Hazard assessment of sediments from a wetland system for treatment of landfill leachate using bioassays.

Four bioassays were used in this study for the hazard assessment of sediments from sediment traps and several ponds in a treatment wetland for landfill leachate at Atleverket, Sweden. In the 6-day solid phase microbiotest with the sediment-dwelling crustacean Heterocypris incongruens both acute and chronic effects were observed with a gradual decrease and loss of toxicity with treatment in the wetland system. Some samples showed a low toxicity in porewater and only one sample was weakly toxic in the whole sediment test when assessed with Aliivibrio fischeri (Vibro fischeri). No genotoxicity was detected in the umu test. The toxicity response in the H4IIE- luc test evaluating the presence of dioxin-like compounds was considerably higher in the samples from the sediment traps. The hazard of the sediment therefore appears to be highest in the sediment traps and pond 1 with the methods employed. The result indicates that the wetland system has a design supporting the concentration and sequestration of toxic substances in the first part of the wetland. Based upon the results we suggest that hazard assessment of sediments from other treatment wetlands for landfill leachate should be conducted.

Ingestion and contact with polyethylene microplastics does not cause acute toxicity on marine zooplankton.

Toxicity of polyethylene microplastics (PE-MP) of size ranges similar to their natural food to zooplanktonic organisms representative of the main taxa present in marine plankton, including rotifers, copepods, bivalves, echinoderms and fish, was evaluated. Early life stages (ELS) were prioritized as testing models in order to maximize sensitivity. Treatments included particles spiked with benzophenone-3 (BP-3), a hydrophobic organic chemical used in cosmetics with direct input in coastal areas. Despite documented ingestion of both virgin and BP-3 spiked microplastics no acute toxicity was found at loads orders of magnitude above environmentally relevant concentrations on any of the invertebrate models. In fish tests some effects, including premature or reduced hatching, were observed after 12 d exposure at 10 mg L-1 of BP-3 spiked PE-MP. The results obtained do not support environmentally relevant risk of microplastics on marine zooplankton. Similar approaches testing more hydrophobic chemicals with higher acute toxicity are needed before these conclusions could be extended to other organic pollutants common in marine ecosystems. Therefore, the replacement of these polymers in consumer products must be carefully considered.

An overview of the safety pharmacology society strategic plan.

Safety Pharmacology studies are conducted to characterize the confidence by which biologically active new chemical entities (NCE) may be anticipated as safe. Non-clinical safety pharmacology studies aim to detect and characterize potentially undesirable pharmacodynamic activities using an array of in silico, in vitro and in vivo animal models. While a broad spectrum of methodological innovation and advancement of the science occurs within the Safety Pharmacology Society, the society also focuses on partnerships with health authorities and technology providers and facilitates interaction with organizations of common interest such as pharmacology, physiology, neuroscience, cardiology and toxicology. Education remains a primary emphasis for the society through content derived from regional and annual meetings, webinars and publication of its works it seeks to inform the general scientific and regulatory community. In considering the future of safety pharmacology the society has developed a strategy to successfully navigate forward and not be mired in stagnation of the discipline. Strategy can be defined in numerous ways but generally involves establishing and setting goals, determining what actions are needed to achieve those goals, and mobilizing resources within the society to accomplish the actions. The discipline remains in rapid evolution and its coverage is certain to expand to provide better guidance for more systems in the next few years. This overview from the Safety Pharmacology Society will outline the strategic plan from 2016 to 2018 and beyond and provide insight into the future of the discipline which builds upon a previous strategic plan established in 2009.

An ecotoxicological view on neurotoxicity assessment.

The numbers of potential neurotoxicants in the environment are raising and pose a great risk for humans and the environment. Currently neurotoxicity assessment is mostly performed to predict and prevent harm to human populations. Despite all the efforts invested in the last years in developing novel in vitro or in silico test systems, in vivo tests with rodents are still the only accepted test for neurotoxicity risk assessment in Europe. Despite an increasing number of reports of species showing altered behaviour, neurotoxicity assessment for species in the environment is not required and therefore mostly not performed. Considering the increasing numbers of environmental contaminants with potential neurotoxic potential, eco-neurotoxicity should be also considered in risk assessment. In order to do so novel test systems are needed that can cope with species differences within ecosystems. In the field, online-biomonitoring systems using behavioural information could be used to detect neurotoxic effects and effect-directed analyses could be applied to identify the neurotoxicants causing the effect. Additionally, toxic pressure calculations in combination with mixture modelling could use environmental chemical monitoring data to predict adverse effects and prioritize pollutants for laboratory testing. Cheminformatics based on computational toxicological data from in vitro and in vivo studies could help to identify potential neurotoxicants. An array of in vitro assays covering different modes of action could be applied to screen compounds for neurotoxicity. The selection of in vitro assays could be guided by AOPs relevant for eco-neurotoxicity. In order to be able to perform risk assessment for eco-neurotoxicity, methods need to focus on the most sensitive species in an ecosystem. A test battery using species from different trophic levels might be the best approach. To implement eco-neurotoxicity assessment into European risk assessment, cheminformatics and in vitro screening tests could be used as first approach to identify eco-neurotoxic pollutants. In a second step, a small species test battery could be applied to assess the risks of ecosystems.

