Chemical Speciation of Environmentally Significant Metals with Inorganic Ligands Part 2: The Cu\u3csup\u3e2+\u3c/sup\u3e-OH\u3csup\u3e-\u3c/sup\u3e, Cl\u3csup\u3e-\u3c/sup\u3e, CO\u3csub\u3e3\u3c/sub\u3e\u3csup\u3e2-\u3c/sup\u3e, SO\u3csub\u3e4\u3c/sub\u3e\u3csup\u3e2-\u3c/sup\u3e, and PO\u3csub\u3e4\u3c/sub\u3e\u3csup\u3e3-\u3c/sup\u3e Systems (IUPAC Technical Report)

Complex formation between CuIIand the common environmental lig-ands Cl–, OH–, CO32–, SO42–, and PO43–can have a significant effect on CuIIspe-ciation in natural waters with low concentrations of organic matter. Copper(II)complexes are labile, so the CuIIdistribution amongst these inorganic ligands canbe estimated by numerical modeling if reliable values for the relevant stability(formation) constants are available. This paper provides a critical review of suchconstants and related thermodynamic data. It recommends values of log10βp,q,r°valid at Im= 0 mol kg–1and 25 °C (298.15 K), along with the equations and spe-cific ion interaction coefficients required to calculate log10βp,q,rvalues at higherionic strengths. Some values for reaction enthalpies, ∆rHm, are also reported whereavailable.In weakly acidic fresh water systems, in the absence of organic ligands, CuIIspeciation is dominated by the species Cu2+(aq), with CuSO4(aq) as a minorspecies. In seawater, it is dominated by CuCO3(aq), with Cu(OH)+, Cu2+(aq),CuCl+, Cu(CO3)OH–, Cu(OH)2(aq), and Cu(CO3)22–as minor species. In weaklyacidic saline systems, it is dominated by Cu2+(aq) and CuCl+, with CuSO4(aq) andCuCl2(aq) as minor species

Chemical Speciation of Environmentally Significant Metals: An IUPAC Contribution to Reliable and Rigorous Computer Modelling

The mobility and bioavailability of metal ions in natural waters depend on their chemical speciation, which involves a distribution of the metal ions between different complex (metal-ligand) species, colloid-adsorbed species and insoluble phases, each of which may be kinetically labile or inert. For example, in fresh water the metal ions are distributed among organic complexes (e.g., humates), colloids (e.g., as surface-adsorbed species on colloidal phases such as FeOOH), solid phases (e.g., hydroxide, oxide, carbonate mineral phases), and labile complexes with the simple inorganic anionic ligands commonly present in natural waters (e.g., for ZnII, the aqueous species, Zn2+, ZnOH+, Zn(OH)2(aq), Zn2OH3+, ZnSO4(aq), ZnCO3(aq)…)