Use of Marsh Plants for Toxicity Testing of Water and Sediment

Walsh, Gerald E.; Weber, DE; Simon, Thomas; Brashers, LK; Moore, JC

doi:10.1520/stp19529s

Cited by 17 publications

(5 citation statements)

References 14 publications

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“…St. Laurent et al (1992) found that concentrations of i>50/~g metolachlor per 1 reduced growth of the green alga S. capricornutum in 96 h microplate algal assay experiments, but Walsh et al (1991) reported that the LOEC for metolachlor for two freshwater wetland plant species was 250-500/~g 1-1. The specific mode of action of metolachlor is unknown, but it is thought to interfere with protein synthesis, terpenoid synthesis and mitotic activity; therefore, it is not surprising that immediate effects of metolachlor on oxygen production were not noted in the present study.…”

Section: Resultsmentioning

confidence: 99%

Short-term effects of herbicides on primary productivity of periphyton in lotic environments

Day¹

1993

Ecotoxicology

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: Freshwater algae are quite sensitive to herbicides that enter running water ecosystems through direct application, aerial drift, and/or watershed run-off. However, due to a lack of suitable methodologies, few studies examine the effects of such contamination on naturally occurring attached algal communities under field conditions (i. e., exposure regimes using pulsed doses or brief episodes of peak concentrations to simulate surface run-off during storm events). This paper describes a method for determining the acute short-term effects of four herbicides (hexazinone, atrazine, tebuthiuron and metolachlor) on the net primary productivity (NPP) of periphytic algae in the field using a portable bankside incubator; NPP was measured by monitoring changes in oxygen production (mg O2 per m(2)) upper surface of rock substrate per h and mg O2 h per mg chlorophyll using the light-dark technique. All herbicides with photosynthetic inhibition as a mode of action significantly reduced NPP. The lowest observed effect concentrations (LOECs) for the herbicides were 43 μg hexazinone l(-1), 109 μg atrazine l(-1) and 137 μg tebuthiuron l(-1). The no observed effect concentrations (NOECs) for these chemicals were <43 μg hexazinone l(-1), 93 μg atrazine l(-1) and 52 μg tebuthiuron l(-1). Metolachlor did not significantly reduce NPP at the concentrations that were tested (range 19.6-274 μg l(-1)). However, community respiration (which included respiration by invertebrates) was significantly reduced at the highest metolachlor concentration (274 μg l(-1)). Community respiration was not significantly affected by any concentration of the other three herbicides used.

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Section: Resultsmentioning

confidence: 99%

Short-term effects of herbicides on primary productivity of periphyton in lotic environments

Day¹

1993

Ecotoxicology

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“…Elodea canadensis and Myriophyllum spicatum can be rooted from vegetative cuttings. Cuttings were taken for the experiment, since seeds often lack sensitivity to chemicals present in their ambient environment 29, 30. At the start of each experiment, uniform cuttings of either 4, 5 or 7 cm were taken from healthy, non‐flowering stems and either placed into the medium directly or inserted 1–2 cm into the sediment.…”

Section: Methodsmentioning

confidence: 99%

Methods for assessing the toxicity of herbicides to submersed aquatic plants

Knauer

Vervliet-Scheebaum

Dark

et al. 2006

Pest Management Science

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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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“…can be rooted from vegetative cuttings. Those cuttings were taken for the experiments because seeds may often be less sensitive to chemicals that are present in their ambient environment (see Table 1; Pfleeger et al 1991;Walsh and Weber 1991).…”

Section: Test Designs and The Respective Test Organismsmentioning

confidence: 99%