Transformation/dissolution characterization of tungsten and tungsten compounds for aquatic hazard classification
The transformation/dissolution protocol (T/DP) for metals and sparingly soluble metal compounds was applied to determine the transformation/dissolution (T/D) characteristics of yellow tungsten trioxide, WO3; blue tungsten oxide, WOx, x taken as 2.9; tungsten disulphide, WS2; tungsten metal, W; 3 samples of tungsten carbide, WC; sodium tungstate, Na2WO4 · 2H2O; ammonium paratungstate (APT), (NH4)10(H2W12O42) · 4H2O; and ammonium metatungstate (AMT) (NH4)6(H2W12O40) · 3H2O. The T/D data were used to derive aquatic hazard classification outcomes under the United Nations Globally Harmonized System of Classification and Labelling of Chemicals (UN GHS) and European Union Classification, Labelling and Packaging of Substances and Mixtures (EU CLP) schemes by comparing the data with selected acute and chronic ecotoxicity reference values (ERVs) of 31 and 3.37 mg W/L, respectively. In addition to the concentration of total dissolved tungsten (W), the T/D solutions were analyzed for the concentration of the tungstate anion, because speciation can be an important factor in establishing the ecotoxicity of dissolved metals. Results show that the tungstate anion was the predominant W‐bearing species in solution for all substances examined at pH 6 and 8.5. It was found that the 100 mg/L loadings of both the yellow WO3 and the blue WOx exceeded the 31 mg/L acute ERV, so they would classify as Acute 3‐Chronic 3 under the UN GHS scheme but they would not classify under the EU CLP. An effect of pH on the reactivity of the W metal was observed with 3% and 16% W dissolution at pH 6 and 8.5, respectively. Tungsten metal would not classify under either the UN GHS or EU CLP schemes nor would the WS2. The WCs were the least reactive in terms of the 1% or less dissolution of the contained W at pH 6. A critical surface area for WC was calculated. The sodium tungstate, APT and the AMT all yielded, at pH 8.5, total dissolved W concentrations that would result in UN GHS Acute 3‐Chronic 3 classifications. Integr Environ Assess Manag 2018;14:498–508. © 2018 Her Majesty the Queen in Right of Canada. Integrated Environmental Assessment and Management © 2018 SETAC
Transformation/dissolution examination of antimony and antimony compounds with speciation of the transformation/dissolution solutions
Speciation is held to be a key factor in controlling the ecotoxicity of metals in solution. Using the United Nations transformation/dissolution protocol (T/DP) for metals and sparingly soluble metal compounds, we have examined the transformation/dissolution (T/D) characteristics in terms of the concentrations of total dissolved Sb at pH 6 and 8.5 in 1, 10, and 100 mg/L loadings over 7 d as well as the concentrations of Sb(III) and Sb(V) at the 1 mg/L loadings over 28 d, of sodium hexahydroxoantimonate (NaSb(OH)6), antimony metal (Sb), antimony trioxide (Sb2O3), antimony sulfide (Sb2S3), sodium antimonate (NaSbO3), antimony tris(ethylene glycolate) (Sb2(C2H4O2)3), antimony trichloride (SbCl3), antimony triacetate (Sb(CH3COO)3), and antimony pentoxide (Sb2O5). We also measured the concentrations of the dissolved Sb(III) and Sb(V) species at the 1 mg/L loadings. Because of complexing, the trivalent organic Sb compounds exhibited little or no oxidation of Sb(III) to Sb(V). However, oxidation of Sb(III) to Sb(V) was evident for the trivalent inorganic Sb compounds. Conversely, with pentavalent Sb compounds, there was no reduction of Sb(V) to Sb(III). Based on the percentage of Sb in the compound dissolved or metal reacted at 28 d and 1 mg/L loadings, the solubility rankings at pH 6 are NaSb(OH)6 > Sb(CH3COO)3 > Sb metal > Sb2(C2H4O2)3 > Sb2S3 > Sb2O3 > NaSbO3 ≈ SbCl3 > Sb2O5. For pH 8.5 the order is NaSb(OH)6 > Sb(CH3COO)3 > Sb metal > Sb2(C2H4O2)3 > SbCl3 > Sb2O3 > Sb2S3 > NaSbO3 > Sb2O5. We provide worked examples of how the T/D data have been used to derive hazard classification proposals for Sb metal and these selected compounds for submission to the European Chemicals Agency under the Registration, Evaluation, Authorization and Restriction of CHemicals (REACH) legislation. Integr Environ Assess Manag 2013; 9: 98–113. © 2012 SETAC
Tethering the Administrative State: The Case Against Chevron Deference for FCC Jurisdictional Claims
Like many other agencies, the Federal Communications Commission has seen significant regulatory growth under President Obama. But unlike health care, financial reform, and other areas, this growth has come without statutory guidance from Congress. The FCC’s assertion of jurisdiction over broadband service is reminiscent of its earlier attempts to regulate cable and to deregulate telephone service, efforts that courts have viewed skeptically in the absence of specific statutory authorization. But this skepticism is in tension with Chevron, which grants agencies substantial deference to interpret ambiguities in the statutes that they administer. This article argues that Chevron deference should not extend to agency jurisdictional claims, such as the FCC’s claim to authority over broadband. For both constitutional and policy reasons, courts should distinguish between agency action that fills a gap in a statutory scheme and action that defines the outer boundary of that scheme. As the Commission’s net neutrality project winds its way through the judicial system, courts should not allow the agency to define the limits of its own authority, and should instead search closely for a grant of authority from Congress.