Surfactant can reduce the interfacial tension in liquid–gas system and may probably improve the rate and/or extent of dissolution. This study was conducted to evaluate the effect of three different surfactants (viz., sodium dodecyl sulfate (SDS), Triton X-100, and cetyltrimethylammonium chloride (CTAC)) on CO₂biomineralization by two ureolytic microorganism—Sporosarcina pasteurii and Bacillus megaterium. In S. pasteurii-mediated biomineralization, headspace CO₂content (2.5 mM) was decreased by 40, 52, and 68 % in the presence of SDS, Triton X-100 or CTAC, respectively within the first 8 h of incubation. CO₂removal with B. megaterium in the presence of Triton X-100 (64 %) and CTAC (56 %) was better in comparison to control without surfactant (48 %). However, appreciable CO₂depletion was not observed with SDS, which was just 4 %. On other hand, headspace CO₂loss in the presence of CTAC with B. megaterium did not get biomineralized, as no calcium carbonate was detected. Crystalline phase and morphology of CaCO₃precipitate also varied between ionic and nonionic surfactants. The result suggests that the effect of surfactant on CO₂capture and biomineralization can be largely different, depending on the surfactant and concerned microbial species involved.

The scarcity of clean water affecting many parts of the world encourages efforts to improve water reclamation processes, which rely on their capability to remove diverse types of water pollutants and contaminants. Thus, this study reports the application of bamboo fiber powders as potential low-cost sorbent for removal of noxious organic compounds in aqueous solution. Bisphenol A, a biorefractory endocrine disruptor compound, was chosen as model compound in order to easily follow the separation process. Principal component analysis of the FTIR spectra and BET surface area measurements were performed on treated bamboo fiber powders. Treatment of the raw powders with alkali, ionic and non-ionic surfactants appeared to improve the bisphenol A removal performance of the bamboo fiber powders with the best removal efficiency reached at 39 % for a sorbent dosage of 4 g L⁻¹ gained after a bamboo treatment using the cationic surfactant. Effects of contact time, sorbent dosage, and particle sizes (55, 300, and 1000 μm) of cationic surfactant-treated bamboo fiber powders towards removal of bisphenol A were further assessed in a batch system with an optimum removal observed for 55 μm in particle size.

Many products contain dyes, such as fabrics. However, most of the industry-generated waste is improperly handled, which causes serious environmental problems for the bodies of water that receive textile effluents. This study aimed to analyze the effect of biosorbents and biosorption techniques on decolorizing the textile azo dye Acid Blue 29 in an aqueous solution employing pine sawdust. Pine sawdust is low-cost substrate with minor environmental impact. A toxicity test was performed with Lactuca sativa seeds to determine the LC₅₀ of the dye. Subsequently, a biosorption test was performed to determine the toxicity of the resulting solutions. We observed that biosorption is a very feasible technique for the discoloration of the solutions and promotes reduction in their toxicity.

The expected growth of the coal seam gas industry in Australia requires baseline information for determining any potential long-term impacts of the industry. As such, a 1-year atmospheric time series measuring radon (²²²Rn), methane (CH₄), carbon dioxide (CO₂), δ¹³C-CO₂ and δ¹³C-CH₄ was conducted in an area where coal seam gas (CSG; also referred to as coal bed methane) extraction is proposed (Casino, New South Wales, Australia). We hypothesise that ²²²Rn can be used as a tracer of soil-atmosphere CH₄ and CO₂ exchange, and that carbon stable isotope values of atmospheric CH₄ and CO₂ can be used to identify the source of greenhouse gases. Radon, CO₂ and CH₄ followed a diurnal pattern related to increased concentrations during the formation of a nighttime inversion layer. The study found a significant inverse linear relationship between ²²²Rn concentrations and both rainfall (r ² = 0.43, p < 0.01) and temperature (r ² = 0.13, p < 0.01), while atmospheric pressure, wind speed and wind direction affected concentrations to a lesser degree over seasonal time scales. ²²²Rn had a significant, but weak positive correlation with both seasonal CO₂ (r ² = 0.15, p < 0.01) and CH₄ (r ² = 0.11, p < 0.01) concentrations. The uncoupling between ²²²Rn and CO₂ and CH₄ was likely due to biogenic sources and sinks of CO₂ and CH₄. δ¹³C values of CO₂ and CH₄ indicated variability in the source and sinks of the gases that seems to be linked to different seasonal, soil and spatial sources. This study provides baseline data from a proposed coal seam gas field from which future comparisons can be made.

The purpose of this review is to describe how plants take up lead and its distribution to plant parts, morphological, physiological, and biological effects of lead on plants, sequestration strategies, and tolerance mechanisms including detoxification. How lead despite its lack of essential function in plants, causes phytotoxicity by changing cell membrane permeability, by reacting with active groups of different enzymes involved in plant metabolism by reacting with the phosphate groups of adenosine diphosphate (ADP) or adenosine-5′-triphosphate (ATP). Moreover, we also address role of hyperaccumulating plants in lead absorption. How synthetic chelators such as ethylenediaminetetraacetic acid (EDTA) enhances the availability of heavy metal lead in soils and increase phytoextraction efficiency in aboveground harvestable plant parts through enhancing the metal solubility and translocation from roots to shoots, metal tolerance, and future prospectives to decrease lead pollution.