Uptake and bioaccumulation of PCDD/Fs in earthworms after in situ and in vitro exposure to soil from a contaminated sawmill site.

Uptake of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) was studied in earthworms collected from a sawmill site in Sweden with severe PCDD/Fs contamination (the hot spot concentration was 690,000ng TEQWHO2005/kg d.w.) in order to investigate the transfer of PCDD/Fs from the site to the biota. PCDD/Fs concentrations in the collected earthworms were compared to PCDD/Fs concentrations in laboratory exposed earthworms (Eisenia fetida), which were exposed to contaminated soils from the sawmill site for 34days. All analyses were performed by high resolution gas chromatography/high resolution mass spectrometry (HRGC/HRMS). PCDD/Fs concentrations in the earthworms ranged from 290 to 520,000pg/g (f.w.). The main congeners found in both soils and earthworms were OCDF, 1234678-HpCDF, OCDD and 1234678-HpCDD. The study showed that the PCDD/Fs in the soil were biovailable to the earthworms and the PCDD/Fs concentrations in the soils correlated with the concentrations in the earthworms. Earthworm samples from soil with lower concentration had higher bioaccumulation factors than samples from soils with high concentration of contamination. Thus, a less contaminated soil could yield higher concentrations in earthworms compared to a higher contaminated soil. Assuming that when assessing risks with PCDD/F contaminated soil, a combination of chemical analysis of soil PCDD/Fs concentrations and bioavailability should be employed for a more comprehensive risk assessment.

Genotoxic activity of nitroarene-contaminated industrial sludge following large-scale treatment in aerated and non-aerated sacs.

An industrial sludge containing a complex mixture of nitroaromatic compounds was treated in industrial large-scale aerobic and anaerobic biodegradation processes, performed in compost sacs. The goal was to study changes in genotoxicity during the two different oxygen regimes using the umuC genotoxicity assay. The composting sac was actively aerated during 3 months and allowed to mature for another 3 months. The anaerobic sac was not aerated for 5 months and aerated during the last month in order to enhance degradation of remaining organic carbon. The sludge was obtained from the wastewater treatment plant at an industrial area in Karlskoga, Sweden. The biodegradation study was performed at a commercial waste treatment plant in Stockholm, according to the company routine procedure when treating household waste in sealed sacs. The material from the non-aerated system showed increased genotoxicity in the acetone-soluble fraction after treatment, as did the water-soluble fraction. The subsequent aeration period did not decrease the toxicity below the genotoxicity limit. The increase in the water-soluble genotoxic compounds may pose an environmental problem during secondary storage or use of sludge treated this way, since leakage of water-dissolved genotoxic compounds may occur. The composting process also generated genotoxicity, but this was restricted to acetone-soluble compounds, while the water-soluble compounds remained low in genotoxicity. The aerated process therefore seems more favorable in term of risk reduction of this industrial sludge, although it is necessary to optimize the aerated process in order to achieve non-toxic levels of potential genotoxic compounds extractable by organic solvents.

Ventilatory responses to chemoreceptor stimulation after hypoxic acclimatization in awake goats.

