Acute and Chronic Effects of Sodium Tungstate on a

Authors: Leslie N Clements Ranulfo Lemus Alicia D Butler Kate Heim Matthew R Rebstock Carmen Venezia Michael Pardus

Publish Date: 2012/05/26

Volume: 63, Issue: 3, Pages: 391-399

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Abstract

Although aquatic toxicity data exists for tungstate substances insufficient data of high quality and relevancy are available for conducting an adequate risk assessment Therefore a series of acute and chronic toxicity tests with sodium tungstate Na2WO4 were conducted on an aquatic invertebrate Daphnia magna green alga Pseudokirchneriella subcapitata and zebrafish Danio rerio Collectively the data from these studies suggest that sodium tungstate exhibits a relatively low toxicity to these taxa under these test conditions All studies were conducted in the same laboratory under good laboratory practice standards using Organisation for Economic Cooperation and Development guidelines with the same stock of test material and the same analytical methods All results are reported as mg W/L The following toxicity values were based on mean measured concentrations For D magna the 21 day test noobservable effect concentration NOEC was 259 mg W/L and the 48h median effective concentration EC50 from the acute test was 955 mg W/L the highest concentration tested The P subcapitata test yielded an ErC50 of 31 mg W/L A 38day test with zebrafish resulted in an NOEC ≥574 mg W/L with no effects at any concentration The 96h LC50 from the acute test with zebrafish was 106 mg W/L The results of the current acute study for daphnids and fish are consistent with published literature whereas the algae results are different from previously reported values Transformation/dissolution T/D studies which were conducted according to United Nations Globally Harmonized System of Classification and Labelling of Chemicals protocol confirmed that the WO 4 −2 anion accounted for most of the tungsten in solution For classification purposes the algae ecotoxity reference value was then compared with T/D data and would not classify Na2WO4 as an aquatic toxicant under the European Union Classification Labelling and Packaging schemeThe authors are grateful for the assistance of Maureen Niemeier ARCADIS in compiling and formatting data as well as John Aufderheide ABC Laboratories Inc and Jim Skeaff CANMET–MMSL for their critical reviews of the manuscript Funding for the research presented in this manuscript was provided by the Tungsten REACH Consortium All studies and results were developed in support of registration of W substances in accordance with the EU legislation on Registration Evaluation Authorisation and Restriction of Chemicals REACH

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