The present study investigates the influence of calcination temperature on the properties and photoactivity of multi-element doped TiO₂. The photocatalysts were prepared by incorporating silver (Ag), fluorine (F), nitrogen (N), and tungsten (W) into the TiO₂ structure via the sol-gel method. Spectroscopic techniques were used to elucidate the correlation between the structural and optical properties of the doped photocatalyst and its photoactivity. XRD results showed that the mean crystallite size increased for undoped photocatalysts and decreased for the doped photocatalysts when calcination was done at higher temperatures. UV-Vis spectra showed that the absorption cut-off wavelength shifted towards the visible light region for the as-synthesized photocatalysts and band gap narrowing was attributed to multi-element doping and calcination. FTIR spectra results showed the shifting of OH-bending absorption bands towards increasing wave numbers. The activity of the photocatalysts was evaluated in terms of gaseous formaldehyde removal under visible light irradiation. The highest photocatalytic removal of gaseous formaldehyde was found at 88%. The study confirms the effectiveness of multi-element doped TiO₂ to remove gaseous formaldehyde in air by visible light photocatalysis and the results have a lot of potential to extend the application to other organic air contaminants.

Organochlorine pesticides (OCPs) were banned by the Stockholm Convention many years ago; however, they are still detected in the environment due to their high persistence, their current illegal use, and their import from countries where they have not been banned. We evaluated the serum concentrations of selected OCPs (hexachlorobenzene (HCB), β-hexachlorocyclohexanes (β-HCH), p,p′-dichlorodiphenyltrichloroethane (DDT) and its metabolite p,p′-dichlorodiphenyldichloroethylene (DDE) in a sample of Lebanese adults using gas chromatography coupled to an ion trap mass spectrometer detector. The mean concentrations of HCB, β-HCH, DDT, and DDE were 7.1, 8.6, 2.1, and 18.9 ng/g of lipids, respectively, and the major contributor among the four OCPs was DDE. The OCP levels in the present study were in general lower than the values observed in several countries worldwide and their concentrations at the 95th percentile were lower than the biomonitoring equivalents (BEs) excluding any appreciable health risk. We observed an inverse association between HCB concentrations and body mass index (BMI) as well as HCB, β-HCH, and DDE levels, and smoking habits. Milk consumption however was positively associated with an increased serum level of β-HCH. This study, which was the first to investigate OCP serum levels in a Lebanese population, provides a baseline to which future measurements can be compared.

Contamination of soils with cadmium (Cd) is a serious problem worldwide. Rice (Oryza sativa L.) is reported to accumulate relatively higher Cd contents in consumable parts and is considered a main source of Cd toxicity to humans from rice-derived products. The aim of this pot trial was to investigate the effect of foliar-applied iron (Fe) complexed with lysine on growth, photosynthesis, Cd concentration in plants, oxidative stress, and activities of antioxidants of rice in soil contaminated with Cd. Rice seedlings (30-day-old) were transferred to the soil, and after 2 weeks, different concentrations of Fe-lysine (0, 1.5, 3.0, 4.5, 6.0, and 7.5 mg L⁻¹) were applied as a foliar spray once in a week for 4 weeks and plant samples were taken after 10 weeks of growth in the soil under ambient conditions. Foliar supply of Fe-lysine complex significantly enhanced the plant height, dry weights of plants, concentration of chlorophyll, and gas exchange attributes in Cd-stressed rice. Fe-lysine decreased the Cd concentrations in plants while increasing the Fe concentrations in rice seedlings being maximum with Fe-lysine of 6.0 mg L⁻¹. Electrolyte leakage decreased while activities of key antioxidant enzymes increased with Fe-lysine compared to the control. According to the present results, Fe-lysine complex can effectively be used to reduce Cd concentrations in rice and probably in other crop species.

