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Arts GHP, van Smeden J, Wolters MF, Belgers JDM, Matser AM, Hommen U, Bruns E, Heine S, Solga A, Taylor S. Seasonal dynamics of the macrophyte test species Myriophyllum spicatum over two years in experimental ditches for population modeling application in risk assessment. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2022; 18:1375-1386. [PMID: 34755447 PMCID: PMC9545951 DOI: 10.1002/ieam.4553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Myriophyllum spicatum is a sediment-rooted, aquatic macrophyte growing submerged, with a wide geographical distribution and high ecological relevance in freshwater ecosystems. It is used in testing and risk assessment for pesticides in water and sediment. Population models enable effects measured under laboratory conditions to be extrapolated to effects expected in the field with time-variable environmental factors including exposure. These models are a promising tool in higher-tier risk assessments. However, there is a lack of data on the seasonal dynamics of M. spicatum, which is needed to test model predictions of typical population dynamics in the field. To generate such data, a two-year study was set up in outdoor experimental systems from May 2017 to May 2019. The growth of M. spicatum was monitored in 0.2025 m2 plant baskets installed in an experimental ditch. Parameters monitored included biomass (fresh weight [FW] and dry weight [DW]), shoot length, seasonal short-term growth rates of shoots, relevant environmental parameters, and weather data. The results showed a clear seasonal pattern of biomass and shoot length and their variability. M. spicatum reached a maximum total shoot length (TSL) of 279 m m-2 and a maximum standing crop above-ground DW of 262 g m-2 . Periodical growth rates reached up to 0.072, 0.095, and 0.085 day-1 for total length, FW, and DW, respectively. Multivariate regression revealed that pH (as a surrogate for the availability of carbon species) and water temperature could explain a significant proportion of the variability in M. spicatum growth rates (p < 0.05). This study has provided an ecologically relevant data set on seasonal population dynamics representative of shallow freshwater ecosystems, which can be used to test and refine population models for use in chemical risk assessment and ecosystem management. Integr Environ Assess Manag 2022;18:1375-1386. © 2021 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).
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Affiliation(s)
- Gertie H. P. Arts
- Environmental Risk AssessmentWageningen University and ResearchWageningenThe Netherlands
| | - Jasper van Smeden
- Environmental Risk AssessmentWageningen University and ResearchWageningenThe Netherlands
| | - Marieke F. Wolters
- Environmental Risk AssessmentWageningen University and ResearchWageningenThe Netherlands
| | - J. Dick M. Belgers
- Environmental Risk AssessmentWageningen University and ResearchWageningenThe Netherlands
| | - Arrienne M. Matser
- Environmental Risk AssessmentWageningen University and ResearchWageningenThe Netherlands
| | - Udo Hommen
- Fraunhofer Institute for Molecular Biology and Applied Ecology IMESchmallenbergGermany
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Labine LM, Simpson MJ. Targeted Metabolomic Assessment of the Sub-Lethal Toxicity of Halogenated Acetic Acids (HAAs) to Daphnia magna. Metabolites 2021; 11:100. [PMID: 33578863 PMCID: PMC7916598 DOI: 10.3390/metabo11020100] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/03/2021] [Accepted: 02/05/2021] [Indexed: 12/19/2022] Open
Abstract
Halogenated acetic acids (HAAs) are amongst the most frequently detected disinfection by-products in aquatic environments. Despite this, little is known about their toxicity, especially at the molecular level. The model organism Daphnia magna, which is an indicator species for freshwater ecosystems, was exposed to sub-lethal concentrations of dichloroacetic acid (DCAA), trichloroacetic acid (TCAA) and dibromoacetic acid (DBAA) for 48 h. Polar metabolites extracted from Daphnia were analyzed using liquid chromatography hyphened to a triple quadrupole mass spectrometer (LC-MS/MS). Multivariate analyses identified shifts in the metabolic profile with exposure and pathway analysis was used to identify which metabolites and associated pathways were disrupted. Exposure to all three HAAs led to significant downregulation in the nucleosides: adenosine, guanosine and inosine. Pathway analyses identified perturbations in the citric acid cycle and the purine metabolism pathways. Interestingly, chlorinated and brominated acetic acids demonstrated similar modes of action after sub-lethal acute exposure, suggesting that HAAs cause a contaminant class-based response which is independent of the type or number of halogens. As such, the identified metabolites that responded to acute HAA exposure may serve as suitable bioindicators for freshwater monitoring programs.