Our objective was to test the hypothesis that exposure to prolonged hypoxia results in altered responsiveness to chemoreceptor stimulation. Acclimatization to hypoxia occurs rapidly in the awake goat relative to other species. We tested the sensitivity of the central and peripheral chemoreceptors to chemical stimuli before and after 4 h of either isocapnic or poikilocapnic hypoxia (arterial PO2 40 Torr). We confirmed that arterial PCO2 decreased progressively, reaching a stable value after 4 h of hypoxic exposure (poikilocapnic group). In the isocapnic group, inspired minute ventilation increased over the same time course. Thus, acclimatization occurred in both groups. In goats, isocapnic hypoxia did not result in hyperventilation on return to normoxia, whereas poikilocapnic hypoxia did cause hyperventilation, indicating a different mechanism for acclimatization and the persistent hyperventilation on return to normoxia. Goats exposed to isocapnic hypoxia exhibited an increased slope of the CO2 response curve. Goats exposed to poikilocapnic hypoxia had no increase in slope but did exhibit a parallel leftward shift of the CO2 response curve. Neither group exhibited a significant change in response to bolus NaCN injections or dopamine infusions after prolonged hypoxia. However, both groups demonstrated a similar significant increase in the ventilatory response to subsequent acute exposure to isocapnic hypoxia. The increase in hypoxic ventilatory sensitivity, which was not dependent on the modality of hypoxic exposure (isocapnic vs. poikilocapnic), reinforces the key role of the carotid chemoreceptors in ventilatory acclimatization to hypoxia.

Ventilatory effects and interactions with change in PaO2 in awake goats.

We utilized selective carotid body (CB) perfusion while changing inspired O2 fraction in arterial isocapnia to characterize the non-CB chemoreceptor ventilatory response to changes in arterial PO2 (PaO2) in awake goats and to define the effect of varying levels of CB PO2 on this response. Systemic hyperoxia (PaO2 greater than 400 Torr) significantly increased inspired ventilation (VI) and tidal volume (VT) in goats during CB normoxia, and systemic hypoxia (PaO2 = 29 Torr) significantly increased VI and respiratory frequency in these goats. CB hypoxia (CB PO2 = 34 Torr) in systemic normoxia significantly increased VI, VT, and VT/TI; the ventilatory effects of CB hypoxia were not significantly altered by varying systemic PaO2. We conclude that ventilation is stimulated by systemic hypoxia and hyperoxia in CB normoxia and that this ventilatory response to changes in systemic O2 affects the CB O2 response in an additive manner.

Two discharge patterns of carotid body chemoreceptors in the goat.

Twenty-nine single carotid body chemoreceptor units recorded during normocapnic normoxia from 20 anesthetized goats were classified into two groups by discharge pattern. Thirteen fibers, which had interspike interval distributions with a prominent peak [24.0 +/- 9.8% (SD)] at 0- to 20-ms bin, were termed bursting fibers (BF). The 16 remaining fibers were termed nonbursting fibers (NBF); these had no notable peak in the interval distributions. During hypoxia and hypercapnia, the chemoreceptor fibers continued to discharge in their established patterns. The interval distribution of most NBF spike trains could be described with the Poisson process, but none of the BF could be. However, except for the intervals in the range of 0-20 ms, the interval distribution of the BF could be described as exponential. This study suggests that 1) there are two distinct populations of the goat chemoreceptor fiber, each with an inherent discharge pattern; 2) the chemoreceptor did not code information about arterial PO2 and PCO2 in different patterns; and 3) the basic chemotransduction mechanism is likely the same in BF and NBF, and the difference in discharge pattern is more likely to reflect processes downstream from the transducer.

Ventilatory afterdischarge in the awake goat.

Ventilatory afterdischarge (VAD) has been defined as a persistent gradually diminishing elevation of ventilatory activity that occurs after withdrawal of a variety of respiratory stimuli. The phenomenon has been well documented in the anesthetized cat, piglet, and lamb in response to electrical stimulation of the carotid sinus nerve. We sought to determine whether VAD could be demonstrated in the standing awake goat (n = 7) by use of an extracorporeal circuit to provide square-wave physiological stimulation of the carotid chemoreceptor (carotid body PO2 40 Torr). After 5 min of isolated carotid body stimulation, the mean time constants for diminishing inspired minute ventilation, tidal volume, and respiratory frequency were 27.7, 34.5, and 25.5 s, respectively. These results indicate that VAD does exist in the awake goat model. A critical factor for the demonstration of VAD is the maintenance of systemic arterial PCO2 (isocapnia) during the period of increased ventilatory activity. If arterial PCO2 is allowed to decrease even slightly during the hyperventilation, the magnitude and duration of VAD are greatly attenuated.

Ventilatory afterdischarge and central respiratory drive interactions in the awake goat.

