Journal of Environmental Protection, 2011, 2, 511-524
doi:10.4236/jep.2011.25059 Published Online July 2011 (http://www.scirp.org/journal/jep)
Assessment of Organochlorine Pesticide Residues
in the Surface Sediments of River Yamuna in Delhi,
India
Puneeta Pandey*, P. S. Khillare, Krishan Kumar
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India.
Received February 4th, 2011; revised April 22nd, 2011; accepted June 3rd, 2011.
ABSTRACT
The present study reports the concentration levels and distribution patterns of the organochlorine pesticide residues in
the surface sediments of river Yamuna in the Indian capital state, Delhi. Analytical measurements were carried out for
twenty organochlorine pesticides (OCPs) in the Pre-monsoon, Monsoon and Post-monsoon seasons, at six different
sampling locations along the 22 km stretch of the river Yamuna in Delhi. The results revealed contamination of the
surface sediments with several persistent organochlorine pesticides. Endrin aldehyde, Endosulfan sulfate and DDT
showed the highest percentage composition of OCP at all the sampling sites in all the three seasons. The total or-
ganochlorine pesticides level ranged from 157.71 - 307.66 ng/g in Pre-monsoon to 195.86 - 577.74 ng/g in Monsoon
and 306.9 - 844.45 ng/g in the Post-monsoon season. This not only demonstrates the pollution of the river with pesticide
residues, but also the necessity of a continuous long-term monitoring of the affected environment.
Keywords: Persistent Organic Pollutants (POPs), Organochlorine Pesticides (OCPs), Yamuna River, Sediments
1. Introduction and Methods
Persistent organic pollutants (POPs) are a major group
of hazardous chemicals having anthropogenic origin and
three main characteristics: persistence, bioaccumulation
and long range transport [1]. In the recent years, there
has been a growing interest in these chemicals due to
their potential toxicity and adverse impacts on human
health [2]. The Stockholm Convention on POPs (2001) is
an outcome of this growing concern about the persistent
organic pollutants. As per the Stockholm Convention,
POPs include nine organochlorine pesticides (OCPs) and
three industrial chemicals or by-products. The nine pesti-
cides targeted by the Stockholm Convention were pro-
duced internationally and used on agricultural crops or
for public health vector control. By 1970s, these pesti-
cides were either banned or restricted in many countries.
Though banned, these chemicals are still being used in
some of the developing countries owing to their low cost
and versatility in industry, agriculture and public health
[3]. In the Indian context, there are currently 179 pesti-
cides registered for use in India; 30 others have been
banned, while seven are restricted, including DDT.
Aldrin, chlordane and heptachlor were banned in Sep-
tember, 1996; while DDT is in restricted use since July,
1989. Dieldrin came in restricted use since May, 1990
and was banned completely in July, 2003. Endrin was
banned in May, 1990 while HCH in April, 1997. Use of
endosulfan and methoxychlor has been permitted while
HCB was never registered as a pesticide [4].
One of the important sink and reservoir for persistent
pollutants discharged into the environment is the sedi-
ment found on river and lake beds [5]. Sediment is a ma-
trix of materials which is comprised of detritus, inorganic
and organic particles, and is relatively heterogeneous in
terms of its physical, chemical and biological character-
istics [6]. Though regarded as a sink, the sediments may
release back to overlying waters the metals and other
pollutants bound on it, as a result of remobilization due
to various diagenetic processes [7]. As a result, sedi-
ments are now regarded as an important source of many
micropollutants that seriously threaten natural ecosys-
tems [8].
River Yamuna, a tributary of River Ganga is a major
river in the North Indian Plains. Along its entire 1376 km
stretch from Yamunotri to Allahabad, its water quality is
influenced by three major urban centers, i.e. Delhi,

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 512
Mathura-Vrindavan and Agra. Among these three, Delhi’s
contribution of pollution load into the river Yamuna is
the greatest. It also receives a fair amount of pesticides as
runoff from the agricultural fields of Haryana upstream
to its entry point in Delhi. A variety of vegetables are
grown in Yamuna flood plains in Delhi, where use of
OCPs is quite prominent. Besides, inundation of surface
sediments along the banks of Yamuna cannot be ruled
out in the monsoon season.
Owing to the greater environmental significance of
OCPs in Indian context and highly polluted status of the
river Yamuna, the study envisages having a proper as-
sessment of the residual presence of OCPs in Yamuna
river sediment. Thus, the objective of the present study
was:
1) To determine the concentration levels of organo-
chlorine pesticides in surface sediment of the river Ya-
muna in Delhi
2) To obtain trends in spatial and temporal variation of
organochlorine pesticides concentration.
The results obtained may be made use of as a baseline
data in developing effective remedial measures to im-
prove the water quality status of the river.