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Affiliation(s)
- Lisa M. Labine
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada;
- Environmental NMR Centre and Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
| | - Myrna J. Simpson
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada;
- Environmental NMR Centre and Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON M1C 1A4, Canada
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Li H, Ma Y, Hu H, Song X, Ma Y, Yan H. Novel ammonium dichloroacetates with enhanced herbicidal activity for weed control. RSC Adv 2020; 10:44512-44521. [PMID: 35517127 PMCID: PMC9058436 DOI: 10.1039/d0ra08707f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/23/2020] [Indexed: 12/29/2022] Open
Abstract
Dichloroacetic acid (DCA) exhibits great potential as an herbicide (nontoxic, easily biodegradable), but its application in agriculture has scarcely been investigated. Since DCA readily undergoes photolysis when exposed to natural light or UV irradiation, there is a large activity loss in controlling weeds. To improve the activity of DCA, we proposed the transformation of DCA into an ionic salt form by using an herbicidal ionic liquids (HILs) strategy. Herein, fifteen novel ammonium dichloroacetates were designed and achieved for the first time. When compared to the anionic precursor DCA, three salts with longer alkyl chains ranging from dodecyl to hexadecyl chains were found to enhance not only the post emergence herbicidal activity but also the rates of activity against some broadleaf weeds under greenhouse conditions. The enhancement was due to the synergistic effect of structural factors, such as the surface activity, solubility and stability arising from their ionic nature. In addition, IL 13 possesses a low phytotoxicity to cotton plants with a favorable selectivity index above 2. This study will be useful for the design of new, high-performance herbicidal formulations.
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Affiliation(s)
- Huanhuan Li
- Plant Protection Department, State Key Laboratory of Cotton Biology, Institute of Cotton Research, The Chinese Academy of Agricultural Sciences Henan Anyang 455000 China +86-372-2562294 +86-372-2562294
| | - Yajie Ma
- Plant Protection Department, State Key Laboratory of Cotton Biology, Institute of Cotton Research, The Chinese Academy of Agricultural Sciences Henan Anyang 455000 China +86-372-2562294 +86-372-2562294
| | - Hongyan Hu
- Plant Protection Department, State Key Laboratory of Cotton Biology, Institute of Cotton Research, The Chinese Academy of Agricultural Sciences Henan Anyang 455000 China +86-372-2562294 +86-372-2562294
| | - Xianpeng Song
- Plant Protection Department, State Key Laboratory of Cotton Biology, Institute of Cotton Research, The Chinese Academy of Agricultural Sciences Henan Anyang 455000 China +86-372-2562294 +86-372-2562294
| | - Yan Ma
- Plant Protection Department, State Key Laboratory of Cotton Biology, Institute of Cotton Research, The Chinese Academy of Agricultural Sciences Henan Anyang 455000 China +86-372-2562294 +86-372-2562294
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University Nanjing Jiangsu 210023 P. R. China
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Turek M, Biczak R, Pawłowska B, Różycka-Sokołowska E, Marciniak B, Deska M, Skalik J, Bałczewski P. Ammonium haloacetates - An alternative to glyphosate? CHEMOSPHERE 2018; 194:650-656. [PMID: 29241140 DOI: 10.1016/j.chemosphere.2017.12.055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 11/15/2017] [Accepted: 12/09/2017] [Indexed: 06/07/2023]
Abstract
This study shows the design, synthesis and evaluation of eco(phyto)toxic and herbicidal activities of quaternary ammonium salts (QASs), derived from haloacetic acids, in context of the search for safer alternatives to the commonly used herbicide, N-(phosphonomethyl)glycine (glyphosate). The structure of the investigated QASs refers to the heteroatom sequence in the anion of glyphosate in which the (P-C)-N nitrogen atom was replaced by one or more halogens (F, Cl). The ecotoxicity of the synthesized QASs was tested against luminescent marine bacteria Vibrio fischeri (Microtox® test) and the crustaceans Heterocypris incongruens (Ostracodtoxkit F™). The phytotoxic effect of QASs was also studied with respect to spring barley (Hordeum vulgare) and common radish (Raphanus sativus L. radicula Pers.), whereas herbicidal activity was investigated in relation to popular weeds species gallant soldier (Galinsoga parviflora Cav.) and common sorrel (Rumex acetosa L.). The results showed that toxicity of the synthesized QASs depends on a number of halo-substituents, especially for bioluminescent bacteria Vibrio fischeri for which EC50 values were those varying the most. Phytotoxicity tests proved that the investigated QASs had a similar high, toxic effect both on monocotyledonous and dicotyledonous plants with exception of DIPA - DCA. Moreover, their herbicidal activity against common sorrel was comparable to glyphosate.
