Andrea Buondonno

Remediation of Cd- and Pb-polluted soil by treatment with organo-zeolite conditioner

The present work is part of a study focused on the use of organo-zeolite conditioner to remediate soil polluted by toxic elements. The Neapolitan yellow tuff (NYT) was utilized as a component of an organo-mineral sorbent/exchanger soil conditioner with pellet manure (NYT/PM) to reduce the mobility of Cd and Pb and recover plant performance in heavily polluted soils from illegal dumps near Santa Maria La Fossa (Lower Volturno river basin, Campania Region, southern Italy). Pot experiments were performed by adding the NYT/PM mixture (1:1, w/w) to polluted soil at the rates of 0%, 25%, 50% or 75% (w/w). Wheat (Triticum aestivum) was used as the test plant. The addition of organo-zeolite NYT/PM mixture significantly reduced the DTPA (diethylene-triamine-pentaaceti c acid)-extractable Cd and Pb from 1.01 and 97.5 mg kg−1 in the polluted soil, to 0.14 and 11.6 mg kg−1, respectively, in the soil amended with 75% NYT/PM. The best plant response was observed in amended soil systems treated with 25% NYT/PM, whereas larger additions induced plant toxicities due to increased soil salinity.

Zeolitized tuffs in pedotechnique for the reclamation of abandoned quarries. A case study in the Campania region (Italy).

The present study aims to assess the evolution of different proto-horizons as embryonic soils built by pedotechnologies for the reclamation and management of derelict and damaged lands, such as abandoned quarries. The model proto-horizons were assembled by utilizing coarse limestone gravel or zeolitized Phlegraean Yellow Tuff (PYT) as mineral components and commercial compost-amendments or a phosphorite-poultry manure mixture as organic matrices for growth of a pasture-grass under controlled conditions. The evolution of the model proto-horizons was followed by an evaluation of the stability and modification of the organic matter (OM) with reference to plant development. The results suggest that the natural carbonatic substrate occurring in limestone quarries was unable to sustain significant plant growth, while the PYT was suitable and efficient as a pedogenic substrate because it supported plant growth and induced a conspicuous accumulation of OM due to root activity. In particular, OM, including humic and non-humic components, greatly increased in the PYT treatment with the phosphorite-poultry manure mixture showing a concurrent trend toward humification. Conversely, an overall tendency toward degradation of OM was detected in the PYT model proto-horizon treated with commercial compost. Feasibility estimates show that quarry restoration costs appear reasonable where environmental impacts are high.

Neapolitan yellow tuff for the recovery of soils polluted by potential toxic elements in illegal dumps of Campania Region

The Neapolitan yellow tuff (NYT) was utilized as a component of an organo-mineral sorbent/exchanger soil conditioner with pellet manure (NYT/PM) to limit the mobility of Cd and Pb in heavily polluted soils from illegal dumps in Low Volturno river basin (Campania Region, southern Italy). The NYT/PM mixture (1:1, w/w) was added to soil at the rates of 0%, 25%, 50% or 75% (w/w). The overall significant effect of the amendment with NYT/PM on soil properties was the substantial reduction of the availability of the toxic elements, with special reference to Pb, connected with an increase of cation exchange capacity and electrical conductivity and a moderate decrease of soil pH. The observed effects were primarily ascribed to the Pb-selectivity of phillipsite and chabazite present in the tuff matrix. On the whole, our findings suggest the suitability of NYT as natural exchanger material to be utilized in strategies for the remediation of polluted sites.

Small-scale patterns of plant functional types and soil features within Mediterranean temporary ponds

Temporary ponds (TPs) are shallow water bodies characterized by alternating phases of drought and flooding. They exhibit a small-scale zonation with a central belt (CB), an intermediate belt, and an outer belt (OB). Starting from the hypothesis that plant assemblage composition is affected by the position within TPs, our aims were to define the small-scale patterns of plant functional types, soil evolution, and soil physicochemical properties and to analyze their relationships and how they were affected by pond characteristics (i.e., elevation, substratum, total size, belt size, maximum water depth, and hydroperiod). Our results pointed out that patterns of plant functional types and soil evolution followed the position within the pond, soil physicochemical properties were weakly affected, and there was a relationship between plant functional types, soil small-scale patterns, and pond characteristics. Principal component analysis showed a positive correlation of Alfisols with CB, aquatic and amphibious species, maximum water depth, and hydroperiod, and of Entisols with OB and terrestrial species. A combined microtopography–hydrology effect was the primary factor controlling soil evolution and plant functional type patterns. As a consequence, modification in topographic shape and/or hydrologic parameters could alter TP environments. The results provide information for management strategies as an answer to the concerns surrounding continued worldwide TP decline.

Ethnopedology in the study of toponyms connected to the indigenous knowledge on soil resource

In taking an integrated ethnopedological approach, this study aims to investigate the meaning of the distribution of the toponyms used in traditional and recent cartography of Sardinia (southern Italy). It is particularly, but not only, focused on those related to soil resources. Sardinia is particularly interesting in this respect, as its unique history, geography, and linguistic position makes it one of the Italian and Mediterranean regions with the greatest number of toponyms. This research investigated the toponyms belonging to an important sub-region of Sardinia, called Ogliastra (central-eastern Sardinia). The research was conducted through the following integrated approach: i) toponymy research and collection from different sources; ii) database creation and translation of toponyms from the Sardinian language (SL); iii) categorization of toponyms; and iv) graphical, statistical, and cartographic data processing. Distribution and diversity of toponyms were assessed using the compiled database, coupled with a geographical information system (GIS). Of around 7700 toponyms collected, 79% had already been reported in SL, while just 21% were in Italian. Of the toponyms in SL, 77% are of known meaning and 54% of these toponyms were characterized by a meaning directly and/or indirectly connected to specific environmental features. On the whole, morphology would appear to be the primary environmental factor able to explain the complex, articulated presence, distribution, and typology of the investigated toponyms. A least squares regression analysis of pedodiversity vs. topodiversity shows a very closed distribution, with an impressive high correlation index (R2 = 0.824). The principal factor analysis (PFA) shows that such a connection may be morphologically based, thereby confirming that pedodiversity and topodiversity are strongly linked each other. Overall, the research shows that an integrated ethnopedological approach, combining indigenous and scientific knowledge may be of great interest in order to mitigate the impressive phenomena of the indigenous knowledge lost.

