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Abstract Concentrations of major ions in coal mine discharge waters and unconventional hydrocarbon produced waters derived from coal bed methane (CBM) production, are potentially harmful to freshwater ecosystems. Bicarbonate is a major constituent of produced waters from CBM and coal mining. However, little is known about the relative toxicity of differing ionic proportions, especially bicarbonate, found in these CBM waters. As all freshwater invertebrates tested are more acutely sensitive to sodium bicarbonate (NaHCO3) than sodium chloride (NaCl) or synthetic sea water, we tested the hypotheses that toxicity of CBM waters are driven by bicarbonate concentration, and waters containing a higher proportion of bicarbonate are more toxic to freshwater invertebrates than those with less bicarbonate. We compared the acute (96 h) lethal toxicity to six freshwater invertebrate species of NaHCO3 and two synthetic CBM waters, with ionic proportions representative of water from CBM wells across New South Wales (NSW) and Queensland (Qld), in Australia. The ranking of LC50 values expressed as total salinity was consistent with the hypotheses. However, when toxicity was expressed as bicarbonate concentration, the hypothesis that the toxicity of coal bed waters would be explained by bicarbonate concentration was not well supported, and other ionic components were either ameliorating or exacerbating the NaHCO3 toxicity. Our findings showed NaHCO3 was more toxic than NaCl and that the NaHCO3 proportion of synthetic CBM waters drives toxicity, however other ions are altering the toxicity of bicarbonate.

© 2018, © 2018 Taylor & Francis. Farmers and farm workers have been recognized as a group at high risk of suicide in Australia. This study aims to identify and better understand environmental factors associated with suicide among Australian farmers and farm workers. Qualitative analysis was undertaken in accordance with the Consolidated Criteria for Reporting Qualitative Research. Male and female focus groups were conducted separately with people who lived or worked on a farm in six farming communities. Qualitative analyses showed that a number of environmental influences may contribute to the increased risk of suicide: extreme climatic events; isolation; service availability; access to, and frequent use of firearms; death and suffering of animals; government and legislation; technology; and property values. Both the physical and socio-cultural environments in which farmers operate appear to contribute to farmer suicide and need to be considered in suicide prevention.

Coal mining and extraction of methane from coal beds generate effluent with elevated salinity or major ion concentrations. If discharged to freshwater systems, these effluents may have adverse environmental effects. There is a growing body of work on freshwater invertebrates that indicates variation in the proportion of major ions can be more important than salinity when determining toxicity. However, it is not known if saline toxicity in a subset of species is representative of toxicity across all freshwater invertebrates. If patterns derived from a subset of species are representative of all freshwater invertebrates, then we would expect a correlation in the relative sensitivity of these species to multiple saline waters. Here, we determine if there is a correlation between the acute (96 h) lethal toxicity in freshwater invertebrates to synthetic marine salts (SMS) and sodium bicarbonate (NaHCO 3 ) added to dechlorinated Sydney tap water. NaHCO 3 is a major component of many coal bed effluents. However, most salinization in Australia exhibits ionic composition similar to seawater, which has very little HCO 3 − . Across all eight species tested, NaHCO 3 was 2–50 times more toxic than SMS. We also observed strong correlations in the acute toxicity of seven of the tested species to SMS and NaHCO 3 . The strongest relationship (LC50 r 2 = 0.906) was dependent on the exclusion of one species, Paratya australiensis (Decopoda: Atyidae), which was the most sensitive species tested to NaHCO 3 , but the second-most tolerant of SMS. We conclude that differences in the toxicity of different proportions of major ions can be similar across a wide range of species. Therefore, a small subset of the invertebrate community can be representative of the whole. However, there are some species, which based on the species tested in the current study appear to be a minority, that respond differently to saline effluent and need to be considered separately. We discuss the implications of this study for the management of saline coal bed waters. This article is part of the theme issue ‘Salt in freshwaters: causes, ecological consequences and future prospects'.

In this work, we test the hypothesis that narrow-line Seyfert 1 galaxies (NSL1s) are active galactic nuclei in their early phase and are therefore younger and more active than the more common broad-line Seyfert 1 galaxies (BLS1s). If that is true, then NLS1s should, on average, have lower black hole masses and higher accretion rates than BLS1s. To test this, we use a sample of 35 NLS1s and 54 BLS1s with similar X-ray luminosity distributions and good XMM-Newton observations. To determine the black hole mass, we apply an X-ray scaling method that is independent of any assumptions on the broad-line region dynamics and the inclination of the objects. We find that, on average, NLS1s have lower black hole masses, but the difference between the average black hole masses of NLS1s and BLS1s in our sample is only marginally significant (at the 2.6 sigma level). According to a Kolmogorov-Smirnov test, the distribution of black hole mass values of NLS1s is different from that of BLS1s at the 99% confidence level. Even stronger differences between NLS1s and BLS1s are inferred when the accretion rate distributions of NLS1s are compared to BLS1s, suggesting that the two populations are indeed distinct. Our study also indicates that the black hole mass values (both for NLS1s and BLS1s) determined with the X-ray scaling method are fully consistent with those obtained using reverberation mapping., Comment: Comments: 13 pages, 6 figures, 7 tables, accepted for publication by MNRAS

Bicarbonate is often a major ionic constituent associated with produced waters from methane gas extraction and coal mining, yet few studies have determined its specific toxicity. Currently, the environmental risk of bicarbonate anion in water discharges is assessed based on the toxicity of sodium chloride or artificial seawater and is regulated via electrical conductivity. Increased NaHCO3 added to Ceriodaphnia dubia in synthetic or natural water gave similar 48-h 10% effective concentration (EC10) values of 1750 ± 125 mg NaHCO3/L (mean ± standard error) and 1670 ± 180 mg NaHCO3/L, respectively. Bicarbonate was toxic to C. dubia in both waters with conductivities above 1900 µS/cm. In contrast, when conductivity was elevated with NaCl, toxicity to C. dubia was observed only above 2800 µS/cm. Bicarbonate also impaired C. dubia reproduction with an EC10 of 340 mg NaHCO3/L. Major ion composition also influenced Zn bioavailability, a common co-occurring metal contaminant in coal mine waters, with sublethal concentrations of NaHCO3 and elevated pH increasing Zn toxicity. Higher pH was the dominant parameter determining a 10-fold increase in the 48-h 50% effective concentration (EC50) for Zn toxicity to C. dubia at pH 8.6 of 34 µg Zn/L (95% confidence limit = 32–37 µg Zn/L) compared with the Zn toxicity at approximately circumneutral pH. Exposure of the freshwater shrimp Paratya australiensis (Atyidae) in natural water to increasing bicarbonate gave a mean 10-d 10% lethal concentration (LC10) of 850 ± 115 mg NaHCO3/L, associated with a mean conductivity EC10 of 1145 µS/cm, which is considerably lower than toxicity of NaCl and artificial seawater to this species reported elsewhere. Because toxicity was influenced by salt composition, specific ions should be regulated rather than conductivity alone in mine wastewater discharges. Environ Toxicol Chem 2014;33:1179–1186. © 2014 SETAC

