Ecotoxicological Potential Research Articles

A new plant-based bioassay for aquatic sediments

To date, standardised bioassays for the assessment of the ecotoxicological potential in sediments and dredged material use test organisms like bacteria, algae and crustaceae. This paper presents the development and application of a novel sediment contact test (whole sediment) withMyriophyllum aquaticum, a representative of rooted aquatic macrophytes. The aim of the present study is to demonstrate the value of a sediment contact test with rooted macrophytes as a supplement to existing test batteries in order to improve the assessment of sediment toxicity. The newly developed sediment contact test withMyriophylhim aquaticum was applied to natural whole sediments. For performing the test, whorls ofMyriophyllum aquaticum were directly planted in the native sediment and incubated in the light at 24°C (cf. section results and discussion). The end points of the test were the number of the shoots and the fresh weight of the whole plants. The duckweed growth inhibition test withLemna minor according to ISO/DIS 20079 was performed in pore waters from sediment samples. The results of the sediment contact test withMyriophyllum aquaticum were compared with each other and with those of the aquatic duckweed test. A test protocol for the new plant-based sediment contact test using the aquatic plantMyriophyllum aquaticum as an indicator was developed. The best control sediment proved to be the OECD sediment (OECD 207). A test period of 10 days appeared to be sufficient for the test. The increase of biomass and the derived growth rate were found to be the most suitable evaluation parameters. The growth behaviour ofMyriophyllum aquaticum differed depending on the origin of sediments. Therefore, plant-affecting contamination, that is bound in sediments, was indicated. The novel sediment contact test withMyriophyllum aquaticum can indicate phytotoxic effects in sediments. Therefore, it allows a better assessment of the overall-toxicity in whole sediments. The sediment contact test withMyriophyllum aquaticum is a valuable tool for the evaluation of the ecotoxicological risk potential of waters and sediments. It should become a complement to a standardised test battery generally used for the assessment of sediment toxicity.

Estimation of ecotoxicological potential of contaminated sediments based on a sequential extraction procedure with supercritical CO 2 and subcritical H 2O solvents

Sediment samples were taken from the Tisza–Szamos area and Gödöllő lake system. A new sequential extraction scheme in a supercritical extractor using supercritical CO 2, subcritical H 2O, and a subcritical mixture of 90% H 2O and 10% CO 2 as solvents was employed. This procedure provides relevant information about environmentally mobile heavy metal fractions (water-soluble, bicarbonate-forming) of sediments during a reasonably short time (5 h). The environmental mobility of Zn and Cd was found to be the highest among the sediments involved in these investigations. This mobility represents detectable ecotoxicity, which can be tested with the subcritical water extracts. Performance of pollen tube growth (PTG) test and the ecotoxicological stable isotope metabolic assay (ESIMA) was compared. Potential ecotoxicity of aqueous extracts was reliably detectable by PTG test during a relatively short time (1 day).

Significance of platinum group metals emitted from automobile exhaust gas converters for the biosphere

Following the introduction of automobile catalytic converters the platinum group metals (PGM) platinum (Pt), palladium (Pd) and rhodium (Rh) gain on increasing interest in environmental research as these metals are emitted with exhaust fumes into the environment. Consequently, elevated PGM levels were found in different environmental matrices such as road dusts, soils along heavily frequented roads, sediments of urban rivers etc. Accordingly, the effects of increasing PGM emissions on the biosphere are controversially discussed. This paper summarizes the present knowledge on the biological availability of PGM to plants and animals. As biological availability is one of the most decisive factors determining the toxicological potential of xenobiotics, this information is very important to evaluate the possible threat of the noble metals to ecosystems. The availability of soluble as well as particle bound PGM to terrestrial plants was demonstrated in several studies. Experimental investigations revealed uptake of Pt, Pd and Rh also by aquatic plants. Additionally, the biological availability of the noble metals for animals has been verified in experimental studies using soluble metal salts, catalytic converter model substances, sediments of urban rivers, road dust or tunnel dust as metal sources. These studies refer mainly to aquatic animals. Beside of free living organisms, in particular worms parasitizing fish demonstrated a high potential to accumulate PGM. This could be of great interest in respect of biomonitoring purposes. Generally, for plants as well as for animals Pd turns out to be the best available metal among the PGM. Compared to other heavy metals, the biological availability of PGM from road dust to zebra mussels (Dreissena polymorpha) ranged between that of Cd and Pb. Especially chronic effects of PGM on the biosphere can not be excluded due to (1) their cumulative increase in the environment, (2) their unexpected high biological availability and bioaccumulation and (3) their unknown toxicological and ecotoxicological potential. However, it appears that acute effects on ecosystems due to anthropogenic PGM emission are not likely. Research on environmental PGM contamination of the biosphere, especially the fauna, and on long-term toxicity of low PGM concentrations is highly appreciated. These studies require very sensitive analytical techniques to determine PGM even in low sample amounts. Research has to be done in particular on reliable determination of (ultra) trace levels of Pd and Rh as the lack of data on these two metals is mainly due to analytical problems.

