Status of organochlorine (DDT) pollutants and steps toward electrocatalytic
reductions*
Welderufael G. Kiflom, Shem O. Wandiga, and Geoffrey N. Kamau
Department of Chemistry, University of Nairobi, P.O.
Box 30197, Nairobi, Kenya
Abstract: The accumulation of DDT in the environment over the
years is a major concern in the world today. The extent to which DDT
may be absorbed and translocated from 14C-p,p¢-DDT contaminated
soils into cowpea plant tissues, and the variation of uptake of p,p¢-DDT
by the plants in relation to the dissipation of p,p¢-DDT in the
soils was studied using a radioisotope technique. Significant absorption
and accumulation of residues was observed for the cowpeas grown in two
different sites, coastal and highland regions. The degree of uptake
varied with soil type and growing conditions. Further results indicated
that the higher the water retention by the soil the higher the rate
of evaporation of p,p¢-DDT. Coastal region p,p¢-DDT soil samples
showed DDE to be the major metabolite. DDT residue in the plants ranged
from 0.94 to 7.73 mg/kg, while that in the soils ranged from 88.9 to
32.0 mg/kg. Preliminary electrode reactions indicated lowering of overpotential
for reduction of p-chlorophenol by about 1 V, using copper phthalocyanine
tetrasodium tetrasulfonate as the catalyst in microemulsion. Microemulsions
and appropriate catalysts are a promising system for the decomposition
of DDT.
* An issue of reviews and research papers based on
presentations made at the IUPAC/ICSU Workshop on
Electrochemistry and Interfacial Chemistry in Environmental Clean-up
and Green Chemical Processes, Coimbra, Portugal, 6-7 April, 2001.
** Corresponding author.
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