Increasing and widespread use of neonicotinoid insecticides all over the world, together with their environmental persistence mean that surface and ground waters need to be monitored regularly for their residues. However, current multi-residue analytical methods for waters are inadequate for trace residue analysis of these compounds, while passive sampling devices are unavailable. A new method using UltraPerformance Liquid Chromatography provided good separation of the five most common neonicotinoid compounds, with limits of quantitation in the range 0.6-1.0ng. The method was tested in a survey of rivers around Sydney (Australia), where 93% of samples contained two or more neonicotinoids in the range 0.06-4.5μgL(-1). Styrenedivinylbenzene-reverse phase sulfonated Empore™ disks were selected as the best matrix for use in passive samplers. Uptake of clothianidin, imidacloprid and thiacloprid in a flow-through laboratory system for 3weeks was linear and proportional to their water concentrations over the range 1-10μgL(-1). Sampling rates of 8-15mLd(-1) were correlated to the hydrophobicity of the individual compounds. The passive samplers and analytical methods presented here can detect trace concentrations of neonicotinoids in water.

The genetic structure of populations is impacted by environmental factors of both natural and anthropogenic origin. These factors can affect dispersion, gene flow and selective pressures. We test whether natural environmental factors or anthropogenic factors influence the genetic structure of the amphipod, Melita plumulosa (Crustacea: Melitidae), which serves as an indicator of environmental health in estuaries along eastern Australia. Sequence data from one mitochondrial and two nuclear loci were collected and analyzed from eight geographically distinct populations spanning the known distribution of this species. We identified two major clades corresponding to the east and south coasts of Australia, and populations also largely grouped according to geography within each clade. Population differentiation indicated all sampling localities to be distinct from one another and sequence divergences suggested ancient divergence, with the deepest genetic divergences between the eastern and southern populations. Reproductive compatibility did not indicate cryptic speciation between populations. Sequence divergence and population differentiation suggest historic geographic isolation dating back to the Pleistocene to have influenced the population biogeography of M. plumulosa.

Melita plumulosa is an epibenthic, detritivorous amphipod found in estuaries along the eastern coast of Australia. It has been utilized as a test organism in rapid ten to thirteen days reproduction toxicity tests for sediment quality assessment. The fecundity of females in the toxicity test has been found to be inhibited by exposure of the amphipods to contaminated sediments enriched with zinc and other metals. This study investigated the proposal that interference in vitellogenesis is the cause of reproductive toxicity of metals in crustaceans. Inspection of the ovaries from amphipods on day 6 of the test either from control or Zn/Pb/Cd/Cu-spiked sediment, that were nearing completion of vitellogenesis, showed that the females in all treatments were producing similar numbers of oocytes undergoing secondary vitellogenesis. The distribution of the Zn, Cu and Pb in the oocytes and ventral caeca of females was examined by X-ray fluorescence microscopy. Elemental mapping revealed a dense accumulation of Zn in primary oocytes and a uniform distribution of Zn and Cu in the secondary oocytes in all treatments. Zn and Cu were also observed to be uniformly distributed in the ventral caeca. Pb was not detected in either of these tissues. The apparent normal morphology and the typical number of oocytes undergoing secondary vitellogenesis suggest that vitellogenesis was not being disrupted by Pb displacing Zn in the metal-binding domain of vitellogenin in amphipods exposed to the contaminated sediment during the test. Alternative mechanisms for the reproductive toxicity of amphipods exposed for six days to metal-contaminated sediment are discussed. © 2013.

Insufficient transparency was one of the shortcomings that financial markets showed in the midst of the financial crisis. It affected not only derivatives, but also fixed income and structured products markets. A certain debate has arisen around regulatory initiatives to increase transparency on non-equities markets and especially on derivatives. The relation with liquidity is at the center of that debate and it is also linked to elements such as the level of central clearing of derivatives and the structure of the derivatives industry. In Europe, several initiatives are set to change the way derivatives are cleared and traded and financial stability is at the center of the logic behind them. We analyse in this article the main elements to consider when addressing the increased pre- and post-trade transparency on derivatives markets, its relation with liquidity and efficiency and its implications on market structure, financial stability and investor protection.

© 2016 Elsevier B.V. High-resolution transmission electron microscopy (HRTEM) examination of nanoparticles requires their placement on some manner of support – either TEM grid membranes or part of the material itself, as in many heterogeneous catalyst systems – but a systematic quantification of the practical imaging limits of this approach has been lacking. Here we address this issue through a statistical evaluation of how nanoparticle size and substrate thickness affects the ability to resolve structural features of interest in HRTEM images of metallic nanoparticles on common support membranes. The visibility of lattice fringes from crystalline Au nanoparticles on amorphous carbon and silicon supports of varying thickness was investigated with both conventional and aberration-corrected TEM. Over the 1–4 nm nanoparticle size range examined, the probability of successfully resolving lattice fringes differed significantly as a function both of nanoparticle size and support thickness. Statistical analysis was used to formulate guidelines for the selection of supports and to quantify the impact a given support would have on HRTEM imaging of crystalline structure. For nanoparticles ≥1 nm, aberration-correction was found to provide limited benefit for the purpose of visualizing lattice fringes; electron dose is more predictive of lattice fringe visibility than aberration correction. These results confirm that the ability to visualize lattice fringes is ultimately dependent on the signal-to-noise ratio of the HRTEM images, rather than the point-to-point resolving power of the microscope. This study provides a benchmark for HRTEM imaging of crystalline supported metal nanoparticles and is extensible to a wide variety of supports and nanostructures.

