Reproductive cycle and gametogenesis in the black abalone Haliotis cracheroidii (Gastropoda: Prosobranchiata)

Seasonal changes in gonald size and stages of gametogenesis in the black abalone Haliotis cracheroidii were related to changes in environmental parameters. H. cracheroidii showed an annual reproductive cycle terminating in a synchronized spawning in late summer. Gametogenesis was initiated immediately after spawning. Gametes were present in the gonad through the winter months. Gametogenesis was initiated a second time in the spring months. Maximal gonad growth (to a gonad index of 20%) occurred during summer months prior to spawning. Changes in gonad size andperiods of initiation of gametogenesis revealed no apparent correlation with changes in seasonal water temperature. Changes in gonad size showed no apparent relation to change in day length. Total polysaccharide levels in foot tissue changed seasonally, indicating that food availability is probably not a factor in directly regulating gonad growth. Gonad index data for the chiton Katharina tunicata (collected over a 10 year period) showed no apparent correlation to seasonal change in water temperature.     

Effective low-temperature thermal aeration of soils

Low-temperature thermal aeration (LTTA) is a remedial technology developed by Canonie Environmental Services Corp. (Canonie) for use on soils containing nonchlorinated hydrocarbons, chlorinated solvents, volatile organic compounds (VOCs), chlorinated pesticides, and low levels of polynuclear aromatic hydrocarbons (PAHs). The LTTA system separates these hazardous constituents from excavated soils and allows the treated soils to be redeposited on-site without restriction. This article describes the various components and operation of LTTA systems for the remediation of soils contaminated with chlorinated and nonchlorinated constituents. The article also details the results of projects completed to date, principally for soil impacted with chlorinated hydrocarbons, and discusses the general characteristics and results of systems used for soils contaminated with nonchlorinated hydrocarbons (gasoline, etc.).     

Using polymer solutions to enhance recovery of mobile coal tar and creosote DNAPLs

Direct pumping and enhanced recovery of coal tar and creosote dense, non-aqueous phase liquids (DNAPLs) from the subsurface have had mixed results because these DNAPLs are viscous fluids that can potentially alter aquifer wettability. To improve the inefficiencies associated with waterflooding, the research presented here considered the use of a polymer solution that can be added to the injected flood solution to increase the viscosity and decrease the velocity of the flooding solution. Results from one-dimensional, vertically oriented laboratory column experiments that evaluate the recovery of coal-derived DNAPL with both water and polymer flooding solutions are presented. The final DNAPL saturation remaining in the column was assessed in water and oil-wet systems for three viscous DNAPLs. Adding polymer to increase the aqueous solution viscosity did not have a significant impact in water-wet systems. A final DNAPL saturation of approximately 19% was achieved for both water and polymer floods. In contrast, the addition of polymer significantly improved recovery in oil-wet systems. The final saturation was over 40% in oil-wet systems after waterflooding, but approximately 19% with a polymer flushing solution. Although the final saturation produced with polymer flooding was similar between the oil- and water-wet systems, differences in the relative permeability and distribution of DNAPL in the porous matrix caused the DNAPL recovery to be much slower in the oil-wet system.