Irrigation with reclaimed water and soil amendment with sewage sludge are becoming common practices in arid and semiarid areas. When wastewater treatments do not efficiently remove all the contaminants, these contaminants can later end up in agricultural soils. These contaminated soils are a potential source of surface and groundwater pollution by leaching and runoff. In the present work, we assessed the behavior of alcohol sulfates (AS) in agricultural soil. For the experimental work, a tract of soil was irrigated with linear alcohol sulfates with 12–18 hydrocarbon chain and subsequently tested for AS concentration from November 2014 to July 2015. The highest concentrations of AS were found at the top layer of soil (29.80 to 6.23 mg kg⁻¹). The adsorption rate and the amount of surfactant adsorbed increased as the length of the hydrocarbon chain increases. AS homologues can leach up to 60 cm. A mathematical model was applied to predict the environmental behavior of AS in the agricultural soils studied. Disappearance rate constant (k) values for AS homologues were between −5.10·10⁻³ and −1.68·10⁻² h⁻¹, and average half-life values were between 37 and 135 h. Coefficients of determination (R ²) between 92.4 and 99.1% showed that the proposed model satisfactorily describes the experimental results. The present study provides a conceptual framework and essential parameters for predicting and understanding the environmental behavior of AS in agricultural soils. Graphical Abstract Behavior of alcohol sulfates in agricultural soils. A seasonal field study

Strategies for management of damaged environments can benefit from understanding of how early petrochemical pollution affect living organisms. One of the general responses to environmental stress in plants is mediated by the regulatory network of heat shock proteins (HSP). Arabidopsis thaliana is a model plant for genetic studies, and laboratory experiments with this species might be informative for predicting analogous responses to toxicants in other species. Here, Arabidopsis seedlings were exposed to time-varying contamination (up to 24 h) with the water soluble fraction of MF380 marine fuel (WSF-MF380). An accurate estimation of expression differences in HSP genes was obtained by real-time quantitative polymerase chain reaction (qPCR). After a thorough selection and validation of reference genes, two gene pairs were found to be stably expressed across control and WSF-MF380-treated samples and were used as normalization factors. Next, we evaluated the normalized expression of five HSP genes in response to the time-varying WSF-MF380 contamination. Four HSPs presented a significant increase in gene expression, which suggests that they might be tested as biomarkers for early exposure to petrochemical compounds. While a nearly immediate response (3 h after contamination) was found for HSP90.1 and two small HSP genes localized in the mitochondria (sHSP23.5 and sHSP26.5), a slightly later response (20 h) was observed for a third small HSP with a cytoplasmic/nuclear localization (sHSP18.2). Overall, these expression changes suggest the existence of a genetic cross-talk between canonical regulatory networks of HSPs and the cellular response to non-heat stress factors, such as marine oil contamination.

Mesoporous silica with wormhole framework structure (HMS-OH) and its amine-functionalized material (HMS-NH₂) were prepared through an electrically neutral assembly pathways, post-grafting process of 3-aminopropyltriethoxysilane (APTES), respectively. Their adsorption behaviors toward cationic dyes as well as heavy metal ions in aqueous system and the capture capacities for CO₂ molecules all have been investigated. As-synthesized HMS-OH showed a high removal efficiency and rapid sorption rate to cationic dyes because of large surface area and versatile pore structure. HMS-NH₂ exhibited better heavy metal ions and more CO₂ gas sorption capacities due to the intrinsic property of amine groups grafted on the surface. The adsorption isotherms of methylene blue (MB) onto HMS-OH, Cu(II) onto HMS-NH₂ were fitted with Langmuir model and kinetic processes followed well the pseudo-second order pattern. There results revealed that both HMS-OH and HMS-NH₂ had a potential application in the treatment of cationic dyes, heavy metal ions, and greenhouse gas CO₂.