Arsenic (As) and lead (Pb) commonly co-exist with high concentrations in paddy soil mainly due to human activities in south of China. This study investigates the effect of ferrous sulfate (FeSO₄) amendment and water management on rice growth and arsenic (As) and lead (Pb) accumulation in rice plants. A paddy soil co-contaminated with As and Pb was chosen for the pot experiment with three FeSO₄ levels (0, 0.25, and 1%, on a dry weight basis) and two water managements (flooded, non-flooded). The concentrations of As and Pb in iron plaques and rice plants were determined. Application of FeSO₄ and non-flooded conditions significantly accelerated the growth of rice plants. With the addition of FeSO₄, iron plaques were significantly promoted and most of the As and Pb were sequestered in the iron plaques. The addition of 0.25% FeSO₄ and non-flooded conditions did not significantly change the accumulation of As and Pb in rice grains. The practice also significantly decreased the translocation factor (TF) of As and Pb from roots to above-ground parts which might have been aided by the reduction of As and Pb availability in soil, the preventing effect of rice roots, and the formation of more reduced glutathione (GSH). Flooded conditions decreased the Pb concentration in rice plants, but increased As accumulation. Moreover, rice grew thin and weak and even died under flooded conditions. Overall, an appropriate FeSO₄ dose and non-flooded conditions might be feasible for rice cultivation, especially addressing the As issue in the co-contaminated soil. However, further detailed studies to decrease the accumulation of Pb in edible parts and the field application in As and Pb co-contaminated soil are recommended.

Dissolved organic nitrogen (DON) is an important component of aquatic environment of which amount impacts water quality. Thus, removal of DON has attracted wide attention. At present, it is difficult for common coagulation to remove DON from the aquatic environment. The cationic polymers can help to improve the removal efficiency of DON to some extent, but the underlying mechanism of the ascension is not clear. In order to grasp its removal behavior and further improve the removal efficiency of DON in the future, we evaluated the effect of a hybridized coagulant of polyacrylamide with iron-based coagulant on removal of aquatic DON. A higher floc growth rate (119.82 μm/min) and recovery factors (26.96) were found in the hybrid coagulation. The parameters affecting the DON and the dissolved organic carbon (DOC) included the molar ratio of Zn to Fe (nZₙ/nFₑ), CPAM content, and molar ratio of OH to Fe (nOH/nFₑ): nZₙ/nFₑ had a larger influence in DON removal than CPAM content; CPAM had a larger influence in the DOC removal; nOH/nFₑ played a moderate effect between CPAM and nZₙ/nFₑ. Mutual effect of hybrid coagulants indicated the colloidal species to be helpful in enhancing DOC and DON removal. Other parameters affecting coagulation performance included the pH: the estimated maximum DON removal efficiency occurred at pH 6, DOC removal efficiency at pH 8. The above results found in this study showed that DON removal was affected by the ingredient and the species composition of the hybrid coagulant, and the water environmental parameter. The enhanced efficiency of DON removal in the presence of CPAM was mainly attributed to the increased adsorption-bridging and sweep-floc.

Commuting in urban environments accounts for a large fraction of the daily dose of inhaled air pollutants, especially in countries where vehicles have old technologies or run on dirty fuels. We measured black carbon (BC) concentrations during bus, walk and bicycle commutes in a Brazilian city and found a large spatial variability across the surveyed area, with median values between 2.5 and 12.0 μg m⁻³. Traffic volume on roadways (especially the number of heavy-duty diesel vehicles), self-pollution from the bus tailpipe, number of stops along the route and displacement speed were the main drivers of air pollution on the buses. BC concentrations increased abruptly at or close to traffic signals and bus stops, causing in-cabin peaks as large as 60.0 μg m⁻³. BC hotspots for the walk mode coincided with the locations of bus stops and traffic signals, whilst measurements along a cycle lane located 12 m from the kerb were less affected. The median BC concentrations of the two active modes were significantly lower than the concentrations inside the bus, with a bus/walk and bus/bicycle ratios of up to 6. However, the greater inhalation rates of cyclist and pedestrians yielded larger doses (2.6 and 3.5 μg on a 1.5-km commute), suggesting that the greater physical effort during the active commute may outweigh the reduction in exposure due to the shift from passive to active transport modes.

