Open biomass burning in Peninsula Malaysia, Sumatra, and parts of the Indochinese region is a major source of transboundary haze pollution in the Southeast Asia. To study the influence of haze on rainwater chemistry, a short-term investigation was carried out during the occurrence of a severe haze episode from March to April 2014. Rainwater samples were collected after a prolonged drought and analyzed for heavy metals and major ion concentrations using inductively coupled plasma mass spectroscopy (ICP-MS) and ion chromatography (IC), respectively. The chemical composition and morphology of the solid particulates suspended in rainwater were examined using a scanning electron microscope coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). The dataset was further interpreted using enrichment factors (EF), statistical analysis, and a back trajectory (BT) model to find the possible sources of the particulates and pollutants. The results show a drop in rainwater pH from near neutral (pH 6.54) to acidic (<pH 4.00) during the haze to non-haze transitional period, suggesting that the deposition rate of sulfate and nitrate in the atmosphere via the precipitation process was relatively lower compared to the mineral components. Zinc, nitrate, and calcium, which were the predominant elements in the first rainwater samples. Besides, the results of the SEM-EDS indicated that the zinc was possibly originated from anthropogenic activities which are consistent with the results obtained from EF. The BT model showed that pollutants transported from the mainland of Indo-China and the marine region in the South China Sea were responsible for the high pollution event in the study area. These findings can be useful in identifying contributions of pollutants from single or multiple sources in rainwater samples during haze episodes.

Cadmium is a toxic metallic element that poses serious human health risks via consumption of contaminated agricultural products. The effect of mixtures of dicalcium phosphate and organic amendments, namely cow manure (MD) and leonardite (LD), on Cd and Zn uptake of three rice cultivars (KDML105, KD53, and PSL2) was examined in mesocosm experiments. Plant growth, Cd and Zn accumulation, and physicochemical properties of the test soils were investigated before and after plant harvest. Amendment application was found to improve soil physicochemical properties; in particular, soil organic matter content and nutrient (N, P, K, Ca, and Mg) concentrations increased significantly. The MD treatment was optimal in terms of increasing plant growth; the MD and LD treatments decreased soil Cd concentration by 3.3-fold and 1.6-fold, respectively. For all treatments, all rice cultivars accumulated greater quantities of Cd and Zn in roots compared with panicles and shoots. Among the three cultivars, RD53 accumulated the lowest quantity of Cd. Translocation factors (<0.28) and bioconcentration coefficients of roots (>1) indicate that the three rice cultivars are Cd excluders. Our results suggest that a mixture of organic and inorganic amendments can be used to enhance rice growth while reducing accumulation of heavy metals when grown in contaminated soil.

Freshwater mussels are at-risk taxa and may be exposed to high levels of carbon dioxide (CO₂) because of the potential use of CO₂ to control the movement of invasive aquatic fish species. One potential behavioral response to a change in the partial pressure of CO₂ (pCO₂) may be altered valve movement. In this study, three species of mussels were fitted with modified sensors and exposed to two regimes of pCO₂ to define thresholds of impaired valve movement. The first experiment demonstrated that Pyganodon grandis were much more tolerant to rising pCO₂ relative to Lampsilis siliquoidea (acute closure at ∼200,000 μatm in comparison to ∼80,000 μatm). The second experiment consisted of monitoring mussels for 6 days and exposing them to elevated pCO₂ (∼70,000 μatm) over a 2-day period. During exposure to high pCO₂, Lampsilis cardium were open for nearly the entire high pCO₂ period. Conversely, P. grandis were closed for most of the period following exposure to high pCO₂. For L. siliquoidea, the number of closures decreased nearly 40-fold during high pCO₂. The valve movement responses observed suggest species differences, and exposure to elevated pCO₂ requires a reactive response.

Arsenic (As) is an abundant toxicant present in groundwater and soil in various parts of the world including eastern part of India. The epidemiological studies have shown that arsenic exposure is linked to developmental defects and miscarriage. Placenta is known to utilize vasculogenesis to develop its vasculature circulation. The effects of four different doses of sodium meta-arsenite (0, 10, 20, 75, and 150 ppm) were assessed on the vascular structure using two different in vivo models, i.e., Matrigel and chorioallantoic membrane (CAM) assay. For the Matrigel assay, mice were exposed to different doses of arsenic through drinking water for 1 month. Placenta and Matrigel plug (which was inserted on gestational day (GD 0.5)) were removed on GD 14. Similar arsenic concentration was used in CAM assay to observe the effect of vessel development in hen’s eggs. The CAM assay outcome evaluated by Angiosys software showed that arsenic exposure reduced the total and mean tubule length in all the arsenic-treated groups. The percentage tubule inhibition was declined significantly in 20, 75, and 150 ppm arsenic-treated groups as evaluated by ImageJ software. Analysis of the CAM outcome by both the image analysis software indicated the adverse effect of arsenic on the tubules. Further, a significant higher blood vessel density in 10 ppm and lower vessel density in 20, 75, and 150 ppm arsenic-exposed mice were also observed in Matrigel plug assay. The placental hypertrophy and dysplasia especially in the labyrinth zone (vasculature) were noted in placenta of arsenic-treated mice. The study indicated that higher arsenic exposures inhibited the angiogenesis which was dose-dependent in both CAM and Matrigel assay and altered structural morphology of placenta. However, no inhibition of blood vessels was noted at lower, i.e., 10 ppm of arsenic-treated group.

