Release Of Other Elements Research Articles

Indicators of peat soil degradation in the Biebrza valley, Poland

Abstract Peat mineralisation leads to net loss of CO2 to the atmosphere, as well as to release of other elements from the decomposed soil organic matter (SOM) to groundwater. This results in the degradation of peat soils and the ecosystems they support. Here we evaluated the practical indicatory suitability of the existing and proposed new indices for the assessment of peat soil degradation in the Biebrza river valley encompassing, unique on European scale, peatland ecosystems. We studied relationships between soil organic carbon (SOC) and total nitrogen (Ntot), dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in a series of degraded peat soils in the Biebrza valley. Samples were taken from soils developed on peat deposits that varied in thickness and the degree of peat decomposition, from undegraded to highly mineralised peats. The relationships between changes in the SOC content and changes in the values of the remaining variables (SOM, Ntot, DOC, DON, C/N ratio), were statistically tested. Linear and non-linear regressions were used to establish the relationships amongst the variables examined. The losses of soil C and N occur independently and differ between stages of peat soil mineralisation. From our study, it results that the peat mineralisation intensity may be estimated based on the loss of SOC. We found that 1% loss of SOC corresponded to 1.028% loss of SOM, regardless of the degree of peat soil mineralisation, whereas SOM solubility, measured by the content of DOC, varied based on the intensity of peat soil mineralisation. The content of DOC decreased with the decrease in the SOC content, whereas the DOC/ SOC ratio increased depending on the intensity of peat decomposition. The C/N ratio is not a reliable indicator of peat mineralisation, because its values are driven not only by the nitrogen natively present in peat soils but also by nitrogen from external sources. The contents of SOC and Ntot did not decrease uniformly during peat decomposition because C and N show various mobility in the processes of SOM mineralisation. We found that the DOC/SOC ratio was most indicative of peat soil mineralisation intensity. © IOŚ-PIB

A Comparative Study of Long‐Term Effects on Fire‐Affected Volcanic Soils in Two Different Ecosystems in the Canary Islands

AbstractVolcanic soils have unique properties that can be specifically affected by fire. In this work, we use a chronosequence approach to investigate the long‐term effects of wildfires on the surface and topsoil (0–30 cm) of volcanic soils in two different ecosystems: the Canary pine forest (dry and fire‐adapted) and the laurel forest or monteverde (subhumid and not prone to fire). Redundancy analysis and partial Kendall's correlation were used to analyse the relationship between soil characteristics and the wildfire chronosequences, controlling most significant environmental variables. No long‐term effects of fire were observed on the pine forest topsoil, but strongly persistent erosion‐related features were found on the soil surface, suggesting that chronic erosion might occur as a result of increased wildfire frequency. The soils of the monteverde were affected over the long term by severe losses of organic matter including highly humified and complexed forms. Organic losses appeared to be mainly due to erosion and associated with decreases in water‐holding capacity and in the levels of organo‐complexed metals and bioavailable nutrients such as boron or zinc. Fire also led to decreased bioavailability of some nutrients (e.g. phosphorus) and increased release of other elements (e.g. silicon), most likely by exposing surfaces of short‐range‐order minerals. Better management is needed to reduce irreversible effects of severe wildfires on these soils. Copyright © 2015 John Wiley & Sons, Ltd.

Ion release from gold/platinum dental alloy: could release of other elements be accountable in the contact allergy attributed to the gold?

The release of metal ions (Al, Ag, Au, Ca, Cd, Co, Cr, Cu, Mg, Mo, Ni, Pd, Pt, Ti, and Zn) from the commercial gold/platinum (Au/Pt) dental alloy of declared composition was studied. Au/Pt was soaked in pH 6.0 phosphate buffer, 3.5 pH phosphate buffer and pH 3.5 mixture of lactic, formic and acetic acid, and incubated at 37 degrees C for 1, 2, 3, 4, 5, 6, 7, 14, 21, and 30 days. Six samples (n = 6) of every solution were prepared for any time period. Inductively coupled plasma atomic emission spectroscopy was used for analysis of the released elements. Results demonstrated release of only Cr, Cu, Fe, and Zn from the tested Au/Pt dental alloy (ANOVA, p < 0.001 for buffer, time, and interaction, respectively); however, only Cu and Zn were declared. The undeclared chromium from Au/Pt dental alloy, or some other element might be responsible for the contact allergy thus far attributed to the gold.

Land Application of Wastewater in Brazil - A scientific challenge: Chemical Characterization of Soil at Populina, São Paulo State (9 pp)

Background, Aims and Scope The rapid increase of wastewater worldwide and the consequently urgently needed treatment measures towards disposal purposes has led to an expansion of alternative treatment methods. Besides conventional and cost intensive systems, domestic wastewater treatment by overland flow process represents an effective and low-cost alternative. However, in addition to beneficial elements in wastewaters, there is a release of other elements of the Periodic Table into the environment, which can be considered as potentially toxic. This requires a reliable chemical characterization of the wastewater element composition as well as the soils onto which it will be applied. This paper aims at presenting the chemical fingerprint methodology to characterize concentrations of a large set of elements in a tropical ferralsol in order to provide information concerning chemical modifications after long-term application of wastewater by overland flow process. The results are also used to estimate environmental implications according to guiding values for soils in Sao Paulo State.