Upland swamps of the Blue Mountains are unique and legislatively protected peat swamp communities. This study investigated water chemistry of surface waters from seven Blue Mountains Upland Swamps (BMUS), four within urbanised catchments and three from naturally vegetated catchments. The purpose of the study was to investigate any ionic contamination from urban development. Water chemistry of non-urban BMUS was acidic (mean pH 4.7) and dilute (mean EC 26.6 μS/cm) and dominated by sodium and chloride ions with most other major ions at low concentrations, often below detection limits. In contrast, urban BMUS had higher pH (mean 6.6) and salinity (mean 153.9 μS/cm) and were dominated by calcium and bicarbonate ions. The results of this study support the hypothesis that urban concrete contamination is modifying the geochemistry of urban BMUS. Further research is required to investigate ecological implications of the contamination and also to explore measures to protect such sensitive wetlands of high conservation value from urban development.

Several laccases from different sources have been used in dye decolourization processes. However, only in a reduced number of studies have efforts been done to identify the metabolites produced by the enzymatic treatment as well as to evaluate the toxicity of degradation products. Taking these gaps into account, the objective of this work was to use a laccase from Ganoderma lucidum in the decolourization of the synthetic dye Congo red (C.I. No. 22120, Direct Red 28), largely used in the textile industry. After 6 h of treatment at pH 4.0 and 40 °C, the enzyme was able to decolourize 80 % of Congo red. Fourier transform infrared spectroscopy (FTIR), photoacoustic spectroscopy (PAS) and mass spectrometry allow concluding that laccase effectively changed the structure of Congo red, reducing the colour by modifying the chromophore groups and other parts of the molecule. Several degradation products with m/z ⁺ ranging from 298 to 745 were identified. It is proposed that the first degradation step could be an asymmetric cleavage of the azo bond present in the Congo red structure forming the intermediate with m/z ⁺ 298. The results also suggest a reduction in the toxicity of Congo red after laccase treatment, as indicated by the lettuce seed germination model. In conclusion, G. lucidum laccase could be used in a novel azo dye bioremediation strategy.

Aggregation of environmental monitoring data into indices is a common procedure when the objective of the assessment is the evaluation of some environmental criterion for large areas, usually with planning purposes. Two types of aggregation functions are commonly used in the construction of indices: the weighted sum and the constant elasticity of substitution. Several criteria have been proposed for the selection of aggregation functions, namely, (i) ambiguity, which happens when all indicators indicate non-contamination, but the index fails to reflect this observation; (ii) eclipsing, i.e., the index fails to reflect contamination indicated by one of the variables; (iii) rigidity occurs when the introduction of more variables result in increased failure in the classification given by the index, as indicated by a decrease of the index. The first two criteria are easily checked, but the latter is more difficult to evaluate. A method to assess rigidity is here proposed and applied. Two other criteria are also proposed: sensitivity and accuracy. The present study compares and discusses the use of pollution indices for the classification of soils as to heavy metal pollution, with both empirical and real-world data. In the end, some criteria for index selection are indicated, along with their ranking for different practical circumstances. The Nemerow pollution index and the ecological risk index complied with all the fundamental criteria making them good general-use indices.

This article evaluates various extraction techniques’ suitability for soil mercury phytoavailable fraction assessment, including DGT method and extraction with microscopic filamentous fungi metabolites, MgCl₂, rainwater, and EDTA. After mercury extraction from contaminated soils by these techniques, the obtained data were compared to mercury accumulation by shoots of barley (Hordeum vulgare L.). Comparison of these values showed that DGT method is able to separate soil mercury with the best agreement to total mercury concentration in shoots of barley. However, comparing mercury extraction efficiency of selected techniques to extraction efficiency of barley, statistical significance at 0.05 significance level was proved for fungal Cladosporium sp. and Alternaria alternata metabolites. Our results indicate that these extraction techniques are suitable for risk assessment of mercury phytoavailability in contaminated areas.

The electrokinetic transport of sulfate was investigated as a means of treating and restoring a sulfate-accumulating saline soil. The electrokinetic treatment decreased the electrical conductivity of the soil, an indicator of soil salinity, to 58.6, 73.1, and 83.5 % for 7, 14, and 21 days, respectively. More than 96 % of the chloride and nitrate were removed within 7 days. However, the removal of sulfate was highly influenced by the anode material. An iron anode removed sulfate effectively, whereas sulfate was hyper-accumulated in the anodic region when an inert anode was used. The iron anode was oxidized in a sacrificial anodic reaction, which competed with the electrolysis reaction of water at the anode, and finally, the reaction prevented the severe acidification of the soil in the anodic region. However, the competing reactions produced hydrogen ions at the anode and the ions were transported toward the cathode, which, in turn, acidified the soil, especially in the anodic region. The acidification switched the surface charge of the soil from negative to positive, increasing the interaction between the soil surface and sulfate and thus inhibiting the transport of sulfate under the electric field. The zeta potential analysis of the soil provided an explanation. The results indicate that preventing severe acidification is an important factor which influences the transport of anions and iron anode for the enhanced removal of anionic pollutants by electrokinetic remediation.