Lead,Zn, and Cd in slags,stream sediments,and soils in an abandoned Zn smelting region,southwest of China,and Pb and S isotopes as source tracers

Purpose  

Smelting activity produced tons of slags with large quantities of highly toxic metals, resulting in contamination in adjacent soils and sediments as well. This study investigated the fractionation and sources of metals Pb, Zn, and Cd in polluted soils and sediments in a region with once prosperous Zn smelting activities in southwestern China. Soils with varying land uses were of a special concern due to their connection to the food chain. Obtained data would offer a valuable reference to the development of land-use management strategy in this region.     

Heavy metal pollution of the world largest antimony mine-affected agricultural soils in Hunan province (China)

Purpose  

The present work concerns the distribution of ten heavy metals (Sb, As, Cd, Cr, Cu, Hg, Mn, Ni, Pb, and Zn) in the surrounding agricultural soils of the world largest antimony (Sb) mine in China. The objective is to explore the degree and spatial distribution of heavy metal pollution of the Sb mine-affected agricultural soils. The presented data were compared with metal concentrations in soils from mining and smelting sites in China and other countries.     

Rhizosphere effects of <Emphasis Type="Italic">Populus euramericana</Emphasis> Dorskamp on the mobility of Zn,Pb and Cd in contaminated technosols

Purpose

This study aimed at investigating the rhizosphere effects of Populus euramericana Dorskamp on the mobility of Zn, Pb and Cd in contaminated technosols from a former smelting site.

Materials and methods

A rhizobox experiment was conducted with poplars, where the plant stem cuttings were grown in contaminated technosols for 2 months under glasshouse conditions. After plant growth, rhizosphere and bulk soil pore water (SPW) were sampled together. SPW properties such as pH, dissolved organic carbon (DOC) and total dissolved concentrations of Zn, Pb and Cd were determined. The concentrations of Zn, Pb and Cd in plant organs were also determined.

Results and discussion

Rhizosphere SPW pH increased for all studied soils by 0.3 to 0.6 units compared to bulk soils. A significant increase was also observed for DOC concentrations regardless of the soil type or total metal concentrations, which might be attributed to the plant root activity. For all studied soils, the rhizosphere SPW metal concentrations decreased significantly after plant growth compared to bulk soils which might be attributed to the increase in pH and effects of root exudates. Zn, Pb and Cd accumulated in plant organs and the higher metal concentrations were found in plant roots compared to plant shoots.

Conclusions

The restricted transfer of the studied metals to the plant shoots confirms the potential role of this species in the immobilization of these metals. Thus, P. euramericana Dorskamp can be used for phytostabilization of technosols.

     

Toxicity assessment using <Emphasis Type="Italic">Lactuca sativa</Emphasis> L. bioassay of the metal(loid)s As,Cu, Mn,Pb and Zn in soluble-in-water saturated soil extracts from an abandoned mining site

Purpose  

We used the different soluble-in-water concentrations of As, Cu, Mn, Pb and Zn from contaminated soils in an abandoned mining area (anthropogenic origin) to assess the phytotoxicity of the abandoned site using the results obtained with a Lactuca sativa L. bioassay.     

Application of bioassays with <Emphasis Type="Italic">Enchytraeus crypticus</Emphasis> and <Emphasis Type="Italic">Folsomia candida</Emphasis> to evaluate the toxicity of a metal-contaminated soil,before and after remediation

Purpose  

A contaminated soil was amended to reduce bioavailability of metals (As, Cd, Cu, Pb, and Zn) and to modify its potential environmental impacts. Reproduction toxicity tests using two different soil invertebrates, Enchytraeus crypticus and Folsomia candida, were used to evaluate efficiency of soil amendments to reduce metal availability.     

A laboratory investigation of microbe-inducing CdCO<Subscript>3</Subscript> precipitate treatment in Cd<Superscript>2+</Superscript> contaminated soil

Background, aim and scope  

This paper discusses a method investigating the reduction of free heavy metal cation contents in soil through the use of microbe-inducing precipitate (MIP).     

Reducing CH<Subscript>4</Subscript> and CO<Subscript>2</Subscript> emissions from waterlogged paddy soil with biochar

Purpose  

A potential means to diminish increasing levels of CO₂ in the atmosphere is the use of pyrolysis to convert biomass into biochar, which stabilizes the carbon (C) that is then applied to soil. Before biochar can be used on a large scale, especially in agricultural soils, its effects on the soil system need to be assessed. This is especially important in rice paddy soils that release large amounts of greenhouse gases to the atmosphere.     

