de verano, la herbivoria y el volcanismo. Aunque ambos ecosistemas de tipo Mediterraneo han mostrado ser resistentes a los incendios de origen antropico, el marcado aumento en la frecuencia de estos puede constituir un aspecto muy importante de considerar, ya que puede resultar en efectos negativos importantes tanto en los patrones sucesionales como en la diversidad vegetal

Metallophytes in Latin America: a remarkable biological and genetic resource scarcely known and studied in the region

America Latina posee una gran abundancia y diversidad de yacimientos minerales metalicos. Sin embargo, se han descrito pocas especies tolerantes e hiperacumuladoras de metales en comparacion con otras regiones del mundo. Esto podria deberse tanto a la escasez de estudios cientificos sobre la vegetacion nativa que se ha desarrollado sobre mineralizaciones superficiales o en suelos enriquecidos antropicamente con metales como a la falta de metodos biogeoquimicos para la prospeccion de minerales, mas bien que a la ausencia real de este tipo de especies vegetales en la region. Latinoamerica es, sin embargo, un area con gran potencial para la presencia de este tipo de especies vegetales, no solo por el gran numero de mineralizaciones y areas contaminadas con metales presentes, sino que por su variada y unica diversidad vegetal. Si las comunidades vegetales presentes sobre mineralizaciones naturales no se estudian antes de que se lleven a cabo procesos de extraccion de minerales, podrian perderse para siempre especies y/o genotipos (ecotipos) claves para ser usados en la mitigacion de problemas ambientales relacionados con el propio sector minero (e.g., fitoextraccion, fitoestabilizacion y fitomineria)

Agricultural soils spiked with copper mine wastes and copper concentrate: implications for copper bioavailability and bioaccumulation.

A better understanding of exposure to and effects of copper-rich pollutants in soils is required for accurate environmental risk assessment of copper. A greenhouse experiment was conducted to study copper bioavailability and bioaccumulation in agricultural soils spiked with different types of copper-rich mine solid wastes (copper ore, tailing sand, smelter dust, and smelter slag) and copper concentrate. A copper salt (copper sulfate, CuSO4) that frequently is used to assess soil copper bioavailability and phytotoxicity also was included for comparison. Results showed that smelter dust, tailing sand, and CuSO4 are more likely to be bioavailable and, thus, toxic to plants compared with smelter slag, concentrate, and ore at equivalent total copper concentrations. Differences may be explained by intrinsic differences in copper solubilization from the source materials, but also by their capability to decrease soil pH (confounding effect). The copper toxicity and bioaccumulation in plants also varied according to soil physicochemical characteristics (e.g., pH and total organic carbon) and the available levels of plant nutrients, such as nitrogen, phosphorus, and potassium. Chemistry/mineralogy of mine materials, soil/pore-water chemistry, and plant physiological status thus should be integrated for building adequate models to predict phytotoxicity and environmental risk of copper.

Amendments Promote the Development of Lolium Perenne in Soils Affected by Historical Copper Smelting Operations

The Puchuncaví valley, central Chile, has been exposed to aerial emissions from a copper smelter. Nowadays, soils in the surroundings are sparsely-vegetated, acidic, and metal-contaminated, and their remediation is needed to reduce environmental risks. We assessed effectiveness of lime, fly ash, compost, and iron grit as amendments to immobilize Cu in soils and promote plant growth. Amended soils were cultivated with Lolium perenne for 60 days under controlled conditions. Total dissolved Cu and Cu2+ activity in the soil solution, ryegrass biomass, and Cu accumulation in plant tissues were measured. Addition of lime and fly ash decreased Cu concentrations and Cu2+ activity in the soil solution, increased plant biomass, and reduced shoot Cu concentration below 22 mg kg−1 (the phytotoxicity threshold for the species). The most effective amendment with respect to the shoot biomass yield was a combination of lime and compost. Water content of the substrate and the K accumulation were positively correlated with the compost application rate. Compost combined with iron grit decreased dissolved Cu concentrations during the period of highest solubility, i.e. during the first 60 days after the compost application. However, iron grit incorporation into soils amended with lime and compost decreased the shoot biomass of ryegrass.

Efficacy of Lime, Biosolids, and Mycorrhiza for the Phytostabilization of Sulfidic Copper Tailings in Chile: A Greenhouse Experiment

Inadequate abandonment of copper mine tailings under semiarid Mediterranean climate type conditions has posed important environmental risks in Chile due to wind and rain erosion. There are cost-effective technologies for tailings stabilization such as phytostabilization. However, this technology has not been used in Chile yet. This study evaluated in a greenhouse assay the efficacy of biosolids, lime, and a commercial mycorrhiza to improve adverse conditions of oxidized Cu mine tailings for adequate establishment and grow of Lolium perenne L. var nui. Chemical characterization of experimental substrates and pore water samples were performed; plant density, biomass production, chlorophyll content, and metal content in shoots was evaluated in rye grass plants after an eight-week growth period. Results showed that neutralization of tailings and superficial application of biosolids increased both aerial biomass production and chlorophyll content of rye grass. Increased Cu solubilization and translocation to shoots occurred after biosolids application (mixed), particularly on unlimed tailings, due to formation of soluble organometallic complexes with dissolved organic carbon (DOC) which can be readily absorbed by plant roots. Positive effects of mycorrhizal inoculation on rye grass growth were restricted to treatments with superficial application of biosolids, probably due to Cu toxicity effects on commercial mycorrhiza used (Glomulus intraradices).

Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper‐rich mine wastes

Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests.

Surficial injuries of several cacti of South America

Abstract Analyses of several species of long-lived columnar cacti in Argentina and Chile show that an accumulation of epicuticular waxes is occurring on many species and that these accumulations obscure stomata. This accumulation leads to visible surficial maladies such as scaling and barking on crests and troughs of ribs similar to those that occur on saguaros, Carnegiea gigantea (giant saguaro) of North America, which results in premature death of individual saguaros. Scaling is the appearance of tan to red-orange discoloration of surfaces. Barking refers to a larger buildup of materials on the surfaces than scaling that appears dark brown to black. Equatorial facing surfaces showed more injuries on stems of Trichocereus pasacana and T. terscheckii in Argentina, and Echinopsis chilensis and E. scotsbergii in Chile, than on polar surfaces. Crest barking was as much as five times greater on equatorial-facing sides compared with polar-facing sides. Spine retention was up to three times greater on equatorial- vs polar-facing sides. the two troughs of a crest were evaluated separately. Results show that injury to one trough of a crest facing the equator was as much as twice that of the second trough facing the south pole. These results show that surficial injuries were greater on equatorial than on polar surfaces, and are related to total incident irradiance on these surfaces.

Interpretation of metameric architecture in dominant shrubs of the Chilean matorral

SummaryThe seasonal progression of phenophases in 21 shrub species of the Chilean matorral was analyzed. Five “modules” or basic units that are responsible for the aboveground architecture of the plants were characterized. These modules appear to be organized in seven different spatial arrangements. In drought-deciduous species a module type with an “absolute short shoot” with limited apical growth, leafy or spiny, predominated. In evergreen species “long shoot” and “temporal leafy short shoot” module types were more frequent. The spatial arrangement of morphologically different modules and the temporal sequence of their formation allow a dynamic interpretation of the modular architecture of the plants.