Background Tamoxifen is a selective estrogen receptor antagonist that is widely used for treatment and prevention of breast cancer. However, tamoxifen use can lead to an increased incidence of thrombotic events. The reason for this adverse event remains unknown. Previous studies showed that tamoxifen and its active metabolite Z-4-hydroxytamoxifen rapidly increased intracellular free calcium ([Ca 2+ ] i ) in human platelets by a non-genomic mechanism that involved the activation of phospholipase C. Platelets play a pivotal role in thrombosis and Ca 2+ elevation is a central event in platelet activation. Therefore the mechanism by which tamoxifen activated Ca 2+ entry into platelets was investigated. Methods [Ca 2+ ] i was measured using the fluorescent indicator fura-2 and reactive oxygen species were measured using lucigenin in isolated human platelets. Results Tamoxifen analogs E-4-hydroxytamoxifen, with weak activity at the nuclear estrogen receptor and Z-4-hydroxytamoxifen, with strong activity at nuclear estrogen receptor, were equally active at increasing [Ca 2+ ] i and synergizing with ADP and thrombin to increase [Ca 2+ ] i in platelets. This result suggests that the effects of tamoxifen and E- and Z-4-hydroxytamoxifen to increase [Ca 2+ ] i are not mediated by the classical genomic estrogen receptor. The effects of tamoxifen to increase [Ca 2+ ] i were strongly inhibited by apocynin and apocynin dimer. This suggests that tamoxifen activates NADPH oxidase which leads to superoxide generation and in turn caused an increase in [Ca 2+ ] i . Free radical scavengers TEMPO and TEMPOL also inhibited tamoxifen-induced [Ca 2+ ] i elevation. Inhibition of phosphoinositide-3-kinase (PI3-kinase), an upstream effector of NADPH oxidase with wortmannin and LY-294,002 also caused substantial inhibition of tamoxifen-induced elevation of [Ca 2+ ] i . Conclusion Tamoxifen increases [Ca 2+ ] i in human platelets by a non-genomic mechanism. Tamoxifen activates phospholipase Cγ as well as PI3-kinase and NADPH oxidase pathway to generate superoxide which causes the release of Ca 2+ from the endoplasmic reticulum, and promotes Ca 2+ influx into the platelets.

The reproductive biology of amphipods is reviewed to update the knowledge of the male and female reproductive processes of oogenesis and spermatogenesis as well as the endocrine systems of amphipods with the aim of advancing studies of reproductive toxicology. The ovarian and reproduction cycles of female gammaridean amphipods are closely correlated with the molt cycle, which is under direct control by the steroid hormone 20-hydroxyecdysone. The ability of males to copulate and subsequently for females to ovulate is restricted to the early postmolt period of the females. New developments in our understanding of the molt cycle and the endocrine regulatory pathways for reproduction using genomics techniques on other crustacean species are also discussed. The arthropod sterol ponasterone A or xenobiotics such as the fungicide fenarimol have been shown to elicit endocrine disruption in some crustaceans by acting as an agonist for 20-hydroxyecdysone at the ecdysone receptor or by inhibiting the synthesis of 20-hydroxyecdysone, respectively, resulting in disruption of molting and reproduction. Recent studies suggest that cadmium can inhibit secondary vitellogenesis in amphipods. Experimental approaches for examining the metabolic pathways associated with ecdysteroid hormonal signaling or metabolism, exoskeleton maintenance and molting, and the regulation of vitellogenin in amphipods are discussed. This information should aid in the identification of useful biomarkers for reproductive toxicity.

Anthropogenic effects such as contamination affect the genetic structure of populations. This study examined the temporal and geographical patterns of genetic diversity among populations of the benthic crustacean amphipod Melita plumulosa in the Parramatta River (Sydney, Australia), following an industrial chemical spill. The spill of an acrylate/methacrylate co-polymer in naphtha solvent occurred in July 2006. M. plumulosa were sampled temporally between December 2006 and November 2009 and spatially in November 2009. Genetic variation was examined at the mitochondrial cytochrome c oxidase subunit I locus. Notably, nucleotide diversity was low and Tajima's D was significantly negative amongst amphipods collected immediately downstream from the spill for 10 months. We hypothesize that the spill had a significant localized effect on the genetic diversity of M. plumulosa. Alternate explanations include an alternate and unknown toxicant or a localized sampling bias. Future proposed studies will dissect these alternatives.

The acute toxicities of the insecticide terbufos and its major breakdown products individually, as binary mixtures, and in combination with the co-applied herbicide atrazine were evaluated using final instar larvae of the midge Chironomus tepperi. Terbufos, terbufos sulfoxide and terbufos sulfone were highly toxic to C. tepperi with mean 96-h EC50 values of 2.13, 3.64 and 2.59 μg/l, respectively. No interaction was observed between atrazine (25 μg/l) and terbufos or its breakdown products while the binary mixture of terbufos sulfoxide and terbufos sulfone exhibited additive toxicity. The high toxicities of terbufos and its environmentally persistent oxidation products suggest that contamination of aquatic systems with this insecticide pose a threat to aquatic organisms whether or not atrazine is also present.

An underlying assumption of laboratory-based toxicity tests is that the sensitivity and exposure of organisms in the laboratory is comparable to that in the field. We sought to make a comparison between field-based and laboratory-based sediment toxicity tests using a recently developed rapid amphipod reproduction test that encompasses gametogenesis, fertilization, and embryo development before hatching. The test species, Melita plumulosa, is an epibenthic, detritivorous amphipod native to Eastern Australia. Test sediments were sourced from Lake Macquarie, a large saltwater lagoon located 100 km north of Sydney (New South Wales, Australia) that has received heavy-metal pollution over many decades, primarily from a Pb/Zn smelter but also from collieries, coal-fired power stations, and urban areas. This has led to a north-south trace-metal concentration gradient, including Pb, Zn, Cd and Cu, in the sediments of Lake Macquarie. Sediments from these northern bays were demonstrated to reduce amphipod fecundity in laboratory-based tests. For the current study, the amphipod reproduction test has been modified for use in situ. In situ test chambers were deployed at the mouth of Cockle Creek, Lake Macquarie. Sediments that were demonstrated to reduce fecundity of M. plumulosa in the laboratory reproduction test were not similarly toxic when amphipods were exposed to the same sediments in situ. Factors related to the regular tidal renewal of overlying water likely altered exposure profiles in situ, including the provision of additional or alternative nutrition that obviated the need for amphipods to interact with the contaminated sediments, and a washout effect that prevented the accretion of dissolved zinc in the overlying water. Environ. Environ. Toxicol. Chem. 2010;29:2566-2574. © 2010 SETAC Copyright © 2010 SETAC.