We have previously established the existence of ventilatory afterdischarge (VAD) in the awake goat by means of an isolated perfused carotid body (CB) technique. In the present series of experiments we used this animal preparation to examine the effects of systemic (central nervous system) hypoxia, mild hypercapnia, and hypocapnia on the manifestation of VAD in ventilatory variables and respiratory muscle electromyogram activity after hypoxic stimulation of the isolated CB. With systemic isocapnic normoxia, inspired minute ventilation remains above control for 30-40 s (time constant = 16.8 s) after termination of CB hypoxia; however, with systemic hypocapnia, VAD is short (time constant = 5.5 s) and hypoventilation is common after removal of CB stimulation. During mild systemic hypercapnia, VAD is prolonged (time constant = 39.9 s). However, systemic (central nervous system) hypoxia did not decrease VAD (time constant = 17.0 s). These results indicate that the manifestation of VAD is more sensitive to the level of arterial PCO2 and central chemoreceptor activity than it is to the state of central oxygenation. Inspiratory and expiratory muscle electromyogram activities qualitatively tracked ventilation during CB stimulation and during the VAD period in all conditions.

Carotid body amine levels in goats exposed to hypoxia or hypercapnia.

The carotid body (CB) contains large amounts of several monoamines. There is considerable evidence that carotid body (CB) chemoreceptor function may be regulated by one or several of these monoamines. In order to test whether conditions stimulating the CB might change the CB content of these monoamines, we measured the norepinephrine, dopamine, 5-hydroxyindoleacetic acid, and 5-hydroxytryptamine content of carotid bodies collected from goats exposed to 4 h of either normoxic-normocapnic, hypoxic-normocapnic, or normoxic-hypercapnic gas mixtures. We found that there were no consistent changes in the levels of these amines associated with exposure to the test gases. These findings would not support the hypothesis that changes in these amine levels in the CB are responsible for the time-dependent changes in carotid chemoreceptor activity in goats exposed to 4 h of hypoxia.

Fate of Ah-receptor agonists in organic household waste during anaerobic degradation--estimation of levels using EROD induction in organ cultures of chick embryo livers.

The fate of 7-ethoxyresorufin O-deethylase (EROD)-inducing compounds in source-separated organic household waste subject to anaerobic degradation (i.e. mesophilic/thermophilic anaerobic treatment) was investigated using organ cultures of embryonic chicken livers from fertilised hen eggs. This bioassay reflects the combined effect of all EROD-inducing, possibly dioxin-like compounds in a sample, including chemicals that are seldom or never analysed. All samples tested induced EROD in the bioassay, indicating the presence of dioxin-like compounds. In the anaerobic processes, the amounts of acid-resistant EROD-inducing compounds coming out of the reactors were considerably higher than the incoming amounts, especially for the low-temperature (mesophilic) process. This apparent production of EROD-inducing compounds may be due to de novo synthesis or to an increase in the EROD-inducing potency of the compounds in the material.

Uptake of dioxin-like compounds from sewage sludge into various plant species--assessment of levels using a sensitive bioassay.

A bioassay for the detection of dioxin-like compounds was used to estimate uptake of dioxin-like compounds in carrots, oil seed rape seeds, zucchinis and cucumbers grown in soil amended with sewage sludge from Swedish sewage treatment plants (STP). This sensitive bioassay is based on 7-ethoxyresorufin O-deethylase (EROD)-induction in cultured chicken embryo livers and reflects the combined biological effect of all dioxin-like compounds in a sample, including ones that seldom are analyzed. The bioassay detected low concentrations of dioxin-like compounds in all carrot, zucchini and cucumber samples, but did not detect any dioxin-like compounds in the rape seeds. In carrots the concentrations were increased up to seven times when grown in soil amended with high applications of some of the sludge samples, while others did not increase the concentrations compared to control. More realistic sludge applications only increased the concentrations slightly. The sludge-fertilized carrots contained the highest concentrations of the investigated plants (up to 14 pg bioassay-derived TCDD equivalents (bio-TEQs)/g d.w.). In the carrots, differences in uptake of dioxin-like compounds depended on the sludge origin, which may be due to more easily bioaccumulated dioxin-like compounds in some sludge samples, or other components that facilitated uptake into the carrots. In the cucumbers, a more than two-fold increase (from 0.2 to 0.5 pg bio-TEQs/g d.w.) was observed in specimens grown in sludge-amended soil when compared to controls, suggesting a small uptake from the roots to the shoots. No sludge-dependent increase in uptake was seen in the zucchini fruits. The bio-TEQ levels were generally low in the consumable above ground plant parts of the investigated species. However, the question if repeated sludge application results in a soil accumulation of dioxin-like compounds, thereby increasing the risk of plant uptake, remains to be investigated.

Levels of dioxin-like compounds in sewage sludge determined with a bioassay based on EROD induction in chicken embryo liver cultures.

