Carbamazepine (CBZ) is a representative of a group of compounds found in our rivers that have been classified as upcoming contaminants. Its pharmacological activity to treat mood and neurological disorders is based on its effects on ion channels, but effects on aquatic organisms have not yet been thoroughly investigated.In our initial analysis, we compared CBZ effects on two microalgae species differing in CBZ sensitivity: Parachlorella kessleri and Neochloris pseudoalveolaris. While we observed a stimulation in the growth rate in cultures of P. kessleri in the presence of 10 μg L⁻¹ CBZ, no effect on growth rates of N. pseudoalveolaris cultures could be documented at this concentration. Any higher tested CBZ concentration led to growth inhibition.To gain insight into these effects, biochemical and physiological parameters of these two microalgae species were measured in the presence of CBZ in a concentration-dependent manner.As the severe inhibition of growth rate correlated with a significant inhibition of most tested parameters in cultures of N. pseudoalveolaris, the primary reason for the adverse effect of CBZ on cultures of this microalgae species could not be identified. In cultures of N. pseudoalveolaris, experimental data indicate that inhibition of growth rate occurs when the microalgae are no longer able to compensate for adverse CBZ-induced ROS effects.Analysis of the CBZ response of cultures of P. kessleri showed a reduction of growth stimulatory effect if the CBZ concentration exceeds a threshold value. In general, cultures of P. kessleri show a great potential to withstand CBZ as an environmental pollutant.

Aeolian dust from hot spots in eastern China and Mongolia can be carried downwind to provinces in China, neighboring countries, the Pacific islands, and cities far beyond the source region. Although dust sources of huge extent have been identified in several countries, few effective countermeasures are available to combat dust emissions in arid regions. We analyzed Moderate Resolution Imaging Spectroradiometer (MODIS) images (1 km spatial resolution) that captured dust emission and dispersion during 2000–2013 to determine dust sources in eastern China and Mongolia. MODIS level 1B data and the brightness temperature difference (BTD) algorithm provided efficient discrimination of dust in this study. The derived dust information, in conjunction with the MODIS land cover product (1 km spatial resolution) and high-resolution Landsat data (30 m spatial resolution; Landsat 8, Operational Land Imager sensor) were used to identify the locations and specific sources of dust. Dust emissions appear to be sporadic in time and space, controlled by both environmental factors and human activity, although past studies have indicated that many dust emissions are from consistently active hot spots. Analysis of MODIS data indicated that three subregions of the eastern China and Mongolia source region are the dominant sources of dust: Horqin Sandy Land, Otintag Sandy Land, and the southeastern Mongolian Gobi; each of these subregions contains dust emission hot spots. We identified the locations of consistent hot spots and verified that some individual dust emissions originated from those hot spots. Our data also indicated that hot spots in southeastern Mongolia have migrated northward since 2006. Our study showed that hot spots such as dry lakes, river beds, mines, and croplands contribute to dust emissions in the eastern China and Mongolia source region. Dust hot spots coincide with regions of expanding industry in Otintag Sandy Land and in some areas of the Mongolian Gobi and with agricultural areas in Horqin Sandy Land and in some parts of the Mongolian Gobi. In Horqin and Otintag sandy lands, dust sources are associated with ephemeral water bodies. Water conservation can be an important countermeasure for initial dust emissions in the Horqin Sandy Land. In the Otintag Sandy Land, attention should be paid to human activities, for example, minimizing the effects of mining disturbances, improving dust suppression in industrial areas, and controlling water use by industry. In Mongolia, protective farming techniques and water conservation in dust emitting basins, and dust suppression and water resource protection in mining zones, must be considered to combat dust emission. MODIS level 1B data can be used to locate dust hot spots and to identify future sources of dust entrainment. Dust hot spots identified from MODIS level 1B data provide small-scale information about dust emission that can be used to locate pollution hot spots, increase understanding of the global dust cycle, and improve dust modeling.

This paper examined the gut digestive enzymes, trypsin and leucine aminopeptidase (LAP), in gypsy moth (Lymantria dispar, L.) larvae exposed to cadmium. We analyzed the 3-day acute effect, chronic effects from hatching until sacrifice, and recovery from long-term dietary treatment with cadmium concentrations of 10 and 30 μg Cd/g dry food. The activities of both examined enzymes declined at the higher level of cadmium after both acute and chronic treatments and did not recover within 3 days of feeding a diet with no added cadmium. Leucine aminopeptidase was more sensitive because its activity was inhibited after both short-term treatments. Three trypsin and one leucine aminopeptidase isoform were detected by electrophoresis. Egg hatches (full-sib families) differed in enzyme activities, index of phenotypic plasticity, and isozyme expression after different treatments. Statistically significant positive correlations between these enzymes pointed to common genetic regulation. Moreover, variances were higher for the control group than for cadmium treatment groups implying that these proteolytic enzymes did not participate directly in detoxification. These results suggest that, with additional research to discover the mechanisms of enzyme inhibition, trypsin and leucine aminopeptidase might be used as biomarkers to indicate the severity of gastrointestinal disease due to cadmium intake.

