Carlos Dorronsoro - Academia.edu (original) (raw)

Papers by Carlos Dorronsoro

Water, Air, and Soil Pollution, 2006

On 1998, a settling pond of a pyrite mine in Aznalcóllar (SW Spain) broke open, spilling some 3.6... more On 1998, a settling pond of a pyrite mine in Aznalcóllar (SW Spain) broke open, spilling some 3.6×10 6 m 3 of water and 0.9×10 6 m 3 of toxic tailings into the Agrio and Guadiamar river basin 40 km downstream, nearly to Doñana National Park. The soils throughout the basin were studied for arsenic pollution. Almost all the arsenic penetrated the soils in the solid phase (tailings) in variable amounts, mainly as a result of the different soil structure. The chemical oxidation of the tailings was the main cause of the pollution in these soils. A study of the relationships between the main soil characteristics and arsenic extracted with different reagents (water, CaCl 2 , acetic acid, oxalic-oxalate and EDTA) indicates a direct relationship with the total arsenic concentration. The highest amount of arsenic was extracted by oxalic-oxalate (24%-36% of the total arsenic), indicating the binding with the iron oxides.

Journal of Environment Quality, 2002

In the carbonate soils contaminated by a toxic spill from a pyrite ides of iron, aluminum, and ma... more In the carbonate soils contaminated by a toxic spill from a pyrite ides of iron, aluminum, and manganese). mine (Aznalcó llar, southern Spain), a study was made of a thin layer (thickness ϭ 4 mm) of polluted soil located between the pyrite tailings In some places in these soils, a thin layer of reddishand the underlying soil. This layer, reddish-yellow in color due to a yellow soil (a few millimeters thick) developed immedihigh Fe content, formed when sulfates (from the oxidation of sulfides) ately underneath the tailings (Fig. 1). This layer apinfiltrated the soil, causing acidification (to pH 5.6 as opposed to 8.0 peared a few weeks after the spill, the color being owed of unaffected soil) and pollution (in Zn, Cu, As, Pb, Co, Cd, Sb, Bi, to abundance of Fe in the tailings (Simó n et al., 1999). Tl, and In). The less mobile elements (As, Bi, In, Pb, Sb, and Tl) Presumably, this layer resulted from the impregnation concentrated in the uppermost part of the reddish-yellow layer, with of the soil by contaminating solutions from the overlying concentration decreasing downward. The more mobile elements (Co, Cd, Zn, and Cu) tended to precipitate where the pH was basic, toward layer of tailings. the bottom of the layer or in the upper part of the underlying soil.

Soil and Sediment Contamination: An International Journal, 2004

Thallium content and chemical speciation was studied at 91 sites contaminated by water and tailin... more Thallium content and chemical speciation was studied at 91 sites contaminated by water and tailings spilled from the settling pond of a pyrite mine into the Agrio and Guadiamar rivers in Aznalcóllar (Spain). The contamination was highly heterogeneous, with 15% of the affected area seriously contaminated, 55% moderately contaminated and 30% uncontaminated. The total Tl content in the surface horizon increased with respect to the background level, more than 4-fold in the uppermost 10 cm of the soils, and clearly decreased with depth without contaminating either the subsoil or groundwater. Most of the Tl (approximately 75%) was in non-extractable forms, either as a component of the particles in the tailings or adsorbed to crystalline oxides. The remaining Tl was held on, or occluded in, amorphous or poorly crystallized oxides. In acidic soils, the adsorption of Tl was dominated by iron oxides (Feo) and, in neutral-alkaline soils, by aluminium oxides (Alo). A relatively high amount of the Tl adsorbed by amorphous oxides in the uppermost 10 cm of the soils was extracted with acetic acid, and was presumably bioavailable (mean values approximately 15% of the Tlo). The EDTA is a strong extractant of inorganic forms of aluminium and, consequently, the quantity of Tl extracted by EDTA in neutral-alkaline soil (mean values more than 10% of the total Tl) could be higher than the truly bio-available fraction. Approximately 1% of the total Tl was extracted with calcium chloride, but only in the neutral-alkaline soil was the extraction significantly related to the cation-exchange capacity and, thus, adsorbed by the negative charges of the clay and organic matter. The Tl soluble in water (<0.1%) declined with the pH in the neutral-alkaline soils, and was unrelated to any soil property in the acid soils. Thus, the behavior of Tl is determined by climatic conditions, soils properties and time.

The potential toxicity in riverbed sediments was assessed with a bioassay using the bioluminescen... more The potential toxicity in riverbed sediments was assessed with a bioassay using the bioluminescent bacteria Vibrio fischeri. The selected area was characterized by the presence of ultramafic rocks (peridotites), and the sediments had high values in Ni, Cr, and Co. For the toxicity bioassay with Vibrio fischeri, water-soluble forms were used. The results indicated that most of the samples had a very low degree of toxicity, with 10% of reduction in luminescence in relation to the control; meanwhile 25% of the samples had a moderate degree of toxicity with a reduction in luminescence between 13 and 21% in relation to the control. The toxicity index correlated significantly with the concentrations of Ni and Cr in the water extracts. This toxicity bioassay was proved to be a sensitive and useful tool to detect potential toxicity in solutions, even with anomalous concentrations in heavy metals of natural origin.

Enseñanza de las …, 2008

Título: Estimación de propiedades físicas del suelo en gabinete y su aplicación en la identificac... more Título: Estimación de propiedades físicas del suelo en gabinete y su aplicación en la identificación de horizontes edáficos Autores: Ortíz, Irene; Fernández, Emilia; Martín, Francisco; Dorronsoro, Carlos Revista: Enseñanza de las Ciencias de la Tierra, 2008; 16 (1) ...