The acute toxicity of terbufos and its major metabolites, tested alone, in binary mixtures or in combination with atrazine were evaluated using neonates of the cladoceran Ceriodaphnia cf dubia. Terbufos, terbufos sulfoxide, and terbufos sulfone tested individually were highly toxic to C. cf dubia, with mean 96-h EC(50) values of 0.08, 0.36, and 0.19 μg/l, respectively. The addition of atrazine (10 μg/l) significantly increased the toxicity of terbufos. The toxicity of terbufos sulfone was unaffected by atrazine, whereas the results for terbufos sulfoxide were equivocal. Equitoxic mixtures of the metabolites showed additive toxicity to C. cf dubia. The high toxicities of terbufos and its environmentally persistent oxidative metabolites suggest that contamination of aquatic systems with this insecticide mixture and the coapplied herbicide atrazine might pose a greater hazard to some biota than their individual toxicities.

The chronic toxicity of dietary cadmium to the saltwater cladoceran Moina monogolica Daday and its relative toxicity compared with aquatic exposure were investigated in the present study. The microalgae Chlorella pyrenoidosa, exposed to cadmium in growth inhibition tests, had a 96-h median effective concentration (EC50) of 81.2 µg Cd/L (95% confidence intervals [CIs] = 71.9–95.1). C. pyrenoidosa exposed for 96 h to sublethal dissolved cadmium concentrations in the range 4.10 ± 0.30 to 70.29 ± 0.31 µg/L resulted in algal cadmium burdens up to 73.86 × 10−16 g Cd/cell. Cellular cadmium burdens accumulated in a dose-dependent manner, whereas cell densities inversely declined from 670 × 104 to 38 × 104 cells/ml with exposure to the increasing aqueous cadmium concentrations. C. pyrenoidosa preexposed to cadmium and used as food in a chronic 21-d toxicity test with the cladoceran M. monogolica, containing no added dissolved cadmium, inhibited reproduction. Significant reductions of the net reproduction rate (R0) per brood were observed in all broods, and the decline in the number of neonates produced increased with each subsequent brood. The cadmium concentration (4.10 ± 0.30 µg/L) in the algal culture water that produced the lowest algal cadmium burden (2.85 ± 0.76 × 10−16 g Cd/cell) was shown to inhibit M. monogolica reproduction and was compared with the water quality criteria (WQC) of China. This comparison indicated that dietary exposure to cadmium may cause sublethal responses at concentrations below the current cadmium WQC of China for aquaculture. Environ. Toxicol. Chem. 2010;29:365–372. © 2009 SETAC

Agricultural landscapes, although often highly altered in nature, provide habitat for many species of amphibian. However, the persistence and health of amphibian populations are likely to be compromised by the escalating use of pesticides and other agricultural chemicals. This review examines some of the issues relating to exposure of amphibian populations to these chemicals and places emphasis on mechanisms of toxicity. Several mechanisms are highlighted, including those that may disrupt thyroid activity, retinoid pathways, and sexual differentiation. Special emphasis is also placed on the various interactions that may occur between different agro-chemicals and between chemicals and other environmental factors. We also examine the indirect effects on amphibian populations that occur when their surrounding pond communities are altered by chemicals. © 2009 Elsevier Ltd.

A model mesocosm system was used to simulate the effect of endosulfan entering a waterway from episodic events such as accidental overspray or in runoff water containing contaminated sediment following storm events. The fate of technical endosulfan applied to a 24-stream mesocosm was compared in experiments where the pesticide was applied either directly as water contamination or after being pre-bound to sediment. The flow of water through the streams was discontinued for a 10-12 h period following the pesticide application. Following the water application, only approximately 3% of endosulfan remained in the streams after 4 days and then was not detectable after 7 days. In contrast, after application pre-bound to sediment, approximately 33% of the endosulfan remained in the streams after 4 days and 14% after 7 days. Additionally, with the sediment-bound application, the proportion of endosulfan was higher in the substrate (11%) after 7 days than in the overlying water (3%), and approximately 1% was oxidised to the sulphate form. The dissipation of endosulfan in the water column of both experiments followed a two-parameter exponential decay model characterised by a relatively fast first-order single-phase process. In sediment of both experiments and the gravel of the sediment-dosing experiment, the dissipation of endosulfan followed more closely a four-parameter bi-exponential decay model characterised by first-order kinetics of two fractions: the first fraction dissipates quickly, and in the longer term the second fraction dominates the overall dissipation with a slower rate. In the gravel section of the water-dosing experiment, endosulfan dissipation was characterised by relatively very slow two-parameter exponential decay. The overall dissipation rates of the alpha- and beta-endosulfan isomers were significantly higher in the water-dosing than in the sediment-dosing experiment, except in the gravel section of the mesocosm. The uptake of the endosulfan into passive samplers constructed from polyethylene membrane bags containing trimethylpentane solvent (TRIMPS) placed in the overlying water was linear. In contrast, TRIMPS buried in sediment failed to uptake endosulfan from the sediment substrate, indicating that short-term deployment of passive samplers can only be used to determine time-weighted average concentrations of bioavailable chemicals in the water column. A 34-h LC50 of 2.8 microg/l [95% confidence interval (CI) 1.5-4.2 microg/l] for juveniles of the native fish Macquaria ambigua was obtained when exposed during the water-dosing experiment. This study demonstrated that the pulse entry of sediment contaminated with endosulfan into a receiving waterway was more persistent compared with direct aqueous contamination and the endosulfan would be bioavailable to pelagic organisms following a gradual partitioning to the water column.