Although a growing number of epidemiological studies have been conducted on size-specific health effects of particulate matter in China, results remain inconsistent. In this study, we investigated acute effect of fine and coarse particular matter on cardiovascular hospital visits in Ningbo, China. We used generalized additive models to examine short-term effects of PM₂.₅ and PM₁₀–₂.₅ on cardiovascular hospital visits by adjustment for temporal, seasonal, and meteorological effects. Subgroup analyses were conducted by age, sex, and season. We also examined the stability of their effects in multi-pollutant models. We found that PM₂.₅ were associated with cardiovascular hospital visits (RR = 1.006; 95% CI 1.000, 1.011) and results remained similar after adjustment for PM₁₀–₂.₅ (RR = 1.005; 95% CI 0.998, 1.013). There was a borderline association between PM₁₀–₂.₅ and cardiovascular hospital visits (RR = 1.007; 95% CI 0.997, 1.016), which disappeared after controlling for PM₂.₅ (RR = 1.000; 95% CI 0.988, 1.013). The associations appeared to be stronger in the cold season and among the elderly (≥ 75 years). The findings of this study suggested significant adverse effects of PM₂.₅, but no independent effects of PM₁₀–₂.₅ on cardiovascular hospital visits. Additional studies are needed to confirm these findings.

Urbanization is responsible for numerous environmental changes including pollution. Information on the susceptibility of reptiles to environmental contaminants is relatively scarce. Tropidurus torquatus represents a potential bioindicator of heavy metal pollution. Levels of heavy metals in tissues from T. torquatus depend on bioavailability and vary among different populations. The aim of this study was to determine the heavy metal concentration in liver and fat tissue of T. torquatus from three distinct populations in the state of Espírito Santo, Brazil. The study areas included coastal rocky outcrops, dunes, and mountain rocky outcrops; each area had a different climate, vegetation, and level of anthropogenic influence. Fifty-one individuals were captured. Biometrics and sexes were determined, and stomach contents were identified. The tissue samples were digested with nitric acid and analyzed via inductively coupled plasma optical emission spectrometry (ICP-OES) for aluminum (Al), arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), copper (Cu), lithium (Li), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), strontium (Sr), titanium (Ti), vanadium (V), and zinc (Zn) contents. The concentration of zinc in Tropidurus torquatus was higher in liver than in fat tissue (432 ± 1380 mg kg⁻¹), and that of aluminum was higher in fat tissue (765 ± 1455 mg.kg⁻¹). The animals’ diet may be related to heavy metal contamination. The study suggests that T. torquatus could be used for soil biomonitoring with liver as a bioindicator for aluminum contamination and fat tissue as a bioindicator for zinc contamination. Graphical abstract ᅟ

Lead (Pb) remains classified as a priority pollutant. Zygophyllum fabago is considered an early colonizer of heavy metal-polluted soils under semiarid conditions, but physiological mechanisms underlying this colonizing capacity remain unclear. In order to characterize Z. fabago plants’ performance on Pb-contaminated soils, we evaluated how Pb influenced root and shoot growth, carbon metabolism, and oxidative status. For that, 30-day-old seedlings from one population colonizing a mine tailing (“Mercader”) at Murcia (southeast Spain) were exposed to 500-μM Pb(NO₃)₂ for 1 week. Results showed that this high dose of Pb induced no plant mortality nor senescence, though promoting plant nanism. Besides the efficiency of roots to accumulate Pb, shoots also demonstrate a high efficiency to translocate and accumulate this metal. Pb exposure decreased Zn uptake to the aerial part and reduced net photosynthetic rate (A), RuBisCO activity, chlorophyll, and soluble sugar contents in shoots. Moreover, in shoots, Pb exposure increased the levels of O₂⁻ and decreased antioxidant capacity, culminating with a loss of cell membrane integrity (electrolyte leakage) and increased protein oxidation. Compared to controls, exposed roots had less Mn and Zn levels, and despite the rise in H₂O₂ levels, they were able to modulate non-protein thiols presenting a robust defense capacity. This capacity may support the roots’ ability to maintain cell membrane integrity (electrolyte leakage) with regard to control. Principal component analysis (PCA) contributed to elucidate how this species adjusts physiological mechanisms to cope with Pb toxicity, showing that roots and shoots evolved different antioxidant defenses, which demonstrates the importance of organ specificity in the response of Z. fabago to heavy metals.