Alkalisation of soil by dust pollution from a cement plant was assumed to be the principal cause of changes in heavy metal uptake and allocation between hybrid aspen (Populus tremula × Populus tremuloides Michx.) compartments. Emission of over 40 years of alkaline dust (pH 12.3–12.6) into the atmosphere had resulted in an increase of pH and an elevated concentration of total heavy metals in the upper layer of the soil (0–30 cm), which is considerable even 14 years after dust pollution has stopped. The accumulation and allocation of heavy metals in stem, shoot and leaves varied between themselves and between the trees from polluted and unpolluted plantations depending more on the mobility of elements and pH than element concentrations in the alkaline soil. High levels of heavy metals in the soil do not mean similar concentrations and ratios in plants growing in contaminated soil.

This study examines the effects of land use change on nitrate concentration and the abundances of ammonia-oxidizing archaea (AOA), ammonia-oxidizing bacteria (AOB), and narG-containing denitrifiers in shallow groundwater. The results reveal a general increase of nitrate in shallow groundwater following the change of land use from paddy fields to vegetable patches. Furthermore, a significant relationship between NO₃ ⁻-N concentrations was observed both in groundwater and in soil at soil depths of 0–20, 20–40, 40–60, 60–80, and 80–100 cm. With regard to gene abundance in groundwater, the AOB amoA gene was most abundant and the AOA amoA gene copy numbers were lowest from the field with long-term paddy cultivation compared with the field under vegetable cultivation. The narG gene copy numbers were higher from the field under short-term vegetable cultivation compared with fields under long-term vegetable cultivation. The NO₃ ⁻-N concentrations in groundwater correlated positively with AOA amoA gene copy numbers, negatively with the AOB amoA gene, but with no significant relationship with the narG gene. In conclusion, land use change from paddy fields to vegetable patches increases nitrate in groundwater, which is correlated significantly with nitrate in soil and the abundance of the amoA gene, but is not related to the narG gene in groundwater. This study also suggests that the removal of groundwater nitrate pollution is not feasible through biological denitrification without additional denitrifiers and that it might even become more aggravated because of the AOA.

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

This study compares a traditional agricultural approach to minimise N pollution of groundwater (incorporation of crop residues) with applications of small amounts of biodiesel co-product (BCP) to arable soils. Loss of N from soil to the aqueous phase was shown to be greatly reduced in the laboratory, mainly by decreasing concentrations of dissolved nitrate-N. Increases in soil microbial biomass occurred within 4 days of BCP application—indicating rapid adaptation of the soil microbial community. Increases in biomass-N suggest that microbes were partly mechanistic in the immobilisation of N in soil. Straw, meadow-grass and BCP were subsequently incorporated into experimental soil mesocosms of depth equal to plough layer (23 cm), and placed in an exposed netted tunnel to simulate field conditions. Leachate was collected after rainfall between the autumn of 2009 and spring of 2010. Treatment with BCP resulted in less total-N transferred from soil to water over the entire period, with 32.1, 18.9, 13.2 and 4.2 mg N kg⁻¹soil leached cumulatively from the control, grass, straw and BCP treatments, respectively. More than 99 % of nitrate leaching was prevented using BCP. Accordingly, soils provided with crop residues or BCP showed statistically significant increases in soil N and C compared to the control (no incorporation). Microbial biomass, indicated by soil ATP concentration, was also highest for soils given BCP (p < 0.05). These results indicate that field-scale incorporation of BCP may be an effective method to reduce nitrogen loss from agricultural soils, prevent nitrate pollution of groundwater and augment the soil microbial biomass.

Cadmium is a toxic element for living organisms. This metal causes different damages to the cell, generating oxidative stress. In order to elucidate cadmium tolerance mechanism and increase tomato plant tolerance by inoculating a Cd-tolerant Burkholderia strain, we analyzed malondialdehyde, hydrogen peroxide content, and the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione S-transferase of two strains, one isolated from a soil contaminated with Cd (strain SCMS54) and the other from a soil without Cd (strain SNMS32). Strains SNMS32 and SCMS54 exhibited different SOD, CAT, and GR isoenzyme profiles in non-denaturing polyacrylamide gel electrophoresis analysis, with strain SCMS54 exhibiting an extra isoenzyme for all enzymes (Mn-SOD, CAT I, and GR IV, respectively). Despite accumulating more Cd, strain SCMS54 did not increase peroxide hydrogen and presented a fast antioxidant response (increasing SOD and CAT after 5 h of Cd exposure). In this way, strain SCMS54 exhibited a higher metabolic diversity and plasticity when compared to strain SNMS32, so it was selected for Cd–Burkholderia–tomato interaction studies. Inoculated tomato plants in the presence of Cd grew more than non-inoculated plants with Cd indicating that the SCMS54 increased tomato Cd tolerance. It appears that the strain isolated from Cd-contaminated soil (SCMS54) triggers a global stress response in tomato increasing plant tolerance, which may enable plants to be cultivated in Cd-contaminated soils.