Aquatic ecotoxicity of pharmaceuticals including the assessment of combination effects

To evaluate the ecotoxicological potential of ten prescription drugs against aquatic organisms from different taxonornical classes, a set of biotests were performed using the cladoceran Daphnia magna, the chlorophyte Desmodesmus subspicatus and the macrophyte Lemna minor. Endpoints were immobilisation for Daphnia and inhibition of the average growth rate for Desmodesmus and Lemna. For most of the substances, toxicities were moderate, with EC 50s in the range from 10 to 100 mg l −1 or even far above, whereas Lemna was the most sensitive test species in the majority of all tested compounds. Tests with combinations of various pharmaceuticals revealed stronger effects than expected from the effects measured singly. Clofibrinic acid and Carbamazepine have been found to act by a non-specific mode of action (non-polar narcosis), and with Daphnia the combination effect of these substances followed the concept of concentration addition, while in the algae test the concept of independent action could be used to calculate the mixture toxicity. The anti-inflammatory drugs Diclofenac and Ibuprofen have also been found to act unspecific by non-polar narcosis and to follow the concept of concentration addition in the algal test as well as in the Daphnia test. The measured toxicities of the tested pharmaceuticals shows that acute effect of single substances in the aquatic environment are very unlikely. But we should keep in mind that considerable combination effects can occur and that toxicity data from chronic studies are needed to assess the environmental risk of drug residues.

Occurrence of stable foam in the upper Rhine River caused by plant-derived surfactants.

For 30 yr, a persistent foam cover has been observed during the summer months in the Rhine River beneath the Rhine Fall, a waterfall near Schaffhausen, Switzerland. This phenomenon has been a matter of public concern ever since its first appearance, but all previous attempts to clarify the origin of this foam had remained inconclusive. With the aid of electrospray LC-MS,triterpene saponins and mono- and digalactosyldiacylglycerolipids (MGDAG and DGDAG), two classes of tensioactive metabolites occurring in the aquatic plant Ranunculus fluitans Lamk. (Ranunculaceae), were detected in river water and foam samples. Saponin concentrations in water and foam samples were monitored at regular intervals during the years 1998 and 2000. Other compound classes with surfactant properties such as proteins, humic acids, and synthetic detergents were also analyzed. Foam occurrence paralleled with saponin concentration and with the amounts of detached Ranunculus biomass accumulating at the dam of the hydroelectric power plant of Schaffhausen located just above the Rhine Fall but not with the concentration of synthetic detergents. The ecotoxicological potential of Ranunculus constituents, water, and foam samples was checked with a representative range of aquatic indicator organisms. No acute toxicity was observed at concentrations that were at least 50-fold higher than those found in the environmental samples.

Assessment of the influence of use on ecotoxicological characteristics of synthetic ester lubricants.

Synthetic ester lubricants need optimisation about their technical and their ecotoxicological characteristics. To determine the ecotoxicological potential the required examinations can be based on the procedure for a risk assessment of chemicals. At present risk classification of lubricant oils is carried out with new oil fluids that are normally prepared before application in aqueous bioassays. In order to improve the ecotoxicological characteristics of some lubricant oils, the quality of the preparation method has been optimised. The resulting preparation protocol leads to aqueous extracts of the oil fluids that can be tested using biological assays. The extent of the changes of the chemical composition caused by the use as well as the ecotoxicological effects caused by additives have to be taken into consideration. For this reason various used lubricants are tested in addition to new oil fluids. In this work various lubricant samples were examined with standardised bacterial growth assays with Vibrio fischeri and Pseudomonas putida, luminescence inhibition assay with V. fischeri, survival assay with Daphnia magna and algal growth inhibition assay with Scenedesmus subspicatus. The chemical characterisation of the aqueous extracts included the determination of pH, conductivity, heavy metals, the content of dissolved organic carbon, inorganic anions and the content of phosphorus. The results emphasize the thesis that environmentally acceptable lubricants can undergo a change of their ecotoxicological potential during the use. Some of the substances that are normally added to base fluids in order to enhance the applicability of the oils may possess a high toxicological potential.