2. Materials and Method
2.1. Site Description
Delhi, the capital state of India, is situated at latitude
of 28°24′17′′ to 28°53′ and the longitude of 76°20′37′′ to
77°20′37′′, with an altitude of 216 meters above mean
sea level. For the collection of sediment samples from
the river Yamuna, six sampling sites were selected along
the river Yamuna in Delhi. Site A (RG), was taken up-
stream to the city, three sites B, C and D in the middle
segment (NGUS, NGDS and ITO) respectively and two
sites E (OK) and F (KK) downstream to the city. Figure
1 represents map of the River Yamuna in Delhi showing
the six sampling sites. Sediment samples were collected
from these sites for Pre-monsoon (June), Monsoon (Au-
gust) and Post-monsoon (October) season and analyzed
for 20 organochlorine pesticides.
2.2. Reagents
Standard mixture containing twenty-two OCPs (22 com-
pounds specified in EPA method 8081B) was purchased
from Supelco (Sigma Aldrich, USA). All solvents (ace-
tone, hexane, dichloromethane etc.) used for sample
processing and analysis, were of HPLC grade.
2.3. Sample Preparation
At each sampling site, the samples were collected in trip-
licates with the help of a stainless steel auger, transferred
into polythene bags and transported to laboratory. After
Figure 1. Map of the Yamuna River in Delhi showing sam-
pling sites.
drying, the samples were mixed thoroughly by the quar-
tering method and then sieved through a 2 mm sieve. The
sediment samples were extracted by Soxhlet extraction
method (USEPA Method 3540 [26,39,34]. Then, the
cleanup was carried out by Silica Gel (Silica gel 60, par-
ticle size 0.0630 - 0.200 mm, 70 - 230 mesh ASTM pur-
chased from Merck KgaA, Darmstadt, Germany) Clean-
up Method (USEPA Method 3630C).
2.4. Analysis
All the samples were analyzed on Gas Chromatograph
(Perkin Elmer Instruments, AutoSystem XL GC), equipped
with ECD (Electron Capture Detector) and a Perkin-
Elmer wide-bore capillary column (PE-5 column) with
the dimensions 30 m × 0.53 mm i.d. × 1.5 μm.
3. Results and Discussion
In the present study, Endosulfan I and α-Chlordane
have been reported together, since they appeared as joint
peak and could not be resolved. For similar reasons, En-
dosulfan sulfate + DDT have also been reported together.
3.1. Spatial Variation of Organochlorine
Pesticides Concentration
In the pre-monsoon period, the total OCPs (Σ OCP) con-
centration ranged from 157.71 ng/g at Ramghat to 307.66
ng/g at Najafgarh Upstream (NGUS). The high concen-
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Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 513
tration of pesticides at RG and NGUS can be attributed
to the pollution load added from the neighboring state of
Haryana as well as the increased sewage flow in the river.
Since the flow decreases downstream, the concentration
of ΣOCP decreased which could be due to degradation of
OCPs in summer due to high temperature. A very low
value at NGDS could be due to microbial action which
further accelerated the degradation processes.
In the monsoon period, the highest average seasonal
concentration was found at KK (577.74 ng/g), while mi-
nimum concentration was at NGUS (195.86 ng/g). Dur-
ing monsoon season, the major source of organic pollu-
tion is industrial wastewater, runoff from agricultural
fields in Haryana upstream of Delhi and Yamuna flood-
plains, garbage dumps and city streets carrying litter.
Since the distribution during monsoon is very heteroge-
nous, it can be said that since the flow of river increased
during monsoon, the pollution load was carried down-
stream to Kalindi Kunj. Further each site also received
runoff from local sources, especially the Najafgarh drain,
hence a high value was observed at NGDS (due to Na-
jafgarh drain), and Okhla (due to Yamuna flood plains).
In the post-monsoon period, the total OCPs (Σ OCP)
concentration ranged from 306.9 ng/g at NGDS to
844.45 ng/g at RG. During Post-monsoon season, besides
contribution from runoff from fields in Haryana, some of
the pesticides find their way into the sediments due to
leaching [9], as there seems to be a time lag between
peak water flow and OCPs reaching the sediment matrix
of the river. Further, the degradation may not have been
substantial as there was a time difference of two months
only between monsoon and post-monsoon sampling,
hence such a high value was observed at Ramghat. Simi-
larly, a high value at ITO could be due to runoff from
agricultural fields in its vicinity, which had not degraded
much. The value is low at NGDS, however, the differ-
ence between NGUS and NGDS is not much pronounced
in post-monsoon, as in pre- monsoon. The concentration
of individual OCPs in the pre-monsoon, monsoon and
post-monsoon season has been given in Table 1, 2 and 3
respectively.
