5 research outputs found
Plant Uptake of Atmospheric Brominated Flame Retardants at an E-Waste Site in Southern China
Brominated flame retardants (BFRs) were measured in eucalyptus
leaves and pine needles as well as the leaf surface particles (LSPs)
of the two species at an e-waste site in southern China in 2007â2008.
The monthly concentrations of total BFRs in the eucalyptus leaves
and pine needles were in range of 30.6â154 and 15.1â236
ng/g dry weight, respectively, and relatively higher concentrations
were observed in winter and spring. Correlation analysis of BFR concentrations
and comparison of PBDE compositions between the plants and LSPs, air
(gaseous and particle-bound phases), and ambient variables were conducted.
The results revealed that BFRs in the plants, especially for less
brominated BFRs, showed positive relationships with BFRs in the LSPs
and negative relationships with the gaseous BFRs and ambient temperature.
The PBDE profiles in the plants were similar to the gaseous profile
for low brominated BDEs (di- through hexa-BDEs) and to the LSP profiles
for highly brominated BDEs (hepta- through deca-BDEs). Applying McLachlanâs
framework to our data suggests that the uptake of BFRs was controlled
primarily by gaseous partitioning equilibrium for compounds with log
octanol-air partition coefficients (<i>K</i><sub>OA</sub>) < 12 and by particle-bound deposition for compounds with log <i>K</i><sub>OA</sub> > 13. Different relationships between
the
plant/air partition coefficient (<i>K</i><sub>PA</sub>)
and <i>K</i><sub>OA</sub>, which depend on the uptake mechanisms,
were observed for polybrominated diphenyl ethers (PBDEs). This paper
adds to the current knowledge of the factors and mechanisms governing
plant uptake of semivolatile organic compounds with relatively high <i>K</i><sub>OA</sub> in the environment
Elevated Levels of Polychlorinated Biphenyls in Plants, Air, and Soils at an EâWaste Site in Southern China and Enantioselective Biotransformation of Chiral PCBs in Plants
E-waste
that contains polychlorinated biphenyls (PCBs) is moved
across national boundaries, often from industrialized countries in
the northern hemisphere, where the items were formerly used, to subtropical
and tropical regions in southeastern Asia and Africa. As a result,
there is a high likelihood that PCBs will be released into the environment
from a primary source due to the elevated temperatures encountered
in these low-latitude regions. In the present study, PCBs and enantiomer
fractions (EFs) of chiral PCBs (PCB 84, 95, 132, 136, 149, and 183)
were analyzed in air, eucalyptus leaves, pine needles, and soil at
an e-waste site and a rural site in southern China. The concentrations
of PCBs at the e-waste site ranged from 7825 to 76330 pg/m<sup>3</sup>, 27.5 to 1993 ng/g, and 24.2 to 12045 ng/g in the air (gas plus
particle), plant leaves, and soils, respectively. The atmospheric
PCB composition profiles in the present study indicated relatively
high abundances of penta- and hexa-PCBs, which were different from
those previously observed in the air across China. The ClausiusâClapeyron
regression analysis indicated that evaporation from local contaminated
surfaces constitutes a primary emission source of PCBs in the air
at the e-waste site. The chiral signatures of PCBs in the air at the
e-waste site were essentially racemic (mean EFs = (0.484 ± 0.022)â(0.499
± 0.004) in the gaseous phase) except for PCB 84 (0.420 ±
0.050), indicating that racemic sources dominate the PCB emission
in the air. PCB chiral signatures in the soils ((0.422 ± 0.038)â(0.515
± 0.016)) were similar to those in the air except for PCB 95.