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Affiliation(s)
- Marika Turek
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Robert Biczak
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Barbara Pawłowska
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Ewa Różycka-Sokołowska
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Bernard Marciniak
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Małgorzata Deska
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland
| | - Joanna Skalik
- Department of Heteroorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, Łódź, 90-363, Poland
| | - Piotr Bałczewski
- Institute of Chemistry, Environmental Protection and Biotechnology, The Faculty of Mathematics and Natural Sciences, Jan Długosz University in Częstochowa, Armii Krajowej 13/15, Częstochowa, 42-201, Poland; Department of Heteroorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, Łódź, 90-363, Poland.
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Heine S, Schmitt W, Schäffer A, Görlitz G, Buresová H, Arts G, Preuss TG. Mechanistic modelling of toxicokinetic processes within Myriophyllum spicatum. CHEMOSPHERE 2015; 120:292-298. [PMID: 25129053 DOI: 10.1016/j.chemosphere.2014.07.065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 07/08/2014] [Accepted: 07/18/2014] [Indexed: 06/03/2023]
Abstract
Effects of chemicals are, in most cases, caused by internal concentrations within organisms which rely on uptake and elimination kinetics. These processes might be key components for assessing the effects of time-variable exposure of chemicals which regularly occur in aquatic systems. However, the knowledge of toxicokinetic patterns caused by time-variable exposure is limited, and gaining such information is complex. In this work, a previously developed mechanistic growth model of Myriophyllum spicatum is coupled with a newly developed toxicokinetic part, providing a model that is able to predict uptake and elimination of chemicals, as well as distribution processes between plant compartments (leaves, stems, roots) of M. spicatum. It is shown, that toxicokinetic patterns, at least for most of the investigated chemicals, can be calculated in agreement with experimental observations, by only calibrating two chemical- specific parameters, the cuticular permeability and a plant/water partition coefficient. Through the model-based determination of the cuticular permeabilities of Isoproturon, Iofensulfuron, Fluridone, Imazamox and Penoxsulam, their toxicokinetic pattern can be described with the model approach. For the use of the model for predicting toxicokinetics of other chemicals, where experimental data is not available, equations are presented that are based on the log (P oct/wat) of a chemical and estimate parameters that are necessary to run the model. In general, a method is presented to analyze time-variable exposure of chemicals more in detail without conducting time and labour intensive experiments.
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Affiliation(s)
- S Heine
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany.
| | - W Schmitt
- Bayer Crop Science AG, Alfred-Nobel-Straße 50, 40789 Monheim am Rhein, Germany
| | - A Schäffer
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
| | - G Görlitz
- Bayer Crop Science AG, Alfred-Nobel-Straße 50, 40789 Monheim am Rhein, Germany
| | - H Buresová
- Department of Environmental Chemistry, Institute of Chemical Technology, Prague, Technicka 5, 166 28 Praha 6, Czech Republic
| | - G Arts
- Alterra, Wageningen University and Research Centre, P.O. Box 47, 6700 AA Wageningen, The Netherlands
| | - T G Preuss
- Institute for Environmental Research, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany
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Vervliet-Scheebaum M, Straus A, Tremp H, Hamer M, Maund SJ, Wagner E, Schulz R. A microcosm system to evaluate the toxicity of the triazine herbicide simazine on aquatic macrophytes. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2010; 158:615-623. [PMID: 19800719 DOI: 10.1016/j.envpol.2009.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 07/31/2009] [Accepted: 08/14/2009] [Indexed: 05/28/2023]
Abstract
This study evaluates the effects of the triazine herbicide simazine in an outdoor pond microcosm test system that contained two submerged rooted species (Myriophyllum spicatum and Elodea canadensis) and two emergent rooted species (Persicaria amphibia and Glyceria maxima) over a period of 84 days. Simazine was applied to the microcosms at nominal concentrations of 0.05, 0.5 and 5 mg/L. General biological endpoints and physiological endpoints were used to evaluate herbicide toxicity on macrophytes and the algae developing naturally in the system. Concentration-related responses of macrophytes and algae were obtained for the endpoints selected, resulting in a no observed ecologically adverse effect concentration (NOEAEC) at simazine concentrations of 0.05 mg active ingredient/L after 84 days. E. canadensis was the most negatively affected species based on length increase, which was consistently a very sensitive parameter for all macrophytes. The experimental design presented might constitute a suitable alternative to conventional laboratory single-species testing.