Science of the total …, 2007

This article was originally published in a journal published by Elsevier, and the attached copy i... more This article was originally published in a journal published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues that you know, and providing a copy to your institution's administrator. All other uses, reproduction and distribution, including without limitation commercial reprints, selling or licensing copies or access, or posting on open internet sites, your personal or institution's website or repository, are prohibited. For exceptions, permission may be sought for such use through Elsevier's permissions site at: http://www.elsevier.com/locate/permissionusematerial A u t h o r ' s p e r s o n a l c o p y Weathering of primary minerals and mobility of major elements in soils affected by an accidental spill of pyrite tailing

Soil Health and Land Use Management, 2012

Arsenic (As) in soil is a serious environmental problem due to its potential high toxicity. Under... more Arsenic (As) in soil is a serious environmental problem due to its potential high toxicity. Under field conditions As can accumulate in contaminated soils because it is only partially removed by leaching, methylation, and erosion or because it is only slightly taken up and accumulated by plants. Chemically, As exists as organic and inorganic species. It has two main oxidation states (+III and +V), depending on the type and amounts of sorbents, pH, redox potential (Eh), and microbial activity (Yong & Mulligan, 2004). Inorganic compounds are the most frequent in soil due to their water solubility. The most thermodynamically stable species within the pH range 4.0-8.0 include H 3 AsO 3 of As III , and HAsO 4 2-and H 2 AsO 4of As v (Smith et al., 1998). As v species predominate in soil solutions under moderate reducing conditions, but As III forms are more abundant when the redox potential is below 500 mV, according to Masscheleyn et al. (1991). These authors also indicate that a rise in pH, or a fall in As v to As III , boost the concentration of As in the solution, while its solubility under moderately reducing conditions is controlled by the dissolution of iron hydroxides (Marin et al. 1993). On the other hand, it is well known that the As concentration in a soil solution is governed by the physical and chemical properties of the soil, which influence adsorption-desorption processes. Arsenic has a high affinity for oxidic surfaces, and the reactivity of the oxides varies considerably with the pH, the charge density, and the composition of the soil solution. The soil texture and the nature of the mineral constituents also affect adsorption processes (Hiltbold, 1974). Pierce and Moore (1980) demonstrated the specificity of the surface of iron hydroxides and the influence of pH in As adsorption. In soils, As has low mobility and under reducing conditions the concentration of dissolved As in soil solution declines. The availability of this element in soils can increase under acidic conditions (mainly pH below 5), due to the greater solubility of the iron and aluminium compounds, which augment As toxicity (O'Neill, 1995). In general, the mobility of this element is directly related to the total amount of As and inversely to time as well as to the iron and aluminium content; also, under oxidation conditions, its bioavailability is strongly limited (Kabata-Pendias & Pendias, 2001).

CATENA, 2002

Palaeosols in the Granada Basin (SE Spain) have been studied in two different situations: surface... more Palaeosols in the Granada Basin (SE Spain) have been studied in two different situations: surface soils on geomorphically stable surfaces since the Early Pleistocene with younger pedogenic overprinting and buried soils on unstable surfaces from the Middle-Late Pleistocene on which successive erosional-depositional episodes have alternated with pedogenic episodes. For each soil clay and iron accumulation indices, the Fe t + Al t /Si t ratio, clay mineralogy and micromorphological features were used to estimate the degree of soil development. From the Early to the early Late Pleistocene, the main pedogenic processes were the leaching of carbonates, weathering, illuviation and rubification, which resulted in Bt horizons with red colours, clay texture, clay coatings and kaolinite neoformation. The degree of weathering and the development of these Bt horizons varied over time, and the soils that formed on the surfaces from the Early Pleistocene show strongest weathering and development. However, after their formation, there were periods in which they were partially truncated and recalcified, resulting in polygenetic soils. The different degrees of development of the buried soils during the last 474,000 years indicate that the wettest warm period was stage 7 and the driest, stage 5. Stages 9 and 11 must have had climates with intermediate wetness. Since the clay accumulation and iron oxide accumulation indices, the differences in Fe t + Al t /Si t ratio between Bt and C horizons, the extent of kaolinite neoformation and the micromorphological features of the soils formed during stage 7 are all similar to the surface soils that formed on Early Pleistocene deposits, these features cannot be used to date surfaces older than 242,000 BP. By contrast, the soils that formed during stage 7 and later periods show different extents of development and thus can be used for the approximate dating of landforms.

Applied Geochemistry, 2008

This work examines the alteration processes triggered after the oxidation of pyrite tailings depo... more This work examines the alteration processes triggered after the oxidation of pyrite tailings deposited for 3 years over a carbonate soil. The infiltration of the acidic solution into the soil is causing important morphological, compositional and mineralogical changes in the profile. After 3 years of continued action of such alteration, a considerable degradation of the main soil properties was evident, the most notable being the decline in the cation-exchange capacity (caused by the decreases in clay and organic matter content), texture variation, greater electrical conductivity (10-fold greater than in unaffected soil), and the appearance of horizons with colorations strongly differing from those of the original soil (a discoloured layer with greyish tonalities in the first 5 mm, followed by a reddish-brown layer to a depth of 65-70 mm). At the same time, the carbonates have weathered, disappearing completely from the upper 35 mm and partially to 80 mm in depth. There has also been an intense acidification of the soil (with pH values close to 2.0 within the greyish layer) as well as a partial hydrolysis of the primary silicates (mainly feldspars and phyllosilicates), causing extreme infertility of the soil. The resulting products in this process give rise to intense neoformation of gypsum and hydroxysulphates of Fe and Al, which, together with the acidic conditions of the medium, determine the distribution of the main elements of the soil, both in their total and soluble forms.