Long-Term Effects of Dredging Operations Program. Design of an Improved ColumnLeaching Apparatus for Sediments and Dredged Material

摘要

This report describes a new column design for investigating contaminant leachingfrom sediments and dredged material. Improved sampling and sample preservation procedures are also described. A review of the literature on column leaching studies is also provided. Three types of columns were reviewed: (a) soil columns, (b) solid waste columns, and (c) sediment and dredged material columns. The review focused on column design and operating parameters, not data interpretation. The literature review showed that the soil column literature is much more extensive than the column literature for either solid wastes or sediments and dredged material. A wide variety of column designs have been used, but nearly all involve a vertical column with a small diameter-to-length ratio, and percolation of water either upward or downward. Improved sample collection and preservation are incorporated into the column design. However, separate columns for investigating metals and organics are required. for metals, an adaptation of the apparatus commonly used to study the chemistry of soil and sediment suspension under controlled redox potential and pH conditions is attached to the column outlet tube.