Considering the distribution of OCPs at various sam-
pling sites, Endrin aldehyde revealed the highest concen-
tration at all the sites except NGDS, wherein Endosulfan
sulfate + DDT dominated during pre-monsoon season. In
the monsoon season, Endosulfan sulfate + DDT revealed
the highest concentration at RG, NGUS, ITO and OK,
while heptachlor epoxide revealed the highest concentra-
tion at NGDS and KK. Finally, during post-monsoon
season, Endosulfan sulfate + DDT showed the highest
concentration at NGUS, NGDS, ITO and OK, Endrin
aldehyde at RG, and heptachlor epoxide at KK. Thus,
Table 1. Spatial variation of OCPs in sediment at different sites of River Yamuna (Pre-monsoon period).
OCPs RG NGUS NGDS ITO OK KK
α-BHC 12.33 ± 1.52 3.95 ± 0.81 12.42 ± 1.06 7.25 ± 0.79 6.51 ± 0.62 6.1 ± 0.67
β-BHC 7.55 ± 0.86 4.5 ± 0.56 1.07 ± 0.34 1.19 ± 0.26 1.2 ± 0.11 0.31 ± 0.05
γ-BHC 9.64 ± 0.73 0.38 ± 0.23 7.85 ± 0.96 3.74 ± 0.45 0.37 ± 0.09 0.88 ± 0.12
δ-BHC 6.99 ± 0.54 1.65 ± 0.54 7.13 ± 0.85 0.11 ± 0.09 3.22 ± 0.31 0.81 ± 0.14
Hep 6.94 ± 0.41 7.36 ± 0.81 4.7 ± 0.26 1.5 ± 0.18 0.79 ± 0.21 0.83 ± 0.08
Ald 3.42 ± 0.28 14.51 ± 0.64 5.81 ± 0.25 7.51 ± 0.46 6.64 ± 0.54 5.29 ± 0.56
Hepex 2.55 ± 0.56 13.76 ± 0.95 2.09 ± 0.32 8.53 ± 1.04 8.04 ± 0.87 8.6 ± 0.96
γ-Chl 2.28 ± 0.14 15.44 ± 0.58 2.63 ± 0.12 9.22 ± 1.5 5.58 ± 0.81 3.76 ± 0.41
Ends1 + α-Chl 0.11 ± 0.23 8.78 ± 0.74 0.37 ± 0.11 5.08 ± 0.41 4.12 ± 0.52 3.08 ± 0.59
DDE 4.88 ± 0.61 24.58 ± 0.56 8.51 ± 1.05 18.43 ± 0.99 14.17 ± 1.11 9.97 ± 1.01
Dield 5.49 ± 0.39 25.18 ± 2.11 9.91 ± 1.54 18.08 ± 1.14 13.58 ± 1.55 11.36 ± 1.52
End 13.7 ± 1.24 31.48 ± 1.96 16.02 ± 2.15 22.55 ± 2.13 18.78 ± 1.46 17.01 ± 1.15
Ends2 11.34 ± 1.92 24.44 ± 3.14 16.14 ± 1.52 16.62 ± 1.84 14.96 ± 2.14 16.76 ± 2.15
DDD 13.42 ± 2.14 24.42 ± 1.85 17.11 ± 1.68 17.27 ± 1.31 14.84 ± 1.84 20.08 ± 1.64
Endal 21.89 ± 0.98 33.19 ± 1.27 27.28 ± 1.86 25.21 ± 1.55 23.47 ± 2.11 29.67 ± 2.18
Endosu + DDT 21.56 ± 1.45 26.67 ± 1.52 28.56 ± 1.45 24.16 ± 2.13 20.59 ± 1.26 29.14 ± 1.67
Endket 5.9 ± 0.53 20.72 ± 1.19 11.19 ± 1.04 18.83 ± 1.41 15.91 ± 1.06 11.45 ± 1.06
Meth 7.72 ± 0.61 26.65 ± 2.56 11.44 ± 0.45 23.2 ± 1.58 19.34 ± 1.18 11.56 ± 0.98
TOTAL 157.71 307.66 190.23 228.48 192.11 186.66

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 514
Table 2. Spatial variation of OCPs in sediment at different sites of River Yamuna (Monsoon period).
