1
|
Mikó Z, Hettyey A. Toxicity of POEA-containing glyphosate-based herbicides to amphibians is mainly due to the surfactant, not to the active ingredient. ECOTOXICOLOGY (LONDON, ENGLAND) 2023; 32:150-159. [PMID: 36680666 PMCID: PMC10008773 DOI: 10.1007/s10646-023-02626-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 01/10/2023] [Indexed: 06/17/2023]
Abstract
Current international legislation regarding agrochemicals requires thorough toxicological testing mainly of the active ingredients. In a 96-h acute toxicity test we exposed Rana dalmatina and Bufo bufo tadpoles to either one of three concentrations of glyphosate, three concentrations of the surfactant (POEA), three concentrations of the two components together, or to non-contaminated water (control), and subsequently assessed mortality and body mass. To investigate whether simultaneous exposure to another stress factor influences effects of the contaminants, we performed tests both in the presence or absence of predator chemical cues. We found that the surfactant had significant harmful effects on tadpoles; survival was lowered by the highest concentration of the surfactant in case of R. dalmatina, while in B. bufo tadpoles it reduced survival already at medium concentrations. Body mass was significantly influenced by medium and high surfactant concentrations in both species. The presence of glyphosate did not have a significant effect by itself, but it slightly increased mortality in tadpoles exposed to medium concentrations of the surfactant in both species. The presence of chemical cues did not have an effect on the examined variables. Our study confirms that the toxicity of glyphosate-based herbicides is mainly due to the examined surfactant. Nonetheless, we found that glyphosate can enhance the harmful effect of the surfactant. These results stress that during the authorization process of new pesticide formulations, not only the active ingredients would need to be examined but the excipients should also be taken into account in an obligatory and systematic manner.
Collapse
Affiliation(s)
- Zsanett Mikó
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - Attila Hettyey
- Department of Evolutionary Ecology, Plant Protection Institute, Centre for Agricultural Research, Eötvös Loránd Research Network, Herman Ottó út 15, Budapest, 1022, Hungary
| |
Collapse
|
2
|
Trudeau VL, Thomson P, Zhang WS, Reynaud S, Navarro-Martin L, Langlois VS. Agrochemicals disrupt multiple endocrine axes in amphibians. Mol Cell Endocrinol 2020; 513:110861. [PMID: 32450283 DOI: 10.1016/j.mce.2020.110861] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 04/17/2020] [Accepted: 05/04/2020] [Indexed: 12/20/2022]
Abstract
Concern over global amphibian declines and possible links to agrochemical use has led to research on the endocrine disrupting actions of agrochemicals, such as fertilizers, fungicides, insecticides, acaricides, herbicides, metals, and mixtures. Amphibians, like other species, have to partition resources for body maintenance, growth, and reproduction. Recent studies suggest that metabolic impairments induced by endocrine disrupting chemicals, and more particularly agrichemicals, may disrupt physiological constraints associated with these limited resources and could cause deleterious effects on growth and reproduction. Metabolic disruption has hardly been considered for amphibian species following agrichemical exposure. As for metamorphosis, the key thyroid hormone-dependent developmental phase for amphibians, it can either be advanced or delayed by agrichemicals with consequences for juvenile and adult health and survival. While numerous agrichemicals affect anuran sexual development, including sex reversal and intersex in several species, little is known about the mechanisms involved in dysregulation of the sex differentiation processes. Adult anurans display stereotypical male mating calls and female phonotaxis responses leading to successful amplexus and spawning. These are hormone-dependent behaviours at the foundation of reproductive success. Therefore, male vocalizations are highly ecologically-relevant and may be a non-invasive low-cost method for the assessment of endocrine disruption at the population level. While it is clear that agrochemicals disrupt multiple endocrine systems in frogs, very little has been uncovered regarding the molecular and cellular mechanisms at the basis of these actions. This is surprising, given the importance of the frog models to our deep understanding of developmental biology and thyroid hormone action to understand human health. Several agrochemicals were found to have multiple endocrine effects at once (e.g., targeting both the thyroid and gonadal axes); therefore, the assessment of agrochemicals that alter cross-talk between hormonal systems must be further addressed. Given the diversity of life-history traits in Anura, Caudata, and the Gymnophiona, it is essential that studies on endocrine disruption expand to include the lesser known taxa. Research under ecologically-relevant conditions will also be paramount. Closer collaboration between molecular and cellular endocrinologists and ecotoxicologists and ecologists is thus recommended.
