The effect of tide-induced water table fluctuations on the sorption of naphthalene in beach aquifers is investigated. In particular, the cases of equilibrium and rate-limited sorption of naphthalene to aquifer solids are studied by examining the partition coefficient and rate of mass transfer from mobile to immobile regions. Results showed that the tidal effect on contaminant concentrations was not only dependent on the spill location but also on the partition coefficient and the rate of mass transfer. A difference of 13% of the initial spilled concentration was observed between the transient- and steady-head boundaries when the sorption partition coefficient between the contaminant and the sorbent was small (1 × 10−4 m3/kg). However, when the partition coefficient increased to 5 × 10−3 m3/kg, these differences became negligible. This suggests that for contaminants with higher hydrophobicity, a steady head may be used to simulate a seaward boundary, thereby reducing the extensive computations associated with the transient-head boundary. Likewise, small rates of mass transfer from mobile to immobile regions have produced different plume sizes in cases of transient- and steady-head boundaries. These differences in plume size disappeared upon an increase in mass transfer rate.
|Number of pages||10|
|Journal||Proceedings of the Institution of Civil Engineers Water Management|
|Publication status||Published - Jul 2012|