Long-term tree growth rate,water use efficiency,and tree ring nitrogen isotope composition of <Emphasis Type="Italic">Pinus massoniana</Emphasis> L. in response to global climate change and local nitrogen deposition in Southern China

Purpose  

We aimed to investigate long-term tree growth rates, water use efficiencies (WUE), and tree ring nitrogen (N) isotope compositions (δ¹⁵N) of Masson pine (Pinus massoniana L.) in response to global climate change and local N deposition in Southern China.     

Bioaccumulation of ivermectin from natural and artificial sediments in the benthic organism <Emphasis Type="Italic">Lumbriculus variegatus</Emphasis>

Purpose  

Although ivermectin is a widely used lipophilic parasiticide, data on its potential bioaccumulation in aquatic invertebrates are scarce. In this study, bioaccumulation patterns of radiolabeled ³H-ivermectin from sediments into tissues of the sediment-dwelling worm Lumbriculus variegatus were investigated and assessed.     

Soil quality assessment under different <Emphasis Type="Italic">Paulownia fortunei</Emphasis> plantations in mid-subtropical China

Purpose

Paulownia, one of the fastest growing broad-leaved tree species in the world, is widely distributed in the warm temperate regions of China. However, there are few commercial-scale Paulownia plantations, and there is only limited information available about the most suitable soil quality for Paulownia fortunei growth in mid-subtropical, Hunan Province, China.

Materials and methods

To understand the effect of the growth of P. fortunei on soil conditions, 25 soil property parameters under Paulownia plantations were studied in Hunan Province, China. Seventy-two standard plots of eight different stand types were analyzed by three statistical approaches to assess soil quality (SQ) in the different P. fortunei plantations.

Results and discussion

The results revealed that a majority of the soil characteristics when intercropping with oilseed rape and the pure P. fortunei (plantation III) were better than intercropping with Camellia oleifera, orange trees, and Cunninghamia lanceolata (Lamb.). Available calcium, available magnesium, available potassium, available phosphorus, soil thickness, slope, soil organic matter, available sulfur, available copper, dehydrogenase, and available zinc were selected as the minimum data set (MDS). The SQ index (SQI) showed that three classes for soil quality among the eight P. fortunei plantations ranged from 0.48 to 0.88 and these were correlated with standing volume (p?<?0.05).

Conclusions

From the results, we concluded that selected MDS indicators can describe the soil fertility quality of P. fortunei plantations, and that the relationship between SQI and standing volume has a biological significance. P. fortunei plantations intercropped with Camellia oleifera, orange trees, and Cunninghamia lanceolata (Lamb.) caused a deterioration in SQ, but intercropping oilseed rape and pure P. fortunei plantations produced an improvement in SQ.

     

Pb<Superscript>2+</Superscript> adsorption on birnessite affected by Zn<Superscript>2+</Superscript> and Mn<Superscript>2+</Superscript> pretreatments

Purpose  

Lead contamination is ubiquitous, and much attention has been paid due to its toxicity. The phyllomanganate birnessite is the most common Mn oxide in soils. The MnO₆ octahedral layers may have significant Mn vacancies in the hexagonal birnessites. Among heavy metal ions, birnessites possess the greatest adsorption affinity and capacity for Pb²⁺. The aim of this study was to understand the relationship between vacant Mn octahedral sites and Pb²⁺ adsorption.     

Joint toxicity of three plant protection products to <Emphasis Type="Italic">Triticum aestivum</Emphasis> (L.) and <Emphasis Type="Italic">Brassica rapa</Emphasis> (L.)

Purpose  

Few studies have been conducted to evaluate the effects of mixtures of chemicals in terrestrial environment. Thus, it seems important to evaluate if the combined application of pesticides currently used in agricultural fields may pose a risk to terrestrial plants.     

Chronic toxicity of ivermectin to the benthic invertebrates <Emphasis Type="Italic">Chironomus riparius</Emphasis> and <Emphasis Type="Italic">Lumbriculus variegatus</Emphasis>

Purpose  

Previous studies have shown that ivermectin, a widely used parasiticide, is very toxic to many non-target invertebrate species. In view of the strong binding of ivermectin to sediments and the scarcity of data on chronic toxicity to freshwater sediment invertebrates, chronic effects of the parasiticide on the midge Chironomus riparius and the oligochaete Lumbriculus variegatus were investigated.     

Interactive effects of Cd and PAHs on contaminants removal from co-contaminated soil planted with hyperaccumulator plant <Emphasis Type="Italic">Sedum alfredii</Emphasis>

Purpose  

Soil contamination by multiple organic and inorganic contaminants is common but its remediation by hyperaccumulator plants is rarely reported. The growth of a cadmium (Cd) hyperaccumulator Sedum alfredii and removal of contaminants from Cd and polycyclic aromatic hydrocarbons (PAHs) co-contaminated soil were reported in this study.     

