Magnetic biomonitoring techniques and in situ topsoil magnetic susceptibility measurements have been shown to be rapid, cost-effective, and useful methods for investigating roadside pollution. However, combustible vegetation in samples makes it very difficult to use them in high-temperature magnetic experiments although the thermal alteration of spontaneous magnetization is a fundamental magnetic property and can be used to identify reliably the magnetic minerals. Here, we report the first magnetic biomonitoring results of dust deposited on plant leaves along the Tateyama-Kurobe Alpine route at the highly protected Midagahara wetland areas of Mt. Tateyama in Toyama, Japan. In-field magnetic susceptibility from 15 sites (161 points) shows higher susceptibilities near the roadside. Dust deposited on the leaves of Sasa kurilensis, or dwarf bamboo, has been wiped off at 12 sites (64 samples) with a commercial ethanol wipe sheet or silica wool damped in ethanol and subjected to rock magnetic analyses. Thermomagnetic remanence curves and low-temperature behaviors for samples collected near the roadside using silica wool show clearly that the main magnetic mineral in the dust is partially oxidized magnetite. Further, detailed rock magnetic analyses and elemental analyses of leaves in the study area indicate that (a) the magnetic mineralogy on leaves’ surface is consistent throughout the study area and (b) higher saturation isothermal remanent magnetization intensities as well as higher concentrations of Pb, Fe, Cr, and Y are observed near the roadside, i.e., the closer to the roadside, the more anthropogenic materials, including partially oxidized magnetite, are present. Also, microscopic observations show the lack of spherical grains, indicating that dust on the roadside leaves is derived from passing vehicle rather than industrial process. Both rock magnetic and geochemical results show that S. kurilensis would be an excellent candidate for investigating air pollution. Also, the proposed wiping-off method of collecting dust from plant surfaces is an effective non-destructive method that can be applied even in highly restricted collection areas, because detailed magnetic mineralogy, including superparamagnetic minerals, could be determined with the use of silica wool for use in both high- and low-temperature experiments.

This paper reports on a study that investigated the aquatic toxicity of new non-ionic surfactants derived from renewable raw materials, polyoxyethylene glycerol ester (PGE), and their binary mixtures with anionic and non-ionic surfactants. Toxicity of pure PGEs was determined using representative organisms from different trophic levels: luminescent bacteria (Vibrio fischeri), microalgae (Pseudokirchneriella subcapitata), and freshwater crustaceans (Daphnia magna). Relationships between toxicity and the structural parameters such as unit of ethylene oxide (EO) and hydrophilic-lipophilic balance (HLB) were evaluated. Critical micellar concentration (CMC) in the conditions of the toxicity test was also determined. It was found that the toxicity of the aqueous solutions of PGE decreased when the number of EO units in the molecule, HLB, and CMC increased. PGEs showed lower CMC in marine medium, and the toxicity to V. ficheri is lower when the CMC was higher. Given their non-polar nature, narcosis was expected to be the primary mode of toxic action of PGEs. For the mixture of surfactants, we observed that the mixtures with PGE that had the higher numbers of EO units were more toxic than the aqueous solutions of pure surfactants. Moreover, we found that concentration addition was the type of action more likely to occur for mixtures of PGE with lower numbers of EO units with non-ionic surfactants (alkylpolyglucoside and fatty alcohol ethoxylate), whereas for the mixture of PGE with lower EO units and anionic surfactant (ether carboxylic derivative), the most common response type was response addition. In case of mixtures involving amphoteric surfactants and PGEs with the higher numbers of EO units, no clear pattern with regard to the mixture toxicity response type could be observed.

