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1.
Chromium, especially the metal and its trivalent and hexavalent compounds, are of great industrial interest. As a matter of fact, chromium workers have an occupational risk. While trivalent chromium compounds are of low toxicity, the hexavalent compounds are strong oxidants which cause not only a direct tissue damage (=acute toxicity), but also possess a carcinogenic, mutagenic and teratogenic potential (=chronic toxicity). Since the kidney is the main target organ after oral and/or dermal uptake of hexavalent chromium is the kidney, tubular necrosis might be the result of an acute toxification. This report presents anin vitro assay with cultured renal epithelial cells which allows the evaluation of the acute toxicity not only of trivalent and hexavalent chromium compounds, but also of various hazardous substances used in industrial production process. As shown here, an acute toxic effect was not detectable for the trivalent chromium (chromium (III)-chloridehexahydrate) within 24 h of exposure to concentrations as high as 200 μmol/l. In contrast, renal epithelial cells which were exposed to hexavalent chromium (potassium chromate) for the same time period exhibited marked signs of toxicity such as a rounding and detachment of the cells from the floor of the culture plates, an elongation and perinuclear development of vacuoles in the vital cells which were still attached, as well as a cells swelling and cellular fragments caused as a result of necrotic cell death and subsequent lysis. This toxic effect was already observed at concentrations above 5 μmol/l. In conclusion, thein vitro assay might be a good tool for the screening of hazardous substances in industrial medicine. More-over, by using additional tests, the chronic toxicity of such substances can also be examined. The selection of specific cell strains such as hepatocytes, neural cells etc. also allows the evaluation of toxic effects in individual organs. Thein vitro assay can not only be applied for the investigation of basic mechanisms of toxification and detoxification of specific compounds, but also delivers a basis for the screening of the reactivity of individual hazardous substances. Finally, the assay would allow a reduction in animal experiments as well as the simultaneous testing of a reactivity to multiple, hazardous substances.  相似文献   

2.
Nanoparticles are now widely applied in products. The synthesis of nanomaterials using biological materials is an emerging field, notably for medical applications because biologically derived compounds can be safe. For instance, calcium phosphate is a natural biomineral that possesses an excellent biocompatibility due to its chemical similarity to human hard tissue such as bone and teeth. Here, we synthesized calcium phosphate nanoparticles by using bark extract of Spanish cherry (Mimusops elengi). Calcium phosphate nanoparticles showed an absorbance at 275 nm by UV–visible analysis and particle size of 25 nm by nanoparticle tracking and analysis. Fourier transform infrared spectroscopy revealed the presence of aromatic amines as a capping and reducing agent. Transmission electron microscopy showed the presence of polydispersed spherical nanoparticles with an average size of 50 nm. Measurements of zeta potential revealed the stability of the synthesized calcium phosphate nanoparticles. These particles demonstrated antibacterial activity against Streptococcus mutans, Staphylococcus aureus and Escherichia coli. We conclude that the synthesis of calcium phosphate nanoparticles by using a M. elengi is easy, eco-friendly and scalable.  相似文献   

3.
《Ecological modelling》2005,188(1):30-40
Although the ecological risks of toxic chemicals are usually assessed on the basis of individual responses, such as survival, reproduction or growth, ecotoxicologists are now attempting to assess the impact of environmental pollution on the dynamics of naturally exposed populations. The main issue is how to infer the likely impact on the population of the toxic effects observed at the individual level. Dynamic energy budget in toxicology (DEBtox) is the most user-friendly software currently available to analyze the experimental data obtained in toxicity tests performed on individuals. Because toxic effects are diverse and because the sensitivity of individuals varies considerably depending on life-cycle stage, Leslie models offer a convenient way of predicting toxicant effects on population dynamics.In the present study, we first show how parameter inputs, estimated from individual data using DEBtox, can be coupled using a Leslie matrix population model. Then, using experimental data obtained with Chironomus riparius, we show how the effects of a pesticide (methiocarb) on the population growth rate of a laboratory population can be estimated. Lastly, we perform a complex sensitivity analysis to pinpoint critical age classes within the population for the purposes of the field management of populations.  相似文献   

