The widespread occurrence of organophosphorus pesticides (OPPs) in the environment poses risks to both ecologic system as well as human health. This study investigated the oxidation kinetics of chlorpyrifos (CP), one of the typical OPPs, by thermoactivated persulfate (PS) oxidation process, and evaluated the influence of key kinetic factors, such as PS concentrations, pH, temperature, bicarbonate, and chloride ions. The reaction pathways and mechanisms were also proposed based on products identification by LC-MS techniques. Our results revealed that increasing initial PS concentration and temperature favored the decomposition of CP, whereas the oxidation efficiency was not affected by pH change ranging from 3 to 11. Bicarbonate was found to play a detrimental role on CP removal rates, while chloride showed no effect. The oxidation pathways including initial oxidation of P=S bond to P=O, dechlorination, dealkylation, and the dechlorination-hydroxylation were proposed, and the detailed underlying mechanisms were also discussed. Molecular orbital (MO) calculations indicated that P=S bond was the most favored oxidation site of the molecule. The toxicity of reaction solution was believed to increase due to the formation of products with P=O structures. This work demonstrates that OPPs can readily react with SO₄ ·⁻ and provides important information for further research on the oxidation of these contaminants.

The environmental influence of biomass burning for civil uses was investigated through the determination of several air toxicants in the town of Leonessa and its surroundings, in the mountain region of central Italy. Attention was focussed on PM₁₀, polycyclic aromatic hydrocarbons (PAHs) and regulated gaseous pollutants (nitrogen dioxide, ozone and benzene). Two in-field campaigns were carried out during the summer 2012 and the winter 2013. Contemporarily, air quality was monitored in Rome and other localities of Lazio region. In the summer, all pollutants, with the exception of ozone, were more abundant in Rome. On the other hand, in the winter, PAH concentration was higher in Leonessa (15.8 vs. 7.0 ng/m³), while PM₁₀ was less concentrated (22 vs. 34 μg/m³). Due to lack of other important sources and to limited impact of vehicle traffic, biomass burning was identified as the major PAH source in Leonessa during the winter. This hypothesis was confirmed by PAH molecular signature of PM₁₀ (i.e. concentration diagnostic ratios and 206 ion mass trace in the chromatograms). A similar phenomenon (i.e. airborne particulate levels similar to those of the capital city but higher PAH loads) was observed in other locations of the province, suggesting that uncontrolled biomass burning contributed to pollution across the Rome metropolitan area.

To identify the effect of chlorine dosage in prechlorination on the formation of disinfection by-products during drinking water treatment process, the relationship between chlorine dosage and concentrations of THMs and HAAs was analyzed. Furthermore, the variation about the ratio of THMs/HAAs was also analyzed. The results indicated that concentrations of THMs and HAAs would rise with the increase of chlorine dosage, and TCM was the main product of four THMs, while DCAA and TCAA were the primary products of five HAAs. Moreover, the ratio of THMs to HAAs rose with the chlorine dosage increase. Thus, chlorine dosage in prechlorination had a significant impact on THMs and HAAs and should be controlled effectively.

Pollution due to oil exploration activities in the Niger Delta region of Nigeria and government under-investments in potable water infrastructure has led to the dependence of the population on personal boreholes. Yet, there are little quality or surveillance reports on such waters. The concentrations of heavy metals in underground water samples from an oil producing area, Umuebulu, in the Niger Delta were therefore investigated. Water samples were collected from three test points, each approximately 300 m from (1) wellhead area (WHA), (2) flare area (FA) and (3) effluent discharge area (EDA), and one control point located 10 km away from any oil-related activity. The concentrations of lead, arsenic and cadmium were determined in the samples using atomic absorption spectrophotometry. All three heavy metals were present in the test, and control water samples at concentrations significantly (P < 0.05) exceeding the maximum contaminant levels recommended by the World Health Organization. The total hazard index of the water samples showed that their consumption constituted significant health risks in the order EDA > FA > WHA > Control. Appropriate water treatment and surveillance is warranted and therefore recommended for underground water resources of the studied community.

The present study was carried out to determine the efficacy of root foraging and the physiological response of Vallisnaria natans grown in heterogeneous sediments. V. natans was cultivated in two homogeneous and two heterogeneous sediments. The results suggested that V. natans grown in heterogeneous sediments presented a significantly higher root proportion in its total biomass, exhibited root foraging, and grew well, as indicated by a total biomass, ramet number, and plant height very close to those of plants grown in nutrient-rich clay sediment. Moreover, the more sensitive physiological response of the roots than the stems or the leaves to sediment nutrients suggested that root foraging occurred, and the approached values between the two heterogeneous sediments and the homogeneous clay sediment indicated that V. natans could satisfy its nutrient requirements via root foraging. The results may be useful in the recovery of macrophytes that remodel part (rather than all) of the substrate and can potentially improve habitats that are unsuitable for plant growth.