Solid organic carbon and zero-valent iron (ZVI) have been used separately as reactive media in permeable reactive barriers (PRBs) to degrade nitrate in groundwater, but few studies have examined the combination of the two materials in one system for nitrate remediation. In the present study, batch tests are conducted to evaluate three common solid organic carbons and their combination with ZVI for nitrate removal from water. The results show that the combined system achieves better denitrification efficiency than that measured with sawdust or cotton alone. However, no obvious difference is noted between the cornstalk alone and its mixture with ZVI treatment. When complete nitrate removal is achieved in the system that combined ZVI with sawdust or cotton, only 72 and 62.6 % of nitrate removal, respectively, are obtained in which the carbon (C) source is used alone. The results indicate that there are synergistic effects in the combined denitrification system, and the effects depend on the type of carbon material used. Sawdust is an alternative carbon source for nitrate removal in a C-ZVI-combined system. In a sawdust-ZVI system, the accumulation of nitrite and ammonium is affected greatly by nitrate concentration, C/N ratio, and Fe/N ratio.

The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates many of the toxic effects of dioxin-like compounds (DLCs) and some polycyclic aromatic hydrocarbons (PAHs). Strong AHR agonists, such as certain polychlorinated biphenyls and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), cause severe cardiac teratogenesis in fish embryos. Moderately strong AHR agonists, such as benzo[a]pyrene and β-naphthoflavone, have been shown to cause similar cardiotoxic effects when coupled with a cytochrome P450 1A (CYP1A) inhibitor, such as fluoranthene (FL). We sought to determine if weak AHR agonists, when combined with a CYP1A inhibitor (FL) or CYP1A morpholino gene knockdown, are capable of causing cardiac deformities similar to moderately strong AHR agonists (Wassenberg and Di Giulio Environ Health Perspect 112(17):1658–1664, 2004a; Wassenberg and Di Giulio Res 58(2–5):163–168, 2004b; Billiard et al. Toxicol Sci 92(2):526–536, 2006; Van Tiem and Di Giulio Toxicol Appl Pharmacol 254(3):280–287, 2011). The weak AHR agonists included the following: carbaryl, phenanthrene, 2-methylindole, 3-methylindole, indigo, and indirubin. Danio rerio (zebrafish) embryos were first exposed to weak AHR agonists at equimolar concentrations. The agonists were assessed for their relative potency as inducers of CYP1 enzyme activity, measured by the ethoxyresorufin-O-deethylase (EROD) assay, and cardiac deformities. Carbaryl, 2-methylindole, and 3-methylindole induced the highest CYP1A activity in zebrafish. Experiments were then conducted to determine the individual cardiotoxicity of each compound. Next, zebrafish were coexposed to each agonist (at concentrations below those determined to be cardiotoxic) and FL in combination to assess if CYP1A inhibition could induce cardiac deformities. Carbaryl, 2-methylindole, 3-methylindole, and phenanthrene significantly increased pericardial edema relative to controls when combined with FL. To further evaluate the interaction of the weak AHR agonists and CYP1A inhibition, a morpholino was used to knockdown CYP1A expression, and embryos were then exposed to each agonist individually. In embryos exposed to 2-methylindole, CYP1A knockdown caused a similar level of pericardial edema to that caused by exposure to 2-methylindole and FL. The results showed a complex pattern of cardiotoxic response to weak agonist inhibitor exposure and morpholino-knockdown. However, CYP1A knockdown in phenanthrene and 3-methylindole only moderately increased pericardial edema relative to coexposure to FL. AHR2 expression was also knocked down using a morpholino to determine its role in mediating the observed cardiac teratogenesis. Knockdown of AHR2 did not rescue the pericardial edema as previously observed with strong AHR agonists. While some of the cardiotoxicity observed may be attributed to the combination of weak AHR agonism and CYP1A inhibition, other weak AHR agonists appear to be causing cardiotoxicity through an AHR2-independent mechanism. The data show that CYP1A is protective of the cardiac toxicity associated with weak AHR agonists and that knockdown can generate pericardial edema, but these findings are also suggestive of differing mechanisms of cardiac toxicity among known AHR agonists.

Copper hydrotalcites with and without adsorbed chlorophyllin exhibit a bactericidal effect that depends on the copper release and the basicity, which can be tuned through the chlorophyllin adsorption. The prepared solids performed well for the elimination of Escherichia coli, Enterobacter aerogenes, Salmonella enterica, and Staphylococcus aureus bacteria. The results showed that the copper-containing hydrotalcite with the adsorbed chlorophyllin is the most active material. Wastewaters from a metal industry were treated with these hybrid compounds, and the bactericidal effect was comparable with the results reported using more complex methods such as photocatalysis. Furthermore, one main advantage of these hybrid compounds is its low human toxicity compared with silver-containing materials.

