Natural Attenuation Of Creosote Contamination In A Tidally Forced Anaerobic Aquifer: A Tracer Study Using C14-naphthalene
Abstract
Historic practices at a wood-preserving facility along a major river in the lower main- land of British Columbia have contaminated the underlying tidally forced anaerobic aquifer. Creosote from the source zone, found mostly as an immobile separate phase, is dissolving and forming an aqueous-phase plume, which is discharging from the aquifer at the river bottom. Previous studies could only explain the plume shape by invoking an attenuation process such as degradation or sorption. A careful study of the on-shore portion of the aquifer using in-situ and laboratory microcosms could not detect any measurable degradation. Similarly, sorption could not explain the plume shape. Here we present the results of a tracer study conducted in the off-shore portion of the aquifer. C14-labeled naphthalene, bromide and deuterated water were intro- duced into the portion of the aquifer beneath the river. Water samples were collected and analyzed for bromide, C-14 naphthalene and C14-labeled CO2, a likely degra- dation product. While C-14 CO2 has been detected, the levels are low, suggesting a very slow degradation process. The study is unique in several respects, including the methodologies used to sample the aquifer beneath the river and the use of a radio- labeled tracer in the field.
- Publication:
-
EGS General Assembly Conference Abstracts
- Pub Date:
- 2002
- Bibcode:
- 2002EGSGA..27.5005B