Search

This investigation relates to the production of materials with noiseproof and vibration-absorbing properties, in the manufacturing of which a number of by-products are formed that require for safe disposal. When solving the production problems connected with wastewater treatment from toxicants, the concentration of which exceeds permissible values, it is proposed to use structured materials based on silicon dioxide as an adsorbent. In the course of conducting research, two experimental samples with a highly developed surface containing an extensive network of pores have been obtained and tested. The experimental testing of adsorbents has shown that such adsorbents are able to provide the removal of toxicants up to attaining a safe concentration level thereof. [ABSTRACT FROM AUTHOR]

We investigate a reaction-diffusion-advection system describing the interaction between a population and a toxicant in open advective environments. The interesting feature of this model is the consideration of a more general advective term and boundary condition. By applying the theory of monotone semi-flow and principal eigenvalue, we obtain the existence and stability of steady states and further present a clear picture on the local and global dynamics. We explore the effects of toxicants on populations and give some sufficient conditions for the existence or extinction of the population. [ABSTRACT FROM AUTHOR]

In recent years, the production and utilization of nanomaterials have increased many folds due to massive advancement in industrialization and urbanization as well as their increasing application in various sectors. Nanoparticles from these nanomaterials may release into the aquatic environment during their different stages of life cycles and may cause deleterious effects on aquatic fauna. The impact of the nanoparticles on the aquatic organisms is still largely unknown and less addressed. Although many studies have been performed to demonstrate toxicity caused by various types of nanoparticles to aquatic organisms, there is still less information related to suitable biomarkers or biological parameters used. Therefore, the aim of this review article is to carry out an assessment of available peer reviewed research reports in which different biological parameters were used to study effect of different nanoparticles on the aquatic organisms, especially fishes. Firstly, in this review the various sources of nanoparticles into the aquatic environment, different uptake routes of nanoparticles into the fish body, and their mechanism of action were discussed. After that, major emphasis as well as less emphasis given biological parameters or biomarkers to study nanoparticles toxicity to fishes by different researchers have been categorized and suitably illustrated. Furthermore, some new biomarkers or biological parameters which can be used to demonstrate nanoparticles toxicity were also discussed. In conclusion, this review will help the researchers to find out new biomarkers to study nanoparticles toxicity so that various biological mechanisms can be explored to assess the adverse effects of nanoparticles. [ABSTRACT FROM AUTHOR]

Medicinal plants are powerful antioxidants which can improve well-being and suppress oxidative stress caused by environmental toxins in aquatic animals. In this regard, the present research was designed to show the potential effects of psyllium (Plantago ovata) seed extract (PSE) on the growth, and immune responses of common carp Cyprinus carpio exposed to acute ammonia toxicity. To perform the study, fish were fed with diets containing 0 (T0), 0.25 (T1), 0.5 (T2), and 1% (T3) PSE for 60 days, and then exposed to ammonia (0.5 mg L−1) for 3 h. The findings showed that fish given the T1 diet outperformed the T3 and control groups in terms of ultimate weight, weight increase, and food conversion ratio. Additionally, the T1 group showed a significantly higher level of total protein and serum lysozyme activity than the other treatment groups. Moreover, the highest serum total immunoglobulin values were recorded in T1 and T2 groups. The results showed that PSE, especially at moderate levels, could successfully upregulate the transcription of immune-related genes (IFN-γ, Hsp70, TNF-ɑ, IL-1ß, IL-10, and IgE) compared to the control group after exposure to ammonia. Furthermore, improving ammonia-induced down regulations of antioxidant-related gene expressions (CYP1A, SOD, and GPX) was observed in fish fed with PSE-included diets compared to the control one. However, PSE-supplemented diets did not affect the mRNA expression level of CAT. Regarding tight junction-associated genes, the higher mRNA expression level of occludin was observed in the T1 group, whereas the downregulation of CLD3 gene occurred in all experimental groups. Conversely, significant upregulation of osmoregulation-associated gene (NKA) was recorded in all experimental groups compared to the control one. Therefore, the administration of PSE (0.25% of the diet) for 60 days is recommended to increase growth performance, improve health, and increase the resistance of common carp to oxidative stress caused by ammonia. [ABSTRACT FROM AUTHOR]

