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Historical Trends and Chiral Signatures of Organochlorine Pesticides in Sediments of Qiandao Lake, China

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This study investigated the enantiomeric and depth profiles of organochlorine pesticides (OCPs) accumulated in the sediments of Qiandao Lake, China. OCP concentrations in sediments have increased gradually since the early 1960s, when extensive OCPs application in China began. Concentrations reached maximum levels after 1992, this timing corresponds with the emerging of the "new" usage of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethane (DDTs). In addition, the degradation of chiral OCPs were enantioselective, resulting in enriched (-)-enantiomers for α-HCH and o, p'-DDD. However, both preferential depletions of (-) enantiomers and (+) enantiomers were observed for o, p'-DDT. This outcome was indicated by enantiomer fractions (EF) values either greater or less than 0.5.
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Vol:.(1234567890)
Bull Environ Contam Toxicol (2017) 99:350–353
DOI 10.1007/s00128-017-2131-5
1 3
Historical Trends andChiral Signatures ofOrganochlorine
Pesticides inSediments ofQiandao Lake, China
HuayunYang1· WeidongLi1· QiLiu2
Received: 14 March 2017 / Accepted: 20 June 2017 / Published online: 22 June 2017
© Springer Science+Business Media, LLC 2017
urban runoff, spillage, disposal and chemical weathering.
Vertical profiles of residues in dated sediment cores have
long been used as historical records of pollution (Blumer
and Youngblood 1975). For many compounds, there is a
subsurface peak in the sediment profile corresponding to
the period of peak production and/or usage, followed by a
slow decline to the sediment–water interface.
Several organochlorine pesticides (OCPs) are manufac-
tured and used as racemic mixtures. However, microorgan-
isms can selectively degrade one enantiomer over the other,
resulting in non-racemic signatures that are retained during
transport processes. Studying chiral signatures can help
assess OCPs releases, deposition and redistribution in the
region (Ali etal. 2003). Reports since the early 1990s have
documented the presence of non-racemic pesticide residues
in the environment (Aigner etal. 1998; Kurt-Karakus etal.
2005; Garrison 2006). This study investigated the histori-
cal progression of OCPs contamination in the sediments of
Qiandao Lake, China. The study also determined the Enan-
tiomeric fractions (EF) values of α-HCH, o, p’-DDT, o, p’-
DDD, trans- and cis-chlorodane (TC and CC).
Materials andMethods
Sampling for this study was done in March 2013. Sediment
surface samples, each 5-cm in depth, were collected using
a stainless steel grab sampler. Sediment core samples were
collected using a gravity corer. All sediment samples were
freeze-dried, homogenized, passed through a 63-μm sieve
and then stored in pre-cleaned dark glass bottles at −18 °C
prior to analysis.
The sediment core was dated using a 210Pb-dating
method described elsewhere (Zhang et al. 2002). Briefly,
the 210Pb activity in sediment samples was determined by
Abstract This study investigated the enantiomeric and
depth profiles of organochlorine pesticides (OCPs) accu-
mulated in the sediments of Qiandao Lake, China. OCP
concentrations in sediments have increased gradually since
the early 1960s, when extensive OCPs application in China
began. Concentrations reached maximum levels after 1992,
this timing corresponds with the emerging of the “new”
usage of hexachlorocyclohexanes (HCHs) and dichlorodi-
phenyltrichloroethane (DDTs). In addition, the degradation
of chiral OCPs were enantioselective, resulting in enriched
(−)-enantiomers for α-HCH and o, p-DDD. However, both
preferential depletions of (−) enantiomers and (+) enan-
tiomers were observed for o, p-DDT. This outcome was
indicated by enantiomer fractions (EF) values either greater
or less than 0.5.
Keywords Organochlorine pesticides (OCPs)·
Sediment· Chiral· Qiandao Lake
Sediments serve as a sink for many pollutants that enter the
aquatic environment (Sahu etal. 2009). The impact of this
pollution is particularly critical in creek ecosystems, such
as Qiandao Lake, China. This area is landlocked, and the
environment is relatively stagnant. Trace and toxic elements
are brought into the creek in the form of dissolved and par-
ticulate inputs from industrial effluents, sewage discharge,
* Huayun Yang
yanghuayun119@163.com
1 Qianjiang College ofHangzhou Normal University,
Hangzhou310012, China
2 College ofLife andEnvironmental Science, Hangzhou
Normal University, Hangzhou310012, China
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... On the other hand, significant preferential accumulation of (-)-o,p'-DDT (EF ≈ 0.13) was observed in many sediment samples collected from Yueqing and Sanmen Bay [57]. Similar preference was observed in Qiandao Lake sediment [73]. In comparison, comparatively faster attenuation of (-)-o,p'-DDT was observed in soil samples collected from Pearl River Delta [35]. ...
... α−HCH as the only chiral isomer of HCH is a major component of the technical HCH (55-80% in weight), which has been extensively found in worldwide air, water, soil and sediment samples [16,23,25,75,76]. As shown in Fig. 1B, preferential attenuation of (+)-α−HCH (EF < 0.5) was observed in sediment samples of Qiandao Lake, Yueqing Bay and Sanmen Bay [57,73]. Similar preferential depletion of (+)-α−HCH (EF = 0.39) was observed in surficial sediments of Northwater Polynya [77]. ...
... Later on, similar enantiomeric enrichment of the (-)-α−HCH was observed in other aerobic microcosms established with surface seawater or soil samples [108], in line with results obtained in field studies [34,78]. All these evidences working together suggested the important role of aerobic microorganisms in the enantioselective HCH degradation in surface environments (Fig.1B) [57,59,73]. Nonetheless, information on the microbial community composition of these microcosms, as well as taxonomy of the key functional microorganisms, remain scarce [84,110]. ...
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