Rainbow trout primary epidermal cell proliferation as an indicator of aquatic toxicity: an in vitro/in vivo exposure comparison

Little or no work has been carried out on primary cell cultures in terms of cellular proliferation and toxicity studies. Cell proliferation represents one of the most relevant cellular functions. Anti-PCNA antibodies have aroused considerable interest recently as potential immunocytochemical markers of proliferation for use in toxicity studies. In this study, PCNA methodology, which was developed primarily for mammalian tissues, was adapted to rainbow trout ( Oncorhynchus mykiss (R.)) primary cultured epidermal cells exposed in vivo i.e. whole animal exposures and in vitro for the study of the ecotoxicological potential of the aromatic amine, 2,4-dichloroaniline (2,4-DCA), a member of a little studied and widespread class of aquatic pollutants. There are many approaches to assess the proliferative activity of cells. Immunocytochemical methods offer a high sensitivity and specificity. The immunohistochemical avidin–biotin complex (ABC) method was used for the detection and quantification of PCNA, one of the best-known endogenous proliferation markers, applying the mammalian monoclonal antibody PC-10 to formalin-fixed primary cultures of rainbow trout skin. Here we describe our experience with the immunocytochemical detection and quantification of this proliferation marker. Results indicate that the antibody cross reacts with the corresponding rainbow trout epitope and that the alterations in PCNA labelling in the in vivo and in vitro exposed cultures followed similar patterns. This paper presents data on the validation of rainbow trout primary epidermal culture as an in vitro ecotoxicity model with epidermal proliferation as an endpoint. It can be concluded that cellular proliferation could be used as an indicator of the aquatic toxicity potential of xenobiotics. Correlations between cellular proliferation responses in primary cultures derived from in vivo exposed rainbow trout and primary cultures exposed in vitro were assessed. A dose-response was evidenced in both approaches, however the in vivo exposures appeared to be approximately two orders of magnitude more sensitive than the in vitro exposures. Responses in vitro occurred between 200 and 1000 μM while in vivo responses were between 2 and 10 μM. The good qualitative correspondence between the in vitro and in vivo results indicates that studies using trout epidermal cells allow the identification of xenobiotic effects in fish skin. However, further work is required before quantitative predictions i.e. effective concentrations in vivo, can be made from in vitro studies. This study suggests that the in vitro exposed rainbow trout primary cultured cell model with proliferation as an endpoint can be used as an alternative testing procedure to the whole animal assay.

Transfer of veterinary drugs and pharmacologically-active feed additives into soil with special consideration of tetracyclines – executive summary

•In intensive animal production, a considerable proportion of the livestock population must be expected to receive animal pharmaceuticals. •The administration of pharmacologically-active feed additives has been influenced through the revocation of approval for some individual substances over the last few years. Aside from the substitution of these forbidden substances, further reductions in the use of antibiotic growth promotors can be expected primarily because of economic reasons. •Animal pharmaceuticals frequently consist of so-called older preparations whose ecotoxicological potentials have only been investigated inadequately. •High elimination rates of the active substances and their stability during storage, which could be demonstrated for tetracyclines, might also lead to a significant incorporation of these substances into the soil even when they are employed correctly. In the future, ecotoxicological investigations should be demanded in cases where the EMEA/CVMP trigger values (which are substantially lower) have been exceeded, a procedure which is currently only required for the newly approved agents. •There is presently a considerable need for research into the environmental fate of these older preparations and their ecotoxicological effects. Here, it will be especially important to take the degradation and transformation processes in the soil into account, as well as especially considering the consequences on the microbiological impacts affecting the soil. •Improved transparency in the application of these substances, in the sense of a quantitative’registration of the animal pharmaceuticals (especially the older preparations) which are employed, as well as the environmental monitoring of animal pharmaceuticals (e.g. in groundwater and surface water), would considerably improve the significance of the basic data for future appraisals.