In this paper, we investigate a delayed diffusive predator-prey model affected by toxic substance. First, the boundedness and persistence property of the model are established. Then by analyzing the associated characteristic equation, we give some conditions for the existence of Hopf bifurcation, Turing bifurcation and Turing-Hopf bifurcation. Furthermore, we study Hopf bifurcation and Turing-Hopf bifurcation induced by the delay. Finally, numerical simulations are given to illustrate our theoretical results. The numerically observed characteristics accord well with the theoretically predicted results. Theoretical and numerical simulations indicate that toxic substance affect the system greatly. [ABSTRACT FROM AUTHOR]

This paper reviews the current state-of-the-art, limitations, critical issues, and new directions in freshwater plant ecotoxicology. We selected peer-reviewed studies using relevant databases and for each (1) publication year, (2) test plant species, (3) reference plant group (microalgae, macroalgae, bryophytes, pteridophytes, flowering plants), (4) toxicant tested (heavy metal, pharmaceutical product, hydrocarbon, pesticide, surfactant, plastic), (5) experiment site (laboratory, field), and (6) toxicant exposure duration. Although aquatic plant organisms play a key role in the functioning of freshwater ecosystems, mainly linked to their primary productivity, their use as biological models in ecotoxicological tests was limited if compared to animals. Also, toxicant effects on freshwater plants were scarcely investigated and limited to studies on microalgae (80%), or only to a certain number of recurrent species (Pseudokirchneriella subcapitata, Chlorella vulgaris, Lemna minor, Myriophyllum spicatum). The most widely tested toxicants on plants were heavy metals (74%), followed by pharmaceutical products and hydrocarbons (7%), while the most commonly utilized endpoints in tests were plant growth inhibition, variations in dry or fresh weight, morpho-structural alterations, chlorosis, and/or necrosis. The main critical issues emerged from plant-based ecotoxicological tests were the narrow range of species and endpoints considered, the lack of environmental relevance, the excessively short exposure times, and the culture media potentially reacting with toxicants. Proposals to overcome these issues are discussed. [ABSTRACT FROM AUTHOR]

This article presents the results of studies of the content of heavy metals (zinc, copper, lead, cadmium, and nickel) in the muscles and liver of the main commercial fish of different levels of the trophic chain, e.g., pike, perch, roach, and bream, caught in the Astrakhan region, Chernoyarsk district in the water of the Volga River. The distribution of metals in the body of hydrobionts is uneven and depends on the properties of the metal itself and the functional characteristics of the organs. It was found that the content of these metals in the Volga water and the muscles of hydrobionts does not exceed the maximum permissible concentration. The goal of our work was to determine the content of heavy metals in the tissues (muscles) and organs (liver) of the most important commercial fish of the Volga basin within the Astrakhan region (Chernoyarsk region) and to assess the safety of their use as food raw materials. For the research, water samples were taken according to GOST 31861-2012. The content of heavy metals in water was determined via inversion voltammetry on a TA-2M analyzer and in the muscle tissue and liver via atomic absorption spectrometry on a Quant-2A instrument. The highest concentration of heavy metals, 0.14–39.6 mg/kg, is found in the internal organs (liver), and the lowest concentration, 0.038–8.13 mg/kg, is found per unit mass of muscle tissue. [ABSTRACT FROM AUTHOR]