4.
Measurements of calcium carbonate contents in soils were performed with FT-IR (Fourier transform infrared) spectroscopy and with the gas volumetric Scheibler method. To the authors’ knowledge it is the first time that carbonate was quantified in soil samples by FT-IR spectroscopy. The carbonate contents of the test soils ranged from 11.3 to 13.1%. Both methods gave similar results, however, results obtained from FT-IR spectra depend on the spectral band used for the carbonate determination. In our investigation we used the bands at 875 and 2506 cm−1. In case of the band at 2506 cm−1 the difference between FT-IR and Scheibler method was a factor of 1.56, in case of 875 cm−1 the respective factor was 1.16. It can be concluded that FT-IR with both bands has a potential to be used in practice as substitution of the Scheibler method. The advantages of the FT-IR method are better reproducibility and the simultaneous characterization of soil organic matter in bulk samples. The disadvantage is its higher cost.  相似文献   

5.
Up to now, sediment studies have mainly used standardized aquatic bioassays with organisms of the three trophic levels. Among these, algae are the only representatives of the entire plant kingdom. Bioassays with higher plants have hardly been used for the assessment of sediments. The aim of the present study is to demonstrate that the use of higher plants in biotests for analyses of anthropogenically contaminated sediments yields valuable results, which may be included in a concept for the integrated assessment of waters. The contamination by environmental chemicals was determined in the River Elbe by means of samples taken at the Fahlberg-List industrial site at Magdeburg in combination with studies in a reference area on the Müritz-Elde Waterway (Eldenburger Kanal). Sediment extracts and pore waters were tested with the aquatic lemna test. For comparison, first sediment contact tests withLemna minor were tried out. The whole extract of the sediment from Fahlberg-List Magdeburg and one fraction F5 caused distinct damages of the plants. Obviously, the phytotoxic substances of the whole extract are preferentially concentrated in the highly polar fraction F5. A comparison with chemical analytical data proved that the whole fraction F0 and the fraction F5 were heavily contaminated with chemicals. Assays with pore water from this sediment and with the whole sediment also caused a strong inhibition of growth. These results confirm the high contamination of the sediment from Magdeburg. The tests with the reference sediment suggested only a moderate toxic contamination. The results of this study prove that the selected aquatic plant,Lemna minor, is basically able to indicate contamination. In the aquatic test of the sediment extracts, it showed weak, but very selective, responses to certain classes of contaminants. Fractionating of the sample and subsequent chemical analysis combined with toxicity tests allow to narrow down the groups of substances causing toxic effects. This toxicity was confirmed by analyses of the pore waters and whole sediment samples. Together with other toxicity tests (e.g. standardized bioassays) and combined with biological benthos examinations, an overall judgment can be given for the integrated assessment of waters.  相似文献   

6.
Over the past half century, countries of Mainland Southeast Asia (MSEA) – Cambodia, Laos, Myanmar, Thailand, and Vietnam – have witnessed increases in commercialized agriculture with rapid expansions of boom-crop plantations. We used MODIS EVI and SWIR time-series from 2001–2014 to classify tree-cover changes across MSEA and performed a supervised change detection using an upscaling approach by deriving samples from existing Landsat classifications. We used the random forest classifier and distinguished 24 classes (16 representing boom-crops) with an accuracy of 82.2%. Boom-crops occupy about 18% of the landscape (8% of which is rubber). Since 2003 74,960 km2 of rubber have been planted; 70% of rubber is planted on former forest land, and 30% on low vegetation area (mainly former croplands). Timing, patterns of change, and deforestation rates, however, differ among the MSEA countries and the high spatial and temporal detail of our classification allowed us to quantify dynamics and discuss political and socio-economic drivers of change.  相似文献   

7.
The fermentation activity of the yeastSaccharomyces cerevisiae is used as a bioindicator to detect aquatoxic effects. This is done by measuring the CO2 production of yeast cells after a multiplication period affected by toxic substances. The concentration of toxicants diminishing the fermentation by 20% is taken as a characteristic value (EC20). Organic compounds (unpolar and polar narcotics), inorganic salts (especially of heavy metals), surfactants and plant pesticides were tested. The results are compared so far as available with data of a ciliata assay usingTetrahymena pyriformis. A congruence of 90% and an equal sensibility of the assays resulted. The results of the yeast assay are therefore representative for ecotoxicological testing. The yeast assay is reproducible, easy to handle, and offers an alternative for sewage testing because sterile handling is not necessary.  相似文献   