OCPs RG NGUS NGDS ITO OK KK
α-BHC 6.87 ± 1.31 15.34 ± 1.21 14.26 ± 1.21 6.67 ± 0.98 25.49 ± 1.61 18.99 ± 0.82
β-BHC 1.6 ± 0.23 12.64 ± 1.32 19.68 ± 1.62 3.99 ± 0.64 30.27 ± 1.87 23.31 ± 0.93
γ-BHC 5.91 ± 1.1 12.26 ± 1.12 17.05 ± 1.54 4.07 ± 0.71 27.85 ± 1.56 26.28 ± 1.1
δ-BHC 1.04 ± 0.24 8.95 ± 0.95 14.95 ± 1.35 0.39 ± 0.23 20.99 ± 0.89 15.48 ± 0.79
Hep 3.33 ± 0.67 9.88 ± 0.89 14.09 ± 1.26 3.16 ± 0.45 25.23 ± 0.98 15.82 ± 0.81
Ald 1.05 ± 0.21 6.87 ± 0.87 18.39 ± 1.98 3.79 ± 0.56 29.1 ± 1.69 20.98 ± 1.23
Hepex 6.76 ± 0.98 4.15 ± 0.79 78.18 ± 2.14 26.17 ± 1.76 35.56 ± 1.98 72.5 ± 2.63
γ-Chl 6.34 ± 1.1 2.96 ± 0.54 10.95 ± 1.24 1.32 ± 0.43 23.71 ± 0.95 17.73 ± 0.74
Ends1 + α-Chl 1.49 ± 1.23 1.1 ± 0.36 8.58 ± 0.97 2.44 ± 0.67 15.63 ± 0.78 12.42 ± 0.68
DDE 10.17 ± 2.31 3.45 ± 0.62 21.61 ± 1.99 10.69 ± 1.26 29.45 ± 1.72 26.24 ± 1.21
Dield 12.81 ± 2.56 5.93 ± 0.74 23.42 ± 2.1 12.79 ± 1.38 30.71 ± 1.76 27.61 ± 1.32
End 17.43 ± 1.73 12.14 ± 1.26 30.31 ± 2.24 20.34 ± 1.67 33.78 ± 1.82 32.72 ± 1.64
Ends2 17.81 ± 1.62 13.08 ± 1.32 31.44 ± 2.35 21.31 ± 1.78 33.71 ± 1.79 33.13 ± 1.76
DDD 21.57 ± 2.86 16.01 ± 1.52 47.12 ± 2.56 26.89 ± 1.98 42.64 ± 1.94 47.34 ± 1.86
Endal 29.54 ± 2.94 23.52 ± 1.73 44.33 ± 2.48 34.17 ± 2.13 43.16 ± 2.1 49.68 ± 1.92
Endosu + DDT 34.14 ± 3.14 26.67 ± 1.99 78.23 ± 2.87 40.84 ± 2.36 55.01 ± 2.76 71.49 ± 2.43
Endket 17.44 ± 1.64 10.25 ± 0.98 21.89 ± 2.11 21.15 ± 1.59 21.76 ± 0.94 32.12 ± 1.56
Meth 18.69 ± 1.82 10.76 ± 1.1 22.01 ± 2.23 22.93 ± 1.76 22.55 ± 0.98 33.9 ± 1.68
TOTAL 213.99 195.86 551.49 263.11 546.6 577.74
Table 3. Spatial variation of OCPs in sediment at different sites of River Yamuna (Post-monsoon period).
OCPs RG NGUS NGDS ITO OK KK
α-BHC 5.76 ± 0.45 0.24 ± 0.21 0.33 ± 0.11 14.48 ± 0.78 12.5 ± 0.78 11.98 ± 0.78
β-BHC 10.49 ± 1.32 2.55 ± 0.51 0.53 ± 0.27 17.6 ± 0.89 15.7 ± 0.86 15.51 ± 0.87
γ-BHC 9.99 ± 1.26 3.56 ± 0.64 7.17 ± 1.23 17.24 ± 0.84 19.82 ± 0.96 24.74 ± 1.13
δ-BHC 9.18 ± 1.19 3.29 ± 0.61 2.06 ± 0.58 14.86 ± 0.79 12.44 ± 0.63 11.36 ± 0.76
Hep 18.36 ± 1.67 4.41 ± 0.72 0.88 ± 0.36 19.72 ± 0.98 15.66 ± 0.86 8.56 ± 0.69
Ald 27.87 ± 1.89 6.86 ± 0.84 4.93 ± 0.77 21.91 ± 1.12 14.18 ± 0.87 10.75 ± 0.74
Hepex 50.32 ± 2.32 12.31 ± 1.11 4.86 ± 0.64 23.76 ± 1.32 16.33 ± 0.98 70.59 ± 2.89
γ-Chl 44.23 ± 2.14 9.19 ± 0.98 5.99 ± 0.86 23.33 ± 1.21 10.86 ± 0.59 6.44 ± 0.59
Ends1 + α-Chl 23.54 ± 1.64 7.59 ± 0.87 5.26 ± 0.78 16.22 ± 0.91 8.48 ± 0.49 5.04 ± 0.48
DDE 72.16 ± 2.89 19.81 ± 1.32 17.04 ± 0.89 31.4 ± 1.32 17.69 ± 1.95 15.11 ± 0.85
Dield 81.8 ± 2.96 23.31 ± 1.65 18.91 ± 0.91 33.95 ± 1.43 19.89 ± 1.1 17.89 ± 0.98
End 67.63 ± 2.68 31.6 ± 1.74 26.91 ± 0.98 40.07 ± 1.64 25.78 ± 1.34 24.48 ± 1.25
Ends2 60.51 ± 2.48 32.33 ± 1.86 28.85 ± 1.21 40.17 ± 1.66 26.92 ± 1.53 25.27 ± 1.34
DDD 64.19 ± 2.65 38.54 ± 1.94 35.37 ± 1.35 47.66 ± 1.78 30.74 ± 1.72 32.61 ± 1.65
Endal 90.87 ± 3.15 46.15 ± 2.11 40.02 ± 1.51 51.77 ± 1.87 33.94 ± 1.84 35.96 ± 1.81
Endosu + DDT 86.19 ± 2.99 55.13 ± 2.23 48.19 ± 1.62 57.31 ± 1.96 42.68 ± 1.91 56.77 ± 1.98
Endket 58.58 ± 2.21 34.85 ± 1.78 28.93 ± 0.91 32.93 ± 1.48 25.44 ± 1.34 24.96 ± 1.26
Meth 62.78 ± 2.53 37.28 ± 1.86 30.67 ± 1.1 35.43 ± 1.51 25.63 ± 1.46 25.72 ± 1.29
TOTAL 844.45 369 306.9 539.81 374.68 423.74
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Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 515
Endosufan sulfate + DDT, Endrin aldehyde, DDD,
Endrin and Methoxychlor were found in significant con-
centrations at all the sites in all the seasons, indicating
their wide use. Dominance of DDT in the sediments may
be attributed to the slow degradation of DDTs or recent
input of DDT in the environment [10,11]. Since Delhi is
highly urbanized, this possibility cannot be ruled out,
though use of DDT in agricultural applications has been
completely banned but vector control programmes are
effectively being carried out in this part of the country.