A passive sampler device selective for hydrophilic analytes was constructed from cellulose membrane (40 μm thickness) pre-stained with ruthenium red for 96–168 h to impede degradation of the cellulose. The sampling device consisted of pre-stained cellulose membrane tubing containing a binary mixture of the solvents 1-dodecanol and 2,2,4-trimethylpentane as the sequestering medium. A laboratory flow-through system was used to investigate the rates of uptake of herbicides into the solvent mixture of the device and their release. The target herbicides were diuron, atrazine, metolachlor and molinate. Uptake of the herbicides into the solvent mixture of the cellulose membrane device was linear for up to 22 days, and daily sampling rates were determined. Release half-lives from the solvent mixture of the sampling device varied from 14 days for diuron, 15 days for atrazine, 84 days for metolachlor and 28 days for molinate. A field study was undertaken to determine if herbicide concentrations in agricultural drainage water derived from the passive sampler devices deployed for periods from 7 to 22 days, using the laboratory-derived sampling rates, would compare closely with time-weighted average herbicide concentrations determined from extractions of daily composite water samples. The concentrations of diuron, atrazine, metolachlor and molinate determined using the cellulose membrane devices were within twofold of the cumulated mean of the daily drainage water extractions.

[Melita plumulosa is an epibenthic estuarine amphipod that has recently been adopted in Australia as a test organism for the evaluation of estuarine-sediment toxicity. In this study, the embryological development of M. plumulosa was observed following the mating of individuals reared in laboratory cultures. Intra-marsupial development until hatching was completed within seven days, and five distinct stages of development were recognized that closely resemble those described previously for gammarid amphipods. There was no distinct relationship between the size of females and the number of embryos. Melita plumulosa est un amphipode epibenthique d'estuaire qui a ete recemment adopte en Australie comme organisme-test pour l'evaluation de la toxicite des sediments estuariens. Au cours de cette etude, le developpement embryonnaire de M. plumulosa a ete observe en suivant la reproduction d'individus eleves au laboratoire. Le developpement intra-marsupial jusqu'a l'eclosion a ete accompli en sept jours et cinq stades distincts de developpement ont ete identifies, qui ressemblent exactement a ceux decrits auparavant chez les amphipodes Gammarides. Il n'y avait pas de relation distincte entre la taille des femelles et le nombre d'embryons., Melita plumulosa is an epibenthic estuarine amphipod that has recently been adopted in Australia as a test organism for the evaluation of estuarine-sediment toxicity. In this study, the embryological development of M. plumulosa was observed following the mating of individuals reared in laboratory cultures. Intra-marsupial development until hatching was completed within seven days, and five distinct stages of development were recognized that closely resemble those described previously for gammarid amphipods. There was no distinct relationship between the size of females and the number of embryos. Melita plumulosa est un amphipode epibenthique d'estuaire qui a ete recemment adopte en Australie comme organisme-test pour l'evaluation de la toxicite des sediments estuariens. Au cours de cette etude, le developpement embryonnaire de M. plumulosa a ete observe en suivant la reproduction d'individus eleves au laboratoire. Le developpement intra-marsupial jusqu'a l'eclosion a ete accompli en sept jours et cinq stades distincts de developpement ont ete identifies, qui ressemblent exactement a ceux decrits auparavant chez les amphipodes Gammarides. Il n'y avait pas de relation distincte entre la taille des femelles et le nombre d'embryons.]

Macromolecular conjugates of tamoxifen could perhaps be used to circumvent some of the limitations of the extensively used breast cancer drug. To test the feasibility of these conjugates, a 4-hydroxytamoxifen analogue was conjugated to a diaminoalkyl linker and then conjugated to activated esters of a poly(methacrylic acid) polymer synthesized by atom transfer radical polymerization. A polymer conjugated to the 4-hydroxytamoxifen analogue with a six-carbon linker showed high affinity for both estrogen receptor alpha and estrogen receptor beta and potent antagonism of the estrogen receptor in cell-based transcriptional reporter assays. These results suggest that the conjugation of 4-hydroxytamoxifen to a polymer results in a macromolecular conjugate that can display ligand in a manner that can be recognized by estrogen receptor and still act as a potent antiestrogen in cells.

The anti-estrogenic drug tamoxifen, which is used therapeutically for treatment and prevention of breast cancer, can lead to the development of thrombosis. We found that tamoxifen rapidly increased intracellular free calcium [Ca2+]i in human platelets from both male and female donors. Thus 10 microM tamoxifen increased [Ca2+]i above the resting level by 197 +/- 19%. Tamoxifen acted synergistically with thrombin, ADP, and vasopressin to increase [Ca2+]i. The anti-estrogen ICI 182780 did not attenuate the effects of tamoxifen to increase [Ca2+]i; however, phospholipase C inhibitor U-73122 blocked this effect. 4-hydroxytamoxifen, a major metabolite of tamoxifen, also increased [Ca2+]i, but other tamoxifen metabolites and synthetic derivatives did not. Three hydroxylated derivatives of triphenylethylene (corresponding to the hydrophobic core of tamoxifen) which are transitional structures between tamoxifen (Ca agonist) and diethylstilbestrol (Ca antagonist) increased [Ca2+]i slightly (6% to 24%) and partially inhibited thrombin-induced [Ca2+]i elevation (68% to 79%). Therefore the dimethylaminoethyl moiety is responsible for tamoxifen being a Ca agonist rather than antagonist. 4-Hydroxytamoxifen and polymer-conjugated derivatives of 4-hydroxytamoxifen increased [Ca2+]i, with similar efficacy. The ability of tamoxifen to increase [Ca2+]i in platelets, leading to platelet activation, and its ability to act synergistically with other platelet agonists may contribute to development of tamoxifen-induced thrombosis.

The present study describes the application of different extraction techniques for the preconcentration of ten commonly found acidic and non-acidic polar herbicides (2,4-D, atrazine, bensulfuron-methyl, clomazone, dicamba, diuron, MCPA, metolachlor, simazine and triclopyr) in the aqueous environment. Liquid-liquid extraction (LLE) with dichloromethane, solid-phase extraction (SPE) using Oasis HLB cartridges or SBD-XC Empore disks were compared for extraction efficiency of these herbicides in different matrices, especially water samples from contaminated agricultural drainage water containing high concentrations of particulate matter. Herbicides were separated and quantified by high performance liquid chromatography (HPLC) with an ultraviolet detector. SPE using SDB-XC Empore disks was applied to determine target herbicides in the Murrumbidgee Irrigation Area (NSW, Australia) during a two-week survey from October 2005 to November 2005. The daily aqueous concentrations of herbicides from 24-h composite samples detected at two sites increased after run-off from a storm event and were in the range of: 0.1-17.8 microg l(-1), < 0.1-0.9 microg l(-1) and 0.2-17.8 microg l(-1) at site 1; < 0.1-3.5 microg l(-1), < 0.1-0.2 microg l(-1) and < 0.2-3.2 microg l(-1) at site 2 for simazine, atrazine and diuron, respectively.