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Affiliation(s)
- Marco Vervliet-Scheebaum
- Plant Biotechnology, Faculty of Biology, University of Freiburg, Schaenzlestr. 1, 79104 Freiburg, Germany.
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Barhorst JB, Kubiak R. Formation of chlorinated disinfection by-products in viticulture. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2009; 16:582-589. [PMID: 19479293 DOI: 10.1007/s11356-009-0186-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Accepted: 05/13/2009] [Indexed: 05/27/2023]
Abstract
BACKGROUND, AIM AND SCOPE The use of sodium hypochlorite (HYP) in viticulture results in effluents which are contaminated with halogenated substances. These disinfection by-products (DBPs) can be quantified as group parameter 'adsorbable organic halogens' (AOX) and have not been determined in effluents of viticulture yet. The substances that are detected as AOX are unknown. The AOX can be composed of harmless substances, but even toxic contaminants. Thus, it is impossible to assess ecological impacts. The aim of this study is to determine the quantification of AOX and DBPs after the use of HYP. This will be helpful to reduce environmental pollution by AOX. MATERIALS AND METHODS The potential of HYP to generate AOX was determined in laboratory-scale experiments. Different model solutions were treated with HYP according to disinfection processes in viticulture and conditions of AOX formation in effluents were simulated. AOX were quantified using the flask-shaking method and identified DBPs were investigated by gas chromatography-mass spectrometry. RESULTS Treatment with HYP resulted in the formation of AOX. The percentage conversion of HYP to AOX was up to 11%. Most important identified DBPs in viticulture are chloroform, dichloroacetic acid and trichloroacetaldehyde. In addition, the formation of carbon tetrachloride (CT), 1,1,1-trichloropropanone, 2,4-dichlorobenzoic acid and 2-chloro-/2,4-dichlorophenylacetic acid was investigated. It was demonstrated that reaction temperature, concentration of HYP and type of organic matter have important influence on the formation of chlorinated DBPs. DISCUSSION The percentage conversion of HYP to AOX was similar to other published studies. Although a correlation of single compounds and AOX is difficult, chloroform was the predominant AOX. Generation of the volatile chloroform should be avoided due to possible adverse effects. The generation of dichloroacetic acid is of minor importance on account of biodegradation. Trichloroacetaldehyde and 1,1,1-trichloropropanone are weak mutagens and their formation should be avoided. CONCLUSIONS The generation of AOX and chlorinated DBPs can be minimised by reducing the concentrations of the organic materials in the effluents. The removal of organic matter before disinfection results in a decreased formation of AOX. HYP is an effective disinfectant; therefore, it should be used at low temperatures and concentrations to reduce the amount of AOX. If possible, disinfection should be accomplished by the use of no chlorine-containing agents. By this means, negative influences of HYP on the quality of wine can also be avoided. RECOMMENDATIONS AND PERSPECTIVES Our results indicate that HYP has a high potential to form AOX in effluents of viticulture. The predominant by-products are chloroform, dichloroacetic acid and trichloroacetaldehyde. In further research, wastewaters from a winery and the in- and outflows of two sewage treatment plants were sampled during vintage and analysed. These results will be discussed in a following paper.
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Affiliation(s)
- Jan Bernd Barhorst
- Institute for AgroEcology (IfA), RLP AgroScience GmbH, 67435 Neustadt/Weinstrasse, Germany.