Oral baiting is a fundamental method for delivering toxicants to pest species. Planning baiting strategies is challenging because bait-consumption rates depend on dynamic processes including space use and demographics of the target species. To determine cost-effective strategies for optimizing baiting, we developed a spatially explicit model of population dynamics using field-based measures of wild-pig (Sus scrofa) space use, bait consumption, and mortality probabilities. The most cost-effective baiting strategy depended strongly on the population reduction objective and initial density. A wide range of baiting strategies were cost-effective when the objective was 80% population reduction. In contrast, only a narrow range of baiting strategies allowed for a 99% reduction. Cost-effectiveness was lower for low densities of wild pigs because of the increased effort for locating target animals. Bait avoidance due to aversive conditioning from sub-lethal dosing had only minor effects on cost-effectiveness when the objective was an 80% reduction, whereas the effect was much stronger when the objective was 99% population reduction. Our results showed that a bait-based toxicant could be cost-effective for substantially reducing populations of wild pigs, but for elimination it may be most cost-effective to integrate additional management techniques following initial toxicant deployment. The nonlinear interaction of cost-effectiveness, initial population size, and reduction objective also emphasized the importance of considering the dynamics of space use and bait consumption for predicting effective baiting strategies. Although we used data for an acute toxicant and wild-pig consumption rates, our framework can be readily adapted to other vertebrate pest species and toxicant characteristics. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is a global pollutant that has wide-ranging impacts on the physiological systems of birds, but almost nothing is known about how this affects migration. We manipulated methylmercury (MeHg) burdens of 24 wild-caught Yellow-rumped Warblers (Setophaga coronata) before releasing them and tracking their spring migration with automated radiotelemetry to study the effect of MeHg on stopover departure behavior and flight orientation. Dosing half the birds for 14 days prior to release resulted in environmentally relevant mean blood total Hg (THg) concentrations of 6.61 (± 0.16) p.p.m., while a group of 12 controls had nearly undetectable blood THg. We observed starkly different departure behavior between groups, with dosed birds leaving the release site significantly sooner than controls. Among birds that were detected beyond the release site, seven (three dosed, four control) initially made a landscape-scale relocation before a longer-distance migratory flight, while two (controls) migrated directly from the release site. All flights were in the seasonally appropriate direction regardless of group. Rapid departures by dosed birds could have been the result of hyperactivity that can be induced by MeHg, or due to decreased social dominance that caused them to seek areas with less resource competition. We found no evidence that MeHg impaired orientation, although sample sizes were small and we had less ability to detect birds flying in "incorrect" than northward directions. The dramatic difference in departure decisions between groups indicates a potential effect of MeHg on the neurological and/or physiological mechanisms that control migratory behaviors of birds. [ABSTRACT FROM AUTHOR]

The present paper studies a predator–prey fishery model which incorporates the independent harvesting strategies and nonlinear impact of an anthropogenic toxicant. Both fish populations are harvested with different harvesting efforts, and the cases for the presence and non-presence of harvesting effort are discussed. The prey fish population is assumed to be infected by the toxicant directly which causes indirect infection to predator fish population through the feeding process. Each equilibrium of the proposed system is examined by analyzing the respective local stability properties. Dynamical behavior and bifurcations are studied with the assistance of threshold conditions influencing the persistence and extinction of both predator and prey. Bionomic equilibrium solutions for three possible cases are investigated with certain restrictions. Optimal harvesting policy is explored by utilizing the Pontryagin's Maximum Principle to optimize the profit while maintaining the sustainability of the marine ecosystem. Bifurcation analysis showed that the harvesting parameters are the key elements causing fishery extinction. Numerical simulations of bionomic and optimal equilibrium solutions showed that the presence of toxicant has a detrimental effect on the fish populations. [ABSTRACT FROM AUTHOR]

Liver cancer remains to be a major health concern in the world today. Several major risk factors such as hepatitis viral infection and non-alcoholic steatohepatitis have been well established for causing liver cancer, but the contribution of environmental pollutants to liver inflammation and carcinogenesis remains poorly studied. Here, we aimed at the development of a rapid assay to test selected environmental toxicants for their potential roles in induction of inflammation and stimulation of liver tumorigenesis. By using an established kras oncogene transgenic zebrafish model for liver cancer, we tested a total of eight selected chemicals. First, using LPS (lipopolysaccharides) as a positive control, we confirmed its effects on induction of inflammation and stimulation of liver tumorigenesis as indicated by increases of neutrophils and the size of oncogenic livers respectively. Next, we tested two heavy metals (arsenic and chromium) and five organic toxicants (bisphenol A, lindane, N-nitrosodiethylamine, and 3,3′,4,4′,5-pentachlorobiphenyl [PCB126], and 2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD]). We observed a good correlation on induction of inflammation and their ability for stimulation of liver tumorigenesis. Most toxicants, namely chromium, bisphenol A, lindane, N-nitrosodiethylamine, and PCB126, resulted in increased inflammation and liver tumorigenesis, while arsenic and TCDD had opposite effects. Thus, our study established a screening system to rapidly assess the effects of candidate chemicals on liver tumorigenesis and inflammation. [ABSTRACT FROM AUTHOR]