8.
This study investigated the source and contamination levels of toxic elements (Cd, Cr, As, Pb, Ni and Hg) present in a coastal environment, Paradip—an industrial hub of the east coast of India. The ecological risk assessment indices and human exposure models were used to evaluate the pollution status. Enrichment factor indicated that all the metal(loid)s found in the sediment are mostly derived from the anthropogenic source. According to the sediment quality quotient, 8.33% of sediments have crossed the ERM limit for Ni that can be fatal to biota. Meanwhile, 66.66, 41.66 and 8.33% of sediments have exceeded PEL range for Cr, Ni and As, respectively, that can register frequent lethal toxicity to benthic biota. As had the highest potential ecological harm coefficient (Erf?>?80), and Hg had moderate ecological harm coefficient (40?<?Erf?<?80). Summarily, the sediment quality of this site is moderate to heavily toxic to benthic organisms. The concentration of toxic metals in seawater was below the permissible limit (CCC and CMC) set by USEPA indicating that water is relatively safer for free floating aquatic biota. The health risk index of toxic metal (loid)s present in soils of the residential sites has confirmed that there is a severe non-carcinogenic threat for children (HI child?>?1) and a borderline carcinogenic risk for both adult and children. THQCr possesses highest non-carcinogenic threat, which contributed approximately 50% to HI followed by THQAs. The contribution of carcinogenic risk of chromium (CRCr) to TCR is approximately 60%. Cr is the significant contaminant of this site that has highest health effects. Highest exposure risks were associated with ingestion pathway accounting for about 85% of the total for most of the elements.  相似文献   

9.
Based on common phenomena of biochemical interaction between plants and microorganisms, the inhibitive effects of three common terrestrial compositae plants, namely Artemisia lavandulaefolia DC., Conyza canadensis (L.) Cronq., and Kalimeris indica (L.) Sch.-Bip. on the blue algae Microcystis aeruginosa was studied. Live compositae plants are co-cultivated with algae in two different inoculation doses for 10 days in 5-pools incubators, in order to exclude the influence of bacteria and nutrients. The results show that Artemisia lavandulaefolia DC has the most inhibitive potential among the three plants as evidenced by the most drastic decrease in optical density (OD680) of the algae. The inhibition rate is 93.3% (with initial inoculation dose of 2.0 × 106 Cells/mL) and 89.3% (with initial inoculation dose of 4.0 × 106 Cells/mL) respectively on the 10th day of cultivation. The average inhibition rate during the later half of the experiment is 0.76 (with initial inoculation dose of 2.0 × 106 Cells/mL) and 0.71 (with initial inoculation dose of 4.06106 Cells/mL), respectively. Logistic model analysis shows that compositae plants such as A. lavandulaefolia DC. causes the reduction of the habitat’s carrying capacity of algae. ANOVA analysis is used to determine the similarity and differences between every experimental group and an average inhibitive rate model is used to evaluate the inhibition effects. The results show that A. lavandulaefolia DC., which grow well in the aquatic environment, may have a great potential in controlling algae bloom in eutrophic water.  相似文献   

10.
The actual harmful effects of industrial wastewater can not be reflected by the conventional water quality index. Therefore, the change in dissolved organic matter and the genetic toxicity of petrochemical wastewater were observed in the current study by examining the wastewater treatment plant of a large petrochemical enterprise in Northwest China. Using XAD-8, MSC, and DA-7 resins, the wastewater was separated into six fractions, namely, hydrophobic acid (HOA), hydrophobic neutral (HOB), hydrophobic alkaline, hydrophilic acid, hydrophilic alkaline, and hydrophilic neutral. Umu-test was used to detect the genetic toxicity of the wastewater samples, and fluorescence spectra were also obtained to examine genetic toxic substances. The results show that wastewater treatment facilities can effectively reduce the concentration of organic matter in petrochemical wastewater (p<0.05). However, the mixing of aniline wastewater can increase the amount of organic carbon (p<0.05) and can overload facilities. This finding shows that the mixed collection and joint treatment of different types of petrochemical wastewater can affect the water quality of the effluent. Particularly, hydrophobic substances can be difficult to remove and account for a relatively large proportion of the effluent. The mixture of aniline wastewater can increase the genetic toxicity of the effluent (p<0.05), and biologic treatment can not effectively decrease the toxicity. Most of the genetic toxicology may exist in the HOA and HOB fractions. Fluorescence spectroscopy also confirms this result, and tryptophan-like substances may play an important role in genetic toxicity.  相似文献   