Atmospheric particulate matter (PM) is a recognized risk factor contributing to a number of diseases in human populations and wildlife globally. Organic matter is a major component of PM, but its contribution to overall toxicity of PM has not been thoroughly evaluated yet. In the present work, the biological activity of organic extracts from PM1 (particles with less than 1 μm of aerodynamic diameter) collected from an urban road site in the centre of Barcelona (NE Spain) was evaluated using a yeast-based assay (AhR-RYA) and different gene expression markers in zebrafish embryos. Dioxin-like activity of the extracts correlated to primary emissions from local traffic exhausts, reflecting weekday/weekend alternance. Expression levels of cyp1a and of gene markers for key cellular processes and development (ier2, fos) also correlated to vehicle emissions, whereas expression of gene markers related to antioxidant defence and endocrine effects (gstal, hao1, ttr) was strongly reduced in samples with strong contribution from regional air masses with aged secondary organic species or with strong influence of biomass burning emissions. Our data suggest that the toxic potential of PM1 organic chemical constituents strongly depends on the emission sources and on the process of ageing from primary to secondary organic aerosols.

China contributes to more than 60 % of the global aquaculture production, and its aquaculture industry has become one of the main players in food security. A large amount of antibiotics is believed to be used in fish cultivation for ensuring adequate production. The use of antibiotics as disease control agents and growth promoter in aquaculture in China has raised significant concerns recently because of the potential threats to human health. The extensive use of antibiotics in aquaculture may result in water and sediment contamination and the development of antibiotic resistance genes. In this review, the role of aquaculture in antibiotic contamination of the environment as well as the emerging concern of antibiotic resistance genes in China is discussed. Based on this review, it has been concluded that more information regarding the types and quantities of antibiotics used by Chinese fish farmers is required. Studies about the contribution of antibiotic usage in aquaculture to environmental levels in surface water, their potential risks on environment and human health, and the existence and spread of antibiotic resistance genes in aquaculture are needed.

Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A—the control, B—natural zeolite addition, and C—3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites andDMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH₃ by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

Iron is an essential nutrient needed for multiple biological processes, but it is also an effective pro-oxidant in its reduced form. Environmental sources of iron toxic species include reduced soils from rice plantations, polluted natural areas from metal industry waste, or iron oxides used in soil bioremediation. Few studies have been conducted to assess the toxicity of iron species in insects. The present work aims to assess the oxidative stress effects of ferrous sulfate administered in drinking water after acute exposure (96 h) to adults of the insect model Oncopeltus fasciatus (Dallas). Mortality was higher in exposed groups and significantly associated with iron treatment (OR [95% CI]; 11.8 [6.1–22.7]). Higher levels of body iron content were found in insects exposed to ferrous sulfate, with an increase of 5–6 times with respect to controls. Catalase activity and lipid peroxidation (TBARS content), but not glutathione S-transferase activity, were significantly higher in exposed insects and significantly correlated with body iron content (Pearson coefficient of 0.68 and 0.74, respectively) and between them (0.78). The present work demonstrates that, despite the disruption in water and food intake caused by iron administration, this metal is accumulated by insect causing lipid peroxidation and eliciting an antioxidant response mediated by catalase.

In this paper, we investigate the sample preparation and analysis process in order to achieve adequate results for surface water collected from rivers that flow through swamps and are consequently rich in organic matter. We show that matrix effects in glyphosate determination can be reduced by optimizing sample volume, liquid chromatography (LC) mobile phase buffer concentration and pH as well as gradient speed. Also, aspects of derivatization procedure (borate buffer concentration, fluorenylmethyloxycarbonyl chloride concentration) and their influence on accuracy are considered in detail. We encountered a cross-talk effect in the mass spectra, interfering with quantization during analysis, which was removed by optimizing MS parameters. As a result it was demonstrated that isotope-labelled internal standard with just one ¹³C atom is sufficient for the analysis.All these aspects were found to strongly impact the accuracy of the glyphosate determination but have received little or no attention in earlier works. We propose a reliable solid phase extraction and LC/ESI/MS/MS method for determination of glyphosate in organic-rich waters and demonstrate that LoD can be decreased by about two times using an ESI nebulizer with a modified design.

Biosynthesis of nanoparticles has received increasing attention due its effective mode of action, eco-friendly preparation methodology, and less cytotoxicity. In the present study, silver nanoparticles (AgNPs) from aqueous seed extract of Myristica fragrans (nutmeg) were characterized. Gas chromatography–mass spectrometry (GC–MS) analysis revealed the presence of bioactive components acts as effective in reducing and capping agents for converting AgNO₃ to AgNPs. The UV-Vis absorption spectrum of the biologically reduced reaction mixture showed the surface plasmon peak at 420 nm, which is the characteristic peak of AgNPs. The functional molecules present in the M. fragrans seed extract and their interaction with the AgNPs were identified by the Fourier transform infrared spectroscopy (FT-IR) analysis. X-ray diffraction (XRD) analysis confirmed the face-centered cubic crystalline structure of metallic silver nanoparticle and diameter was calculated using Scherrer’s equation. Transmission electron microscope (TEM) image showed spherical shaped particles with an average size of 25 nm. The scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) confirmed the presence of elemental silver. The antibacterial activity of biosynthesized AgNPs was evaluated against multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi) according to agar well diffusion, MIC (minimum inhibitory concentration), and IC₅₀ (inhibitory concentration 50%). The results confirm that bacterial growth was significantly reduced in a dose-dependent manner. Further, the cytotoxic effect of biosynthesized AgNPs on rat spleenocytes was analyzed. Thus, it is suggested that the nutmeg-biosynthesized AgNPs could be a lead drug and used effectively to control the MDR S. Typhi, thereby reducing public health issues and environmental pollution.