Modelling pedogenization of zeolitized tuff: effects of water and phenolic substances on weathering rates of the Campanian Ignimbrite (yellow facies)

Abstract An experimental pedology research project, based on a ‘‘process-system’’ pedogenetic model, was initiated to investigate the weathering of Phlegraean Yellow Tuff (PYT) - the yellow facies of the Campanian Ignimbrite with phillipsite > chabazite -as representative of the parent rock material as the soil-forming factor. PYT was weathered by water (W) and tannic acid solutions (TA) at concentrations ranging from 3×101 to 3×104 μmol l-1. The most concentrated TA solution (3×104 μmol l-1) showed the greatest extracting efficiency. Na and K were continually solubilized by W; Al, Ca and Mg contributed to the ionic composition of all the TA supernatants. A significant dissolution of the amorphous component and an associated decrease of the zeolite content, especially phillipsite, were noted. The features of PYT weathered outcomes fitted the ‘‘processsystem’’ model very well. PYT showed a pedogenic potential, in being prone to weathering, as well as in releasing elements of importance for plant settlement and development, such as K, Ca, Mg and Fe.

Zeolitized tuffs as pedogenic substrate for soil re-building. Early evolution of zeolite/organic matter proto-horizons

An investigation was undertaken aiming to evaluate the suitability of zeolitized tuffs as an anthropogeomorphic material for soil re-building in degraded and desertified areas. Four artificial soil proto-horizons were prepared utilizing fine limestone gravel or Neapolitan yellow tuff as inorganic components, and sewage sludge or pellet manure as organic parent materials. The proto-horizons evolution was followed by analyzing leachates periodically collected over 80 days. After 80 days, the body of proto-horizons was also analyzed. Our results showed that the release of C- and N- compounds in the leachates was strictly dependent on the nature of the parent organic material. The presence of Neapolitan yellow tuff in the proto-horizon bodies clearly favored an advantageous evolution and stabilization of parent organic matrices, in optimizing the carbon to nitrogen ratios by increasing the C/N values, and by protecting the organic matter tuff is a promising material in pedotechnique strategies for soil reconstruction and fight against desertification; on contrary, the organic matter appeared to be excessively demolished in the presence of limestone gravel.

Modeling pedogenization of zeolitized tuffs. II: medium-term weathering of phlegraean yellow tuff and red tuff with black scoriae by water and humic acids

An experimental pedology research program was started aiming at modeling the potential pedogenization of zeolitized tuffs. The present study deals with a medium-term weathering of Phlegraean Yellow Tuff (PYT, with phillipsite>chabazite) and Red Tuff with Black Scoriae (RTBS, with chabazite>phillipsite) under discontinuous treatment by water (W) and by humic acids (HA). Significant amounts of cations, increasing in the sequence Al<Fe<Mg<Ca, were extracted by both water and humic acids. The humic acids showed in all cases the highest extracting efficiency. All cations, especially calcium, were more easily removed from PYT than from RTBS. The only exception was iron which was preferentially removed from RTBS by HA. At the end of the experiment, smectite was not any more detected in the PYT residues. On the whole, the results indicate that PYT is more prone than RTBS to both humic acid and water weathering due to its different mineralogy.

Properties of zeolitized tuff/organic matter aggregates relevant for their use in pedotechnique. III: organic matter stability and exchange properties

Abstract A study was performed to evaluate the suitability of zeolitized tuffs to restore degraded soils. Ca-saturated Neapolitan yellow tuff or clinoptilolite-rich tuff from Turkey were mixed with organic matter either as humic matter (tannic acid, humic acids) or non-humic matter (polygalacturonic acid). Organic matter was strongly stabilized in clinoptilolite-rich tuff aggregates based on humic matter, whereas it was more easily oxidized in models with non-humic matter. Cation exchange capacity (CEC) was determined according to Ba/Mg-TEA method and by ammonium acetate procedure. The former method underestimated the CEC of the zeolitized tuffs, but was able to detect the contribution of organic matter to the CEC of aggregates. The latter method provided consistent CEC values for the zeolitized tuffs, but underestimated the exchange activity of the organic components of aggregates. CEC of aggregates including tannic acid was practically nil. Binding tannic acid to zeolite via Ca-bridges, results evidently in occlusion of zeolite pores.

Properties of zeolitized tuff/organic matter aggregates relevant for their use in pedotechnique I. Chemical and physical-chemical properties

Abstract A study aiming at evaluating the technical and economic suitability of zeolitized tuffs as mineral substrate for soil re-building in pedotechnique strategies was carried out. The chemical and physical-chemical properties of aggregates ped models, obtained by interaction between tannic acid, i.e., an organic matrix precursor of humic substances, and a zeolitized material, namely Neapolitan Yellow Tuff, using Ca ions as “bridge”, were investigated. Ped models were characterized according to chemical and physical standard methods for soil analysis, color analysis by visual interpretation and by spectro-radiometry, as well as by FT-IR spectrometry. The results suggest that the interaction between zeolite, Ca ions and tannic acid leads to the formation of stable aggregates with peculiar chemical and chemical-physical properties.