Early detection of landfill leachate plumes may minimise aquifer degradation and financial expenditure for the landfill operator. Current methods of landfill leachate monitoring typically include analysis of groundwater field parameters such as electrical conductivity (EC), coupled with laboratory analysis of a selection of major cations and anions. In many instances, background influences can mask the impact of leachate, which only becomes apparent once a significant impact has occurred. Here, we investigate the potential for changes in fluorescent dissolved organic material (FDOM) concentration to be used as an indicator of leachate impact. The research was undertaken in a fractured rock aquifer located downgradient of a local government-operated putrescible landfill in Central West NSW, Australia. Field measurement of groundwater FDOM was undertaken using an in situ fluorometer (FDOM probe) which provides a relative measurement of FDOM. To quantify the FDOM values, a bench fluorescence spectrophotometer was used to collect excitation/emission spectra. A plume of elevated FDOM and EC levels within the fractured rock system up to 600 m downgradient of the landfill was identified, whereas analysis of major cations and anions from boreholes within the plume did not detect leachate impacts above background. Excitation/emission matrices of groundwater from these locations confirmed that similar fluorescence signatures to those collected from the landfill were present. Photodegradation experiments were conducted to determine if fluorescent whitening agents (FWAs) were a component of the fluorescence signal. Observed photodegradation of 40 % compared to background (8 %) suggests that a component of the fluorescence signal can be attributed to FWAs. FDOM in groundwater therefore provides an indicator of low-level (up to 98 % dilution) leachate influence, and the identification of FWAs within groundwater can be considered confirmation of a leachate signal.

Road dust organic matter plays a vital role in mobilization of contaminants. This study investigated and characterized organic matter (OM) presents in road dust particles of various sizes. Road dust samples were collected from an industrialized city of Ulsan, Republic of Korea and fractionated into four groups: <75, 75–180, 180–850, and 850–2000 μm. OM extracted from the four fractions was characterized by excitation-emission matrix fluorescence and analyzed by parallel factor analysis (PARAFAC). The PARAFAC identified four major fluorophore components (C1–C4). These components were related to microbial humic-like, anthropogenic organic, fulvic-like, and low molecular weight OM contributed by anthropogenic activity, respectively. There were subtle changes in specific OM composition with change in particle size. The finest fraction contained more microbial humic-like substances whereas the coarse fraction was enriched with fulvic acid. The OM in two fractions (75–180 and 180–800 μm) showed dual characteristics. Our findings demonstrated that PARAFAC approach can assist to assess the accumulation of pollutants in road dust.

In this work, we developed a method based on ultrasound-assisted emulsification microextraction (USAEME) for the determination of nickel by flame atomic absorption spectrometry (FAAS). The method is based on the use of the organic solvent trichloroethylene and 2,2′-thiazolylazo-p-cresol (TAC) as a chelating reagent in a solution containing nickel ions. After ultrasonic emulsification, the mixture is centrifuged to separate the phases. Subsequently, the supernatant is discarded, and the enriched phase is diluted with nitric acid. The nickel content in this new mixture is quantified by FAAS. The following variables were optimized: type of solvent (trichloroethylene), type of chelating reagent (TAC), volume of extraction solvent (100 mL), concentration of chelating reagent (0.015 % w/v), pH (8.0), time of sonication (5.0 min), and time of centrifugation (4.0 min). The limits of detection and quantification were calculated under optimum conditions (0.23 and 0.77 μg L⁻¹, respectively). The enrichment factor obtained was 190. The relative standard deviation (RSD%) of the method (10.0 μg L⁻¹) was 2.3–4.1 %. The proposed method is simple, economical, fast, and efficient for the determination of nickel by FAAS. The procedure was applied to the determination of nickel in certified reference material (BCR-713, wastewater) and water samples.

In this work, metal sorption onto grape stalks waste structural compounds and extractives has been studied for determining their role in Cr(VI), Cu(II) and Ni(II) metal sorption. For this purpose, a sequential extraction of extractives and other compounds from the lignocellulosic material has been carried out. The resulting solid samples obtained in the different extraction processes were used as sorbents of Cr(VI), Cu(II) and Ni(II). Sorption results were discussed taking into account the elemental composition and polarity of the solid extracts. Results indicated that tannins and polyphenols are involved in chromium reduction and sorption. Lignin and celluloses are involved in chromium, Cu(II) and Ni(II) sorption. FTIR analysis confirmed the involvement of lignin moieties in the studied metal ions sorption by grape stalks waste. This study presents a new approach on metal sorption field as the knowledge of the role of the sorbent chemical compounds is essential to determine the key sorbent compounds in the sorption process.