India is ranked the biggest consumer and manufacturer of
HCH and DDT in the world [12]. Moreover, pre-domi-
nance of Endrin aldehyde suggests the decomposition of
Endrin to Endrin aldehyde. The results of the present
study are consistent with the findings of Cavanagh et. al.
(1999) [13] that the volatilization of POPs such as OCPs
occurs in warmer climate of tropical regions. Methoxy-
chlor is tightly bound to soil and is insoluble in water, so
it is not expected to be very mobile in moist soils [14,15].
Methoxychlor breaks down slowly in air, water and soil
by sunlight and microscopic organisms. It may take sev-
eral months [16], thus, explaining its abundance in sedi-
ments.
3.2. Correlation
Correlation analysis was performed by using univariate
Pearson correlation coefficient for all pairs of compounds
to determine relationships between individual compounds.
Due to their extensive previous applications in agricul-
ture and resistance to degradation, all organochlorine
pesticides were found in significant concentrations at all
the sampling sites. All the organochlorine pesticides may
have a common source of origin and similar environ-
mental behaviour, they may, therefore, display signifi-
cant positive correlations among themselves [9]. Detailed
analysis of the data set showed that there were some sig-
nificant correlations existing between a few components
in the sediments with correlation coefficients frequently
greater than 0.5. α- BHC was found to be significantly
correlated to the other BHC isomers due to similar che-
mical properties, thus, indicating association between
them in terms of their applications. A very strong corre-
lation was observed among Endosulfan1 + α-Chlordane,
DDE, Dieldrin, Endrin, Endosulfan2, DDD, Endrin al-
dehyde, Endosulfan sulfate + DDT, Endrin ketone and
Methoxychlor (0.72 - 0.99). This can be attributed to the
fact that all OCPs are all related derivatives, and that they
are commonly used in agriculture and vector control
programmes. Further, since these compounds bind tightly
to soil and sediments, this explains their presence even
long time after discharge. The correlation values for the
20 pesticides in the surface sediments are shown in Ta-
ble 4.
Table 4. Correlation coefficient matrix for individual OCPs.
al-
B
H
C
b-BHC g-BHC d-BHCHep Ald Hepexg-ChlEnds1 +
al-Chl DDEDieldEndEnds2DDD Endal
Endosu
+ DDT Endket Meth
al-BHC 1
b-BHC 0.85 1
g-BHC 0.81 0.92 1
d-BHC 0.86 0.95 0.92 1
Hep 0.73 0.91 0.79 0.911
Ald 0.54 0.79 0.63 0.78 0.91 1
Hepex 0.39 0.64 0.6 0.59 0.5 0.57 1
g-Chl 0.18 0.47 0.33 0.47 0.72 0.87 0.361
Ends1 +
al-Chl 0.23 0.56 0.42 0.55 0.77 0.92 0.44 0.97 1
DDE 0 0.32 0.21 0.330.58 0.79 0.38 0.97 0.931
Dield –0.02 0.3 0.2 0.310.57 0.76 0.38 0.960.921 1
End –0.02 0.35 0.25 0.360.61 0.79 0.42 0.950.950.98 0.981
Ends2 0.05 0.44 0.36 0.45 0.66 0.8 0.49 0.910.940.93 0.94 0.971
DDD 0.18 0.58 0.51 0.570.7 0.81 0.65 0.820.890.83 0.84 0.89 0.961
Endal –0.01 0.35 0.28 0.370.58 0.73 0.47 0.890.890.940.960.960.980.93 1
Endosu
+ DDT 0.21 0.59 0.57 0.59 0.64 0.72 0.79 0.690.760.72 0.73 0.78 0.87 0.96 0.86 1
Endket –0.17 0.24 0.22 0.240.45 0.62 0.38 0.820.840.89 0.91 0.93 0.95 0.88 0.94 0.8 1
Meth –0.22 0.19 0.15 0.180.41 0.61 0.34 0.830.840.90.91 0.94 0.93 0.84 0.92 0.75 0.991

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 516
3.3. Ratios of OCPs
Isomeric ratios of Dieldrin/Aldrin, Heptachlor epoxide/
Heptachlor, DDD/DDE and α-BHC γ-BHC have been
given in Table 5.