Antiestrogens used for breast cancer therapy can be categorized into two classes that differ in their effect on estrogen receptor (ER) alpha stability. The selective estrogen receptor modulators (SERMs) stabilize ER alpha and the selective estrogen receptor downregulators (SERDs) cause a decrease in cellular ER alpha levels. A clinically relevant antiestrogen, GW7604, appears to work through a SERD-like mechanism, despite sharing the same molecular scaffold as 4-hydroxytamoxifen, a SERM. In order to investigate potential structural features of GW7604 responsible for SERD activity, GW7604 and two analogs were synthesized using a new, improved synthetic route and tested for their effects on ER alpha function and cell proliferation. The two analogs, which have an acrylamide or a methyl vinyl ketone replacing the acrylic acid group of GW7604, display lower binding affinity for ER alpha than GW7604, but show similar antagonism of estradiol-induced activation of ER alpha-mediated transcription as GW7604 and inhibit estradiol-induced proliferation of the MCF-7 cell line with a similar potency as GW7604. Unlike GW7604, neither analog has a significant effect on cellular ER alpha levels, suggesting that the carboxylate is a key determinant in GW7604 action and, for the first time, showing that this group is responsible for inducing ER alpha degradation in breast cancer cells.

A laboratory continuous-flow system delivering known aqueous concentrations of pesticides to passive samplers was used to examine the kinetics of pesticide uptake and release. The passive samplers were constructed of low-density polyethylene membrane bags containing 2,2,4-trimethylpentane solvent (TRIMPS). Both uptake and release experiments were run in triplicate. Each experiment involved four treatments, including a control and three fivefold dilutions of a pesticide mixture that included the usual range of these pesticides as measured in the riverine environment of cotton-growing regions of Australia. The results indicated that for nonpolar pesticides with a log K o w > 3.5, uptake was linear over the 42-d exposure time and was independent of the treatment concentration. The half-lives for release of these pesticides from the TRIMPS varied from 26 to 130 d in clean water. The relatively polar pesticides with a log K o w < 3.5 had lower uptake rates into the TRIMPS because of their affinity for water. Release of trimethylpentane from the TRIMPS placed in 0.85-mm mesh nylon bags in river water was used as an indicator for chemical diffusion across the aqueous boundary to examine the effect of environmental factors. Most variability in solvent release in the field-deployed TRIMPS across all sites was explained by time of deployment and was not significantly influenced by river flow or water temperature. This suggests that river flow and water temperature may not be important in influencing uptake rates of pesticides into TRIMPS when employed in the field.

Some aspects of ligand-regulated transcription activation by the estrogen receptor (ER) are associated with the estrogen-dependent formation of a hydrophobic cleft on the receptor surface. At least in vitro, this cleft is required for direct interaction of ER with an helix, containing variants of the sequence LXXLL, found in many coactivators. In cells, it is unknown whether ER interactions with the different LXXLL-containing helices are uniformly similar or whether they vary with LXXLL sequence or activating ligand. Using fluorescence resonance energy transfer (FRET), we confirm in the physiological environment a direct interaction between the estradiol (E2)-bound ER and LXXLL peptides expressed in living cells as fusions with spectral variants of the green fluorescent protein. This interaction was blocked by a single amino acid mutation in the hydrophobic cleft. No FRET was detected when cells were incubated with the antiestrogenic ligands tamoxifen and ICI 182,780. E2, diethylstilbestrol, ethyl indenestrol A, and 6,4dihydroxyflavone all promoted FRET and activated ER-dependent transcription. Measurement of the level of FRET of ER with different LXXLL-containing peptides suggested that the orientations or affinities of the LXXLL interactions with the hydrophobic cleft were globally similar but slightly different for some activating ligands. (Molecular Endocrinology 16: 487–496, 2002)

The toxicity of the organochlorine pesticide endosulfan to macroinvertebrate communities was tested using a system of 24 artificial streams. Macroinvertebrate communities in the streams were exposed to a range of endosulfan concentrations for a 12-h period and then monitored for 96 h. Endosulfan was prebound to fine river sediment and applied to the streams as a contaminated sediment slurry. This did not cause changes in the structure of benthic communities; however, significant changes (P

The two subtypes of human estrogen receptor, alpha (hERalpha) and beta (hERbeta), regulate transcription at an AP-1 response element differently in response to estradiol and the anti-estrogens tamoxifen and raloxifene. To better understand the protein determinants of these differences, chimeric and deletional mutants of the N-terminal domain and the F region of ERalpha and ERbeta were made and tested in transient transfection assays at the classical estrogen response element (ERE) site as well as at an AP-1 site. Although the same regions on each receptor subtype appeared to be primarily responsible for estradiol activation at an ERE and in HeLa cells, major differences between ERalpha and ERbeta mutants were seen in the estrogen and anti-estrogen responses at an AP-1 site. This differential ligand response maps to the N-terminal domain and the F region. These results suggest that different estrogenic and anti-estrogenic ligands use different mechanisms of activation and inhibition at the AP-1 site. In contrast to previous studies, this work also shows that many of subtype-specific responses are not transferred to the other subtype by swapping the N-terminal domain of the receptor. This implies that there are other unique surfaces presented by each subtype outside of the N-terminal domain, and these surfaces can play a role in subtype-selective signaling. Together, these data suggest a complex interface between ligand, response element, and receptor that underlies ligand activation in estrogen signaling pathways.