Neue horizonte für die chemie

The term ‘sustainable development’ is defined and discussed with regard to its significance and its application in the field of chemistry. This is presented using the synthetic organic chemistry as an example. A review of the history of chemistry indicates clearly the necessity for further developments in the course of concepts involving sustainability. Following the eras of bituminous coal tar and mineral oil in both of the two past centuries, a search for new raw materials and a reduction in the global ecotoxicological potential for danger is being strived for. Critical contemplations are mandatory in order to avoid making this term ‘persistence’ into a keyword. Consequently, one must take into consideration the field of research and development as well as reflecting about the classification of chemical and scientific research projects, and their political as well as social relationships. Aside from the new methods of synthesis, this will also require the formulation of other decision-relevant criteria.

Surfactants – standard determination methods in comparison with substance specific mass spectrometric methods and toxicity testing by Daphnia magna and Vibrio fischeri

The recovery of different types of surfactants formerly applied and up-coming new ones from spiked wastewater and ultra-pure water was examined by sum parameter determinations (substance-group-specific Methylene Blue (MBAS), Bismuth Active (BiAS) and Disulfine Blue Active Substances (DSBAS)) and by substance-specific mass spectrometric detection (MS). For MS determination atmospheric pressure chemical ionization (APCI) and electrospray ionization (ESI) was applied in the flow injection (FIA) and liquid chromatographic separation (LC) mode. Quantitation was performed in the multiple ion detection mode using mass and tandem (MS/MS) mass spectrometric detection. In parallel the ecotoxicological potential of these surfactants was determined by Daphnia magna and Vibrio fischeri toxicity testing. MS was found to provide more reliable data in surfactant analysis than the substance-group-specific methods. The toxicity of the up-coming new surfactants against water organisms should not be neglected.

Formation, characterization and release of non-extractable residues of [14C] -labeled organic xenobiotics in soils

The amount of non-extractable residues (NER) of organic xenobiotics in the soil can considerably exceed the amount of extractable residues which are accessible to normal residue analysis. The NER therefore present a burden to the soil, the toxicological and ecotoxicological potential of which is largely unknown. For the characterization of bound residues and their binding type, special solubilization methods such as supercritical fluid extraction are applied and experiments with radiolabeled model polymers are performed. Mineralization experiments with [(14)C] labeled xenobiotics in natural soil show that a total degradation is still also possible in the environment when in a bound form. Ecotoxicological effects of non-extractable residues may be recorded when their concentration is high, when the parent compound exhibits a high ecotoxicity and the applied detection method is sufficiently sensitive.

Toxicity of Diphenylamine and Some of Its Nitrated and Aminated Derivatives to the Luminescent Bacterium Vibrio fischeri

Aqueous samples containing various nitrated and aminated diphenylamine derivatives were subjected to the luminescent bacterium Vibrio fischeri NRRL-B-11177 to determine their ecotoxicological potential. As the most important toxicological parameter, EC 50, the concentration needed to reduce bacterial luminescence by 50%, was calculated. All compounds tested must be classified to the category "very toxic to aquatic organisms" using the widely accepted classification scheme of D., Strupp, H. P. Lühr, H. T. Grunder, J. Gerdesmann, and J. Ahlers (1990, UWSF-Z. Umweltchem. Okotox. 2, 151-156). Only 2,4-diaminodiphenylamine can be classified as "less toxic to aquatic organisms." EC 50 values after 30, 60, and 90 min of incubation of the test compounds are presented. For many of the compounds tested in this study there are no toxicological data in the literature.

Toxicity of explosives and related compounds to the luminescent bacterium Vibrio fischeri NRRL-B-11177