The electrochemical oxidation (ECO) of carbamazepine (CBZ), an antiepileptic drug, has been carried out in this study. A response surface methodology approach (RSM) was used in order to optimize the treatment process for CBZ removal on synthetic effluent. Four different operating parameters (current intensity, treatment time, recycling flow rate, and anode type) were chosen as key factors while a single response (CBZ removal) was considered. In the first part of the study, a factorial design (FD) methodology was carried out in order to evaluate the effects and interactions between the selected factors. Results showed that anode type is the most important parameters affecting CBZ degradation (with 67% of the overall effect) followed by the treatment time, the current intensity, and then the recirculation flow rate. Subsequently, a central composite design (CCD) was conducted in order to optimize the overall process taking into account efficiency (CBZ removal) and energy consumption. The contribution of direct and indirect effects of CBZ electro-oxidation was also investigated. As expected, direct oxidation was the most dominant mechanism during ECO with approximately 66% whereas indirect oxidation contributed with only 12%. Finally, the determined optimal conditions were applied on real pharmaceutical wastewater. Despite the effect matrix, 84% of CBZ was obtained after only 100 min of treatment with 23% of mineralization. Finally, CBZ by-products such as salicylic acid, catechol, and anthranilic have been detected during the oxidation process.

Inter-basin water transfer and source water switching will be increasingly launched due to significant population increase and the shortage of the local water resources in cities around the world. Source water switch may cause physiochemical and microbiological de-stabilization of pipe material, biofilms, and loose deposits in drinking water distribution system (DWDS). Great sulfate alteration during source water switch had been deemed as the main cause of a red water case that occurred in a northern China city. To ascertain the relationship between water quality changing and bacterial communities of biofilms in DWDS and possible bacteria risk in a red water case, water quality changing experiments in simulated DWDSs were conducted for approximately 2 years. Twenty-five corrosion scale samples and eight water samples collected from pipe harvest sites or during experimental periods were analyzed for their bacterial community composition by 454-pyrosequencing technology. Taxonomy results together with redundancy analysis (RDA) or canonical correspondence analysis (CCA) and hierarchical cluster analysis all indicated that bacterial community of samples with groundwater (GW) or surface water (SW) supply history and their variations under high sulfate water were rather different owing to different water source histories and the original pipe scale characteristics. Potential opportunistic pathogens: Burkholderia, Escherichia-Shigella, Mycobacterium, Serratia, Ralstonia, Novosphingobium, Flavobacterium, Sphingomonas, and Sphingopyxis were observed in scale or water samples.

A standard method for the detection and isolation of microplastics is required to adequately investigate plastic ingestion by juvenile fish. Dissections of juvenile fish guts require precise handling, which can affect the processing time if sample numbers are high. To investigate the efficacy of nitric acid (HNO₃) in aiding the isolation of microplastics using whole fish, we digested juvenile glassfish, Ambassis dussumieri (Cuvier, 1828), at room temperature and at 80 °C. For a complete digestion, overnight incubation in 10 mL of 55% analytical-reagent (AR) HNO₃ was sufficient for a whole fish of 1 g at room temperature. When coupled with elevated temperature, the digestion time is shortened to a few minutes and larger fish of 3 g can be digested in 30 min. Four of the five types of plastic survived the process, with nylon being the exception. This is a shortfall to the method; however, until a better method replaces it, we still value the use of HNO₃ for its simple, inexpensive, swift and complete digestions of whole fish. Four fish species from two feeding guilds were digested using this method to validate its use. The number of plastic particles ingested did not differ between benthic and pelagic species and microplastic fibres comprised the majority of the plastic types found.

The objective of this research was to evaluate the biodegradation of chloroform by using biotrickling filter (BTF) and determining the dominant bacteria responsible for the degradation. The research was conducted in three phases under anaerobic condition, namely, in the presence of co-metabolite (phase I), in the presence of co-metabolite and surfactant (phase II), and in the presence of surfactant but no co-metabolite (phase III). The results showed that the presence of ethanol as a co-metabolite provided 49% removal efficiency. The equivalent elimination capacity (EC) was 0.13 g/(m³ h). The addition of Tomadol 25-7 as a surfactant in the nutrient solution increased the removal efficiency of chloroform to 64% with corresponding EC of 0.17 g/(m³ h). This research also investigated the overall microbial ecology of the BTF utilizing culture-independent gene sequencing alignment of the 16S rRNA allowing identification of isolated species. Taxonomical composition revealed the abundance of betaproteobacteria and deltaproteobacteria with species level of 97%. Azospira oryzae (formally dechlorosoma suillum), Azospira restrica, and Geobacter spp. together with other similar groups were the most valuable bacteria for the degradation of chloroform.