3.3.1. Dieldrin/Aldrin
In the environment, aldrin gets converted to dieldrin,
which is more stable. In the present study, the ratio ob-
served was not much higher, suggesting high persistency
of chemical in the environment. However, a very high
value was observed at Ramghat in the monsoon season,
which could be due to runoff from agricultural fields in
Haryana, upstream of Ramghat. Although Aldrin was
being used as an anti-termite agent against potato crops
earlier, it is under complete ban in the country since Sep-
tember, 1996 [4].
3.3.2. Heptachlor Epoxide/Heptachlor
The ratio of heptachlor epoxide to heptachlor in the
sediments ranged between 0.37 - 10.36, thus, indicating
the early time usage of the pesticide in the region. Hep-
tachlor gets metabolized to heptachlor epoxide in the
environment, which is more stable. Heptachlor epoxides
adsorb strongly to the soil and are very resistant to bio-
degradation [17]. During pre- monsoon, the ratio was
moderately high at ITO and considerably high at Okhla
and Kalindi Kunj, which indicates greater degradation of
heptachlor due to high temperature conditions. In mon-
soon, the ratio was high at Najafgarh downstream and
Okhla, which may be due to fresh inputs from the drains.
Further, in post- monsoon, ratio was high only at Kalindi
Kunj, indicating transport of pollution load downstream.
3.3.3. DDD/DDE
The ratio of only DDD/DDE was taken and not (DDE +
DDD)/DDT because DDT could not be separated from
Endosulfan sulfate, hence could not be quantified. Both
DDD and DDE are degradation products of DDT. DDT
is degraded under aerobic conditions by micro-organisms
to DDE and under anaerobic conditions to DDD. The
ratio in this study varied from 0.22 - 1.12, indicating
more inputs of DDE and DDD to sediment from the wea-
thered DDT, and there has not been much recent expo-
sure to DDT in the environment [18]. Further, this re-
flects the aerobic conditions of the weathering process of
DDTs in sediments in recent years [19].
3.3.4. α-BHC/ γ-BHC
Residues of BHC isomers in significant concentrations in
the sediments may be attributed to the heavy use of this
pesticide in Indian agriculture until recently. The ratios
of α- to γ- isomer in the present study ranged from 0.05 -
17.59, suggesting for the earlier use of BHC with signa-
ture of continued recent use.
3.4 Percentage distribution of Isomers
3.4.1. BHC Isomers
The concentration of the four isomers of BHC reveals a
heterogenic nature of distribution. The composition of
BHC isomers may be relative to isomerization of BHC
during the process of transport and transformation.
α-BHC may eventually be converted to γ-BHC. In pre-
monsoon season, no definite trend was observed for the
BHC isomers except for α-BHC which showed an in-
creasing trend from Ramghat to Kalindi Kunj which
could be due to discharges from drains joining the river
Yamuna. No trend was observed for BHC isomers during
monsoon and post- monsoon. However, during post-
monsoon, concentration of γ-BHC was higher than α-
BHC which implies that α-BHC got transformed to γ-
BHC in post- monsoon. Percentage distribution of BHC
Isomers in Pre-monsoon, Monsoon and Post-monsoon
season has been given in Figure 2.
3.4.2. DDD and DDE
The composition of organochlorines and its metabolites
can provide a tool for better understanding of the origin
and transport pathways of these contaminants in the en-
vironment. Both DDD and DDE are degradation prod-
ucts of DDT. While DDE is the more stable end-product,
resistant to further degradation, DDD is an intermediate
metabolite in conversion of DDT to DDE. In this study,
the percent distribution of DDD was higher than DDE
suggesting fresh input of DDT rather than historical usage.
Table 5. Isomeric Ratios of OCPs.
