Bicarbonate toxicity to Ceriodaphnia dubia and the freshwater shrimp Paratya australiensis and its influence on zinc toxicity. (27th March 2014)

• Record Type: Journal Article
• Authors: Vera, Carolina Lopez; Hyne, Ross V.; Patra, Ron; Ramasamy, Sunderam; Pablo, Fleur; Julli, Moreno; Kefford, Ben J.
• Is Part Of: Environmental toxicology and chemistry. Volume 33:Number 5(2014:May)
• Page Start: 1179
• Page End: 1186
• Publication Date: 2014-03-27
• Subjects: Pollution -- Environmental aspects -- Periodicals; Environmental chemistry -- Periodicals; 615.902
• DOI: 10.1002/etc.2545
• Languages: English
• ISSNs: 0730-7268

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="etc2545-sec-0001" sec-type="section"> <p>Bicarbonate is often a major ionic constituent associated with produced waters from methane gas extraction and coal mining, yet few studies have determined its specific toxicity. Currently, the environmental risk of bicarbonate anion in water discharges is assessed based on the toxicity of sodium chloride or artificial seawater and is regulated via electrical conductivity. Increased NaHCO<sub>3</sub> added to <italic>Ceriodaphnia dubia</italic> in synthetic or natural water gave similar 48‐h 10% effective concentration (EC10) values of 1750 ± 125 mg NaHCO<sub>3</sub>/L (mean ± standard error) and 1670 ± 180 mg NaHCO<sub>3</sub>/L, respectively. Bicarbonate was toxic to <italic>C. dubia</italic> in both waters with conductivities above 1900 µS/cm. In contrast, when conductivity was elevated with NaCl, toxicity to <italic>C. dubia</italic> was observed only above 2800 µS/cm. Bicarbonate also impaired <italic>C. dubia</italic> reproduction with an EC10 of 340 mg NaHCO<sub>3</sub>/L. Major ion composition also influenced Zn bioavailability, a common co‐occurring metal contaminant in coal mine waters, with sublethal concentrations of NaHCO<sub>3</sub> and elevated pH increasing Zn toxicity. Higher pH was the dominant parameter determining a 10‐fold increase in the 48‐h 50% effective concentration (EC50) for Zn toxicity to <italic>C. dubia</italic> at pH 8.6 of 34 µg Zn/L (95% confidence limit = 32–37 µg Zn/L) compared with the Zn toxicity at approximately circumneutral pH. Exposure of the freshwater shrimp <italic>Paratya australiensis</italic> (Atyidae) in natural water to increasing bicarbonate gave a mean 10‐d 10% lethal concentration (LC10) of 850 ± 115 mg NaHCO<sub>3</sub>/L, associated with a mean conductivity EC10 of 1145 µS/cm, which is considerably lower than toxicity of NaCl and artificial seawater to this species reported elsewhere. Because toxicity was influenced by salt composition, specific ions should be regulated rather than conductivity alone in mine wastewater discharges. <italic>Environ Toxicol Chem 2014;33:1179–1186</italic>. © 2014 SETAC</p> </sec> </abstract>