However, the chiral PCBs in the plants (especially the eucalyptus
leaves) had significantly nonracemic residues ((0.368 ± 0.075)â(0.561
± 0.045)) compared to those in the air and soil. This finding
suggests that enantioselective biotransformation of these atropisomeric
PCBs was very likely to occur in the plant leaves, possibly due to
metabolism by cytochrome P-450 enzymes in leaves. To our knowledge,
this is the first report on the enantioselective metabolism of chiral
PCBs in plants under field conditions
Using Compound-Specific Stable Carbon Isotope Analysis to Trace Metabolism and Trophic Transfer of PCBs and PBDEs in Fish from an eâWaste Site, South China
Two fish species (mud carp and northern
snakehead) forming a predator/prey
relationship and sediment samples were collected from a pond contaminated
by e-waste. The concentrations and stable carbon isotope ratios (ÎŽ<sup>13</sup>C) of individual polychlorinated biphenyl (PCB) and polybrominated
diphenyl ether (PBDE) congeners were measured to determine if compound-specific
carbon isotope analysis (CSIA) could be used to provide insight into
the metabolism and trophic dynamics of PCBs and PBDEs. Significant
correlations were found in the isotopic data of PCB congeners between
the sediment and the fish species and between the two fish indicating
identical origin of PCBs in sediment and fish. Most PCB congeners
in the fish species were enriched in <sup>13</sup>C compared with
the PCB congeners in the sediments as a result of isotopic fractionation
during the metabolism of PCBs in fish. The isotopic data of several
PCB congeners showing isotopic agreement or isotopic depletion could
be used for source apportionment or to trace the reductive dechlorination
process of PCBs in the environment. The PCB isotopic data covaried
more in the northern snakehead than in the mud carp when compared
to the sediment, implying that a similar isotopic fractionation occurs
from the prey to the predator fish for a PCB congener possibly due
to similar metabolic pathways. The PBDE congener patterns differed
in the three sample types with a high abundance of BDE209, 183, 99,
and 47 in the sediment, BDE47, 153, and 49 in the mud carp and BDE47,
100, and 154 in the northern snakehead. The isotopic change of BDE
congeners, such as BDE47 and BDE49, in two fish species, provides
evidence for biotransformation of PBDEs in biota. The results of this
study suggest that CSIA is a promising tool for deciphering the fate
of PCBs and PBDEs in the environment
Polychlorinated Biphenyls (PCBs) in Human Hair and Serum from EâWaste Recycling Workers in Southern China: Concentrations, Chiral Signatures, Correlations, and Source Identification
Hair
is increasingly used as a biomarker for human exposure to
persistent organic pollutants (POPs). However, the internal and external
sources of hair POPs remain a controversial issue. This study analyzed
polychlorinated biphenyls (PCBs) in human hair and serum from electronic
waste recycling workers. The median concentrations were 894 ng/g and
2868 ng/g lipid in hair and serum, respectively. The PCB concentrations
in male and female serum were similar, while concentrations in male
hair were significantly lower than in female hair. Significant correlations
between the hair and serum PCB levels and congener profiles suggest
that air is the predominant PCB source in hair and that hair and blood
PCB levels are largely dependent on recent accumulation. The PCB95,
132, and 183 chiral signatures in serum were significantly nonracemic,
with mean enantiomer fractions (EFs) of 0.440â0.693. Nevertheless,
the hair EFs were essentially racemic (mean EFs = 0.495â0.503).
Source apportionment using the Chemical Mass Balance model also indicated
primary external PCB sources in human hair from the study area. Air,
blood, and indoor dust are responsible for, on average, 64.2%, 27.2%,
and 8.79% of the hair PCBs, respectively. This study evidenced that
hair is a reliable matrix for monitoring human POP exposure
Semivolatile Organic Compounds (SOCs) in Fine Particulate Matter (PM<sub>2.5</sub>) during Clear, Fog, and Haze Episodes in Winter in Beijing, China
Few efforts have been made to elucidate
the influence of weather
conditions on the fate of semivolatile organic compounds (SOCs). Here,
daily fine particulate matter (PM<sub>2.5</sub>) during clear, haze,
and fog episodes collected in the winter in Beijing, China was analyzed
for polycyclic aromatic hydrocarbons (PAHs), brominated flame retardants
(BFRs), and organophosphate flame retardants (OPFRs). The total concentrations
of PAHs, OPFRs, and BFRs had medians of 45.1 ng/m<sup>3</sup> and
1347 and 46.7 pg/m<sup>3</sup>, respectively. The temporal pattern
for PAH concentrations was largely dependent on coal combustion for
residential heating. OPFR compositions that change during colder period
were related to enhanced indoor emissions due to heating. The mean
concentrations of SOCs during haze and fog days were 2â10 times
higher than those during clear days. We found that BFRs with lower
octanol and air partition coefficients tended to increase during haze
and fog episodes, be removed from PM<sub>2.5</sub> during clear episodes,
or both. For PAHs and OPFRs, pollutants that are more recalcitrant
to degradation were prone to accumulate during haze and fog days.
The potential source contribution function (PSCF) model indicated
that southern and eastern cities were major source regions of SOCs
at this site