Resource managers need effective tools to control invasive fish populations. In this study, we tested under-ice carbon dioxide (CO) injection as a novel piscicide method for non-native Silver Carp ( Hypophthalmichthys molitrix), Bighead Carp ( Hypophthalmichthys nobilis), Grass Carp ( Ctenopharyngodon idella), Common Carp ( Cyprinus carpio) and native Bigmouth Buffalo ( Ictiobus cyprinellus). Fish were held overwinter in nine outdoor ponds (0.04 ha surface area; 340,000 L volume) treated with no CO (control), 43.5-44.0 kg CO (low treatment), and 87.5-88.5 kg CO (high treatment). Ponds were harvested immediately after ice-out to assess survival and condition. Resulting survival in low (mean = 32%) and high (mean = 5%) CO-treated ponds was significantly lower than untreated control ponds (mean = 84%). Lethal efficacy varied across species with no Bighead Carp, Silver Carp, or Bigmouth Buffalo surviving the high CO treatment. External infections were observed more frequently after CO treatments (means = 49-67%) relative to untreated ponds (mean = 2%), suggesting a secondary mechanism for poor survival. This study demonstrates that CO can be used as a lethal control for invasive fishes, but effectiveness may vary by species and CO concentration. [ABSTRACT FROM AUTHOR]

Exposure to environmental mercury has been proposed to play a part in autism. Mercury is selectively taken up by the human locus ceruleus, a region of the brain that has been implicated in autism. We therefore looked for the presence of mercury in the locus ceruleus of people who had autism, using the histochemical technique of autometallography which can detect nanogram amounts of mercury in tissues. In addition, we sought evidence of damage to locus ceruleus neurons in autism by immunostaining for hyperphosphorylated tau. No mercury was found in any neurons of the locus ceruleus of 6 individuals with autism (5 male, 1 female, age range 16-48 years). Mercury was present in locus ceruleus neurons in 7 of 11 (64 %) age-matched control individuals who did not have autism, which is significantly more than in individuals with autism. No increase in numbers of locus ceruleus neurons containing hyperphosphorylated tau was detected in people with autism. In conclusion, most people with autism have not been exposed early in life to quantities of mercury large enough to be found later in adult locus ceruleus neurons. Human locus ceruleus neurons are sensitive indicators of mercury exposure, and mercury appears to remain in these neurons indefinitely, so these findings do not support the hypothesis that mercury neurotoxicity plays a role in autism. [ABSTRACT FROM AUTHOR]

Tissue heavy metal concentrations in painted (Chrysemys picta) and snapping (Chelydra serpentina) turtles from Lake Michigan coastal wetlands were analyzed to determine (1) whether turtles accumulated heavy metals, (2) if tissue metal concentrations were related to environmental metal concentrations, and (3) the potential for non-lethal sampling techniques to be used for monitoring heavy metal body burdens in freshwater turtles. Muscle, liver, shell, and claw samples were collected from painted and snapping turtles and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, and zinc. Turtle tissues had measurable quantities of all eight metals analyzed. Statistically significant correlations between tissue metal concentrations and sediment metal concentrations were found for a subset of metals. Metals were generally found in higher concentrations in the larger snapping turtles than in painted turtles. In addition, non-lethal samples of shell and claw were found to be possible alternatives to lethal liver and muscle samples for some metals. Human consumption of snapping turtles presents potential health risks if turtles are harvested from contaminated areas. Overall, our results suggest that turtles could be a valuable component of contaminant monitoring programs for wetland ecosystems. [ABSTRACT FROM AUTHOR]

We studied the efficiency of bubbling air as a method of detoxification of the blood plasma and its mixtures with plasma substitutes from CCl4. The efficiency of detoxification depended on the characteristics of the obtained foams: foam forming ability, frequency rate, dispersion, stability of a foam skeleton, syneresis, etc. A hardware-software complex for extracorporeal blood plasma detoxification was developed and the programs for the control and regulation of this process were tested. Physical and mathematical models of toxicant excretion from the body during extracorporal blood detoxification were proposed. Verification of the mathematical model demonstrates high correspondence between the theoretical and experimental data. [ABSTRACT FROM AUTHOR]

