The immobilized algae Sargassum vulgare was used as biosorbent for Fe³⁺ removal through a batch and continuous system in order to study the biosorption capacity and to establish a new method of the valorization of this waste. The kinetic data could be described by the pseudo first-order and pseudo second-order kinetic models. The batch equilibrium was fitted by the Langmuir model with a value of correlation coefficient (R² = 0.98) higher than that of the Freundlich (R² = 0.89). The process was exothermic and spontaneous and the biomass was successfully desorbed using 0.1 M HCl. Furthermore, the Thomas model, Bohart-Adams model, and Yoon-Nelson model were successfully applied to evaluate the dynamic behavior of Fe³⁺ biosorption in a fixed-bed column. The lower flow rate of 1.04 ml/min showed the greater performance of the process. Fourier transform infrared spectroscopy revealed the presence of several active binding sites, and scanning electron microscopy micrograph confirmed the metal adsorption on the surface. The results reveal that the immobilized algae have a potential removal for Fe³⁺ in a batch and continuous system.

The fact that hairdressers are exposed to toxic substances through the handling of creams and smoothing products prompted this study whose aim was to quantify the occupational exposure of hairdressers to formaldehyde by comparing the results of exposure for different types of beauty salon. The study population consisted of 23 beauty salons located in the city of Bauru, São Paulo state, Brazil. The samples were collected by inhaled air tests during the most critical 15-min period of the hair straightening procedure and during the 8-h work shift. The concentrations of formaldehyde contained in the formulations of these products were also evaluated and compared with exposure levels. The results were evaluated according to the exposure limits prescribed in Brazilian (NR15) and North American (US OSHA and US NIOSH) standards. The analysis of the smoothing products showed concentrations of formaldehyde of between 3 and 11% in their compositions, i.e., up to 54 times above the 0.2% limit allowed by the National Agency of Sanitary Surveillance (ANVISA). The present study showed that hairdressers are chronically exposed to high concentrations of formaldehyde in the workplace and these exposures are mainly associated with the work process, where many variables of this process influence the intensity of exposure.

The objective of this study was to investigate whether δ¹³C values can be used to identify pollen specie in the atmosphere. A Burkard 7-day recording volumetric spore trap was used to collected pollens in the atmosphere in Tainan City, Taiwan, from January 2 to December 28, 2006, and a light microscope was used to identify the pollen species and concentrations. A Burkard cyclone sampler was used to collect particulate matter and an elemental analyzer with an isotope ratio mass spectrometer was used to analyze the δ¹³C values. Our data showed that the predominate pollen specie in the atmosphere was Broussonetia papyrifera pollen and that the annual average concentration was 27 grains/m³ (pollen season, 36; nonpollen season, 9 grains/m³). The average δ¹³C value was − 26.19‰ for particulate matter in the atmosphere (pollen season, − 26.00‰; nonpollen season, − 26.28‰). No significant association was observed between δ¹³C values and Broussonetia papyrifera pollen concentrations. However, the δ¹³C value in the atmosphere was associated with the levels of Broussonetia papyrifera pollen among the samples with a diameter of particulate matter smaller than 10 μm at a level lower than 40 μg/m³. In addition, the relative contribution of Broussonetia papyrifera pollen to the carbon in the atmosphere using a two end-member mixing models was found to be associated with the Broussonetia papyrifera pollen concentration. In summary, our study suggested that δ¹³C values can be applied in the assessment of Broussonetia papyrifera pollen specie under specific conditions in the atmosphere.

The endophytic bacteria live in close nuptial relationship with the host plant. The stress experienced by the plant is expected to be transferred to the endophytes. Thus, plants thriving at polluted sites are likely to harbor pollutant-degrading endophytes. The present study reports the isolation of phenylurea herbicides assimilating Bacillus sps. from Parthenium weed growing at diuron-contaminated site. The isolated endophytes exhibited plant growth–promoting (PGP) activities. Among five isolated diuron-degrading endophytes, the most efficient isolate Bacillus licheniformis strain SDS12 degraded 85.60 ± 1.36% of 50 ppm diuron to benign form via formation of degradation intermediate 3, 4-dichloroaniline (3,4-DCA). Cell-free supernatant (CFS) obtained after diuron degradation by strain SDS12 supported algal growth comparable with the pond water. The chlorophyll content and photosynthetic efficiency of green algae decreased significantly in the presence of diuron-contaminated water; however, no such change was observed in CFS of strain SDS12, thus, suggesting that strain SDS12 can be applied in aquatic bodies for degrading diuron and reducing diuron toxicity for primary producers. Further, the use of PGP and diuron-degrading bacteria in agriculture fields will not only help in remediating the soil but also support plant growth.