Isomers Dield/Ald Hepex/Hep DDD/DDE al-BHC/g-BHC
Sites PrM Mon PoM PrM MonPoMPrM MonPoM PrM Mon PoM
RG 1.61 12.2 2.94 0.37 2.032.74 0.36 0.471.12 1.28 1.16 0.58
NGUS 1.74 0.86 3.4 1.87 0.422.79 1.01 0.220.51 10.39 1.25 0.07
NGDS 1.71 1.27 3.84 0.44 8.035.52 0.5 0.460.48 1.58 0.84 0.05
ITO 2.41 3.37 1.55 5.69 8.281.2 1.07 0.4 0.66 1.94 1.64 0.84
OK 2.05 1.06 1.4 10.18 1.411.04 0.95 0.690.58 17.59 0.92 0.63
KK 2.15 1.32 1.66 10.36 4.588.25 0.5 0.550.46 6.93 0.72 0.48
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Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India517
Figure 2. Percentage distribution of BHC Isomers in Pre-monsoon, Monsoon and Post-monsoon season.
This can be attributed to the fact that vector control pro-
grammes are more effective in urban areas. Percentage
distribution of DDD and DDE in Pre-monsoon, Monsoon
and Post-monsoon season is given in Figure 3.
3.5. Comparison with Other Studies at National
Level
The concentrations of individual OCPs reported in this
study are consistent with other studies of OCPs reported
at the national level. However, the values reported in
Kolleru lake wetland [20] are exceedingly high compared
to this study, which has been attributed to intensive use
of organochlorine pesticides in the Kolleru lake region. A
comparative account of the literatures reporting study of
OCPs in India has been mentioned in Table 6.
3.6. Comparison with Other Studies at
International Level
This study is also in agreement with other studies re-
ported at the international level, as the values of OCPs
observed in this study are comparable to those reported
by other authors. Table 7 lists different studies together
with the individual OCP concentrations observed in dif-
ferent parts of the world.
4. Conclusions
On the basis of the results obtained, it can be safely con-
cluded that Endosufan sulfate + DDT, Endrin aldehyde,
DDD, Endrin and Methoxychlor were found in signifi-
cant concentrations at all the sites in all the seasons, in-
dicating their wide use. No definite trend at six sampling
sites was observed, however, the site RG was observed to
have been the prominent recipient site in post-monsoon
and site KK also observed highest OCP concentration in
Monsoon. Correlation coefficient matrix for individual
OCPs in sediment revealed significant correlations be-
tween various components in the sediments, with corre-
lation coefficients frequently greater than 0.5. The con-
centration of the four isomers of BHC reveals a hetero-
genic nature of distribution with no definite trend in any
of the seasons. The ratios of Dieldrin/Aldrin, Heptachlor
epoxide/Heptachlor, DDD/DDE and α-BHC/γ-BHC re-
vealed a heterogenous nature, with degradation of OCPs
at almost all the sites with fresh input of OCPs intermit-
tently.
Although the values of OCPs in sediments reported in
Figure 3. Percentage distribution of DDD and DDE in Pre-monsoon, Monsoon and Post-monsoon season.

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 518
Table 6. Comparison of the present study with other studies within India.
Location Year OCPs Values(ng/g) Reference
Yamuna river, Delhi Present Study al-HCH 0.24 - 25.49 Present Study
b-HCH 0.31 - 30.27
g-HCH 0.37 - 27.85
d-HCH 0.11 - 20.99
Heptachlor 0.79 - 25.23
Aldrin 1.05 - 29.1
Heptachlor epoxide 2.09 - 78.18
g-Chlordane 1.32 - 23.71
Endosulfan 1 + al-Chlordane 0.11 - 23.54
DDE 3.45 - 72.16
Dieldrin 5.49 - 81.8
Endrin 12.14 - 67.63
Endosulfan 2 11.34 - 60.51
DDD 13.42 - 64.19
Endrin aldehyde 21.89 - 90.87
Endosulfan sulfate+ DDT 20.59 - 86.19
Endrin ketone 5.9 - 58.58
Methoxychlor 7.72 - 62.78
Bay of Bengal, India 2005 DDE 0.03 - 4.42 Babu Rajendran et al., 2005
DDD 0.01 - 0.53
DDT 0.01 - 0.02
Hugli estuary, India 2003 al-HCH BDL-0.003 Bhattacharya et al., 2003
b-HCH BDL-0.25
g-HCH BDL-0.16
d-HCH BDL-0.006
DDT BDL-0.11
DDE BDL-0.01
Endosulfan 1 BDL-0.008
Endosulfan sulfate BDL-0.4
West coast of India 1997 t- HCH 0.85 - 7.87 Sarkar et al., 1997
Aldrin 0.1 - 0.27
Dieldrin 0.7 - 3.33
Endrin 0.42 - 0.95
t-DDT 1.47 - 25.17
East and West coast of India 2001 al-HCH BDL-721.88 Pandit et al., 2001
b-HCH BDL-251.7
g-HCH BDL-55.6
d-HCH BDL-79.9
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Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India519
DDE BDL-464.55
DDD BDL-17.88
DDT BDL-109.5
Aldrin BDL-3
Endosulfan 1 BDL-1.4
Endosulfan 2 BDL-0.1
Hugli estuary, northeast India 2005 al-HCH 0.05 - 0.26 Guzzella et al.,2005
b-HCH <0.05 - 0.06
g-HCH 0.06 - 0.15
d-HCH <0.05
DDE <0.01 - 0.39
DDD <0.01 - 0.35
DDT 0.12 - 1.29
Dieldrin <0.05
Endrin <0.05
Methoxychlor <0.1
Himalayan Lakes 1997 DDE <0.4 - 10.48 Galassi et al.,1997
DDD <0.4 - 0.63
DDT 0.44 - 5.84
g-HCH 1.17 - 2.89
HCB ND - 1.10
Yamuna river, Delhi, India 1999 t-DDT 17.10 - 236.62 Sethi et al.,1999
t-HCH 2.635 - 36.265
Kolleru lake wetland, India 2006 al-BHC 22.4 - 174.2 μg/g Amaraneni, 2006
g-BHC 44.2 - 234 μg/g
Endosulfan 89.6 - 238 μg/g
Dieldrin BDL - 19.6 μg/g
DDT BDL - 128.6 μg/g
Table 7. Comparison of the present study with other studies at the International level.