Aqueous samples containing various explosives, their reduced metabolites, as well as related compounds were subjected to the luminescent bacterium Vibrio fischeri NRRL-B-11177 to determine their ecotoxicological potential. As the most important parameter, the EC50 values of 24 test compounds were calculated. The EC50 value means the concentration of a chemical compound that is needed to reduce bacterial luminescence by 50%. According to the widely accepted classification scheme of Strupp et al. (1990) and in consideration of an incubation period of 30 min (Deutsche Einheits verfahren zur Wasser-, Abwasser-, und Schlammuntersuchung-Testverfahren mit Wasserorganismen; Gruppe L; DIN 38412, L34; DEV 1991) TNT, 26DNT, 2A6NT, 4A2NT, 34DNT, TNB, TNBA, TETRYL and HEXYL must be classified in the category “very toxic to aquatic organisms”; 2A46DNT, 4A26DNT, 24DA6NT, 24DNT, 2A4NT, RDX, HMX and PETN must be classified in the category “toxic to aquatic organisms”; and 26DA4NT, TAT, TNPh, 26DAT, 24DAT, HMT and NQ can be classified in the category “less toxic to aquatic organisms”. EC50 values after 30, 60, and 90 min of incubation of the test compounds are presented and discussed. For many of the compounds tested in this study, there are no, or only a few, toxicological data in the literature available.

Evaluation of the luminescent bacteria bioassay for the estimation of the toxicological potential of effluent water samples—Comparison with data from chemical analyses

Investigations of toxic effects of water samples from industrial plants and landfill effluents on bioluminescent bacteria were carried out. The results of a standardised bioassay (LUMIStox) were compared to chemical analytic data (heavy metal concentrations, COD, and BOD). A reduction of bioluminescent activity was observed in most of the samples. The degree of reduction showed good correlation with the concentrations of anorganic and organic pollutant indicators. The applicability of the luminescent bacteria bioassay for the evaluation of the ecotoxicological potential of these kinds of polluted effluents was demonstrated.

Covalent binding of chemicals to plant cuticles: Quantitative determination of epoxide contents of cutins

The epoxy groups contained in the cuticles of some plant species covalently bind residues of chemicals having a carboxyl function. This may lead to an increased persistence of these compounds in the environment. In order to assess the ecotoxicological potential of this reaction, an analytical method for the determination of cuticular epoxides was developed. Stable derivatives can be quantitatively formed by treating cuticles with 0.2M HC1 in 1,4-dioxane. This reaction leads to the formation of the corresponding chlorohydrins. It proceeds rapidly and without side-effects both in isolated cuticles andin situ. The derivatives can be analyzed by standard thin-layer and capillary gas Chromatographic methods. Electron impact and chemical ionization mass spectrometry was used to identify the chlorohydrins derived fromClivia andFicus leaf cutin.

Concepts and procedures in ecotoxicology.

A multitude of non-biological substances are being produced at present in an attempt to provide a steadily increasing world population with better living conditions. This industrial activity causes measurable changes in the material quality of the environment. A comprehensive and thorough assessment of the effects of all the chemical compounds which are found widespread in the environment is not possible because of the overwhelming number of such products. In order to detect any undesired effects upon the natural environment as early as possible, it is essential to investigate representative model substances which are suitable for such studies because of their production levels, areas of application, persistence, distribution behaviour, degradability and expected biological activity. These topics are also the bases for the present world-wide activities as regards environmental chemicals laws. Since a large number of single factors determine the behaviour of chemicals in the environment, it is necessary to use step-wise elucidations for legal purposes. This is achieved by estimating the ecotoxicological behaviour by physico-chemical characteristics and upon feasible test procedures. At present, globally about 50000 chemicals are produced and used with an integral production level of about 150 million tons annually. Realizing this it is evident that a well structured assessment of their ecotoxicological potential is needed according to appropriate criteria. These are for individual chemicals : production level, use pattern, dispersion tendency, persistence, biotic and abiotic conversion, and biological activity. In principle, there are different approaches for assessment : Monitoring, Occurrence and Effects in Ecosystems This results in real data both for occurrence and changing the physical environment as well as populations of flora and fauna but gives no immediate prospective information. Assessment of Trends in Occurrence and Effects (Environmental specimen banking and long-term monitoring) This approach allows by backward analyses of stored samples estimation of trends in the occurrence of a chemical. Its correlation with long-term ecological monitoring allows for prospective evaluation. Simulation of the Environment Simulation experiments give rather good data for the estimation of the fate of chemicals in the environment. With respect to effects on organisms they are limited except the most sensitive indicator organisms or indicatory effects are available. Screening in Simple Test Procedures This gives indications on the potential for occurrence and effects and should be used mainly on a comparative basis. According to the potential of a chemical for ecotoxicological effects derived from production and fate (exposure probability), the approaches have to be selected as appropriate.