To reveal the seasonal variations and sources of PM₂.₅-bound polycyclic aromatic hydrocarbons (PAHs) during haze and non-haze episodes, daily PM₂.₅ samples were collected from March 2015 to February 2016 in a mixed multi-function area in Hangzhou, China. Ambient concentrations of 16 priority-controlled PAHs were determined. The sums of PM₂.₅-bound PAH concentrations during the haze episodes were 4.52 ± 3.32 and 13.6 ± 6.29 ng m⁻³ in warm and cold seasons, respectively, which were 1.99 and 1.49 times those during the non-haze episodes. Four PAH sources were identified using the positive matrix factorization model and conditional probability function, which were vehicular emissions (45%), heavy oil combustion (23%), coal and natural gas combustion (22%), and biomass combustion (10%). The four source concentrations of PAHs consistently showed higher levels in the cold season, compared with those in the warm season. Vehicular emissions were the most considerable sources that result in the increase of PM₂.₅-bound PAH levels during the haze episodes, and heavy oil combustion played an important role in the aggravation of haze pollution. The analysis of air mass back trajectories indicated that air mass transport had an influence on the PM₂.₅-bound PAH pollution, especially on the increased contributions from coal combustion and vehicular emissions in the cold season.

Two elementary schools (Shiuguang and Fongrong) from Yulin County in Taiwan, near a main area of potential exposure to Aeolian river-dust, were selected to collect outdoor and indoor PM₁₀ aerosols and to measure five metals in PM₁₀ (As, Ni, Cr, Cd, and Mn). Significant relationships (p < 0.01) were found between outdoor PM₁₀ concentrations at Lunbei’s air quality monitoring station and the two elementary schools. The outdoor PM₁₀ concentrations at the monitoring station and the schools’ indoor PM₁₀ concentrations also showed significant correlations. This study also established a relationship between the outdoor and indoor concentrations of PM₁₀ and metals in the schools. Estimations were made regarding students’ 8 h of exposure to metal concentrations from river-dust episodes during 1994–2012, based on correlation equations that were shown to be statistically significant.

A novel PCR-free DNA-based assay was developed for the detection of Vibrio spp. A sandwich hybridization format using an immobilized capture probe and a labeled signal probe was selected and combined with chemiluminescent method for the detection of the RNA target. In a first step, probes were validated using positive controls (PCs). A linearity was observed between 0.1 and 2.5 nM of PC, and detection limit was determined as 0.1 nM. In a second step, specificity was checked by using RNA extracted from a panel of 31 environmental bacterial strains. Detection limit of 5 ng μL⁻¹ of total fragmented RNA was obtained, and the assay allowed a good discrimination between the 21 Vibrio and the 10 non-Vibrio strains tested. Finally, the DNA-based assay was successfully applied to analysis of spiked and natural environmental samples. Stability and analysis time of the DNA-based assay were also investigated to optimize working conditions. We demonstrated that microplates can be coated beforehand with capture probe and stored at 4 °C without any buffer in wells for at least 30 days. The use of the pre-made plates enables the assay to be completed in 2 h. The developed assay appeared as an interesting tool to determine the presence of bacteria in environmental samples.

Veterinary antimicrobials are emerging environmental contaminants of concern. In this study, the sorption of enrofloxacin (ENR) onto humic acids (HAs) extracted from three Brazilian soils was evaluated. HAs were characterized by elemental analysis and solid ¹³C nuclear magnetic resonance spectroscopy. The sorption of ENR onto HAs was at least 20-fold higher than onto the soils from which they were separated. Ionic and cation bridging are the primary interactions involved. The interactions driven by cation exchange are predominant on HAs, which appear to have abundant carboxylic groups and a relatively high proportion of H-bond donor moieties with carbohydrate-like structures. Interactions explained by cation bridging and/or surface complexation on HAs are facilitated by moieties containing conjugated ligands, significant content of oxygen-containing functional groups, such as phenolic-OH or lignin-like structures. HAs containing electron-donating phenolic moieties and carboxylic acid ligand groups exhibit a sorption mechanism that is primarily driven by strong metal binding, favoring the formation of ternary complexes between functional groups of the organic matter and drugs.

