Evaluation of natural attenuation processes for trichloroethylene and technetium-99 in the Northeast and Northwest plumes at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

Clausen, Jay L.; Sturchio, Neil C.; Heraty, Linnea J.; Huang, Ling; Abrajano, T.A.

doi:10.2172/757234

Cited by 5 publications

(1 citation statement)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The amount of dissolved TCE in the plume is estimated at 3200-4700 kg, with larger amounts present as DNAPL in the source area (25). Using the conventional geochemical criteria for evaluating natural attenuation of CAHs in groundwater (15,16), the PGDP site ranks low in terms of its potential for anaerobic biodegradation of TCE (17).…”

Section: Introductionmentioning

confidence: 99%

Chlorine Isotope Investigation of Natural Attenuation of Trichloroethene in an Aerobic Aquifer

Sturchio

Clausen

Heraty

et al. 1998

Environ. Sci. Technol.

Self Cite

120

View full text Add to dashboard Cite

Natural attenuation of chlorinated aliphatic hydrocarbons (CAHs) can be an important mechanism for groundwater remediation. It is difficult to determine the effectiveness of natural CAH attenuation from chemical analyses of groundwater samples because mixing, dispersion, and secondary reactions can mask the chemical evidence of attenuation. In this paper, we explore the application of stable chlorine isotope ratio measurements as a new tool for for evaluating natural attenuation of CAHs. We report stable isotope ratios of chlorine in both trichloroethene (TCE) and inorganic chloride in groundwater from an aerobic aquifer beneath an extensively contaminated industrial site, the Paducah Gaseous Diffusion Plant in western Kentucky. Variations in the concentrations and chlorine isotope ratios of TCE and chloride in the groundwater are consistent with those expected from natural attenuation. These data support a model in which partial TCE degradation occurred in relatively impermeable, clay-rich sediments above the aquifer, and little or no further degradation of TCE occurred within the aquifer. A record of changing conditions within the TCE source area can be inferred from the spatial variation of chlorine isotope ratios for TCE and chloride within the plume.

show abstract

Section: Introductionmentioning

confidence: 99%

Chlorine Isotope Investigation of Natural Attenuation of Trichloroethene in an Aerobic Aquifer

Sturchio

Clausen

Heraty

et al. 1998

Environ. Sci. Technol.

Self Cite

120

View full text Add to dashboard Cite

show abstract

Technetium in Water

Clausen

2004

Water Encyclopedia

View full text Add to dashboard Cite

Technetium, element 43, was predicted on the basis of its location in the periodic table. Twenty‐two isotopes of technetium whose masses range from 90 to 111 are known, and all are radioactive. Technetium has three long‐lived radioactive isotopes: technetium‐97 [ 97 Tc] (half‐life {T 1/2 } = 2.6 × 10 6 years), 98 Tc (T 1/2 = 4.2 × 10 6 years), and 99 Tc (T 1/2 = 2.13 × 10 5 years). An important isotope is 95m Tc (“m” stands for metastable state) [T 1/2 = 61 days], which is used in tracer work. However, the most useful isotope of technetium is 99m Tc (T 1/2 = 6.01 hours), which is used in many medical radioisotope tests because of its short half‐life, easy detection of the gamma ray it emits, and the ability of technetium to bind chemically to many biologically active molecules Technetium‐99 is a surface water and groundwater contaminant at a number of DOE sites such as the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky; the Portsmouth Gaseous Diffusion Plant in Piketon, Ohio; Currently, the largest annual release of 99 Tc to the environment occurs at the two nuclear fuel‐reprocessing facilities in Sellafield, United Kingdom. The most extensive groundwater distribution of 99 Tc is at the PGDP where a mile long plume of 99 Tc contaminated groundwater is commingled with the solvent trichloroethene. The 99 Tc was introduced to the site during the 1970s when fissioned uranium was reprocessed. The technologies explored for remediating 99 Tc in water include ion exchange, liquid–liquid extraction, precipitation with various forms of iron, redox manipulation, the FORAGER sponge, granular activated carbon (GAC), and natural attenuation.

show abstract