A simple strategy and method is presented to monitor NO₂ health standards in busy streets of middle large South East Asian cities.

The aim of this study is to develop a new method for the preconcentration of copper via a dispersive liquid–liquid microextraction method using 4-phenyl-3-thiosemicarbazide as a ligand and determination with FAAS in different sample types such as plants, soils and natural waters such as seawater. Optimum experimental conditions were determined, and the applicability of the proposed dispersive liquid–liquid microextraction method was investigated. In the first step of the work, the parameters that affect complex formation and extraction, such as volume of extractant/disperser solvent, pH and concentration of the chelating agent, NaCl and surfactant, were optimised. The interference effects from potential concomitants on the determination of the Cu(II) ion were investigated in synthetic mixtures that contain high levels of these ions. These results showed the analytical applicability of the proposed method in different kinds of samples. Under the optimal conditions, the calibration curve was linear over the range 2–600 μg L⁻¹of copper, and the detection limit was 0.69 μg L⁻¹in the original solution (3 Sb/m). The accuracy of the developed method was checked by analysing certified reference materials (QCS-19 (high purity standard), LGC 6156 (harbour sediment) and NBS 1572 (citrus leaves)). Results obtained were in agreement with certified values with a t test showing that no significant differences at the 95 % confidence interval levels were found. The proposed method was applied to seawater, river water, and plant and soil samples. The recovery values for spiked water samples were between 99.7 and 117.3 %.

Phosphorus (P) management in agriculture is crucial for both environmental health and future availability of P resource. Application of P as fertilisers (organic or inorganic) often results in either P accumulation in soil or loss to water bodies, rendering them unavailable to crops. In this study, the mobility of inorganic (KH₂PO₄(PP)) and organic (poultry manure (PM)) P sources, as affected by coal combustion products (CCPs: fly ash (FA) and fluidised bed combustion ash (FBC)) application to soils, was evaluated using column leaching experiments. The incubated samples were also characterised using X-ray diffraction (XRD) and scanning electron microscopy (SEM) to understand their surface properties in relation to P adsorption and leaching. The results showed differential effects of CCPs to P treatments—in the case of PP, the CCPs decreased P leaching by 12.11 % (FA) and 20.56 % (FBC), whereas in the case of PM treatment, both CCPs increased P in leachates by 35.53 % (FA) and 18.44 % (FBC). The decrease in P leaching for PP-treated soil as affected by CCPs was attributed to high pH and Ca concentration. There was a negative relationship between the increase in CCP-induced pH and P leaching demonstrating that pH plays a crucial role in P immobilisation, transformation and leaching. The increase in P leaching for CCP-incubated–PM-treated soils was because of the mineralisation of organic P from PM. The surface chemistry from XRD and SEM results showed an increased surface area for CCPs-incubated soil compared to the control and also showed the presence of Ca-rich minerals in CCPs such as ettringite, wollastonite and merwinite.

The novel adsorbent Cu-impregnated activated coke (CAC) has been successfully prepared using a Cu(NO₃)₂solution impregnated activated coke (AC). The optimum preparation conditions of CAC are the concentration of Cu(NO₃)₂of 0.1 mol/L, pH of 6, loading time of 4 h, and loading temperature of 333 K. The characterizations of CAC are analyzed by N₂adsorption, X-ray diffraction, scanning electron microscope, and energy dispersive X-ray spectroscopy. Also the adsorption behavior of CAC to organic materials in TNT red water is studied. The adsorption data are simulated by Freundlich isotherm and Langmuir isotherm. Below 333 K Freundlich isotherm is more suitable, while Langmuir isotherm model is more fitted when the temperature is higher than 333 K. The adsorption kinetics follows a pseudo second-order model, and thermodynamic analysis indicates an endothermic and spontaneous adsorption processes, and the process appears to be controlled by the chemisorption process. Chemical oxygen demand of 85.34 % can be removed as CAC prepared under optimized conditions is used as absorbent. In summary, CAC has excellent absorption characteristics and can be used in the removal of organic materials from TNT red water.

In order to assess and accurately predict the self-purification capabilities of rivers with respect to enteric pollution, a thorough understanding of mechanisms such as dispersion, particle association, and inactivation in the water column is crucial. In this study, we firstly performed particle size distribution analyses of wastewater and investigated the Escherichia coli and enterococci loadings of each size fraction. It was seen that 91 % of E. coli and 83 % of enterococci were associated with particle sizes less than or equal to 12 μm. Particles larger than 63 μm contributed less than 1 % to overall E. coli and enterococci loadings. Based on these results, batch experiments were performed to investigate the effect of particle size and total suspended solids (TSS) concentration on UV inactivation of the two fecal indicator bacteria (FIB). A direct relationship between the particle size to which FIB were associated and their UV inactivation rate was noted. E. coli and enterococci associated with particles smaller than or equal to 12 μm were inactivated on average 2 × and 1.7 × faster than those associated with the larger particle fraction of 12 to 63 μm. It was additionally seen that as the TSS concentrations increased, the UV inactivation rates decreased. A tailing effect of UV inactivation was however noted at TSS concentrations above approximately 100 mg L⁻¹.