In this study, a sensitive and low-cost multi-wavelength spectrophotometric method for the determination of hydrogen peroxide (H₂O₂) in water was established. The method was based on the oxidative coloration of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) via Fenton reaction, which resulted in the formation of green radical (ABTS•⁺) with absorbance at four different wavelengths (i.e., 415 nm, 650 nm, 732 nm, and 820 nm). Under the optimized conditions (CABTS = 2.0 mM, CFₑ²⁺ = 1.0 mM, pH = 2.60 ± 0.02, and reaction time (t) = 1 min), the absorbance of the generated ABTS•⁺ at 415 nm, 650 nm, 732 nm, and 820 nm were well linear with H₂O₂ concentrations in the range of 0–40 μM (R² > 0.999) and the sensitivities of the proposed Fenton-ABTS method were calculated as 4.19 × 10⁴ M–¹ cm–¹,1.73 × 10⁴ M–¹ cm–¹, 2.18 × 10⁴ M–¹ cm–¹, and 1.96 × 10⁴ M–¹ cm–¹, respectively. Meanwhile, the detection limits of the Fenton-ABTS method at 415 nm, 650 nm, 732 nm, and 820 nm were respectively calculated to be 0.18 μM, 0.12 μM, 0.10 μM, and 0.11 μM. The absorbance of the generated ABTS•⁺ in ultrapure water, underground water, and reservoir water was quite stable within 30 min. Moreover, the proposed Fenton-ABTS method could be used for monitoring the variations of H₂O₂ concentration during the oxidative decolorization of RhB in alkali-activated H₂O₂ system.

Cadmium (Cd) phytoextraction efficiency basically depends on Cd accumulation in their tissues. Thus, our aim in this study was to select biochemical, morpho-physiological, nutritional, and productive responses associated to Cd accumulation in the roots, stems and sheaths, and leaf blades of Panicum maximum cv. Massai (Massai grass), using the random forests analysis. Massai grass was exposed to combinations of three sulfur (S) concentrations (0.1, 1.9, and 3.7 mmol L⁻¹) and two Cd concentrations (0.0 and 0.1 mmol L⁻¹) in nutrient solutions. The dry biomass production of Massai grass exposed to Cd decreased by around 50% in relation to control. However, there were no visual symptoms of Cd toxicity in the shoot of this plant, even with Cd concentrations in their shoot exceeding 100 mg kg⁻¹ DW. The lowest dry biomass production of the plants exposed to Cd combined with the absence of visual symptoms of Cd toxicity indicates us that Massai grass is a bioindicator plant that can greatly cope with the Cd-induced stress, but in a little bit different way from other plants. Antioxidant enzymes apparently are not essential for Massai grass cope with Cd-induced stress, differently of other mechanisms (e.g., higher synthesis of thiol compounds and amino acids involved on reactive oxygen species (ROS) scavenging and Cd chelation). Probably, the plant responses that most explained Cd accumulation in Massai grass can be used to identify grasses with high capacity to accumulate Cd in phytoremediation programs with this group of plants.

In recent years, China has constantly strengthened environmental regulation (ER) to force the manufacturing industry to upgrade. This study theoretically analyzes interaction mechanism of ER on the upgrading of manufacturing industry through foreign direct investment (FDI) and technological innovation (TI) and carries out empirical verification by using provincial panel data from 2000 to 2016 in China. The results demonstrate that the current ER intensity in China is unable to directly promote the upgrading of manufacturing industry, while through the interaction effects of FDI and TI do boost the upgrading of the industry. The above mechanisms are also robust even if we take the regional heterogeneity into consideration. Basic education and urbanization are favorable for the upgrading of the manufacturing industry. However, the increase in dependence on foreign trade is not conducive to upgrading manufacturing industry. Chinese government should further strengthen ER and give full play of the interaction mechanism of ER to guide the flow of foreign investment and force enterprises to carry out TI. In the meanwhile, Chinese government also needs to ensure balanced regional development, thus better promoting the upgrading of manufacturing industry.

