Biotransformation of polychlorinated biphenyls in St. Lawrence River sediments: reductive dechlorination and dechlorinating microbial populations

Cho, Y C; Kim, J; Sokol, Roger C.; Rhee, G‐Yull

doi:10.1139/f99-239

Cited by 16 publications

(11 citation statements)

References 18 publications

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“…We did not detect dechlorination below 0.50 μmol Cl/g sediment (40 ppm) in the present study, but other investigations have shown dechlorination of Aroclor 1242 at concentrations as low as 0.13 and 0.25 μmol Cl/g sediment (10 and 20 ppm, respectively) [4,5]. However, these lower values are not necessarily contradictory to the findings reported here, because the threshold concentration can be affected by the kind of dechlorinating microorganisms involved [15, 16] and by a variety of other factors that affect bioavailability, such as particle size, organic content of sediments, and age of exposure. Our earlier studies [7] have also demonstrated, as do the present investigations, that no growth of dechlorinating microorganisms occurred below the threshold concentration.…”

Section: Discussioncontrasting

confidence: 93%

Kinetics of polychlorinated biphenyl dechlorination by Hudson River, New York, USA, sediment microorganisms

Cho¹,

Sokol²,

Rhee³

2002

Enviro Toxic and Chemistry

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The kinetics of polychlorinated biphenyl (PCB) dechlorination by Hudson River (New York, USA) sediment microorganisms were investigated using Aroclor 1242 at 10 concentrations ranging from 0 to 900 ppm (0-11.2 micromol Cl/g sediment). The time course of PCB dechlorination and population growth were determined by congener-specific analysis and the most-probable-number technique, respectively, over a 44-week incubation period. Dechlorination rate (nmol Cl removed/g sediment/d) was a linear function of PCB concentrations similar to the dechlorination of Aroclor 1248 by sediment microorganisms from the St. Lawrence River (New York, USA). However, the rate was much slower, with the linear slope being only 24% that of the St. Lawrence River. The threshold concentration below which no dechlorination occurs was (mean +/- standard deviation) 1.06 +/- 0.18 micromol Cl/g sediment (85 +/- 14 ppm), threefold higher than that for the dechlorination of Aroclor 1248. The maximum extent of dechlorination was greater at higher Aroclor concentrations. Dechlorinating microorganisms did not show any significant growth until late in the lag phase of dechlorination, and their maximum was greater at higher initial Aroclor 1242 concentrations. Although dechlorination rates were significantly lower with the Hudson River inoculum, when normalized to the maximum number of dechlorinating organisms, they were not significantly different from those for Aroclor 1248 by St. Lawrence River microorganisms. These results further support the idea that PCB dechlorination is tightly linked to the growth of dechlorinating microorganisms.

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Section: Discussioncontrasting

confidence: 93%

Kinetics of polychlorinated biphenyl dechlorination by Hudson River, New York, USA, sediment microorganisms

Cho¹,

Sokol²,

Rhee³

2002

Enviro Toxic and Chemistry

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“…This concentration dependence of the plateau appears to be due at least in part to the fact that different subpopulations of dechlorinators are selected by PCB concentrations; since certain meta ‐dechlorination was observed at high concentrations but not low concentrations [6], it seemed that microorganisms for this type of dechlorination require high concentrations for growth. When PCB‐dechlorinating microorganisms were fractionated by the dilution technique in sediments contaminated with a high level of Aroclor 1248 (∼300 ppm), meta ‐dechlor‐inators were found only in low dilutions, indicating that these subpopulations were present in lower numbers than other de‐chlorinators [30].…”

Section: Discussionmentioning

confidence: 99%

Kinetics of polychlorinated biphenyl dechlorination and growth of dechlorinating microorganism

Rhee¹,

Sokol²,

Bethoney³

et al. 2001

Enviro Toxic and Chemistry

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The present study has investigated a correlation between the kinetics of polychlorinated biphenyl (PCB) dechlorination and the growth of dechlorinating microbial populations. Microorganisms were eluted from Aroclor 1248-contaminated St. Lawrence River (NY, USA) sediments and inoculated into clean sediments spiked with Aroclor 1248 at 10 concentrations ranging from 0 to 3.12 micromol/g sediment (0-900 ppm). The time course of PCB dechlorination and population growth were concurrently determined by congener-specific analysis and the most probable number technique, respectively. The specific growth rate was a saturation function of PCB concentrations above the threshold concentration (0.14 micromol/g sediment, or 40 ppm), below which no dechlorination or growth of dechlorinations were observed. The maximum growth rate was 0.20/d with a half-saturation constant of 1.23 micromol/g sediment. The yield of dechlorinating microorganisms showed a peak at 0.70 micromol/g sediment (200 ppm), with a value of 10.3 x 10(12) cells/mol Cl removed, and decreased below and above this concentration. The dechlorination rate (micromol Cl removed/g sediment/d) was a linear function of Aroclor concentration. Both the log of this rate and the maximum level of dechlorination were significantly correlated with growth rate. The biomass-normalized dechlorination rate (micromol Cl removed/g sediment/cell/d) was first order because of the exponential manner of the population growth. The first-order rate constant was a saturation function of Aroclor concentrations, with a maximum of 0.24/d (a half-life of 2.9 d) and a half-saturation constant of 1.18 micromol/g sediment, which are similar to the constants for growth. These results indicate that the dechlorination rate is tightly linked to the population growth of dechlorinating microorganisms.