White clover (Trifolium repens L.) is an important pasture legume in temperate areas throughout the world, providing fodder for grazing animals and improving soil fertility via symbiotic nitrogen fixation. However, the persistence and stress tolerance of white clover are affected by a number of viruses including alfalfa mosaic virus. Transgenic white clover plants with ectopic expression of the alfalfa mosaic virus coat protein were resistant to the virus under field and greenhouse conditions. With all genetic modifications of major consequence, there is the possibility of unintended effects on forage quality and natural toxicant levels. In this paper, we describe the evaluation of a range of parameters related to the nutritive value of white clover herbage to grazing animals and a suite of naturally occurring secondary metabolites that have the potential to be natural toxicants in transgenic white clover plants and wild-type control plants with a similar genetic background. Samples were collected from plants grown under both field and glasshouse conditions. Several commercial cultivars were included for comparison. Although there was plant-to-plant variation, as expected from an obligate outcrossing species, there were no significant differences in the range of this variation between transgenic and wild-type plants. Furthermore, no consistent significant differences were found between groups of transgenic and wild-type plants from the same generation, when mean nutritional parameters (crude protein, in vitro dry matter digestibility, neutral detergent fibre and water-soluble carbohydrates) and natural toxicants (cyanogenic glucosides, phytoestrogens and saponins) were compared. [ABSTRACT FROM AUTHOR]

In order to be a relevant indicator of exposure towards teratogenic stressors, morphological defects should not be passed on to the next generation. In this study, we compare morphological variations in Chironomids collected from a contaminated river stretch with those of their progeny, reared in uncontaminated sediment under laboratory conditions. We focused on mentum defects (deformities, fluctuating asymmetry and mean shape change), measured by geometric morphometrics. We observed no significant variation in deformity rate between the parental generation and its progeny. On the contrary, we observed a significant increase in fluctuating asymmetry and a significant decrease in mentum centroid size in the offspring. Our results suggest that shape defects are not caused by direct exposure to teratogenic stressors alone. We propose four hypotheses to explain this: (a) teratogenic contaminants are present in egg-clutches, (b) contaminants at the sampling site have mutagenic effects, (c) costs of tolerance, and (d) contamination-induced genetic impoverishment. [ABSTRACT FROM AUTHOR]

Background: Cigarette smoke emissions are mainly produced by distillation, pyrolysis and combustion reactions when the tobacco is burnt. Some studies have shown that heating tobacco to temperatures below pyrolysis and combustion temperatures has the potential to reduce or eliminate some toxicants found in cigarette smoke. In this study, we designed a bench-top tube furnace that heats tobacco between 100-200°C and systematically studied the effects of heating temperatures on selected gas phase and aerosol phase compounds using an ISO machine-smoking protocol. Results: Among a list of target chemical compounds, seven toxicants (nicotine, carbon monoxide, acetaldehyde, crotonaldehyde, formaldehyde, NNN and NNK) were quantifiable but not at all temperatures examined. The levels of the compounds generally displayed an increasing trend with increasing temperatures. The observed carbon monoxide and aldehydes represented the initial thermal breakdown products from the tobacco constituents. Water was the largest measured component in the total aerosol phase collected and appeared to be mainly released by evaporation; nicotine release characteristics were consistent with bond breaking and evaporation. Quantifiable levels of NNK and NNN were thought to be the result of evaporative transfer from the tobacco blend. Conclusions: These results demonstrate the practical utility of this tool to study low-temperature toxicant formation and emission from heated tobacco. Between 100 to 200°C, nicotine and some cigarette smoke compounds were released as a result of evaporative transfer or initial thermal decomposition from the tobacco blend. [ABSTRACT FROM AUTHOR]

A number of environmental toxicants affect our health through physical, biological or chemical mechanisms. There is growing evidence indicating that microRNA (miRNA) plays an important role in toxicogenomics, disease aetiology and the effect of toxicants. This article summarises recent findings on miRNAs associated with various toxicants and those targeted in the development of therapeutics. Environmental epigenetic studies have revealed the role of miRNAs in the regulation of gene activities induced by environmental changes after exposure to toxic substances. Toxicant-induced changes in miRNA expression have a potential to be informative markers in the evaluation of toxicant risks. miRNAs are now considered to be predictive biomarkers or indicators of tissue injury due to toxicant exposure; thus, miRNAs can also be utilised as therapeutic targets. [ABSTRACT FROM AUTHOR]