Citrus peels were utilized for dynamic biosorption of Pb, Cd, and Zn from mono- and bi-component solutions in fixed-bed columns at feed concentrations of 0.1 meq/L. Uptake at breakthrough and saturation followed the order Zn < Cd < Pb in single-metal biosorption. An overshoot of the Zn or Cd effluent concentration was observed in Pb-Zn and Pb-Cd bimetal systems, where Pb displaced initially bound Zn and Cd. The desorption efficiency of the saturated column using 0.1 N nitric acid was 74 to 100 %, achieving a concentration factor (CF) of 34 to 129, based on the average desorbed metal concentration. The common practice of defining the concentration factor based on the peak concentration overestimates the CF value. Increasing Ca concentrations in Pb-Ca and Cd-Ca systems reduced target metal uptake, especially for Cd which had a lower affinity than Pb. Actual mining effluent was treated successfully. A sigmoid function was applied to describe experimental breakthrough data. A novel simple two-parameter model was introduced to simulate overshoot and desorption curves.

From April 2006 to April 2007, the geographical and seasonal variation in nitrogen content in terricolous lichen (Cladonia portentosa) and atmospheric ammonia concentrations were measured at five heathland sites. The seasonal variation in the nitrogen content of the lichen was small, even though there was a large seasonal variation in the air concentration of ammonia. A sizable local variation in the nitrogen content of the lichen was found even at the scale of a few kilometres. The nitrogen content in the lichen showed a high correlation to the yearly mean value of the measured ammonia concentration in air at the different locations. This investigation is part of a larger attempt to incorporate effects of nitrogen in the conservation status of terrestrial habitat types.

This contribution is concerned with the comparison of the efficiency of the removal of four pure neonicotinoid active ingredients (AIs) and their commercial formulations (CFs) from aqueous solutions by using different advanced oxidation processes at the pH 2.8. The AIs of thiamethoxam and imidacloprid, and their CFs (Actara and Confidor), having a nitroguanidine functional group, exhibited low persistence to photolysis. In contrast to them, thiacloprid and acetamiprid and their CFs (Calypso and Mospilan), containing a cyanoimine functional group, were stable during the UV irradiation period. As expected, the degradation rate of the studied neonicotinoids increased significantly in the combined action of UV radiation and H₂O₂. In the case of thiacloprid and acetamiprid and their CFs, the reaction of the OH radicals formed and molecules of these insecticides was the major destruction pathway. The increased photodegradation efficiency of the UV/7.2Fe/TiO₂/H₂O₂ and vis/7.2Fe/TiO₂/H₂O₂ processes was attributed to the surface photoreduction of Fe³⁺ to Fe²⁺, which produces new OH radicals in the reaction with H₂O₂. In the presence of visible light, the efficiency may be partly due to the formation of the H₂O₂–TiO₂ complexes. For the 7.2Fe/TiO₂/H₂O₂ process in the presence of UV or visible radiation, no significant influence on the efficiency of photodegradation was observed in dependence of the structural differences of selected neonicotinoids. These results strongly suggest that highly reactive hydroxyl radicals, generated on the catalyst’s surface in the reaction involving H₂O₂, are responsible for this oxidation. In order to investigate degree of mineralization for all insecticides, TOC measurements were also conducted. Also, it was observed that the removal of pure AIs and their CFs by dark adsorption was almost negligible.

The main objective of this study was to evaluate residuals from 28 pharmaceuticals and three phthalate esters (PAEs) in drinking waters, which were stored and further purified in different manners. Samples of drinking water from two different supply networks in Taiwan were collected in two batches from two research institutes (i.e., sampling sites N and S) in this study. Each batch of sampling was conducted on one Friday afternoon and the next Monday morning. Water storage tanks used in these two sampling sites are composed of different materials. Sampling points at each sampling site included one tap water pipeline, five water storage tanks, and five drinking fountains. It was found that retention of drinking water in the storage tanks over the weekend would be beneficial to spontaneous degradation of pharmaceuticals and PAEs. The preliminary results also showed that city water might have dissolved DiNP from modular water tanks made of fiberglass-reinforced plastics, whereas no such evidence was observed for water tanks made of stainless steel. Furthermore, a trace amount of pharmaceuticals and PAEs still could be detected in city waters, even in drinking fountain water.

Magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were prepared by the facile citrate-gel thermal decomposition process. Their microstructure and magnetic properties were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX), and vibrating sample magnetometer (VSM). The as-prepared magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were characterized with about 8-nm grains, specific surface area of 119.3 m²/g, and magnetization of 38.7 Am²/kg. The adsorption kinetics and adsorption isotherms of methyl blue (MB) and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites at room temperature were investigated. Adsorption kinetics of MB and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites have been researched using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, the statistic results show that the pseudo-second-order kinetic model is fitted well to describe the MB and As(V) adsorption process. The adsorption equilibrium data of MB and As(V) onto the magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites at room temperature were analyzed with Langmuir, Freundlich, and Temkin models, and the adsorption isotherms was more effectively described by the Freundlich model based on the values of the correlation coefficient. Figure The magnetic 0.8Ni₀.₅Zn₀.₅Fe₂O₄/0.2SiO₂ nanocomposites were prepared by the citrate-gel thermal decomposition process. They show high adsorption capacities for methyl blue (MB) and arsenic(V) in aqueous solution, and the adsorption kinetics and isothermals were analyzed.