TiO<Subscript>2</Subscript> photocatalytic degradation of 4-chlorobiphenyl as affected by solvents and surfactants

Purpose  

TiO₂ photocatalytic degradation of 4-chlorobiphenyl (PCB3) in aqueous solution under UV irradiation was investigated as affected by different environmental factors, including initial PCB3 concentration, TiO₂ content, UV intensity, H₂O₂ concentration, cosolvents, and surfactants.     

Elevated UV-B radiation increased the decomposition of <Emphasis Type="BoldItalic">Cinnamomum camphora</Emphasis> and <Emphasis Type="BoldItalic">Cyclobalanopsis glauca</Emphasis> leaf litter in subtropical China

Purpose  

Ultraviolet-B (UV-B) radiation reaching the earth's surface has been increasing due to ozone depletion and can profoundly influence litter decomposition and nutrient cycling in terrestrial ecosystems. The role of UV-B radiation in litter decomposition in humid environments is poorly understood; we thus investigated the effect of UV-B radiation on litter decomposition and nitrogen (N) release in a humid subtropical ecosystem in China.     

In situ phytoremediation of PAH-contaminated soil by intercropping alfalfa (<Emphasis Type="Italic">Medicago sativa</Emphasis> L.) with tall fescue (<Emphasis Type="Italic">Festuca arundinacea</Emphasis> Schreb.) and associated soil microbial activity

Purpose  

A 7-month field experiment was conducted to investigate the polycyclic aromatic hydrocarbon (PAH) remediation potential of two plant species and changes in counts of soil PAH-degrading bacteria and microbial activity.     

Development of an express method for measuring soil nitrate,phosphate, potassium,and pH for future in-field application

Background

In practical farming, there is often a need for short-term availability of information on the soil nutrient status.

Aims

To develop a new express method for the extraction of major plant-available nutrients and measurement of soil nutrients. In future, this method shall serve for in-field measurements of soil samples with an ion-sensitive field-effect transistor (ISFET).

Methods

Various extraction conditions such as type of extractant, soil-to-solution ratio, time, and intensity were investigated on a broad selection of dried soil samples in the laboratory. Based on 83 field-moist soil samples with varying clay contents, these conditions were compared to standard laboratory methods.

Results

With increasing extraction time, the nutrient concentrations increased. When the soil-to-solution ratio was reduced, a greater share of nutrients was extracted, independent of soil type. H₂O and 0.01 M CaCl₂ and standard calcium-acetate-lactate (CAL) solution proved to be too weak in the short period to reach the ISFET sensor measurement range. Higher concentrated CAL solutions performed much better. Finally, a 5-min CaCl₂ extraction followed by the removal of an aliquot for the determination of soil pH and NO₃⁻ was found to be effective. The remaining solution was then mixed with 0.20 M CAL solution for the analysis of H₂PO₄⁻ and K⁺ at 10 min of extra extraction time. This extraction method showed very good correlations with the values based on the German laboratory reference methods for pH (R² = 0.91) and for nitrate (R² = 0.95). For phosphorus and potassium, we obtained an R² of 0.70 and 0.81, respectively, for all soils. When soils were grouped according to clay content higher correlations were found.

Conclusions

A new express method based on a wet-chemical approach with a soil preparation procedure was successfully developed and validated. This seems to be a valuable basis for future in-field measurements via ISFET.     

A liquid chromatographic/mass spectrometric method to evaluate <Superscript>13</Superscript>C and <Superscript>15</Superscript>N incorporation into soil amino acids

Purpose  

Amino acids are highly associated with biogeochemical cycling and represent an important potential source and sink of carbon (C) and nitrogen (N) in terrestrial ecosystems. Tracing the isotope dynamics of amino acids can improve the understanding of the origin and transformation of amino acids in soil matrix at process-levels; hence, the liquid chromatographic/mass spectrometric (LC/MS) method to evaluate ¹³C or ¹⁵N enrichment in amino acids is necessary to be established.     

Soil fungal communities differ in native mixed forest and adjacent <Emphasis Type="Italic">Araucaria cunninghamii</Emphasis> plantations in subtropical Australia

Purpose  

Commercial monoculture plantations of the native Australian Araucaria cunninghamii are common in subtropical and tropical Queensland and are generally established following clearing of native mixed forest. The consequences of such forest conversion for soil fungal communities, however, have not been assessed in detail.