skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Subsurface fate and transport of cyanide species at a manufactured-gas plant site

Abstract

Cyanide is present at manufactured-gas plant (MGP) sites in oxide-box residuals, which were often managed on-site as fill during active operations. Cyanide can leach from these materials, causing groundwater contamination. Speciation, fate, and transport of cyanide in a sand-gravel aquifer underlying an MGP site in the upper Midwest region of the US were studied through characterization, monitoring, and modeling of a plume of cyanide-contaminated groundwater emanating from the site. Results indicate that cyanide in the groundwater is primarily in the form of iron-cyanide complexes (>98%), that these complexes are stable under the conditions of the aquifer, and that they are transported as nonreactive solutes in the sand-gravel aquifer material. Weak-acid-dissociable cyanide, which represents a minute fraction of total cyanide in the site groundwater, may undergo chemical-biological degradation in the sand-gravel aquifer. It seems that dilution may be the only natural attenuation mechanism for iron-cyanide complexes in sand-gravel aquifers at MGP sites.

Authors:
; ; ;
Publication Date:
OSTI Identifier:
20001044
Resource Type:
Journal Article
Resource Relation:
Journal Name: Water Environment Research; Journal Volume: 71; Journal Issue: 6; Other Information: PBD: Sep-Oct 1999
Country of Publication:
United States
Language:
English
Subject:
01 COAL, LIGNITE, AND PEAT; COAL GASIFICATION PLANTS; CYANIDES; ENVIRONMENTAL IMPACTS; ENVIRONMENTAL TRANSPORT; WATER POLLUTION; GROUND WATER