Elements uptake, histological distributions as well as mycorrhizal and physiological statuses of Atriplex halimus were determined on trace metal and metalloid polluted soils from the surrounding spray zones of a former lead smelter in the South-East coast of Marseille (France). Analyses of heavy metal and arsenic distribution in soil and plant organs showed that A. halimus tolerance is largely due to exclusion mechanisms. No specific heavy metal concentration in leaf or root tissues was observed. However, accumulation of salts (NaCl, KCl, Mg and Ca salts) on leaf bladders and peripheral tissues of roots was observed and may compete with metal element absorption. Occurrence of endomycorrhizal structures was detected in roots and may contribute to lower element transfer from root into the aerial parts of plants. The non-destructive measurements of leaf epidermal chlorophylls, flavonols and phenols showed a healthy state of the A. halimus population on the metal and metalloid polluted sites. Considering the low metal bioaccumulation and translocation factors along with a reduced metal stress diagnosis, A. halimus appeared as a good candidate for phytostabilization of trace metals and metalloids and notably arsenic in contaminated soils of the Mediterranean spray zone. However, its invasive potential has to be determined before an intensive in situ use.

In this study, lead (Pb) and antimony (Sb) sorption experiments were conducted to elucidate the mechanisms of Pb and Sb sorption by combined applications using single or combined applications of hydroxyapatite (HAP) and ferrihydrite (FH), to evaluate the contribution of each material in Pb and Sb sorption, and to assess the chemical stability of the sorbed Pb and Sb. In the combined application, isotherms of Pb sorption and Sb sorption were well fitted to Langmuir and Freundlich isotherm models, respectively. The Pb and Sb amounts sorbed in the combined application were the same levels as the summed totals of those sorbed in the single applications, indicating that in the combined application, Pb sorption and Sb sorption were not suppressed. Pb was mainly sorbed on HAP in the combined application, at a 90 % level of the total adsorbed Pb. The HAP and FH contributions to Sb sorption were 32 and 68 % of the total adsorbed Sb, respectively, and Sb was sorbed on each material independently even in the combined application. The percentages of both Pb and Sb dissolved from the sorbed materials in the combined applications at pH 4 and 6 were the same levels as those in the single applications. However, the percentages of Sb dissolved in both combined and single applications were high at an alkaline pH. These results suggest that HAP and FH in a combined application would be useful for simultaneous Pb and Sb immobilization in soil with acidic to neutral pH, but not in soil with an alkaline pH.

In a study on the behaviour of pesticides in a soil–plant–water system, the quick, easy, cheap, effective, rugged and safe (QuEChERS) method for analysing pesticide or metabolite residues in soil and maize (leaves, roots and kernels) was optimized and validated. The pesticides bentazone, chloridazon and terbuthylazine and their metabolites bentazone-methyl, chloridazon-desphenyl, chloridazon-methyl-desphenyl, terbuthylazine-desethyl and terbuthylazine-2-hydroxy were selected in this study. The QuEChERS extracts obtained from soil and maize matrices and the collected leachate were analysed by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS) using a high-performance liquid chromatography and an ultra-high-performance liquid chromatography (UHPLC) analytical column. As expected, shorter run times and higher sensitivity were achieved with the UHPLC column. Validation studies focused on recovery, repeatability, matrix effects, limits of detection and quantification. Recoveries (and repeatability relative standard deviation (RSD)) of the spiked samples were in the range of 55 to 98 % (7.4–18) in soil, 23 to 101 % (1.7–20) in maize and 82 to 105 % (4.4–25) in leachate. Quantification limits were lower than 3.0 μg kg⁻¹ in soil, 7.3 μg kg⁻¹ in maize and 0.080 μg l⁻¹ in leachate.

Chemically prepared activated carbon derived from durian seed (DSAC) was used as adsorbent to adsorb Malachite green (MG) dye. The prepared DSAC was characterized using Brunauer–Emmet–Teller (BET), Fourier transform infrared (FTIR), scanning electron microscope (SEM), and proximate analysis, respectively. Batch adsorption studies were carried out for the removal of MG dye from aqueous solutions by varying operational parameters like contact time, initial MG dye concentration, solution temperature, and initial solution pH. Maximum dye removal of 97 % was obtained at pH 8. Experimental data were analyzed by eight model equations—Langmuir, Freundlich, Temkin, Dubinin–Radushkevich, Radke–Prausnitz, Sips, Vieth–Sladek, and Brouers–Sotolongo isotherms—and it was found that the Freundlich isotherm model fitted the adsorption data the most. Adsorption rate constants were determined using pseudo-first-order and pseudo-second-order rate equations, Elovich, intraparticle diffusion, and Avrami kinetic model. The results clearly showed that the adsorption of MG dye onto DSAC followed the pseudo-second-order model, and the mechanism of adsorption was controlled both by film diffusion and intraparticle diffusion. Thermodynamic parameters such as ∆G, ∆H, and ∆S were also calculated for the adsorption process. The process was found to be spontaneous and endothermic in nature. This work provided an attractive adsorbent for the removal of MG dye from wastewaters.

The aims of this study were to assess sulfate adsorption in Japanese forest soils and to find and evaluate traces of past heavy anthropogenic sulfur deposition based on the degree of saturation as calculated based on the theoretical adsorption capacity determined by isotherm experiments and the amount of actual adsorbed sulfate. Investigations were conducted at two forest sites, a site in Yokkaichi that is exposed to serious air pollution containing sulfur compounds and a site in Inabu that is unpolluted. The distribution of phosphate-extractable sulfate concentration did not differ between the Yokkaichi site (1.11–13.2 mmol kg⁻¹) and the Inabu site (0.40–11.0 mmol kg⁻¹), and the values were higher than published data for North America and Europe. In contrast, the degree of sulfate saturation in soils of the Yokkaichi site was higher than that in soils of the Inabu site. These results indicate that the degree of sulfate saturation is valuable information for the evaluation of sulfur deposition history. The higher degree of saturation at Yokkaichi site may be due to enhanced sulfate adsorption by soils resulting from substantial past sulfur deposition.