Xenobiotics alter the balance of competition between species and induce shifts in community composition. However, little is known about how these alterations affect the recovery of sensitive taxa. We exposed zooplankton communities to esfenvalerate (0.03, 0.3, and 3 μg/L) in outdoor microcosms and investigated the long-term effects on populations of Daphnia spp. To cover a broad and realistic range of environmental conditions, we established 96 microcosms with different treatments of shading and periodic harvesting. Populations of Daphnia spp. decreased in abundance for more than 8 weeks after contamination at 0.3 and 3 μg/L esfenvalerate. The period required for recovery at 0.3 and 3 μg/L was more than eight and three times longer, respectively, than the recovery period that was predicted on the basis of the life cycle of Daphnia spp. without considering the environmental context. We found that the recovery of sensitive Daphnia spp. populations depended on the initial pesticide survival and the related increase of less sensitive, competing taxa. We assert that this increase in the abundance of competing species, as well as sub-lethal effects of esfenvalerate, caused the unexpectedly prolonged effects of esfenvalerate on populations of Daphnia spp. We conclude that assessing biotic interactions is essential to understand and hence predict the effects and recovery from toxicant stress in communities. [ABSTRACT FROM AUTHOR]

Natural zeolites (klinoptiolits) were treated with Onkosorb adsorbent (N,N′-bis(3-triethoxysilyl-propyl-thiocarbamide)) to attain greater nitrosamine (NA) and polycyclic aromatic hydrocarbon (PAH) adsorption capacity. The efficiency of volatile NA recovery rose from 30 to 77%; that of PAH recovery, from 20 to 63.7 %. The increased adsorption efficiency of the toxicants from an air-gas mixture was also reflected in biological indicators. Prolonged exposure of rats to the air-gas mixture (similar in composition to the air in industrial zones) led to a 25% reduction in the maximum rates of succinate oxidation and the efficiency of oxidative phosphorylation in liver mitochondria. The changes in the energetics of mitochondria were apparently associated with the action of the toxicants, as is indicated by a 22 % increase of P-450 cytochrome content in the liver tissue. An air-gas mixture passed through an Onkosorb adsorbent layer on zeolite did not produce any of the above changes in the mitochondrion energetics or the effect on P-450 cytochrome content in the liver tissue. We assume a high level of efficiency for Onkosorb adsorbent on zeolite in PAH and NA absorption. [ABSTRACT FROM AUTHOR]

In this paper we propose a periodic impulsive delay two-species competitive system in which two species have toxic inhibitory effects on each other. It is assumed that the system is impulsively controlled by means of harvesting and stocking controls. By using the theory of impulsive differential equation and analysis techniques, a set of sufficient conditions are derived for the permanence and partial extinction of the system. It turns out that the impulsive controls play a crucial role in shaping the above dynamics of the system. Numerical simulations are presented to substantiate the analytical results. [ABSTRACT FROM AUTHOR]

Static bioassay were carried out using two aquatic crocodiles (the short nosed crocodile, Osteolemus tetraspis and the Nile crocodile, Crocodilus niloticus) as test organisms in soft natural dilution water, with Petroleum waste drilling fluid as the test material, at 28 ± 2 °C. Comparison of results for the control and different concentrations of the waste drilling fluid were made by means of the F-statistic method. Both crocodile species exhibited a high insensitivity to the undiluted waste drilling fluid and the different dilutions. Differences in concentration of waste drilling fluid did not influence the response of crocodiles to the potential toxicant. Percentage of deaths which was never greater than 0.2% in control tanks was not significantly different from that in test tanks where mortality values of organisms was typically 1.6% or less in most cases. There was a delay toxicant – induced mortality effect. [ABSTRACT FROM AUTHOR]

Phytoremediation, or the use of plants for removal and detoxification of environmental pollutants, has garnered great attention in recent years. This heightened interest is both scientifically, due the fascinating processes utilized by plants for tolerance and removal of harmful compounds, and commercially, as plants represent a more environmentally compatible and less expensive method of site remediation compared to standard approaches. The majority of phytoremediation studies have been with naturally occurring plant species after empirical discovery of their exceptional abilities for such applications. This has led to a growing body of literature and wider acceptance for plants in many aspects of environmental rehabilitation. However, this has occurred with little understanding of their basic biological mechanisms of action or investigation of alternative strategies for enhancing the capabilities of these extraordinary plants. Better understanding of plant physiology, biochemistry and molecular biology in response to specific contaminants is critical for optimization and advancement of phytoremediation. By applying the tools of biotechnology, the potential for plants as an aggressive method of environmental decontamination may be realized. This paper will serve as an introduction to the first Symposium assembled exclusively to review the use of molecular genetic and biotechnological methods for improvement of plants for phytoremediation. After a brief review of the other invited speakers' works (with more extensive papers following), the pioneering work using bacterial genes expressed in plants for removal of mercurial compounds will be surveyed. [ABSTRACT FROM AUTHOR]