The present work described that tertiary ammonium surfactants containing bromide ion as novel metal-free catalysts were innovatively coupled with peroxymonosulfate (PMS) to build a simple catalytic oxidation system, possessing outstanding catalytic ability with organic dye Reactive Red M-3BE (RR M-3BE) as the target pollutant. Furthermore, cetyltrimethylammonium bromide (CTAB), a representative of cationic surfactant, was selected to further investigate the catalytic oxidation performance. It is found that at the critical micelle concentration (CMC) of CTAB, the oxidation efficiency of the CTAB/PMS system was optimal due to the strong electrostatic attraction between the CTA⁺ micelle and reactive anions (Br⁻ and HSO₅ ⁻), concentrating HSO₅ ⁻ and Br⁻ at the micellar surface, which accelerated the catalytic oxidation reaction between Br⁻ and HSO₅ ⁻, generating a mass of highly active reactive species. A hybrid method that combined radical scavenger (methanol) with electron paramagnetic resonance (EPR) technology was adopted for the investigation of reactive species, and the results indicated that hydroxyl radical (•OH) was generated and had a major role in the process. The findings from this work provide a practicable pathway for highly efficient PMS activation in wastewater treatment, and also initiate a promising research area of surfactants in the field of environmental catalysis.

Insect repellents are widely applied to various materials and to both human and animal skin to deter mosquitoes and ticks. The most common deterrent compounds applied are DEET, EBAAP and icaridin (picaridin, Bayrepel). Due to their extensive application, these repellents are frequently detected in surface waters in considerable concentrations. As these compounds are designed to alter invertebrates’ behaviour rather than to intoxicate them, we hypothesised that insect repellents have the potential to modify the natural behaviour of non-target invertebrates in natural freshwater bodies. To test this, we used a well-established laboratory assay designed to quantify the odour-mediated foraging behaviour of freshwater gastropods and the great pond snail Lymnaea stagnalis (Linnaeus, 1758) as a model organism to test for potential deterrent effects of insect repellents on aquatic snails. Using a wide concentration range from the picogramme per litre to microgramme per litre range (and by far exceeding the range of concentrations reported from natural waters), we found no evidence for a deterrent effect of either of the three repellents on foraging L. stagnalis. Our data and other recent studies give no indication for undesirable behavioural alterations by common insect repellents in surface waters.

Atrazine and S-metolachlor are two of the most widely used herbicides for agricultural purposes; consequently, residues of both compounds and their metabolites had been detected in ground and superficial waters. Unlike atrazine, the complete degradation of metolachlor has not been achieved. Hence, the purpose of this research is to study the biodegradation of a commercial mixture of atrazine and S-metolachlor in a prototype of a multi-channel packed-bed-biofilm reactor (MC-PBR) designed with the aim of solving the problems of pressure drop and oxygen transfer, typically found on this type of bioreactors.Because the removal efficiency of the herbicides was increased when Candida tropicalis was added to the original microbial community isolated, the reactor was inoculated with this enriched community. The operational conditions tested in batch and continuous mode did not affect the removal efficiency of atrazine; however, this was not the case for S-metolachlor. The removal rates and efficiencies showed a notable variation along the MC-PBR operation.

Harmful algal blooms (HABs) are global threats to marine ecosystems, fisheries, and human health. Therefore, developing effective and accurate methods for identifying causative algae and monitoring seawater quality is urgent. However, traditional, microscopy-based methods are complex, inaccurate, and time-consuming. Here, we present a novel method for effective and sensitive detection of Chattonella marina using hyper-branched rolling circle amplification (HRCA) and HRCA-based strip test (HBST). The large subunit (LSU) ribosomal DNA (rDNA) D1–D2 region of C. marina was firstly sequenced to design a species-specific padlock probe (PLP). The HRCA reaction with two amplification primers and further HBST for C. marina was established. The optimized reaction conditions for HRCA were PLP concentration, 20 pM; ligation temperature, 65 °C; ligation time, 60 min; amplification temperature, 61 °C; and amplification time, 60 min. The developed HBST detection procedure involved HRCA reaction, test strip preparation, hybridization, coloration, and judgment of hybridization by the naked eye. Specificity and sensitivity of the established methods were validated. Moreover, the results showed that the established detection methods were specific and sensitive to C. marina. The detection limits of HRCA and HBST assays were 10 copies and 1 copy μL–¹ of plasmid with LSU rDNA of C. marina, which are of two and three respective magnitude orders higher than conventional PCR. Finally, the protocols were applied to the simulated field samples and the results showed that the developed HBST assay had higher detection sensitivity than HRCA and PCR. In conclusion, the methods presented in this study are promising for sensitive, intuitive, and specific detection of C. marina in field monitoring natural samples and may provide a good detection model for other harmful algae in the future.