Collapse
Affiliation(s)
- Vance L Trudeau
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
| | - Paisley Thomson
- Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec (Québec), G1K 9A9, Canada.
| | - Wo Su Zhang
- Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, ON, K1N 6N5, Canada.
| | - Stéphane Reynaud
- Laboratoire d'Ecologie Alpine, UMR UGA-USMB-CNRS 5553, Université Grenoble Alpes, CS 40700, 38058, Grenoble cedex 9, France.
| | - Laia Navarro-Martin
- Institute of Environmental Assessment and Water Research, IDAEA-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
| | - Valérie S Langlois
- Institut National de la Recherche Scientifique (INRS), Centre Eau Terre Environnement, 490 de la Couronne, Québec (Québec), G1K 9A9, Canada.
| |
Collapse
|
3
|
Edge CB, Baker LF, Lanctôt CM, Melvin SD, Gahl MK, Kurban M, Navarro-Martín L, Kidd KA, Trudeau VL, Thompson DG, Mudge JF, Houlahan JE. Compensatory indirect effects of an herbicide on wetland communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 718:137254. [PMID: 32087583 DOI: 10.1016/j.scitotenv.2020.137254] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/09/2020] [Accepted: 02/09/2020] [Indexed: 06/10/2023]
Abstract
The direct effects of large-scale disturbances are readily studied because their effects are often apparent and result in large changes to ecosystems. Direct effects can cascade through the ecosystem, leading to indirect effects that are often subtle and difficult to detect. Managing anthropogenic disturbances, such as chemical contamination, requires an understanding of both direct and indirect effects to predict, measure, and characterize the impact. Using a replicated whole-ecosystem experiment and path analyses (assesses the effects of a set of variables on a specified outcome, similar to multiple regression), we examined the direct and indirect effects of a glyphosate-based herbicide and nutrient enrichment on wetland communities. The latter did not impact any measured endpoints. The strongest drivers of macrophyte, benthic invertebrate, and amphibian assemblages were the ephemerality and the size of wetlands, factors which were not altered by herbicide applications. The herbicide had a direct negative effect on macrophyte cover, amphibian larval abundance, and the proportion of predatory benthic invertebrates. However, both amphibians and invertebrates were positively affected by the reduction in the macrophyte cover caused by the herbicide applications. The opposing directions of the direct and indirect effects lead to no net change in either group. The compensatory dynamics observed herein highlight the need for a better understanding of indirect effects pathways to determine whether common anthropogenic disturbances alter the ecological communities in small wetland ecosystems.
Collapse
Affiliation(s)
- Christopher B Edge
- Canadian Forest Service, Natural Resources Canada, Atlantic Forestry Centre, New Brunswick, Canada.
| | - Leanne F Baker
- Department of Biology, University of Waterloo, Ontario, Canada
| | - Chantal M Lanctôt
- Australian Rivers Institute, Griffith University Gold Coast, Australia
| | - Steven D Melvin
- Australian Rivers Institute, Griffith University Gold Coast, Australia
| | - Megan K Gahl
- College of Natural Sciences, Minerva Schools at KGI, CA, USA
| | | | - Laia Navarro-Martín
- Institute of Environmental Chemistry, Institute of Environmental Assessment and Water Research, Barcelona, Spain
| | - Karen A Kidd
- Department of Biology and School of Geography and Earth Sciences, McMaster University, Ontario, Canada; Biology Department, University of New Brunswick Saint John, New Brunswick, Canada
| | - Vance L Trudeau
- Department of Biology, University of Ottawa, Ontario, Canada
| | - Dean G Thompson
- Canadian Forest Service, Natural Resources Canada, Great Lakes Forestry Centre, Ontario, Canada
| | - Joseph F Mudge
- The Co-operators General Insurance Company, Business Intelligence, Ontario, Canada
| | - Jeff E Houlahan
- Department of Biology and School of Geography and Earth Sciences, McMaster University, Ontario, Canada
| |
Collapse
|
4
|