A bioassay for the detection of dioxin-like compounds was used to estimate levels in sewage sludge from Swedish sewage treatment plants (STPs). The sludge extracts were HPLC-separated into three fractions containing a) monoaromatic/aliphatic, b) diaromatic (e.g. polychlorinated biphenyls [PCBs], polychlorinated dibenzodioxins and polychlorinated dibenzofurans [PCDDs/Fs]), and c) polyaromatic compounds (e.g. polycyclic aromatic hydrocarbons [PAHs]). The bioassay, which is based on EROD (7-ethoxyresorufin O-deethylase) induction in cultured chicken embryo livers detected dioxin-like activity in all unfractionated extracts and in the di- and polyaromatic fractions of all sludge extracts, but not in the monoaromatic/aliphatic fractions. The levels ranged between 6 and 109 pg bio-TEQ/g sludge (d.w.). In sediment samples from rural lakes in Sweden, levels of about 5 pg bio-TEQ/g (d.w.) have been found. The polyaromatic fractions of the sludge samples were potent in the bioassay, probably due to various PAHs and other polyaromatics in the sludge. The levels of six PAHs that are screened for in the sludge at Swedish STPs accounted for only 3-10% of the observed EROD-induction by the polyaromatic fractions. Consequently, many other polyaromatic EROD-inducing compounds were present in the sludge. Inclusion of a biological test like the chicken embryo liver bioassay in the screening of sludge would improve the ability to detect the presence of bioactive dioxin-like compounds. A theoretical estimation of bio-TEQ concentrations in farm-soil following long-term application of sludge with bio-TEQ concentrations similar to those observed in this investigation indicated that the bio-TEQ levels in soil would increase very slowly over time. The chicken embryo liver bioassay proved useful in assessing levels of dioxin-like compounds in sewage sludge and it gives valuable complementary information to chemical analysis data.

Chronic obstructive pulmonary disease in a dog.

Chronic obstructive pulmonary disease was diagnosed in a 3-year-old Basset Hound that was referred to the hospital because of respiratory distress. Results of radiography, bronchoscopy, and pulmonary function tests indicated lung hyperinflation, airflow restriction, and loss of elastic recoil of the lungs. Because of the poor response to treatment, the dog was euthanatized. Postmortem findings revealed emphysema, bronchiectasis, and bronchitis, which comprise chronic obstructive pulmonary disease.

Cheetah teams.

Your crucial new product is on the fast track, when suddenly a problem develops that threatens to derail it. Time to bring in the cheetah team.

[A model for perfusing the carotid body in the awake goat and its evaluation].

A model for perfusing the carotid body (CB) in the awake goat was described in detail. The main surgical procedures were: (1) to ligate the occipital artery, cut the carotid sinus nerve and excise the CB on one side; (2) to rearrange some arteries, which supply the brain and neck on the other side (perfusion side), for isolating the CB; (3) to place cannulae in the jugular vein and the carotid artery for drawing blood and perfusing the intact CB on the perfusion side. Perfusion of the CB with goat own blood can be carried out via an extracorporal circuit during the experiment. The remark able advantages of this perfusion model are: (1) the animal can be kept in a normal physiological condition; (2) the arterial gases and pH in the CNS and CB can be controlled separately. The NaCN test was done in three steps to evaluate the model by judging the sensitivity of the peripheral chemoreceptors including the aortic and perfused carotid bodies. Applications of this model were also discussed.

Treatment of sludge containing nitro-aromatic compounds in reed-bed mesocosms - Water, BOD, carbon and nutrient removal.

Since the mid-1970s, Sweden has been depositing 1 million ton d.w sludge/year, produced at waste water treatment plants. Due to recent legislation this practice is no longer a viable method of waste management. It is necessary to improve existing and develop new sludge management techniques and one promising alternative is the dewatering and treatment of sludge in constructed wetlands. The aim of this study was to follow reduction of organic carbon, BOD and nutrients in an industrial sludge containing nitro-aromatic compounds passing through constructed small-scale wetlands, and to investigate any toxic effect such as growth inhibition of the common reed Phragmites australis. The result showed high reduction of all tested parameters in all the outgoing water samples, which shows that constructed wetlands are suitable for carbon and nutrient removal. The results also showed that P. australis is tolerant to xenobiotics and did not appear to be affected by the toxic compounds in the sludge. The sludge residual on the top of the beds contained low levels of organic carbon and is considered non-organic and could therefore be landfilled. Using this type of secondary treatment method, the amount of sludge could be reduced by 50-70%, mainly by dewatering and biodegradation of organic compounds.