Plant and Animal Uptake

Framework for Dredged Material Management

May 2004

Evaluation of Landfill Performance model (Schroeder et al. 1984) have also been used to

estimate water balance (budget) for dredged material CDFs (Palermo et al. 1989;

Francingues and Averett 1988). Additional procedures and computer estimating tools are

also available to estimate attenuation of contaminants in the subsurface (Schroeder and

Aziz 2003; Aziz and Schroeder 1999a; Aziz and Schroeder 1999b; Schroeder et al.

1994a; Schroeder et al. 1994b; Schroeder et al. 2004). Source terms for partitioning

analysis and attenuation calculations can be found in Streile et al. (1996).

If leachate concentrations exceed applicable criteria, or criteria are not available

and effects cannot be shown to be acceptable using risk assessment (USEPA 1998; Cura,

Wickwire and McArlde in preparation), controls for leachate must be considered. These

may include proper site specification to minimize potential movement of water into

aquifers, dewatering to reduce leachate generation, chemical modifications to retard or

immobilize contaminants, physical barriers such as clay and synthetic liners,

capping/vegetating the surface to reduce leachate production, or collection and treatment

of the leachate.

5.3.7 Plant and Animal Uptake

Some contaminants can be bioaccumulated in plant tissue and become further

available to the food chain. There are few reference values available specifically for

assessing the potential for adverse plant or animal uptake from dredged material. Criteria

established for sewage sludge are sometimes used, but apply to a limited number of

metals, and are based on conservative assumptions that are not directly applicable to a

disposal area. A computerized screening program has been developed which compares

measured sediment concentrations to available reference values. The

Diethylenetriamine-pentaacetic acid (DTPA) extract test has also been utilized to provide

a simplified assessment of the potential for plant and animal uptake (Lee et al. 1978;

Folsom, Lee, and Bates 1981; Lee, Folsom, and Engler 1982; Lee, Folsom, and Bates

1983; U.S. Army Engineer Waterways Experiment Station 1987, USACE 2003). A

computerized program, the Plant Uptake Program (PUP) uses the results of the DTPA

extraction procedure to predict bioaccumulation of metals from freshwater dredged

material by freshwater plants and compare the results to a background or reference

sediment or soil (Folsom and Houck 1990).

If the contaminants are identified in the dredged material at levels, which cause a

concern, a more extensive evaluation may be performed based on a plant or animal

bioassay. Appropriate plant or animal species are grown in either a flooded or dry soil

condition using the appropriate experimental procedure and laboratory or field test

apparatus (Folsom and Lee 1985; Simmers, Rhett, and Lee 1986; American Society for

Testing and Materials (ASTM) 1997; USACE 2003). Contaminant uptake is then

measured by chemical analysis of the biomass (tissue). Growth, phytotoxicity, and

bioaccumulation of contaminants are monitored during the growth period in the case of

the plant bioassay. An index species is also grown to serve as a mechanism to extrapolate

the results to allow use of other databases, such as metals uptake by agricultural food

crops. This indexing procedure provides information upon which a decision can be made