11.
Background Ecotoxicology utilizes alterations of biological parameters of organisms as biomarkers of toxic exposure or effects. In environmental monitoring, biomarkers function as sensitive indicators of chemical pollution or as early warning signal of late effects Aim The pre-requisite for using a biological parameter as biomarker is the ability to unequivocally distinguish between the natural or normal and the induced or abnormal expression of the marker. This article discusses problems in discriminating between the normal and induce state, using morphological biomarkers as an example. Results and Discussion Morphological and/or anatomical parameters are intuitively considered to be rather invariable. This article shows for the example of gonad morphology of fish that this expectation is not always correct, but that morphological markers may display pronounced baseline variability. The reasons for this variability are often not understood. This is limiting the utility and interpretation of the biomarker response, in particular when organisms are not only exposed to chemical but to multiple stressors. Outlook The problem of discriminating between natural and induced variability of biomarkers is of particular relevance in low dose exposure scenarios, when stressors other than toxic chemicals may confound the toxicant-induced changes of the biomarker status. To better handle this problem and to be able to distinguish between adaptive and adverse changes, ecotoxicology has to set out for improved understanding of the phenotypic plasticity of organisms and genotypes,  相似文献   

12.
In this study we developed a dynamic growth model for Scots pine (Pinus sylvestris L.) plantations in Galicia (north-western Spain). The data used to develop the model were obtained from a network of permanent plots, of between 10 and 55-year-old, which the Unidade de Xestión Forestal Sostible (Sustainable Forest Management Unit) of the University of Santiago de Compostela has set up in pure plantations of this species of pine in its area of distribution in Galicia. In this model, the initial stand conditions at any point in time are defined by three state variables (number of trees per hectare, stand basal area and dominant height), and are used to estimate stand volume, classified by commercial classes, for a given projection age. The model uses three transition functions expressed as algebraic difference equations of the three corresponding state variables used to project the stand state at any point in time. In addition, the model incorporates a function for predicting initial stand basal area, which can be used to establish the starting point for the simulation. This alternative should only be used when the stand is not yet established or when no inventory data are available. Once the state variables are known for a specific moment, a distribution function is used to estimate the number of trees in each diameter class, by recovering the parameters of the Weibull function, using the moments of first and second order of the distribution (arithmetic mean diameter and variance, respectively). By using a generalized height–diameter function to estimate the height of the average tree in each diameter class, combined with a taper function that uses the above predicted diameter and height, it is then possible to estimate total or merchantable stand volume.  相似文献   

13.
人类活动导致大量毒害污染物进入水体和沉积物,从而对水生生物产生诸多不利影响.开展毒害污染物的生态风险评价,筛选高风险毒害污染物,是毒害污染物风险管控和生态系统保护的基础.对美国和欧盟等发达国家和地区毒害污染物的生态风险评价方法进行了综述.水体和沉积物中毒害污染物风险评价的基本方法首先是采用预测或测定环境浓度(PEC或M...  相似文献   

14.
To make a macrofaunal (crustacean) habitat potential map, the spatial distribution of ecological variables in the Hwangdo tidal flat, Korea, was explored. Spatial variables were mapped using remote sensing and a geographic information system (GIS) combined with field observations. A frequency ratio (FR) and logistic regression (LR) model were employed to map the macrofauna potential area for the Ilyoplax dentimerosa, a crustacean species. Spatial variables affecting the tidal macrofauna distribution were selected based on abundance and biomass and used within a spatial database derived from remotely sensed data of various types of sensors. The spatial variables included the intertidal digital elevation model (DEM), slope, distance from a tidal channel, tidal channel density, surface sediment facies, spectral reflectance of the near infrared (NIR) bands and the tidal exposure duration. The relation between the I. dentimerosa and each spatial variable was calculated using the FR and LR. The species was randomly divided into a training set (70%) to analyse habitat potential using FR and LR and a test set (30%) to validate the predicted habitat potential map. The relations were overlaid to produce a habitat potential map with the species potential index (SPI) value for each pixel. The potential habitat maps were compared with the surveyed habitat locations such as validation data set. The comparison results showed that the LR model (accuracy is 85.28%) is better in prediction than the FR (accuracy is 78.96%) model. The performance of models gave satisfactory accuracies. The LR provides the quantitative influence of variables on a potential habitat of species; otherwise, the FR shows the quantitative influence of a class in each variable. The combination of a GIS-based frequency ratio and logistic regression models and remote sensing with field observations is an effective method to determine locations favorable for macrofaunal species occurrences in a tidal flat.  相似文献   