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Brain RA, Cedergreen N. Biomarkers in aquatic plants: selection and utility. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2009; 198:49-109. [PMID: 19253039 DOI: 10.1007/978-0-387-09647-6_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This review emphasizes the predictive ability, sensitivity and specificity of aquatic plant biomarkers as biomonitoring agents of exposure and effect. Biomarkers of exposure are those that provide functional measures of exposure that are characterized at a sub-organism level. Biomarkers of effect require causal linkages between the biomarker and effects, measured at higher levels of biological organization. With the exception of pathway specific metabolites, the biomarkers assessed in this review show variable sensitivity and predictive ability that is often confounded by variations in growth conditions, rendering them unsuitable as stand alone indicators of environmental stress. The use of gene expression for detecting pollution has been, and remains immature; this immaturity derives from inadequate knowledge on predictive ability, sensitivity and specificity. Moreover, the ability to the detect mode of action of unknown toxicants using gene expression is not as clear-cut as initially hypothesized. The principal patterns in gene expression is not as clear-cut as initially hypothesized. The principal patterns in gene expression are generally derived from stress induced genes, rather than on ones that respond to substances with known modes of action (Baerson et al. 2005). Future developments in multivariate statistics and chemometric methods that enhance pattern analyses in ways that could produce a "fingerprint", may improve methods for discovering modes of action of unknown toxicants. Pathway specific metabolites are unambiguous, sensitive, correlate well to growth effects, and are relatively unaffected by growth conditions. These traits make them excellent biomarkers under both field and laboratory conditions. Changes in metabolites precede visible growth effects; therefore, measuring changes in metabolite concentrations (Harring et al. 1998; Shaner et al. 2005). The metabolic phase I enzymes (primarily associated with P-450 activity) are non-specific biomarkers, and few studies relate them to growth parameters. P-450 activity both increases and decreases in response to chemical stress, often confounding interpretation of experimental results. Alternatively, phase II metabolic enzymes (e.g., glutathione S-transferases; GST's) appear to be sensitive biomarkers of exposure, and potentially effect. Some GST's are affected by growth factors, but others may only be induced by xenobiotics. Measuring xenobiotic-induced GST's, or their gene expression patterns, are good candidates for future biomarkers of the cumulative load of chemical stress, both in the laboratory and under field conditions. Phytochelatins respond to some but not all metal ions, and may therefore be used as biomarkers of exposure to identify the presence and bioavailability of ions to which they respond. However, more data on their specificity to, and interactions with growth factors, in more species are needed. The flavenoids are only represented by one heavy metal exposure study; therefore their use as biomarkers is currently difficult to judge. Stress proteins tend to be specific for toxicants that affect protein function. Growth factors are known to affect the level of stress proteins; hence, the use of stress proteins as biomarkers will be confined to experiments performed under controlled growth conditions, where they can be excellent indicators of proteotoxicity. Reactive oxygen species (ROS), ROS scavenging enzymes, changes in pigment content, photosynthesis and chlorophyll fluorescence are all affected by growth factors, particularly light and nutrient availability. Therefore, these biomarkers are best suited to investigate the mode of action of toxicants under controlled growth conditions. These biomarkers are sensitive to xenobiotic stressors that affect various processes in the photosynthetic apparatus, and can be used to diagnose which photosynthetic process or processes are primarily affected. Chlorophyll fluorescence is a non-destructive measure, and is thereby well suited for repeated measures of effect and recovery (Abbaspoor and Streibig 2005; Abbaspoor et al. 2006; Cedergreen et al. 2004). Bi-phasic responses (over time and with dose) are probably major sources of variation in sensitivity for many biomarkers. Metabolic enzymes, stress proteins, ROS and their corresponding scavenging enzymes increase in a time-frame and at doses in which plant cell damage is still repairable. However, when toxicity progresses to the point of cell damage, the concentration/activity of the biomarker either stabilizes or decreases. Examples of this response pattern are given in Lei et al. (2006); Pflugmacher et al. (2000b); Teisseire et al. (1998); and Teisseire and Guy (2000). Gene expression is also a time-dependent phenomenon varying several fold within a few hour. Therefore, bi-phasic response patterns make timing and dose-range, within which the biomarkers can be used as measures of both exposure and effect, extremely important. As a result, most biomarkers are best suited for situations in which the time and dose dependence of the biomarker, in the investigated species, are established. Notwithstanding the previously mentioned limitations, all assessed biomarkers provide valuable information on the physiological effects of specific stressors, and are valuable tools in the search for understanding xenobiotic modes of action. However, the future use of aquatic plant biomarkers will probably be confined to laboratory studies designed to assess toxicant modes of action, until further knowledge is gained regarding the time, dose and growth-factor dependence of biomarkers, in different species. No single biomarker is viable in gaining a comprehensive understanding of xenobiotic stress. Only through the concomitant measurement of a suite of appropriate biomarkers will our diagnostic capacity be enhanced and the field of ecotoxicology, as it relates to aquatic plants, advanced.
