Effect of Kinetics of Complexation by Humic Acid on Toxicity of Copper to Ceriodaphnia Dubia

Ma, Hongjuan; Kim, Sang Don; Daniel, K.; Allen, Herbert E.

doi:10.1897/1551-5028(1999)018<0828:eokocb>2.3.co;2

Cited by 135 publications

(149 citation statements)

References 25 publications

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“…The DOC concentration in this water was 3.7 Ϯ 0.1 mg L Ϫ1 . Stable metal and radioisotope additions were made 24 h prior to mussel exposures to attempt to reach equilibration between different pools (Ma et al 1999), although speciation of the stable and radioisotopes was not checked and may not have completely equilibrated (Piro et al 1973).…”

Section: Methodsmentioning

confidence: 99%

Rates and routes of trace element uptake in zebra mussels

Roditi

Fisher

1999

Limnology & Oceanography

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The zebra mussel, Dreissena polymorpha, a nonindigenous invasive species, is now widespread throughout the eastern half of North America. Because zebra mussels are ubiquitous and because they effectively filter particulate matter out of suspension, the cycling and residence times of particle-reactive metals will likely be affected in waters with zebra mussels. This study describes experiments designed to assess the possibility of using this species as a bioindicator of metals in ambient freshwater environments. Laboratory exposures of zebra mussels to 110m Ag, 109 Cd, 51 Cr, 14 C, 203 Hg, and 75 Se were employed to measure their assimilation efficiencies (percentage of ingested element that crosses gut lining) from eight food types (four algal species and bacteria, seston, and mineral assemblages), absorption efficiencies from water (percentage of element pumped by the mussel that is absorbed by the animal), and rates of depuration of these elements from mussels following long-term exposures to food and water. Assimilation efficiencies of elements from foods ranged from 4 to 29% for silver (Ag), 19 to 72% for cadmium (Cd), 42 to 85% for carbon (C), 2 to 19% for chromium (Cr), 4 to 40% for mercury (Hg), and 8 to 46% for selenium (Se). Absorption efficiencies from the dissolved phase were 1.87% for Ag, 1.02% for Cd, 0.47% for Cr(III), 0.27% for Cr(VI), 1.17% for Hg, and 0.03% for Se. Efflux rate constants (d Ϫ1 ) following long-term exposure to food and water were 0.067 and 0.084 for Ag, 0.013 and 0.011 for Cd, 0.019 and 0.011 for Cr, 0.050 for Hg (food only), and 0.026 and 0.035 for Se. These loss rates corresponded to biological half-lives ranging from 8 d for Ag to 76 d for Se. Loss rates of trace elements from zebra mussel feces followed the following sequence: Cr Ͻ Ag Ͻ Se Ͻ Hg Յ Cd, with average retention half-times being 59, 43, 11, 6.7, and 5.1 d, respectively, which indicates that geochemical cycling rates from zebra mussel biodeposits are element specific. Egestion patterns of the radioisotopes indicated two digestive phases, extracellular and intracellular digestion. The extent of intracellular digestion ranged from 7 to 40%, depending on the food source, and correlated with assimilation efficiency for Ag, Cd, and Hg. The bioaccumulation parameters measured for D. polymorpha can be used in kinetic models to quantify the relative importance of food and water as sources of metals and to predict on a site-specific basis the tissue concentrations of metals in these mussels, as shown for Cd. Because D. polymorpha accumulates metals from dissolved and particulate sources in proportion to ambient concentrations, this species can be an effective bioindicator of freshwater metal contamination.

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Section: Methodsmentioning

confidence: 99%

Rates and routes of trace element uptake in zebra mussels

Roditi

Fisher

1999

Limnology & Oceanography

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“…This had All Supplemental Data may be found in the online version of this article. See Table S1 for the number of citations and rank of all the "Top 100" papers, which in this essay are references [1][2][3][4] regulatory consequences, including incorporation of the BLM approach into the USEPA aquatic life criterion for copper [19] and other actions in various jurisdictions [20]. Significant BLM research and development continues.…”

Section: Genesis Of the Blm Approachmentioning

confidence: 99%

The biotic ligand model approach for addressing effects of exposure water chemistry on aquatic toxicity of metals: Genesis and challenges

Erickson

2013

Enviro Toxic and Chemistry

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A major uncertainty in many aquatic risk assessments for toxic chemicals is the aggregate effect of the physicochemical characteristics of exposure media on toxicity and how this affects extrapolation of laboratory test results to natural systems. A notable example of this is how metal toxicity in freshwater varies because of factors such as water hardness, alkalinity, pH, dissolved organic carbon, and suspended solids. This has been the subject of hundreds of studies over the last 50 yr and of various papers in Environmental Toxicology and Chemistry since its inception, including 4 of the "Top 100" cited papers [1][2][3][4]. One study found median lethal concentrations (LC50s) for acute copper toxicity to fathead minnows to vary by more than 100-fold across various exposure water compositions well within the range observed in natural systems [1]. Approaches for modeling and predicting such variation have also been the subject of these efforts. An important example of this is the biotic ligand model (BLM), an approach first described and implemented in Di Toro et al. [2] and Santore et al. [3], and a focus of considerable research activity and regulatory development over the last 15 years. GENESIS OF THE BLM APPROACHThe BLM represents an integration of decades of work regarding metal speciation, accumulation, toxicity, and physiology [5] that can be only briefly summarized here. Studies in the 1960s and 1970s demonstrated that the toxicity of several metals to freshwater organisms varied with hardness, alkalinity, pH, and organic ligands, for which 2 major mechanisms were inferred [6][7][8]. First, the toxicity of a metal varies with its chemical speciation and often is closely correlated with the "free" (uncomplexed) metal ion, although in some situations other metal species contribute to accumulation or toxicity. Second, cations such as calcium and hydrogen ions can have effects on toxicity independent of toxic metal speciation; these cations were postulated to ameliorate toxicity by competing with toxic metal ions for binding sites on the gill [9]. These mechanisms pertain to bioavailability-how exposure conditions affect the amount of metal accumulation relative to the total concentration in the exposure medium. However, calcium was also recognized to have effects on gill permeability and thus could affect toxicity other than as a competing cation [6,8].Some of these early toxicological findings were incorporated into water quality regulations, such as the hardness dependence of the US Environmental Protection Agency's (USEPA) aquatic life criteria for metals [10]. However, such simple correlation models incompletely describe the effects of exposure chemistry. A broader, mechanistic perspective of these effects was articulated by Morel [11], and by Pagenkopf [12] in his gill surface interaction model (GSIM). In the GSIM, bioavailability is modeled based on the binding of toxic metal species (free metal or other species) to sites on the gill surface, this binding being affected by 1) metal speciation that det...

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“…Initial laboratory testing was performed in order to compare the degree of Chelex 100 ® resin copper retention in a fresh water (300 μg/L dissolved copper, pH 6.5 buffered with 30 mg/L calcium carbonate, n=3) to a saline water (300 μg/L dissolved copper, 25 parts per thousands (ppt) salinity, pH 8) with and without 20 mg/L organic matter in the form of Aldrich Humic Acid (Aldrich Chemical Co.). All solutions with copper and NOM were allowed to equilibrate for 24 hours before testing [21]. Preliminary laboratory tests varied copper concentration, salinity, humic acid and pH through adjustment by adding either 10 M NaOH or 10 M HCl.…”

Section: A Chelex 100 ® Resin: Preparation and Evaluationmentioning

confidence: 99%