Transformation of 2,4-dichlorophenoxyacetic acid in four different marine and estuarine sediments: effects of sulfate, hydrogen and acetate on dehalogenation and side-chain cleavage
Aw. Boyle et al., Transformation of 2,4-dichlorophenoxyacetic acid in four different marine and estuarine sediments: effects of sulfate, hydrogen and acetate on dehalogenation and side-chain cleavage, FEMS MIC EC, 29(1), 1999, pp. 105-113
Enrichments initiated with marine and estuarine sediments from the Arthur K
ill (NY/MJ estuary) and Paleta Creek (San Diego Bay, CA), transformed 2,4-d
ichlorophenoxyacetic acid to 4-chlorophenol in the presence of sulfate (25
mM). Transformation of 2,4-dichlorophenoxyacetic acid was not observed with
two other marine sediments from Tuckerton, NJ and Flax Pond (Stony Brook,
NY). The lag period prior to 2,4-dichlorophenoxyacetic acid loss or the lim
e required for 50% removal of 2,4-dichlorophenoxyacetic acid (t(50)) in Art
hur Kill and San Diego enrichments was not affected by the presence of sulf
ate, although the addition of hydrogen and acetate decreased the lag period
s and t(50) values in these enrichments. The first step in the transformati
on of 2,4-dichlorophenoxyacetic acid was side-chain removal forming 2,4,dic
hlorophenol which was then dechlorinated to 4-chlorophenol. Second-generati
on Arthur Kill cultures dechlorinated 2,4-dichlorophenoxyacetic acid to 4-c
hlorophenoxyacetic acid. This dechlorination occurred both in the presence
and absence of sulfate (25 mM); however, sulfate reduced the rate of dechlo
rination by approximately 50%. Second-generation cultures inoculated with t
he sulfate-amended enrichments consumed sulfate and dechlorinated 2,4-dichl
orophenoxyacetic acid to 4-chlorophenoxyacetic acid concurrently when suppl
ied with hydrogen and acetate; the rate of dechlorination was twice that of
cultures that did not receive hydrogen and acetate. Sulfate consumption oc
curred only in cultures supplemented with hydrogen and acetate. These resul
ts indicate that dechlorination of an organochlorine pesticide in marine an
d estuarine sediments occurs in the presence of sulfate and the addition of
readily utilizable carbon and electron donors can stimulate dechlorinating
activity. (C) 1999 Federation of European Microbiological Societies. Publi
shed by Elsevier Science B.V. All rights reserved.