Donald C. Girvin
Pacific Northwest National Laboratory
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Featured researches published by Donald C. Girvin.
Environmental Science & Technology | 1987
John M. Zachara; Donald C. Girvin; R.L. Schmidt; Charles T. Resch
Chromate adsorption on amorphous iron oxyhydroxide was investigated in dilute iron suspensions as a single solute and in solutions of increasing complexity containing CO2(g), SO4S (aq), H4SiO4(aq), and cations (K , MgS , CaS (aq)). In paired-solute systems (e.g., CrO4S -H2CO3*), anionic cosolutes markedly reduce CrO4S adsorption through a combination of competitive and electrostatic effects, but cations exert no appreciable influence. Additionally, H4SiO4 exhibits a strong time-dependent effect: CrO4S adsorption is greatly decreased with increasing H4SiO4 contact time. In multiple-ion mixtures, each anion added to the mixture decreases CrO4S adsorption further. Adsorption constants for the individual reactive solutes were used in the triple-layer model. The model calculations are in good agreement with the CrO4S adsorption data for paired- and multiple-solute systems. However, the model calculations underestimate CrO4S adsorption when surface site saturation is approached. Questions remain regarding the surface interactions of both CO2(aq) and H4SiO4. The results have major implications for the adsorption behavior of CrO4S and other oxyanions in subsurface waters.
Archive | 2006
Vince R. Vermeul; Jim E. Szecsody; Michael J. Truex; Carolyn A. Burns; Donald C. Girvin; Jerry L. Phillips; Brooks J. Devary; Ashley E. Fischer; Shu-Mei W. Li
This treatability study was conducted by Pacific Northwest National Laboratory (PNNL), at the request of the U. S. Environmental Protection Agency (EPA) Region 2, to evaluate the feasibility of using in situ treatment technologies for chromate reduction and immobilization at the Puchack Well Field Superfund Site in Pennsauken Township, New Jersey. In addition to in situ reductive treatments, which included the evaluation of both abiotic and biotic reduction of Puchack aquifer sediments, natural attenuation mechanisms were evaluated (i.e., chromate adsorption and reduction). Chromate exhibited typical anionic adsorption behavior, with greater adsorption at lower pH, at lower chromate concentration, and at lower concentrations of other competing anions. In particular, sulfate (at 50 mg/L) suppressed chromate adsorption by up to 50%. Chromate adsorption was not influenced by inorganic colloids.
Applied Geochemistry | 1991
L. E. Eary; E. A. Jenne; L. W. Vail; Donald C. Girvin
Abstract The Integrated Lake Watershed Acidification Study (ILWAS) model was used to simulate the recovery of the highly acidified Clearwater Lake, Ontario. Recovery started in the mid-1970s and continued through the 1980s in response to an estimated 30–50% decrease in S deposition from smelter emissions in nearby Sudbury, Ontario. Appreciable recovery of Clearwater Lake between the mid-1970s and 1987 is simulated by the ILWAS model, as indicated by a 50% decrease in SO − 4 concentration, an 80% decrease in total Al concentration, an increase in acid-neutralizing capacity (ANC) from −60 to −17 μeq/l, and an increase in pH from 4.2 to 4.8. These decreases in acidic constituents are in good agreement with monitoring data. Long-term simulations indicate that deacidification may continue until ∼2020, if S deposition rates remain at or less than the 1987 level. Simulations for years beyond 2020 yield yearly average ANC values of 18–40 μeq/l and pH values of 6.2–6.6, which are comparable to the estimated pre-smelter pH of 6.0–6.5 for Clearwater Lake. The agreement between simulated and monitoring data for the first 10 a of recovery and the simulated long-term recovery of the lake to its presmelter level of acidity lend confidence in the capability of numerical models to simulate the reversibility of watershed acidification and suggest that some highly acidic watersheds may eventually recover, given substantial decreases in acid deposition.
Chemosphere | 2004
Jim E. Szecsody; Donald C. Girvin; Brooks J. Devary; James A. Campbell
Applied Geochemistry | 2002
K. Prasad Saripalli; B. Peter McGrail; Donald C. Girvin
Environmental Science & Technology | 2000
J. M. Vanbriesen; Bruce E. Rittmann; Luying Xun; Donald C. Girvin; Harvey Bolton
Environmental Science & Technology | 1996
Luying Xun; Robert B. Reeder; Andrew E. Plymale; Donald C. Girvin; Harvey Bolton
Archive | 2007
James E. Szecsody; Carolyn A. Burns; Robert C. Moore; Jonathan S. Fruchter; Vincent R. Vermeul; Mark D. Williams; Donald C. Girvin; James P. McKinley; Michael J. Truex; Jerry L. Phillips
Archive | 2007
James E. Szecsody; Steve D. Comfort; Herbert L. Fredrickson; Hardiljeet K. Boparai; Brooks J. Devary; Karen T. Thompson; Jerry L. Phillips; Fiona H. Crocker; Donald C. Girvin; Charles T. Resch; Patrick J. Shea; Ashley E. Fischer; Lisa Durkin
Soil Science Society of America Journal | 2009
Donald C. Girvin; Paul L. Gassman; H. Jr. Bolton