The aim of this study was to evaluate the acute and chronic effects caused by exposure to the 2,4 dichlorophenoxyacetic acid (2,4-D)-based commercial herbicide Amina Zamba® on Physalaemus albonotatus tadpoles from Gosner stage 25. The lethal concentration (LC50) was determined after exposure to different concentrations of Amina Zamba® (350 to 2400 mg/L) at 96 h. Sublethal effects were evaluated after chronic exposure to four fractions of the LC50₉₆ₕ obtained (12.5, 25, 50, and 75% of LC50₉₆ₕ) and a control. The biological responses analyzed included survival, growth and development, morphological abnormalities, and histological changes in the liver. The LC50 values of Amina Zamba® at 48, 72, and 96 h were 1040.2, 754.2, and 350 mg/L, respectively. The chronic exposure to the herbicide altered the survival of exposed tadpoles and caused several morphological abnormalities and liver histological alterations, mainly at the highest concentrations tested. Oral disc malformations and intestinal abnormalities were the most frequent abnormalities in all treated tadpoles. Histological alterations observed in the liver structure included hepatocyte vacuolization, enlargement of sinusoids, dilation of blood vessels, and a significant increase in the number of melanomacrophages in tadpoles exposed to 25, 50, and 75% LC50₉₆ₕ with respect to control (P < 0.05). Furthermore, the treated tadpoles showed an accelerated development rate, reaching Gosner stages 38 and 42 before controls. These results demonstrate that the chronic exposure to this commercial formulation affects the survival, accelerates metamorphosis, and induces morphological abnormalities and liver damage in P. albonotatus tadpoles.

Since nitrosamine disinfection by products is highly carcinogenic, they have attracted considerable attention due to their increased presence in ambient waterways and potable water supplies. For the present study, the potential formation of nitrosamines from corresponding precursor secondary amines during ozonation was investigated. The results revealed that five nitrosamines were observed during the ozonation of their corresponding secondary amines. The molar yields initially increased and then decreased with longer contact times and higher ozone doses. These phenomena indicated that ozone not only promoted nitrosamine formation but also degraded the formed nitrosamines. High pH had a positive influence on nitrosamine formation at room temperature. Further, coexisting substances including nitrate, nitrite, humic acid, and tert-butanol inhibited the generation of nitrosamines due to hydroxyl radical (·OH) competition and scavengers, whereas in the presence of hydroxylamine, nitrosamine formation increased considerably without ozone due to its capacity for independent formation between secondary amines and hydroxylamine. Further, the generation of nitrosamines from secondary amines was primarily attributed to O₃ and ·OH oxidation, which was produced through the decomposition of ozone. The transformation pathways were mainly comprised of the indirect routes between the O₃/·OH intermediates. The findings of this study were helpful toward expanding the knowledge of nitrosamine formation during the corresponding precursor secondary amine ozonation process.

²²²Rn, ²²⁰Rn, and their decay products are significant contributors to background radiation dose. Their concentration level, pertaining exposure, and consequent dose are prime concerns in indoor environments. The present study was performed in 101 dwellings of different villages of Almora district situated in Kumaun hills of Indian Himalayan belt. Measurement of gases and decay products were made in three different types of dwellings (i.e., mud, cemented, and stone with plaster) in three seasons (winter, summer, and rainy). Concentration values for ²²²Rn and EERC were found to be varying in the order of winter > summer > rainy while obtained least in rainy season for the case of ²²⁰Rn and EETC. Concentration values for ²²²Rn and EERC were found to be lesser for cemented houses. Relative standard deviation of concentration values was found to be higher for the rainy season. Yearly averaged concentration values for ²²²Rn, EERC, ²²⁰Rn, and EETC were noted to be higher than the global averages but comparable to some Indian studies. Annual inhalation dose due to ²²²Rn, ²²⁰Rn, and their progeny was found to be 0.55–4.71 mSv/year with an average value of 2.36 ± 0.83 mSv/year. These values were measured for the first time in the study area and provide a link for future studies in the dwellings representing higher concentration values.