15.
Snakes are common predators of organisms, such as amphibians, with toxic defenses that can be lethal to other predators. Because snakes do not have the option of dissecting prey into edible versus inedible components, they face a full dose of any chemical defenses encountered during attempted predation. This limitation has likely resulted in intense selection favoring the evolution of alternative mechanisms for dealing with prey toxins. These mechanisms can be physiological (e.g., resistance to prey toxins) or behavioral (e.g., toxin sampling and rejection). When physiological resistance arises, the possibility of bioaccumulation of a toxin results. We examined the coevolutionary interaction between the common garter snake (Thamnophis sirtalis) and the rough-skinned newt (Taricha granulosa), which contains a powerful neurotoxin called tetrodotoxin (TTX). In some populations syntopic with newts, individuals of T. sirtalis have evolved resistance to TTX. We examined the persistence of TTX in T. sirtalis after administration of an oral dose of TTX to investigate the possibility that snakes are sequestering TTX. The half-life of TTX in snake liver was estimated at 8.1?days. Accordingly, clearance of 99% of a single dose of TTX averages 61?days. Negative fitness consequences of intoxication during and after newt consumption may be balanced by co-opting the newts?? chemical defense for protection from the snakes?? own predators. Accounting of the coevolutionary dynamic between snakes and newts must incorporate post-consumption affects of lingering TTX.  相似文献   

16.
There are few efficient, rapid and cheap methods to remove toxic metals from contaminated waters. Here we hypothesised that cathodic protection, an existing method used to control the corrosion of metallic structures, may trap toxic metals. Indeed, in seawater, the application of a cathodic current on a metallic structure induces the precipitation of limestone (CaCO3) and magnesium dihydroxyde (Mg(OH)2), thus forming a calcareous deposit on the metal surface. We therefore presumed that such calcareous deposit may trap metals dissolved in waters. Actually calcareous deposit formation has never been studied in the presence of dissolved metallic contaminants such as nickel. Here we tested ionic nickel (Ni2+) precipitation in calcareous deposit with a galvanized steel electrode by spiking artificial seawater with a NiCl2 salt during 7 days of applied current. We analysed deposit surface and cross section by µ-Raman spectroscopy and scanning electron microscopy (SEM) with X-ray microanalysis. Ni concentration in the deposit was quantified by inductively coupled plasma analysis, after deposit dissolution in 60% HNO3. Results show that in 7 days up to 24% of nickel can be trapped in the calcareous deposit. Scanning electron microscopy reveals that Ni is trapped under a pure CaCO3 layer of aragonite. Raman spectra show that nickel is incorporated as nickel dihydroxyde (Ni(OH)2), as evidence by vibration bands at 446 and 510 cm?1. Overall our findings disclose a new and efficient method, calcareous electrochemical precipitation, which has potential applications to remove toxic metals from contaminated waters.  相似文献   

17.
Thermodynamics is a powerful tool for the study of system development and has the potential to be applied to studies of ecological complexity. Here, we develop a set of thermodynamic indicators including energy capture and energy dissipation to quantify plant community self-organization. The study ecosystems included a tropical seasonal rainforest, an artificial tropical rainforest, a rubber plantation, and two Chromolaena odorata (L.) R.M. King & H. Robinson communities aged 13 years and 1 year. The communities represent a complexity transect from primary vegetation, to transitional community, economic plantation, and fallows and are typical for Xishuangbanna, southwestern China. The indicators of ecosystem self-organization are sensitive to plant community type and seasonality, and demonstrate that the tropical seasonal rainforest is highly self-organized and plays an important role in local environmental stability via the land surface thermal regulation. The rubber plantation is at a very low level of self-organization as quantified by the thermodynamic indicators, especially during the dry season. The expansion of the area of rubber plantation and shrinkage of tropical seasonal rainforest would likely induce local surface warming and a larger daily temperature range.  相似文献   