Many studies have been conducted regarding the degradation of PAHs. One of the technologies that has been widely used is bioremediation due to its relatively low cost and greater efficiency for those compounds with structural complexity. Biotechnology has been used in several countries for many years and consists in the use of microorganisms (bacteria and fungi) to transform contaminants into inert substances, which is a result of the microbial activity from biochemical processes. This study aimed to develop a bioremediation methodology for the pollutant benzo[a]pyrene (B[a]P), which belongs to the group of PAHs. The potential use of a microbial consortium with Pseudomonas aeruginosa, Candida albicans, Aspergillus flavus, and Fusarium sp. for bioremediation was assessed. To confirm the pollutant reduction, quantifications of the samples were performed via gas chromatography–mass spectrometry (GC-MS). The contamination was prepared with a soil previously contaminated with B[a]P at the concentration of 3.74 mg kg⁻¹. The microbial consortium was added (16 μL g⁻¹), and samples were incubated for 42 days in an oven at 35 °C. The microbial growth curves showed representative differences between the samples in the presence and absence of the pollutant, demonstrating the possibility of bioremediation process. The final quantification of soil showed a mean concentration of 1.29 mg kg⁻¹, showed that 65.51 ± 0.95 % of the pollutant was degraded, which is an important and representative performance.

Fluorene belongs to the polycyclic aromatic hydrocarbons (PAHs) which are potentially carcinogenic or mutagenic. However, very few studies on biodegradation of three-ring fluorene were investigated as compared to other three-ring PAHs such as phenanthrene and anthracene. The aim of this work is to evaluate fluorene degradation by fungal strain isolated from the decayed wood in tropical rain forest, Malaysia, and examine the effectiveness of the strain for degrading fluorene in liquid culture supplemented with the nonionic surfactants. Detailed taxonomic studies identified the organisms as Pestalotiopsis species and designated as strain Pestalotiopsis sp. W15. In this study, fluorene was totally degraded by Pestalotiopsis sp. W15 after incubation for 23 days. Various analytical studies confirmed the biotransformation of fluorene by detection of two metabolites in the treated medium: indanone (R f 0.45; λ ₘₐₓ 240 and 290 nm; t R 7.1 min and m/z 132) and salicylic acid (λ ₘₐₓ 205, 235, 290 nm; t R 9.4 min and m/z 382). Based on these products, a probable pathway has been proposed for the degradation of fluorene by Pestalotiopsis sp. W15. None of the intermediates were identified as dead-end metabolites.

Bacteria that harbor the mer operon in their genome are able to enzymatically reduce mercury (II) to the volatile form of mercury Hg (0). Detoxification of contaminated waste by using these bacteria may be an alternative to conventional methods for mercury removal. Residual glycerol from the biodiesel industry can be used as a carbon source to accelerate the process. This work shows for the first time the feasibility of using residual glycerol as a carbon source for Hg removal by bacteria prospected from contaminated environments. Eight bacterial isolates were able to remove mercury and degrade glycerol in mineral medium and residual glycerol. Mercury removal was monitored by atomic absorption spectroscopy and glycerol degradation by high performance liquid chromatography. The best results of mercury removal and glycerol degradation were obtained using isolates of Serratia marcescens M25C (85 and 100 %), Klebsiella pneumoniae PLB (90 and 100 %), Klebsiella oxytoca (90 and 100 %), and Arthrobacter sp. U3 (80 and 75 %), with addition of 0.5 g L⁻¹ yeast extract. The Arthrobacter sp. U3 isolate is common in soils and has proven to be a promising candidate for environment applications due to its low pathogenicity and higher Hg removal and glycerol degradation rates.

This study assessed the suitability of passive sampler extracts for use with a GC-MS-database rapid screening technique for around 940 organic chemicals. Chemcatcher™ passive sampler systems containing either Empore™ SDB-XC or C18FF disks were deployed at 21 riverine sites in and near Melbourne, Victoria, Australia, for a period of 28 days during September–October 2008. Methanolic elution of the SDB-XC and C18FF disks produced an extract that, after evaporation and inversion into hexane, was compatible with the GC-MS-database method enabling over 30 chemicals to be observed. The sources of the non-agricultural chemicals are still unclear, but this study was conducted in a relatively dry season where total rainfall was approximately 40 % lower than the long-term mean for the catchment during the study period. Thus, the risks may be greater in wetter seasons, as greater quantities of chemicals are likely to reach waterways as the frequency, extent and intensity of surface run-off events increase. This study provides valuable information for policy and decision-makers, both in Australia and other regions of the world, in that passive sampling can be conveniently used prior to analysis by multi-residue techniques to produce data to assess the likely risks trace organic chemicals pose to aquatic ecosystems.