THE EFFECT OF FLUE GAS DESULFURIZATION RESillUE ON CORN (Zea mays L.) GROWTH AND LEACHATE SALINITY: MULTIPLE SEASON DATA FROM AMENDED MESOCOSMS
T. Punshon, J .C. Seaman, and D.C. Adriano
Savannah River Ecology Laboratory, University of Georgia, Drawer E,
Aiken. SC 29802, USA.
1. ABSTRACT
The environmental effects of applying a weathered flue gas desulfurization
residue (FGD) to soil was monitored in a mesocosm experiment conducted
over several cropping periods. Dry biomass and elemental composition of
crop plants were measured, as well as the quality and chemical composition
of soil and leachate collected from treated mesocosms. Data collected
in the first year following FGD amendment showed no effect on the gennination
of corn (Zea mays L. VaT Dekalb DK-683), soybean (Glycine
max L. Merr. Var. Haskell Pupa 94), radish (Raphanus sativus
L. var. Sparkler), and cotton (Gossypius hirsutus L. var. Deltapine
51) and a significant stimulation in biomass. Metal and metalloid enrichment
of plant tissues, specifically As, B, Se and Mo was also significant.
Application of FGD residue drastically altered the pH of the soil and
the salinity of the leachate. Studies were continued into a second season
to monitor the duration of beneficial and deleterious effects arising
from FGD amendment, as it is expected that the majority of environmental
effects will occur in the initial season following application. Second
season data using a monoculture of com showed no significant stimulation
or inhibition of biomass, in contrast to findings of the initial year.
Concentrations of metals and metalloids within plant tissues in the second
season were lower, although still elevated above control concentrations.
Electrical conductivity of mesocosm leachate; elevated from a control
level of 0.05 dS m.l to 3.4 dS m.l with addition of 100 tons FGD 'acre-1,
was still elevated 550 days after application. Repeated monitoring of
leachate salinity showed evidence of only a slight decline 928 days after
application. Soil data collected at the end of the second growth season
showed that Se concentration had fallen below detection limits, and levels
of As had also fallen by approximately 29%. The duration of environmental
effects from FGD residue application can be summarized in terms of their
half-lives, i.e. the length of time required for a 50% reduction in altered
environmental parameters toward control levels. When half-lives for plants,
soil and leachate are compared, the increase in soil pH and leachate salinity
have the longest half-lives, and stimulation of plant biomass the shortest.
SREL Reprint #2751
Punshon, T., J. C. Seaman and D. C. Adriano. 2003. The effect of flue gas desulfurization residue on corn (Zea mays L.) growth and leachate salinity: multiple season data from amended mesocosms, p. 265-273. In Chemistry of Trace Elements in Fly Ash, edited by K. S. Sajwan, A. K. Alva and R. F. Keefer. Kluwer Academic/Plenum Publishers.