Constructed wetlands are typical best management practices (BMPs) often used to reduce nutrient loads in streams. Evaluating the effectiveness of wetland design on nutrient removal is essential to assist watershed managers in optimal design of BMP dimensions and placement. In this study, we assess performance of two constructed wetland systems (comprising of nine wetlands) installed in downstream of Longhongjian Stream in Hangzhou City, China. These wetland systems are monitored and evaluated for their effects on nutrient removal, particularly TN, NO₃-N, TP, and PO₄-P. Based on wetland input–output metrics, removal efficiency (RE) is used to quantify wetland system. Results show that both wetland systems effectively removed nutrients, with RE as high as 45% of TN, 57% of NO₃-N, 78% of TP, and 86% of PO₄-P. In general, nutrient removal efficiency is seasonally dependent, with better removal efficiency occurring during warmer seasons than others. Macrophyte uptake is a primary removal process in these wetlands. We observe that more wetlands working concurrently can provide a greater level of control on nutrients in lotic environments. Wetland design parameters play an important role in removal of nutrients in streams. Increasing flow volume and surface area of wetland, designing curvilinear shoreline, and longer flow paths can be used as design criteria for wetland systems aimed at nutrient removal.

Zeolite and limestone were tested for their capability of removing As and Fe from acidic water in batch and column experiments. Synthetic acidic water with 3 mg/L As and 50 or 100 mg/L Fe at pH = 2 was used in the column experiments. In the batch experiments, the As concentration, the mass of media, and the contact time were varied between 0.2 and 5 mg As/L, 0.5 and 50 g, and 0.25 and 42 h, respectively. Maximum As sorption capacity as indicated by the Langmuir model was 0.17 mg/g for zeolite and 1.3 mg/g for limestone, at 18-h contact time and 6.3 g/L medium concentration. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analyses revealed that As and Fe were retained in zeolite at the end of the batch experiments. The main factors affecting As and Fe removal efficiency and pH raising capacity were the contact time and the media concentration. This was confirmed in the column experiments, since zeolite and limestone columns presented 99% As removal, under a hydraulic loading rate of 21.8 mm/day. However, limestone columns presented a higher Fe removal: 99 versus 73% for zeolite. The results indicate that limestone could be more appropriate than zeolite when As and Fe are present under acidic conditions, given its higher capacity to remove both As and Fe and to raise pH.

Arsenate (As(V)) is an analog of phosphate (Pᵢ), and previous studies have shown that As(V) and Pᵢ are absorbed via the same transport systems in some organisms. However, little is known about which periplasmic phosphate-binding proteins (PBPs) of ABC-type Pᵢ transporters play major roles in As(V) uptake by cyanobacteria. In this study, the model cyanobacterium Synechocystis sp. PCC 6803 (Synechocystis) was chosen to study the ability of PBPs to discriminate between Pi and As(V). We found that As(V) and Pᵢ competed for uptake via Pᵢ transporters when Synechocystis was treated with As(V) and/or Pᵢ in short-term incubation. The As/P molar ratios of Synechocystis wild type (WT) and mutants (∆sphX, ∆pstS2, ∆sll0540, and ∆sphXpstS1) were measured, and they were significantly different with the order WT > ∆pstS2 > ∆sll0540 > ∆sphXpstS1 > ∆sphX. Furthermore, As(V) uptake by Escherichia coli strain Transetta expressing PBP genes, particularly sphX or sll0540, was significantly increased when PBP gene (pstS1, pstS2, sphX, or sll0540) was separately expressed in Transetta at the same level. Subsequent phylogenetic analyses of PBPs showed that SphX and Sll0540 belonged to the low-affinity PBPs, while PstS1 and PstS2 were clustered with the high-affinity PBPs. These results implied that As(V) was taken up via Pᵢ transporters, and the low-affinity PBPs, SphX and Sll0540, made a significant contribution to As(V) uptake.