Edge CB, Fortin M. Habitat network topology influences the importance of ecological traps in metapopulations. Ecosphere 2020. [DOI: 10.1002/ecs2.3146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Christopher B. Edge
- Natural Resources Canada Canadian Forest Service Fredericton New Brunswick E3B5P7 Canada
| | - Marie‐Josée Fortin
- Department of Ecology and Evolutionary Biology University of Toronto Toronto Ontario M5S 3B2 Canada
| |
Collapse
|
5
|
Turhan DÖ, Güngördü A, Ozmen M. Developmental and lethal effects of glyphosate and a glyphosate-based product on Xenopus laevis embryos and tadpoles. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2020; 104:173-179. [PMID: 31932905 DOI: 10.1007/s00128-019-02774-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/14/2019] [Indexed: 06/10/2023]
Abstract
Effects of pure glyphosate and a glyphosate-based product were evaluated comparatively using two embryonic development stages of Xenopus laevis as model system. When pure glyphosate was applied in pH adjusted media, lethal or developmental effects were not observed at concentrations up to 500 mg L-1. The 96 h LC50 values for the commercial herbicide, in contrast, were 32.1 and 35.1 mg active ingredient L-1 for embryos and tadpoles, respectively. Since pure glyphosate has no effect on the selected biomarkers, it is thought that developmental toxic effects caused by glyphosate-based products are increased mainly due to formulation additives.
Collapse
Affiliation(s)
- Duygu Özhan Turhan
- Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts and Sciences, Inonu University, 44280, Malatya, Turkey
| | - Abbas Güngördü
- Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts and Sciences, Inonu University, 44280, Malatya, Turkey.
| | - Murat Ozmen
- Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts and Sciences, Inonu University, 44280, Malatya, Turkey
| |
Collapse
|
6
|
Mikó Z, Ujszegi J, Gál Z, Hettyey A. Standardize or Diversify Experimental Conditions in Ecotoxicology? A Case Study on Herbicide Toxicity to Larvae of Two Anuran Amphibians. ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 73:562-569. [PMID: 28660298 DOI: 10.1007/s00244-017-0427-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 06/19/2017] [Indexed: 06/07/2023]
Abstract
Despite a steeply increasing number of ecotoxicological studies on the effects of pesticides on nontarget organisms, studies assessing the adequacy and reliability of different experimental approaches have remained scarce. We scrutinized effects of a glyphosate-based herbicide on larvae of two European anuran amphibians by estimating species-specific LC50 values, assessing how an additional stress factor may influence outcomes, and investigating whether replicate experiments yielded qualitatively the same results. We exposed Rana dalmatina and Bufo bufo tadpoles to two predator treatments (no predator vs. predator chemical cues) combined with varying herbicide concentrations, repeated the experiment with a subset of the experimental treatments and partly with slight modifications 1 week later and assessed survival. Our results indicated that the herbicide was moderately toxic to tadpoles. The presence of predator chemical cues did not affect the lethality of the herbicide in either species. The estimated sensitivity of R. dalmatina tadpoles varied considerably across experiments, whereas in case of B. bufo LC50 values remained very similar. Our results suggest that differences in the experimental setup may often have no influence on the measured effects of pesticides, whereas replicated experiments can deliver widely differing results in other cases, perhaps depending on the studied species, the population origin of the tested individuals, or the test conditions. This draws attention to the suggestion that strict standardization may not deliver widely applicable insights into the toxicity of contaminants and, instead, intentionally introducing variation into the design of ecotoxicological experiments and replicating entire experiments may prove highly beneficial.
Collapse
Affiliation(s)
- Zsanett Mikó
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, 1022, Hungary.