Freshwater fluvial suspended sediment particle size characteristics alter temporally when allowed to stand, undergoing continuous aggregation to form larger composite particles (aggregates or flocs) that can settle from the water column and are stable to hand shaking. Treatments to inhibit the spontaneous aggregation of laboratory prepared and fluvial suspended sediments were investigated. A novel method using formaldehyde to fix suspended sediment was developed, which inhibited aggregation of the suspended particles. The formaldehyde-treated particle suspensions formed fragile aggregates on settling, but they were redispersed by hand shaking. When assessed by particle size distribution, photography and turbidity measurements following resuspension, treatments with 2% (v/v) formaldehyde showed little alteration of the initial existing particles or aggregate composition and turbidity. The fixation of fluvial water samples with formaldehyde immediately after collection allowed the transportation and storage of the samples containing suspended sediment for laboratory analysis, weeks after collection.

A class of thyroid hormone metabolites has dramatic physiological effects on metabolism and heart rate by still-unknown mechanisms of action. A recent study has discovered that thyronamines can inhibit neuronal reuptake of neurotransmitters and prevent the intracellular transport of monoamines for release. This discovery presents a third signaling pathway for thyroid hormone, expands the role that thyroid plays in the central nervous system, and suggests mechanisms of action for the effects of thyronamine-derived neuromodulators.

Bicarbonate is often a major ionic constituent associated with produced waters from methane gas extraction and coal mining, yet few studies have determined its specific toxicity. Currently, the environmental risk of bicarbonate anion in water discharges is assessed based on the toxicity of sodium chloride or artificial seawater and is regulated via electrical conductivity. Increased NaHCO(3) added to Ceriodaphnia dubia in synthetic or natural water gave similar 48-h 10% effective concentration (EC10) values of 1750 ± 125 mg NaHCO(3)/L (mean ± standard error) and 1670 ± 180 mg NaHCO(3)/L, respectively. Bicarbonate was toxic to C. dubia in both waters with conductivities above 1900 µS/cm. In contrast, when conductivity was elevated with NaCl, toxicity to C. dubia was observed only above 2800 µS/cm. Bicarbonate also impaired C. dubia reproduction with an EC10 of 340 mg NaHCO(3)/L. Major ion composition also influenced Zn bioavailability, a common co-occurring metal contaminant in coal mine waters, with sublethal concentrations of NaHCO(3) and elevated pH increasing Zn toxicity. Higher pH was the dominant parameter determining a 10-fold increase in the 48-h 50% effective concentration (EC50) for Zn toxicity to C. dubia at pH 8.6 of 34 µg Zn/L (95% confidence limit = 32-37 µg Zn/L) compared with the Zn toxicity at approximately circumneutral pH. Exposure of the freshwater shrimp Paratya australiensis (Atyidae) in natural water to increasing bicarbonate gave a mean 10-d 10% lethal concentration (LC10) of 850 ± 115 mg NaHCO(3)/L, associated with a mean conductivity EC10 of 1145 µS/cm, which is considerably lower than toxicity of NaCl and artificial seawater to this species reported elsewhere. Because toxicity was influenced by salt composition, specific ions should be regulated rather than conductivity alone in mine wastewater discharges.

Populations subject to anthropogenic contaminants often display altered patterns of genetic variation, including decreased genetic variability. Selective pressures of contaminant exposure are also reflected in differential tolerance between genotypes. An industrial chemical spill in a major eastern Australian waterway in July 2006 resulted in altered patterns of genetic variability in a nearby population of the amphipod, Melita plumulosa for up to one year post-spill, despite the site being declared clean after 48 h. Here, we investigate the toxicant response of three mitochondrial lines naturally occurring at the impacted site by comparing survivorship and life-history trait variables following naphthalene exposure. Overall, M. plumulosa demonstrated differential survivorship between mitochondrial lines under exposure to high concentrations of naphthalene. In addition, we identified differential fecundity and frequencies of gravidity in female amphipods between the mitochondrial haplotypes examined. These findings suggest that the patterns of genetic variability previously identified may be linked with differential tolerance and/or reproductive performance between mitochondrial lineages.

Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) are popular and powerful techniques used to characterize heterogeneous catalysts. Rapid developments in electron microscopy – especially aberration correctors and in situ methods – permit remarkable capabilities for visualizing both morphologies and atomic and electronic structures. The purpose of this review is to summarize the significant developments and achievements in this field with particular emphasis on the characterization of catalysts. We also highlight the potential and limitations of the various methods, describe the need for synergistic and complementary tools when characterizing heterogeneous catalysts, and conclude with an outlook that also envisions future needs in the field.

A passive sampler device suitable for monitoring of residues of the hydrophilic ionic herbicide amitrole in irrigation waterways was developed. Uptake of amitrole on styrenedivinylbenzene-reverse phase sulfonated Empore™ disks was linear and proportional to its water concentration over the range of 1-10 μg/L with a sampling rate of 23.1 mL/day under laboratory flow-through conditions. Performance of the sampler was evaluated by deployment in an agricultural irrigation drain for 10 days. The amount of amitrole adsorbed by the passive samplers compared well with the cumulative mean water concentrations calculated from daily spot samplings of the drain water. © 2013 Springer Science+Business Media New York.

The binding of the mannose/glucose specific lectins from Canavalia ensiformis (concanavalin A) and Dioclea grandiflora to a series of C-glucosides were studied by titration microcalorimetry and fluorescence anisotropy titration. These closely related lectins share a specificity for the trimannoside methyl 3,6-di-O-(alpha-D-mannopyranosyl)-alpha-D-mannopyranoside, and are a useful model system for addressing the feasibility of differentiating between lectins with overlapping carbohydrate specificities. The ligands were designed to address two issues: (1) how the recognition properties of non-hydrolyzable C-glycoside analogues compare with those of the corresponding O-glycosides and (2) the effect of presentation of more than one saccharide recognition epitope on both affinity and specificity. Both lectins bind the C-glycosides with affinities comparable to those of the O-glycoside analogues; however, the ability of both lectins to differentiate between gluco and manno diastereomers was diminished in the C-glycoside series. Bivalent norbornyl C-glycoside esters were bound by the lectin from Canavalia but only weakly by the lectin from Dioclea. In addition to binding the bivalent ligands, concanavalin A discriminated between C-2 epimers, with the manno configuration binding more tightly than the gluco. The stoichiometry of binding of the bivalent ligands to both di- and tetrameric lectin was two binding sites per ligand, rather than the expected 1:1 stoichiometry. Together, these results suggest that concanavalin A may possess more than one class of carbohydrate binding sites and that these additional sites show stereochemical discrimination similar to that of the previously identified monosaccharide binding site. The implications of these findings for possible in vivo roles of plant lectins and for the use of concanavalin A as a research tool are discussed.