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Affiliation(s)
- Richard A Brain
- Center for Reservoir and Aquatic Systems Research, Department of Environmental Science, Baylor University, Waco, Texas 76798, USA
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Sánchez D, Graça MAS, Canhoto J. Testing the use of the water milfoil (Myriophyllum spicatum L.) in laboratory toxicity assays. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2007; 78:421-6. [PMID: 17492386 DOI: 10.1007/s00128-007-9131-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 03/16/2007] [Indexed: 05/15/2023]
Abstract
Tests aiming to determine the toxic properties of compounds discharged into aquatic systems have relied more on fish or invertebrates than on primary producers and among a number of producers; algae are the most popular test organisms. Macrophytes are important ecological elements in freshwaters and are therefore potentially key organisms for use in toxicity testing of compounds suspected of acting in primary producers. The most common macrophyte used in toxicity testing is Lemna sp., but as a floating plant, it has the limitation of being exposed to toxic compounds only through its lower leaf surface, including roots and rhizoids. Therefore, it is questionable whether tests with Lemna may accurately predict potential effects on submersed and exposed plant species, which have different routes of exposure and morphology. Few other submersed macrophytes have been tested, notably Myriophyllum. In the Iberian peninsula M. spicatum is the most common species within its genus and has been presented as a good bioaccumulator of heavy metals (Wang et al. 1996) and as being sensitive to several toxicants (e.g. Hanson et al. 2003). The aim of this study was to assess the potential of M. spicatum as a testing organism in laboratory assays, by obtaining axenic cultures of this plant and exposing them to several reference compounds to determine the sensitive endpoints.
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Affiliation(s)
- David Sánchez
- IMAR, Departament of Zoology, University of Coimbra, 3004 517 Coimbra, Portugal
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Knauer K, Vervliet-Scheebaum M, Dark RJ, Maund SJ. Methods for assessing the toxicity of herbicides to submersed aquatic plants. PEST MANAGEMENT SCIENCE 2006; 62:715-22. [PMID: 16703656 DOI: 10.1002/ps.1226] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A new test design for the non-axenic submergent aquatic macrophytes Elodea canadensis Michx. and Myriophyllum spicatum L. has been developed for potential use in herbicide toxicity testing. For the non-axenic cultures, the best growth conditions were observed in the Elendt-M4 medium in which no growth of algae or bacteria was observed. Cuttings were placed in beakers containing only the artificial M4 medium or were planted in small beakers containing OECD (Organisation for Economic Cooperation and Development) sediment (5% peat, 75% sand, 20% kaolinite), which were then placed in larger vessels with the M4 medium. The plants were observed for main and secondary shoot length, biomass and root formation within 2-3 weeks of planting. Growth rates were calculated for total plant length and biomass. The variance between the replicates was low throughout the experiment [coefficient of variation (CV) < 26% for total plant length, and between 16 and 40% for biomass]. Relative growth rates based on total plant length were determined as 0.028 and 0.050 per day for M. spicatum in the systems containing M4 medium only and medium plus sediment respectively. Similar results were observed for E. canadensis, with relative growth rates of 0.26 and 0.073 per day in the two test systems. The root-shoot ratio at harvest was greater by a factor of 2-3 for E. canadensis in the M4 medium than in the system containing sediment. However, comparable ratios were observed for M. spicatum in the two test systems. Both growth in total plant length and growth in biomass of the two species have potential as measures of toxicity.