| | - János Ujszegi
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, 1022, Hungary
- Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, Budapest, 1117, Hungary
| | - Zoltán Gál
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, 1022, Hungary
- Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert utca 4, Gödöllő, 2100, Hungary
| | - Attila Hettyey
- Lendület Evolutionary Ecology Research Group, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, 1022, Hungary
| |
Collapse
|
7
|
Wagner N, Veith M, Lötters S, Viertel B. Population and life-stage-specific effects of two herbicide formulations on the aquatic development of European common frogs (Rana temporaria). ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2017; 36:190-200. [PMID: 27291460 DOI: 10.1002/etc.3525] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/15/2016] [Accepted: 06/09/2016] [Indexed: 05/02/2023]
Abstract
Environmental contamination is suggested to contribute to amphibian population declines. However, the effects of a contaminant on a particular amphibian species can differ among populations. The authors investigated the toxic effects of 2 herbicide formulations on different populations and on representative developmental stages of the European common frog (Rana temporaria). Larvae from forest populations were more sensitive to a commonly used glyphosate-based herbicide compared with individuals from agrarian land. Median lethal concentrations correlated with measured glyphosate levels in the breeding ponds, which may be a sign of evolved tolerances. The reverse result was observed for a less commonly used cycloxydim-based herbicide. Effects of the glyphosate-based herbicide were stronger for earlier larval stages compared with later larval stages. Hence, applications in early spring (when early larvae are present in breeding ponds) pose greater risk concerning acute toxic effects on R. temporaria. With regard to late larval stages, short exposure (96 h) of prometamorphic larvae prolonged time to metamorphosis, but only at the highest test concentration that did not significantly induce mortality. This could be due to impairment of the thyroid axis. Notably, nearly all test concentrations of the 2 herbicides provoked growth retardation. Further research on how evolved or induced tolerances are acquired, actual contamination levels of amphibian habitats, and potential endocrine effects of glyphosate-based herbicides is necessary. Environ Toxicol Chem 2017;36:190-200. © 2016 SETAC.
Collapse
Affiliation(s)
- Norman Wagner
- Trier University, Department of Biogeography, Trier, Germany
| | - Michael Veith
- Trier University, Department of Biogeography, Trier, Germany
| | - Stefan Lötters
- Trier University, Department of Biogeography, Trier, Germany
| | - Bruno Viertel
- Trier University, Department of Biogeography, Trier, Germany
| |
Collapse
|
8
|
Rissoli RZ, Abdalla FC, Costa MJ, Rantin FT, McKenzie DJ, Kalinin AL. Effects of glyphosate and the glyphosate based herbicides Roundup Original(®) and Roundup Transorb(®) on respiratory morphophysiology of bullfrog tadpoles. CHEMOSPHERE 2016; 156:37-44. [PMID: 27160633 DOI: 10.1016/j.chemosphere.2016.04.083] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/20/2016] [Accepted: 04/21/2016] [Indexed: 06/05/2023]
Abstract
Glyphosate-based herbicides are widely used in agriculture and are commonly found in water bodies. Roundup Original(®) (RO) contains an isopropylamine glyphosate (GLY) salt containing the surfactant POEA, while Roundup Transorb R(®) (RTR) contains a potassium salt of GLY with unknown surfactants. Both contain different compositions of so-called "inert" ingredients, more toxic than glyphosate. Amphibian tadpoles often experience variations in O2 availability in their aquatic habitats; an ability to tolerate hypoxia can condition their survival and fitness. We evaluated the impacts of sublethal concentrations of GLY (1 mg L(-1)), RO (1 mg L(-1) GLY a.e) and RTR (1 mg L(-1) GLY a.e) on metabolic rate (V·O2 - mLO2 Kg1 h(-1)) of bullfrog tadpoles during normoxia and graded hypoxia, and related this to morphology of their skin, their major site of gas exchange. In control (CT) V·O2 remained unaltered from normoxia until 40 mmHg, indicating a critical O2 tension between 40 and 20 mmHg. GLY significantly reduced V·O2, possibly due to epidermal hypertrophy, which increased O2 diffusion distance to O2 uptake. In contrast, RTR increased V·O2 during hypoxia, indicating an influence of "inert" compounds and surfactants. V·O2 of RO did not differ from CT, suggesting that any increase in V·O2 caused by exposure was antagonized by epidermal hypertrophy. Indeed, all herbicides caused marked alterations in skin morphology, with cell and epithelium wall presenting hyperplasia or hypertrophy and chromatid rupture. In summary, GLY, RO and RTR exert different effects in bullfrog tadpoles, in particular the surfactants and inert compounds appear to influence oxygen uptake.