The current study was designed to determine whether exposure of mice to aerosolized jet fuel (JP8+100) resulted in changes in the cellular distribution or immunoreactivity of the enzyme glutathione-S-transferase (GST), a biomarker of toxicant exposure. Male mice were exposed to JP8+100 at 1000 mg/m3 or 2500 mg/m3 in aerosol for 1 h per day for 7 days and then sacrificed. The retinas were studied by immunohistochemical methods. The JP8+100 exposure caused a marked increase in the immunoreactivity of anti-GSTM antibodies with the radial glial cells of the retina, the Müller cells. These results are consistent with the hypothesis that JP8+100 acts as a toxicant to mouse retina by permitting the flux of materials across the blood-retina barrier. The findings are relevant to humans because recent studies indicate that Air Force personnel assigned to clean and maintain fuel pods may be exposed to concentrations of JP8+100 exceeding 1000 mg/m3. [ABSTRACT FROM AUTHOR]

The effect of thiamethoxam insecticide on liver protein content of Oreochromis niloticus (Trewavas) was investigated. The study revealed that there was a significant ( p < 0.05) increase in the total liver protein between 12.5, 25 and 50 mg l doses of thiamethoxam, though the level was lower than the control. Whereas, the rate of increase was higher in 7 days exposure period (EP) than 14 days EP. Such dose depended increase in the protein level was probably due to the interacting effects between the toxicant and the biological system concerned. [ABSTRACT FROM AUTHOR]

The toxicity of solutions of phenol in combination with cadmium and cobalt for a culture of micro-seaweed and the opportunity of decreasing their toxicity by the influence of electromagnetic radiation in the range of the highest frequencies (UHF irradiation) are studied. The synergism between phenol and metals and a decrease in their toxicity under the influence of electromagnetic radiation are revealed. [ABSTRACT FROM AUTHOR]

Purpose Of Review: Diabetes is a burgeoning threat to public health in the USA. Importantly, the burden of diabetes is not equally borne across society with marked disparities based on geography, race/ethnicity, and income. The etiology of global and population-specific diabetes risk remains incompletely understood; however, evidence linking environmental toxicants acting as endocrine-disrupting chemicals (EDCs), such as particulate matter and arsenic, with diabetes suggests that environmental policies could play an important role in diabetes risk reduction.Recent Findings: Evidence suggests that disproportionate exposures to EDCs may contribute to subgroup-specific diabetes risk; however, no federal policies regulate EDCs linked to diabetes based upon diabetogenic potential. Nevertheless, analyses of European Union data indicate that such regulation could reduce diabetes-associated costs and disease burden. Federal laws only regulate EDCs indirectly. The accumulating evidence linking these chemicals with diabetes risk should encourage policymakers to adopt stricter environmental standards that consider both health and economic impacts. [ABSTRACT FROM AUTHOR]

Adaptation to toxicants in animal populations is influenced primarily by two counteracting forces. First, the intensity and duration of peak concentrations of toxicants is responsible for the actual level of selection pressure on the population. Second, the process of adaptation can be disrupted by gene flow as a result of crossings with nontolerant individuals. These counteracting forces were analyzed in riverine insects in which we expected that the level of metal adaptation is subject of considerable fluctuations, due to variable dilution of metals and a variable transport of nontolerant individuals in river water. To this purpose, the stability of metal adaptation in differentChironomus riparius populations was analyzed during a 5-month periodin a heavily polluted lowland river. This was examined by measuring mortality, larval dry weight, and accumulation of zinc under laboratory conditions. The results showed that in midge populations originating from metal-contaminated field sites several life-history parameters (like control mortality and growth response under cadmium exposure)of the laboratory reared F1 generations showed considerable temporalvariation. In addition, the presence of metal-adapted midge populations was indicated on several occasions on the metal-exposed field sites. Reference populations on the other hand, showed stable life history patterns throughout the sampling period, and no signs of metal adaptation were found. These observations showed that the actual level of metal adaptation varies considerably, both in time and space. Adaptation to metals in riverine chironomids, therefore, should be looked on as a highly dynamic process. [ABSTRACT FROM AUTHOR]