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“…Each contributed approximately half the total PCB dechlorination. One group, which preferentially dechlorinated mostly meta ‐substituted congeners such as 2,5,2′,5′‐, 2,3,2′,5′‐ and 2,5,2′‐chlorobiphenyls, was about two orders of magnitude less abundant than the other [7]. We also identified two different dechlorinating patterns when sediments were treated with the metabolic inhibitor of methanogens, 2‐bromoethanesulfonate.…”

Section: Introductionmentioning

confidence: 77%

“…The PCB congeners were identified and quantitated using a calibration standard containing a 1:1:1:1 mixture of Aroclors 1016, 1221, 1254 and 1260 (0.2 μg ml −1 of each in hexane). Peaks were identified and calibrated as previously described [7,15,17,19]. Our analysis resolved 98 peaks, representing 127 congeners.…”

Section: Methodsmentioning

confidence: 99%

“…It may be possible to overcome this problem of recalcitrance if the level of chlorination can be reduced. Investigations in recent years have demonstrated the wide‐spread occurrence of microorganisms in anaerobic sediments that can remove chlorines from PCBs [3–8]. Dechlorination is mainly observed at meta and para positions and is determined by the pattern of chlorine substitution on the biphenyl ring [3].…”

Section: Introductionmentioning

confidence: 99%

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Enhancement of microbial PCB dechlorination by chlorobenzoates, chlorophenols and chlorobenzenes

Cho

Ostrofsky

Sokol

et al. 2002

FEMS Microbiology Ecology

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We investigated the effects of chlorobenzoates (3-, 2,3-, 2,4-, 2,5-, 2,3,5- and 2,4,6-chlorobenzoate), chlorophenols (2,3-, 3,4-, 2,5-, 2,3,6- and penta-chlorophenol), and chlorobenzenes (1,2-, 1,2,3-, 1,2,4- and penta-chlorobenzene) on polychlorinated biphenyl (PCB) dechlorination and on the enrichment of PCB-dechlorinating microorganisms. When the natural microbial populations eluted from St. Lawrence River sediments were enriched with each of the 15 haloaromatic compounds (HACs) in PCB-free sediments, PCB-dechlorinating microorganisms were found in all but pentachlorophenol-amended sediments. Similarly, dechlorinating microorganisms were also found in PCB-spiked sediments amended with all HACs, except for those with pentachlorophenol. In HAC-amended PCB sediments there was a long lag in PCB dechlorination until the HACs were reduced to a plateau level. Despite this lag, once PCB dechlorination started it was faster in the HAC-amended sediments compared to the unamended controls. The overall extent of PCB dechlorination was significantly enhanced by all HACs except pentachlorophenol and pentachlorobenzene, but the extent as well as the pattern of the enhancement varied. Of the 13 effective HACs, six (2,3-, 2,4- and 2,4,6-chlorobenzoates; 3,4- and 2,3,6-chlorophenols; and 1,2,3-chlorobenzene) enhanced only meta-dechlorination, whereas five (3-chlorobenzoate; 2,3- and 2,5-chlorophenols; and 1,2- and 1,2,4-chlorobenzenes) increased both meta- and para-dechlorination, and two (2,5- and 2,3,5-chlorobenzoates) promoted overall, substitution non-specific dechlorination. When the maximum extent of dechlorination was plotted against the highest number of PCB-dechlorinating microorganisms for each HAC, there was a linear relationship (P<0.01), suggesting that dechlorination enhancement was related to the increase in their population size. However, there was also evidence to suggest that different dechlorinating microorganisms were selected.

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Biotransformation of polychlorinated biphenyls in St. Lawrence River sediments: reductive dechlorination and dechlorinating microbial populations

Cited by 16 publications

References 18 publications

Kinetics of polychlorinated biphenyl dechlorination by Hudson River, New York, USA, sediment microorganisms

Kinetics of polychlorinated biphenyl dechlorination by Hudson River, New York, USA, sediment microorganisms

Kinetics of polychlorinated biphenyl dechlorination and growth of dechlorinating microorganism

Enhancement of microbial PCB dechlorination by chlorobenzoates, chlorophenols and chlorobenzenes

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