Collapse
Affiliation(s)
- Rafael Zanelli Rissoli
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil
| | | | - Monica Jones Costa
- Department of Biology, Federal University of São Carlos, Sorocaba, SP, Brazil
| | - Francisco Tadeu Rantin
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil
| | - David John McKenzie
- UMR9190 Centre for Marine Biodiversity Exploitation and Conservation, University of Montpellier, France
| | - Ana Lucia Kalinin
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, SP, Brazil.
| |
Collapse
|
9
|
Güngördü A, Uçkun M, Yoloğlu E. Integrated assessment of biochemical markers in premetamorphic tadpoles of three amphibian species exposed to glyphosate- and methidathion-based pesticides in single and combination forms. CHEMOSPHERE 2016; 144:2024-35. [PMID: 26595308 DOI: 10.1016/j.chemosphere.2015.10.125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 10/29/2015] [Accepted: 10/29/2015] [Indexed: 06/05/2023]
Abstract
In this study, we evaluated the toxic effects of a glyphosate-based herbicide (GBH) and a methidathion-based insecticide (MBI), individually and in combination, on premetamorphic tadpoles of three anuran species: Pelophylax ridibundus, Xenopus laevis, and Bufotes viridis. Based on the determined 96-h LC50 values of each species, the effects of a series of sublethal concentrations of single pesticides and their mixtures after 96-h exposure and also the time-related effects of a high sublethal concentration of each pesticide were evaluated, with determination of changes in selected biomarkers: glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH). Also, the integrated biomarker response (IBR) was used to assess biomarker responses and quantitatively evaluate toxicological effects. Isozyme differences in CaE inhibition were assessed using native page electrophoresis; results showed that GBH to cause structural changes in the enzyme but not CaE inhibition in P. ridibundus. In general, single MBI and pesticide mixture exposures increased GST activity, while single GBH exposures decreased GST activity in exposed tadpoles. The AChE and CaE activities were inhibited after exposure to all single MBI and pesticide mixtures. Also, higher IBR values and GST, GR, AST, and LDH activities were determined for pesticide mixtures compared with single-pesticide exposure. This situation may be indicative of a synergistic interaction between pesticides and a sign of a more stressful condition.
Collapse
Affiliation(s)
- Abbas Güngördü
- Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts and Science, Inonu University, 44280, Malatya, Turkey.
| | - Miraç Uçkun
- Department of Food Engineering, Faculty of Engineering, Adiyaman University, 02040, Adiyaman, Turkey
| | - Ertan Yoloğlu
- Department of Science Education, Faculty of Education, Adiyaman University, 02040, Adiyaman, Turkey
| |
Collapse
|
10
|
Vincent K, Davidson C. The toxicity of glyphosate alone and glyphosate-surfactant mixtures to western toad (Anaxyrus boreas) tadpoles. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2015; 34:2791-5. [PMID: 26084619 DOI: 10.1002/etc.3118] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 04/13/2015] [Accepted: 06/11/2015] [Indexed: 05/24/2023]
Abstract
Pesticide choice based on toxicity to nontarget wildlife is reliant on available toxicity data. Despite a number of recent studies examining the effects of glyphosate on amphibians, very few have aimed to understand the toxicological effects of glyphosate in combination with surfactants as it is commonly applied in the field. Land managers interested in making pesticide choices based on minimizing impacts to nontarget wildlife are hindered by a lack of published toxicity data. Short-term acute toxicity trials were conducted for glyphosate in the form of isopropylamine salt (IPA) alone and mixed with 2 surfactants: Agri-dex and Competitor with western toad (Anaxyrus [Bufo] boreas) tadpoles. Glyphosate IPA mixed with Competitor was 6 times more toxic than glyphosate IPA mixed with Agri-dex, and both mixtures were more toxic than glyphosate IPA alone. The median lethal concentrations reported for 24-h and 48-h exposures were 8279 mg/L (24 h) and 6392 mg/L (48 h) for glyphosate IPA alone; 5092 mg/L (24 h) and 4254 mg/L (48 h) for glyphosate IPA mixed with Agri-dex; and 853 mg/L (24 h) and 711 mg/L (48 h) for glyphosate IPA mixed with Competitor. The present study indicates that the toxicity of a tank mix may be greatly increased by the addition of surfactants and may vary widely depending on the specific surfactant.
Collapse
Affiliation(s)
- Kim Vincent
- Department of Biology, San Francisco State University, San Francisco, California, USA
| | - Carlos Davidson
- Environmental Studies Program, San Francisco State University, San Francisco, California, USA
| |
Collapse
|