Citation Formats

Ghosh, R.S., Dzombak, D.A., Luthy, R.G., and Nakles, D.V. Subsurface fate and transport of cyanide species at a manufactured-gas plant site. United States: N. p., 1999. Web. doi:10.2175/106143096X122474.
Ghosh, R.S., Dzombak, D.A., Luthy, R.G., & Nakles, D.V. Subsurface fate and transport of cyanide species at a manufactured-gas plant site. United States. doi:10.2175/106143096X122474.
Ghosh, R.S., Dzombak, D.A., Luthy, R.G., and Nakles, D.V. 1999. "Subsurface fate and transport of cyanide species at a manufactured-gas plant site". United States. doi:10.2175/106143096X122474.
@article{osti_20001044,
title = {Subsurface fate and transport of cyanide species at a manufactured-gas plant site},
author = {Ghosh, R.S. and Dzombak, D.A. and Luthy, R.G. and Nakles, D.V.},
abstractNote = {Cyanide is present at manufactured-gas plant (MGP) sites in oxide-box residuals, which were often managed on-site as fill during active operations. Cyanide can leach from these materials, causing groundwater contamination. Speciation, fate, and transport of cyanide in a sand-gravel aquifer underlying an MGP site in the upper Midwest region of the US were studied through characterization, monitoring, and modeling of a plume of cyanide-contaminated groundwater emanating from the site. Results indicate that cyanide in the groundwater is primarily in the form of iron-cyanide complexes (>98%), that these complexes are stable under the conditions of the aquifer, and that they are transported as nonreactive solutes in the sand-gravel aquifer material. Weak-acid-dissociable cyanide, which represents a minute fraction of total cyanide in the site groundwater, may undergo chemical-biological degradation in the sand-gravel aquifer. It seems that dilution may be the only natural attenuation mechanism for iron-cyanide complexes in sand-gravel aquifers at MGP sites.},
doi = {10.2175/106143096X122474},
journal = {Water Environment Research},
number = 6,
volume = 71,
place = {United States},
year = 1999,
month =
}
  • The following chapter emphasizes subsurface environmental research investigations over the past 10 to 15 years that couple hydrological, geochemical, and biological processes as related to contaminant fate and transport. An attempt is made to focus on field-scale studies with possible reference to laboratory-scale endeavors. Much of the research discussed reflects investigations of the influence of coupled processes on the fate and transport of inorganic, radionuclide, and organic contaminants in subsurface environments as a result of natural processes or energy and weapons production endeavors that required waste disposal. The chapter provides on overview of the interaction between hydro-bio-geochemical processes in structured,more » heterogeneous subsurface environments and how these interactions control contaminant fate and transport, followed by experimental and numerical subsurface science research and case studies involving specific classes of inorganic and organic contaminants. Lastly, thought provoking insights are highlighted on why the study of subsurface coupled processes is paramount to understanding potential future contaminant fate and transport issues of global concern.« less
  • Polycyclic aromatic hydrocarbons (PAHs) in manufactured gas plant (MGP) site sediments are often associated with carbonaceous particles that reduce contaminant bioavailability. Although black carbon inclusive partitioning models have been proposed to describe elevated PAH partitioning behavior, questions remain on the true loading and association of PAHs in different particle types in industrially impacted sediments. In the studied MGP sediments, the light density organic particles (coal, coke, wood, and coal tar pitch) comprised 10-20% of the total mass and 70-95% of the PAHs. The remainder of the PAHs in sediment was associated with the heavy density particles (i.e., sand, silt, andmore » clays). Among the different particle types, coal tar pitch (quantified by a quinoline extraction method) contributed the most to the bulk sediment PAH concentration. Aqueous partition coefficients for PAHs measured using a weathered pitch sample from the field were generally an order of magnitude higher than reported for natural organic matter partitioning, and match well with theoretical predictions based on a coal tar-water partitioning model. A pitch-partitioning inclusive model is proposed that gives better estimates of the measured site-specific PAH aqueous equilibrium values than standard estimation based on natural organic matter partitioning only. Thus, for MGP impacted sediments containing weathered pitch particles, the partitioning behavior may be dominated by the sorption characteristics of pitch and not by natural organic matter or black carbon. 25 refs., 5 figs., 1 tab.« less
  • A new high temperature transfer line, membrane inlet probe (HTTL-MIP) coupled to a photoionization detector (PID) and gas chromatograph/mass spectrometer (GC/MS) was used to rapidly profile and speciate polycyclic aromatic hydrocarbons (PAH) in the subsurface. PID signals were in agreement with GC/MS results. Correlation coefficients of 0.92 and 0.99 were obtained for discrete and composite samples collected from the same exact location. Continuous probe advancement with PID detection found coal tar, a dense nonaqueous phase liquid, in soil channels and saturated media. When samples were collected conventionally, split, solvent extracted, and analyzed in the field and confirmation laboratory, GC/MS measurementmore » precision and accuracy were indistinguishable; despite the fact the field laboratory produced data five times faster than the laboratory using standard EPA methods. No false positive/negatives were found. Based on these findings, increased confidence in site conceptual models should be obtained, since PID response indicated total PAH presence/absence in 'real-time', while GC/MS provided information as to which PAH was present and at what concentration. Incorporation of this tool into a dynamic workplan will provide more data at less cost enabling environmental scientists, engineers, and regulators to better understand coal tar migration and its impact on human health and the environment. 24 refs., 3 figs., 4 tabs.« less
  • The spatial and temporal distribution of solutes in groundwater is controlled by several physical and chemical processes. Among the chemical processes, sequential degradation phenomena play an important role in determining the fate of radioactive materials and certain types of organic compounds. The authors present a numerical model designed to evaluate the simultaneous transport and kinetically controlled sequential degradation (straight and branched chains) of several dissolved components in groundwater systems. The model utilizes a two-step quasi-linearization algorithm to solve the equations of chemical transport and transformation. The transport equations are solved explicitly using the integral finite difference method. The chemical transformationmore » equations are solved using an implicit finite difference (in time) algorithm for each volume element in the discretized flow domain. Although this algorithm is designed to solve problems involving first-order kinetics, it may be modified in certain instances to accomodate rate mechanisms other than first order. The chemical transformation module and the transport module are coupled via a source/sink term in the transport equation. This combination results in a numerical code that is computationally efficient. The authors have found that the model yields solutions which are in excellent agreement with available analytical solutions. Solution of a test problem based on the sequential degradation of the pesticide aldecarb demonstrates that the model can provide useful insights into the fate of solutes subject to certain degradation regimes in heterogeneous groundwater systems. Although the illustrative examples presented are one dimensional, the model itself is capable of handling two- and three-dimensional problems. In addition, the modular structure of the model is built upon user-specified chemical reactions. 25 refs., 8 figs., 1 tab.« less
  • A unique, holistic modeling approach, combining theoretical, empirical, and deterministic elements, was developed to define the ambient background transport of polychlorinated biphenyl (PCB) from New Bedford Harbor, to provide a baseline for remediation assessment of this Superfund site. Both empirical and deterministic elements characterized sediment processes. The deterministic section employed experimental data to describe flocculation through fluid shear, differential settling, and Brownian motion mechanisms, yielding a sediment settling velocity. The empirical portion of the model used this settling velocity, along with suspended solids, and flow field data to characterize sediment action. The remaining PCB transport mechanisms (volatilization and sorption) aremore » theoretically considered to give a complete contaminant transport assessment. The PCBs in New Bedford Harbor tend to volatilize at the rate of 5.9 g/d; or sorb, with sorption coefficients increasing with percent chlorination from 10{sup {minus}2.2} to 10{sup {minus}0.4} m{sup 3}/g for Aroclors 1016 and 1260, respectively, rather than stay in solution. The deterministic model showed that fluid shear was the most significant flocculation mass removal mechanism contributing to the settling velocity calculation. From the empirical model, the dominant sediment action mechanisms, resuspension and deposition, were driven by the change in suspended solids concentration and tides. The cycling of PCB-laden sediment, indicated by the PCB sorption tendency and the presence and dominance of resuspension, and subsequent transport from the site, can lead to PCB contamination of the water column, atmosphere, or downstream (marine) areas.« less