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Affiliation(s)
- Katja Knauer
- Syngenta Crop Protection AG, Schwarzwaldallee, Vesalgasse 1, Switzerland.
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Hanson ML, Solomon KR. Haloacetic acids in the aquatic environment. Part II: ecological risk assessment. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2004; 130:385-401. [PMID: 15182971 DOI: 10.1016/j.envpol.2003.12.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2003] [Accepted: 12/26/2003] [Indexed: 05/24/2023]
Abstract
Haloacetic acids (HAAs) are environmental contaminants found in aquatic ecosystems throughout the world as a result of both anthropogenic and natural production. The ecological risk posed by these compounds to organisms in freshwater environments, with a specific focus on aquatic macrophytes, was characterized. The plants evaluated were Lemna gibba, Myriophyllum spicatum and M. sibiricum and the HAAs screened were monochloroacetic acid (MCA), dichloroacetic acid (DCA), trichloroacetic acid (TCA), trifluoroacetic acid (TFA) and chlorodifluoroacetic acid (CDFA). Laboratory toxicity data formed the basis of the risk assessment, but field studies were also utilized. The estimated risk was calculated using hazard quotients (HQ), as well as effect measure distributions (EMD) in a modified probabilistic ecological risk assessment. EMDs were used to estimate HAA thresholds of toxicity for use in HQ assessments. This threshold was found to be a more sensitive measure of low toxicity than the no observed effect concentrations (NOEC) or the effective concentration (EC10). Using both deterministic and probabilistic methods, it was found that HAAs do not pose a significant risk to freshwater macrophytes at current environmental concentrations in Canada, Europe or Africa for both single compound and mixture exposures. Still, HAAs are generally found as mixtures and their potential interactions are not fully understood, rendering this phase of the assessment uncertain and justifying further effects characterization. TCA in some environments poses a slight risk to phytoplankton and future concentrations of TFA and CDFA are likely to increase due to their recalcitrant nature, warranting continued environmental surveillance of HAAs.
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Affiliation(s)
- Mark L Hanson
- Centre for Toxicology and Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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McRae BM, LaPara TM, Hozalski RM. Biodegradation of haloacetic acids by bacterial enrichment cultures. CHEMOSPHERE 2004; 55:915-925. [PMID: 15041296 DOI: 10.1016/j.chemosphere.2003.11.048] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2003] [Revised: 08/28/2003] [Accepted: 11/03/2003] [Indexed: 05/24/2023]
Abstract
Haloacetic acids (HAAs) are toxic organic chemicals that are frequently detected in surface waters and in drinking water distribution systems. The aerobic biodegradation of HAAs was investigated in serum bottles containing a single HAA and inoculated with washed microorganisms obtained from enrichment cultures maintained on either monochloroacetic acid (MCAA) or trichloroacetic acid (TCAA) as the sole carbon and energy source. Biodegradation was observed for each of the HAAs tested at concentrations similar to those found in surface waters and in drinking water distribution systems. The MCAA culture was able to degrade both MCAA and monobromoacetic acid (MBAA) with pseudo-first order rate constants of 1.06 x 10(-2) and 1.13 x 10(-2) l(mg protein)(-1) d(-1), respectively, for concentrations ranging from 10(-5) to 2 mM. The pseudo-first order rate constant for TCAA degradation by the TCAA culture was 6.52 x 10(-3) l(mg protein)(-1) d(-1) for concentrations ranging from 5.33 x 10(-5) to 0.72 mM. The TCAA culture was also able to degrade MCAA with the rate accelerating as incubation time increased. Experiments with radiolabeled HAAs indicated that the 14C was primarily converted to 14CO2 with minor incorporation into cell biomass. The community structure of the enrichment cultures was analyzed by both cultivation-dependent and cultivation-independent approaches. Denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified 16S rRNA gene fragments showed that each of the two enrichment cultures had multiple bacterial populations, none of which corresponded to HAA-degrading bacteria cultivated on HAA-supplemented agar plates. This research indicates that biodegradation is a potential loss mechanism for HAAs in surface waters and in drinking water distribution systems.
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Affiliation(s)
- Bethany M McRae
- Department of Civil Engineering, University of Minnesota, 122 Civil Engineering Building, 500 Pillsbury Drive SE, Minneapolis, MN 55455, USA
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