The free energies of binding of various C- and O-glycosides to the lectin concanavalin A were measured using fluorescence anisotropy. Fluorescein derivatives of mannose and glucose were synthesized and were shown to bind to concanavalin A with free energies of -5.1 and -4.3 kcal mol(-)(1), respectively. Competition experiments were performed to determine the binding energies of different nonfluorescent carbohydrates, and the results were in excellent agreement with the binding energies determined by microcalorimetry. The minimum carbohydrate epitope that fills the lectin carbohydrate binding site, methyl 3,6-di-O-(alpha-mannopyranosyl)-alpha-mannopyranoside, competes directly for the site with the fluorescent ligands, indicating that the fluorescent ligands bind specifically. The binding affinities of C-glycosides to concanavalin A were compared with those of O-glycosides. The free energies of binding for corresponding C- and O-glycosides differed by less than 0.5 kcal mol(-)(1), indicating that recognition properties of C- and O-glycosides are very similar. It was found that for some ligands the use of a carbon linkage rather than an oxygen linkage caused the specificity of binding to decrease slightly.

Transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) are popular and powerful techniques used to characterize heterogeneous catalysts. Rapid developments in electron microscopy – especially aberration correctors and in situ methods – permit remarkable capabilities for visualizing both morphologies and atomic and electronic structures. The purpose of this review is to summarize the significant developments and achievements in this field with particular emphasis on the characterization of catalysts. We also highlight the potential and limitations of the various methods, describe the need for synergistic and complementary tools when characterizing heterogeneous catalysts, and conclude with an outlook that also envisions future needs in the field.

The effects of a co-occurring insecticide–herbicide mixture were evaluated using model ecosystems (microcosms) in the laboratory. Microcosms dosed with a high concentration (10 μg/L) of the insecticide terbufos, alone and as a mixture with the herbicide atrazine (25 μg/L), exhibited community level effects attributed to the elimination and decline of invertebrate populations, and also indirect effects. There were no community level effects at a lower concentration of terbufos (0.1 μg/L) alone or in a mixture with atrazine, although delayed population effects were observed. Female chironomids also emerged later and those from terbufos-only microcosms were smaller. Exposure to atrazine alone was also associated with lower abundances of cladocerans and reduced emergence of chironomids. The risk posed by atrazine is low and is unlikely to exacerbate the effects of terbufos. Nevertheless, the population-level effects highlight that terbufos poses a potential risk to aquatic ecosystems, regardless of whether atrazine is also present.

In 1859, Charles Darwin and Alfred Russell Wallace independently proposed the theory of evolution by natural selection. This theory propounded that the inter-generational success of all living organisms is restricted by their range of environmental tolerances and organismal requirements. In the current post-genomics era the impact of environmental stressors upon the genetic structure of populations and species continues to be a fascination from both theoretical and practical perspectives. From a theoretical perspective stressors can give deep insight into processes causing genetic subdivision. Practically, stressors can influence genetic diversity and this can provide us with information on the health of an ecosystem. While stressors in the environment can be both anthropogenic as well as natural in origin, in this review we focus on man-made stressors.

Hypothesizing that rapid estrogen signaling could be modulated from different estrogen receptors with unique localization patterns, a number of groups have attempted to design drug conjugates that target or restrict compounds to specific subcellular compartments. This article will briefly discuss the history of using conjugates to dissect rapid estrogen signaling and different strategies to attempt to target estrogens and antiestrogens to different locations. It will also detail some of the potential issues that can arise with different types of conjugates, using examples drawn from the authors’ own work.

To examine the link between corn agriculture and the observed decline of the endangered southern bell frog (SBF), the effects of two corn crop pesticides on larval growth and development were investigated. Tadpoles were exposed to terbufos sulfone (10 μg/L), a major breakdown product of the insecticide terbufos, and the herbicide atrazine (25 μg/L) individually and as a mixture until the completion of metamorphosis. Atrazine did not interact synergistically with terbufos sulfone or result in significant effects on growth and development alone, although there was some indication of accelerated metamorphosis in the pilot study. Terbufos sulfone alone and as a mixture (terbufos/atrazine) significantly slowed larval development and ultimately delayed metamorphosis. The observed developmental effects from an environmentally relevant concentration of terbufos sulfone indicates a risk posed by this persistent degradation product to the endangered SBF, which breeds and develops in the rice bays adjacent to corn fields treated with pesticides. © 2010 Published by Elsevier Ltd.

Artificial substrates consisting of fine milled silica with or without α-cellulose were evaluated for their capacity to support survival, growth, and fecundity in the amphipod Melita plumulosa. There were no significant differences in the survival and fecundity of adult amphipods maintained for up to 13 d on natural sediment, silica-only, or silica/α-cellulose substrate when fed two algal foods, Sera® micron and Rotiselco®-ALG. However, growth among juveniles maintained on the silica/α-cellulose mixture was significantly inhibited over 14 d compared with natural sediment. Addition of a microencapsulated shrimp feed, Frippak®, to the algal foods improved juvenile growth over 28 d but still did not match the nutritive value of natural sediment. Fine silica without cellulose was subsequently used in acute and reproductive toxicity tests with waterborne zinc. With food, a 10-d median lethal concentration (LC50) of 140μg Zn/L and a 10-d no-effect concentration (NEC) of 80μg Zn/L were obtained for juvenile survival on silica. In contrast, a 10-d LC50 of 200μg Zn/L and a 10-d NEC of 180μg Zn/L were obtained for juveniles in water-only exposures. Similarly, exposure of adult females to Zn without food on silica compared with water-only exposures gave 10-d LC50s of 380 and 490μg Zn/L and 10-d NECs of 130 and 370μg Zn/L, respectively. The reproduction toxicity test indicated significant adult mortality at 92μg Zn/L and significantly reduced fecundity at 22μg Zn/L. We surmised that the toxicity of waterborne zinc to M. plumulosa increased when maintained on nutrient-depleted silica compared with water-only exposure because of increased energy expended through foraging, in concert with the likely increased exposure to Zn via the digestive tract and the gills. © 2011 SETAC.