Table 5. Suggested Phytoreclamation Considerations for Polychlorinated Biphenlys

Technical Note DOER-C9

November 1999

3. Polychlorinated Biphenyls (PCBs): The group agreed that the phytoreclamation of PCBs

is not an effective technology at present. Some studies are being conducted using tree

species as shown in Table 5. The degradation of PCBs by phenol-like root excretions has

been identified as a likely process. It was indicated that sequential wet/dry soil conditions

and inoculation with specific microbes is necessary for success. Phytoreclamation may be

more effective on PCBs in conjunction with a bioreclamation process such as biomounds.

Table 5

Suggested Phytoreclamation Considerations for Polychlorinated Biphenlys

Compound

Plant Species

Soil Conditions

Remarks

Aroclors

Mulberry

Sequential wet/dry

Inoculate with microbes.

Phenol-like root excretion

(Fletcher, Donnelly, and

Heagle 1995)

Cogeners

Hackberry

Sequential wet/dry

Analyze congeners first

and last; aroclors always.

Longer time required.

(None specified)

4. Pesticides and Dioxins: Although pesticides are present in very low concentrations in

many sediments, particularly near agricultural lands, there have been few situations in

dredged material placement where they were considered a problem. No plant species are

indicated in Table 6. If pesticides were a concern, the primary approach to reduce adverse

effects would be to stabilize and render the compound inactive. This can be achieved by

the addition of compost materials using the manufactured soil technology.

Dioxins are sometimes present in sediment from a number of sources including historical

spills and discharges from paper mills. At present no reported phytoreclamation processes

have been shown to degrade or remove dioxins from dredged material or any other soil

material.

Table 6

Suggested Phytoreclamation Considerations for Pesticides and Dioxins

Compound

Plant Species

Soil Conditions

Remarks

Most Pesticides

Compost additions

Stabilize and render

Manufacured soil

inactive (Schnoor 1997;

technology

Cole, Liu, and Zhang

1994)

Dioxins

No reported degradation

in NY/NJ study (Lee et al.,

in preparation)

SUMMARY AND CONCLUSIONS: The conclusions of the Phytoreclamation Working Group

meeting were that phytoreclamation of dredged material would not be as readily effective as its

application to more heavily contaminated industrial sites. There are many instances, however,

where phytoreclamation would be a cost-effective alternative compared with other cleanup