18.
The goal of this work is to make ecotoxicologically-relevant substance bands visible on thin-layer chromatographic plates. Bacteria (Bacillus subtilis, Vibrio fischeri, Salmonella typhimurium), fungi (Aspergillus niger), algi (Pseudokirchneriella subcapitata) and pollen (Impatiens walleriana) were used as test organisms. With the aid of these organisms, it has been possible to identify bactericide, fungicide, algicide, phytotoxic and genotoxic bands.  相似文献   

19.
Background, aim, and scope In Part 1 of this paper test thresholds for radionuclides in soil have been derived on the basis of methods and scales of the German Ordinance on Soil Protection (BBodSchV). In this paper, these test thresholds are checked with regard to their plausibility. Materials, methods, results are described in Part 1 of this paper. Discussion This contribution demonstrates that the test thresholds derived in Part 1 are plausible and feasible according to the requirements of the established methods. The epidemiological basis for the treatment of ionizing radiation is well founded. Risks can be quantified via the knowledge of cancer risks due to radiation. As a reference value the overall fatal risk coefficient of 5?% per Sv recommended by ICRP is used. The test thresholds obtained are sufficiently far from background levels in soils of northern Germany. Consequently, the test thresholds are applicable without any background corrections. Exposures by external radiation outdoors and exposures by inhalation of radon in cellar rooms result in calculated test thresholds in the order of background levels. Nevertheless, feasible results are obtained because in the case of toxic substances without threshold levels the additional exposures are considered for determination of test thresholds. Conclusions The approach of test thresholds for radioactive soil contamination presented in Part 1 of this paper complies with the criteria of the German methods for calculation of test thresholds in soil protection regarding plausibility and feasibility. It enables the soil protection authorities to assess radioactive contaminations of the ground according to the established rules in the field of soil protection and to make decisions according to Articles 9 and 10 of the German Soil Protection Act. Part 3 of this paper discusses the application of the test thresholds and the possibilities of determining the need for remediation actions.  相似文献   

20.
Soil fertility is conventionally evaluated by soil properties such as C, N, and P contents. Evaluation of soil fertility is now becoming a routine work for soil management and crop production. However, laboratory-analysis based determination of soil properties is time and cost consuming, which is not suitable for precision agriculture. Here, infrared spectroscopy (IR) appears as an alternative and fast technique to measure soil fertility. The IR transmission method is generally used in soil qualitative analysis, while the IR reflectance can be used in soil quantitative analysis, and most of soil-related research is focused on reflectance spectroscopy. Infrared reflectance spectra, including diffuse reflectance spectra and total attenuated reflectance spectra, are involved in soil quantitative analysis. We observe an excellent performance of predicting soil C and N contents using IR spectra. Moreover, in most of cases the predictions of the contents of soil P, K, Ca, Mg, S, and some other microelements are satisfactory. Soil water, soil clays, and soil microbes can also be characterized and evaluated using IR spectroscopy. In recent years, a new method named infrared photoacoustic spectra was applied in soil analysis. Infrared-photoacoustic spectra is indeed more convenient for sample pretreatment and spectra recording, and the recorded soil spectra contain more useful information versus conventional reflectance spectroscopy. Though currently the application of infrared photoacoustic spectroscopy in soil analysis is limited, it appears promising to measure soil fertility. The application of infrared spectroscopy in soil fertility is largely dependent on spectra pretreatment and multivariate calibration due to strong interferences in the spectra. Partial least square (PLS) and artificial neural network (ANN) are two widely used mathematical tools in the prediction of soil properties, and more mathematical tools combined models will benefit the prediction performance. To make full use of soil infrared spectra, soil spectra library construction is needed in future, and a standard procedure should be first decided in the construction. Based on soil infrared spectra library soil fertility can be fast evaluated combining suitable mathematical model, which will play an important role in the sustainable agriculture.  相似文献   

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