Continuous and simultaneous measurements of ammonia gas (NH₃) and fine particulate ammonium (PM₂.₅NH₄ ⁺) were performed in two distinct urban areas: Osaka, Japan, and Ho Chi Minh City (HCMC), Vietnam. Measurements were performed using a new online instrument. Two measurement periods were conducted during February 11–March 12, 2015 (cold period), and July 1–September 14, 2015 (warm period), at the urban site in Osaka, while 17 days of measurements, from May 21 to June 8, 2015, were conducted at the urban site in HCMC. The average NH₃ concentration at the HCMC site was much higher than that at the Osaka site. The differences in the NH₃ levels between the two cities are a result of their different emission sources. Traffic emission is a significant contributor to the NH₃ levels within the urban area in Osaka. Conversely, the contribution of traffic emission to the NH₃ levels in the HCMC urban area is negligible. With a population of around 8.5 million people living in the urban area of HCMC, the high NH₃ level is due to human sources and poor waste management systems, especially because of the high temperature (30 °C) and dense population of the city (density up to 42,000 inhabitants per km²). In contrast to the NH₃ levels, the highest PM₂.₅NH₄ ⁺ level occurred during the cold period at the Osaka site, and the average level at this site was higher than that at the HCMC site. The availability of atmospheric acids, low temperature, and high humidity facilitates the formation of ammonium. Our results indicate that NH₃ plays a key role in secondary inorganic aerosol formation; therefore, it contributes to a significant amount of PM₂.₅ at the Osaka site. In contrast, the high levels of PM₂.₅ observed at the HCMC site are likely from road traffic emission, mainly motorcycles, rather than secondary inorganic aerosol formation.

This study, for the first time, presents the results of activity concentration determinations for ¹³⁷Cs and ⁴⁰K in a high number (21 species, 87 composite samples, and 807 fruiting bodies) of mushrooms of the genus Boletus from across Yunnan in 2011–2014 and Sichuan (Boletus tomentipes) using high-resolution high-purity germanium detector. Activity concentrations of ¹³⁷Cs demonstrated some variability and range from <4.4 to 83 ± 3 Bq kg⁻¹ dry biomass in caps and from <3.8 to 37 ± 3 Bq kg⁻¹ dry biomass in stipes, and of ⁴⁰K, respectively, from 420 ± 41 to 1300 ± 110 and from 520 ± 61 to 1300 ± 140 Bq kg⁻¹ dry biomass. No significant variations were observed regarding ¹³⁷Cs and ⁴⁰K activity concentrations among the same Boletus species from different sampling sites. No activity concentrations from ¹³⁴Cs were detected in any mushrooms. Internal dose rates estimated were from intake of 1 kg of mushrooms per annum for ¹³⁷Cs range for species and regions from around <0.0031 to 0.047 ± 0.003 μSv, while those for ⁴⁰K were from around 0.22 ± 0.04 to 1.2 ± 0.1 μSv. The overall intake of ¹³⁷Cs was low since low contamination was found in Boletus species.

A series of V₂O₅/TiO₂-carbon nanotube (CNT) catalysts were prepared and tested to decompose gaseous 1,2-dichlorobenzene (1,2-DCBz). Several physicochemical methods, including nitrogen adsorption, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and H₂ temperature-programmed reduction (TPR) were employed to characterise their physicochemical properties. To better understand the effect of CNT properties on the reactivity of V₂O₅/TiO₂-CNT catalysts, the 1,2-DCBz residue remaining in the off-gas and on the catalyst surface were both collected and analysed. The results indicate that the outer diameter and the surface functional groups (hydroxide radical and carboxyl) of CNTs significantly influence upon the catalytic activity of CNT-containing V₂O₅/TiO₂ catalysts: the CNT outer diameter mainly affects the aggregation of CNTs and the π-π interaction between the benzene ring and CNTs, while the introduction of –OH and –COOH groups by acid treatment can further enlarge specific surface area (SSA) and contribute to a higher average oxidation state of vanadium (V ₐₒₛ) and supplemental surface chemisorbed oxygen (Oₐdₛ). In addition, the enhanced mobility of lattice oxygen (Oₗₐₜₜ₎ also improves the oxidation ability of the catalysts.

Abscisic acid (ABA) regulates much important plant physiological and biochemical processes and induces tolerance to different stresses. Here, we studied the regulation of exogenous ABA on adaptation of rice seedlings to simulated acid rain (SAR) stress by measuring biomass dry weight, stomatal conductance, net photosynthesis rate, nutrient elements, and endogenous hormones. The application of 10 μM ABA alleviated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and decreases in contents of nutrient (K, Mg, N, and P) and hormone (auxin, gibberellins, and zeatin). Moreover, 10 μM ABA could stimulate the Ca content as signaling molecules under SAR stress. Contrarily, the application of 100 μM ABA aggravated the SAR-induced inhibition on growth, stomatal conductance, net photosynthesis rate, and contents of nutrient and hormone. The results got after a 5-day recovery (without SAR) show that exogenous 10 μM ABA can promote self-restoration process in rice whereas 100 μM ABA hindered the restoration by increasing deficiency of nutrients and disturbing the balance of hormones. These results confirmed that exogenous ABA at proper concentration could enhance the tolerance of rice to SAR stress.