A serial enrichment culture has been grown in an alkaline Fe(III)-citrate-containing medium from an initial inoculum from a soil layer beneath a chromium ore processing residue (COPR) disposal site where Cr(III) is accumulating from Cr(VI) containing leachate. This culture is dominated by two bacterial genera in the order Clostridiales, Tissierella, and an unnamed Clostridium XI subgroup. This paper investigates the growth characteristics of the culture when Cr(VI) is added to the growth medium and when aquifer sand is substituted for Fe(III)-citrate. The aim is to determine how the availability and chemical form of Fe(III) affects the growth of the bacterial consortium, to determine the impact of Cr(VI) on growth, and thus attempt to understand the factors that are controlling Cr(III) accumulation beneath the COPR site. The culture can grow fermentatively at pH 9.2, but growth is stronger when it is associated with Fe(III) reduction. It can withstand Cr(VI) in the medium, but growth only occurs once Cr(VI) is removed from solution. Cr(VI) reduced the abundance of Tissierella sp. in the culture, whereas the Clostridium XI sp. was Cr(VI) tolerant. In contrast, growth with solid phase Fe(III)-oxyhydroxides (present as coatings on aquifer sand) favoured the Tissierella C sp., possibly because it produces riboflavin as an extracellular electron shuttling compound allowing more efficient electron transfer to solid Fe(III) phases. Thus, it is suggested that bacterially mediated Cr(III) reduction in the soil beneath the COPR site is dependent on Fe(III) reduction to sustain the bacterial community.

In this study, the samples of the spatial soil and organs of the grapevine (Vitis vinifera) cultivar Tamjanika were collected from the selected zones near the Mining and Smelting Complex Bor (East Serbia). They were analyzed by ICP-OES to determine the content of Cu, Zn, Pb, As, Cd, and Ni with the aim of ascertaining if these data may help in the assessment and improvement of the quality of environment in polluted areas such as Bor and its surrounding area. The results obtained from the calculated biological and enrichment factors, as well as from the Pearson correlation study and hierarchical cluster analysis confirmed that very useful information is recorded in plant organs: root, stem, leaves, and fruit. Yet, when the atmospheric pollution is the sphere of interest, the most informative data are found in unwashed leaves. The results of this study indicated also that the investigated plant species has some highly effective strategies involved in tolerance to the stress induced by heavy metals, which makes it an excellent candidate for phytostabilization purposes. Planting of this grapevine cultivar can be recommended in all areas that are severely polluted with heavy metals.

SrCO₃ was formed and added as a carrier into copper-based catalyst (CuZnAl catalyst) prepared by hydrothermal method before the catalyst incorporates with HZSM-5. The CuZnAlSr catalyst was characterized by SEM, BET, XRD, IR, and activity-evaluation system in a fixed-bed tubular reactor equipped with chromatograph (GC). The conversion of CO₂ reaches 30.30 %, and the overall yield of methanol and dimethyl ether is 27.80 %. Catalytic property as to CO₂ conversion has only slight decrease even up to 150 h of reaction time. The addition of SrCO₃ enhanced the activity of the catalyst through providing a tridimensional frame and electron transfer bridge.

The intensive pig production has been causing huge amounts of pig slurry with high content of potential pollutants. However, there is a lack of information on the efficiency of combined techniques applied to pig slurry purification. The objective of this research was to assess the pollutant removal efficiency and pathogenic microorganism decrease using mechanical treatments, phytoextraction, and microalgae bioremediation. The purification system was located in the southeast of Spain. Physico-chemical and microbiological parameters were studied in each module of treatment. We observed significant declines for total suspended solids (89 %), settleable solids (100 %), chemical oxygen demand (91 %), biochemical oxygen demand (90 %), total phosphorus (97 %), copper (96 %), zinc (92 %), total nitrogen (89 %), total coliforms (78 %), fecal coliforms (70 %), fecal streptococcus (75 %), Salmonella, Shigella, and Escherichia coli (100 %) in the final effluent of the combined purification system. This survey pointed out the effectiveness of phytoextraction and bioremediation treatments. The results indicated the high efficiency of the purification system, minimizing environmental and human risks.

Chelating reagents impregnated or incorporated into solid sorbents have been widely used in the preconcentration of metal species. In this work, polystyrene-divinylbenzene functionalized with 2-hydroxyacetophenone was used for the preconcentration and determination of cadmium, cobalt, and nickel in sediment samples by flame atomic absorption spectrometry. The sorbent was characterized by infrared spectroscopy and scanning electron microscopy. The influence of variables on the extraction of the metal ions was studied. Under optimized conditions, the method showed enrichment factors of 20 (Cd), 37 (Co), and 32 (Ni) and detection limits of 0.1 (Cd), 0.8 (Co), and 0.6 μg L⁻¹(Ni). The accuracy of the method was tested by analysis of a certified reference material composed of inorganics in marine sediment (NIST 2702). The method was applied to the determination of cadmium, cobalt, and nickel in real sediment samples. Cadmium and cobalt were not found in the sediment samples. Nickel was found in two samples (5.2 and 8.2 μg g⁻¹).

The sorption behavior of cobalt by a sodium-modified zeolite-rich tuff was investigated using cobalt solutions prepared with water from the cooling system of a nuclear reactor. The sorption kinetics shows that the equilibrium was reached in less than 20 h. The isotherms showed that the sorption capacity of the sodium-modified zeolite-rich tuff for cobalt was 20.73 mg/g at 60 °C. The pH affects the sorption capacity of the sodium-modified zeolite-rich tuff for cobalt. The sorption capacity of the sodium-modified zeolite-rich tuff for cobalt was higher using nuclear purity water than water from other aqueous matrices.