Location Year OCPs Values(ng/g) Reference
Yamuna river, Delhi 2006 al-HCH 0.24 - 25.49 Present Study, 2006
b-HCH 0.31 - 30.27
g-HCH 0.37 - 27.85
d-HCH 0.11 - 20.99
Heptachlor 0.79 - 25.23
Aldrin 1.05 - 29.1
Heptachlor epoxide 2.09 - 78.18
g-Chlordane 1.32 - 23.71
Endosulfan 1 + al-Chlordane0.11 - 23.54
DDE 3.45 - 72.16
Dieldrin 5.49 - 81.8

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 520
Endrin 12.14 - 67.63
Endosulfan 2 11.34 - 60.51
DDD 13.42 - 64.19
Endrin aldehyde 21.89 - 90.87
Endosulfan sulfate + DDT 20.59 - 86.19
Endrin ketone 5.9 - 58.58
Methoxychlor 7.72 - 62.78
Coastal marine sediment, Singapore2005 al-HCH 0.9 - 9.3 Wurl and Obbard, 2005
b-HCH 0.7 - 11.1
g-HCH <0.7 - 13.4
d-HCH 0.9 - 13.3
DDT <0.5 - 4.2
DDD 1.3 - 4.0
DDE 0.6 - 4.7
al-Chlordane <0.3 - 9.0
g-Chlordane 1.2 - 10
Heptachlor <0.9 - 9.0
Heptachlor epoxide <0.7 - 6.8
Aldrin <0.3 - 1.4
Dieldrin <1.3 - 3.4
Endrin <1.3 - 4.0
Endrin aldehyde <2.0 - 4.2
Endosulfan 1 <0.9 - 2.2
Endosulfan 2 <1.0 - 1.6
Endosulfan sulfate <0.7 - 1.3
Methoxychlor <0.4 - 1.2
River Po sediment, 2002 DDT 0.6 - 3.1 Camusso et al.,2002
DDD 0.4 - 1.8
DDE 0.8 - 11.1
Ebro river, Mediterranean Sea 2006 DDT 1.3 - 7.2 Gomez-Gutierrez et al., 2006
Lindane 0.54 - 5.64
HCB 0.43 - 1.21
Paranoa lake, Brazil 1999 HCH 0.49 - 0.9 Caldas et al., 1999
Heptachlor epoxide 0.14 - 2.0
DDE 0.52 - 12.6
Coastal lagoon watershed, Argentina2001 HCH 57 - 156 Menone et al., 2001
Heptachlor <0.1 - 2
Heptachlor epoxide 581 - 1302
Dieldrin 3.0 - 14
Endrin <0.1 - 17
Endosulfan 1 0.2 - 3.0
Endosulfan 2 <0.2 - 11
Endosulfan sulfate 4.0 - 58
Methoxychlor <0.2 - 127
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Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India521
Bay of Ohuira, Mexico 2002 d-HCH 11 - 119 Osuna-Flores and Riva, 2002
DDT BDL-26
DDE 12 - 123
Endosulfan 1 BDL-45
Heptachlor BDL-57
Heptachlor epoxide 20 - 132
Haleji lake, Pakistan 2002 HCB 0.4 - 1.7 Sanpera et al., 2002
DDE 1.4 - 10.3
Stream sediment, Spain 2005 al-HCH 29 - 387 Gonzalez-Lopez et.al.,2005
b-HCH 45 - 392
Farming community, Ghana 2001 HCB 0.9 Ntow, 2001
Lindane 3.2
DDE 0.46
Heptachlor epoxide 0.63
Endosulfan 1 0.19
Endosulfan 2 0.13
Endosulfan sulfate 0.23
Lake Orta sediments, Italy 1997 al-HCH 0.04 - 0.61 Guzzella, 1997
b-HCH 0.07 - 11.03
g-HCH 0.24 - 13.73
DDT 0.14 - 9.02
DDD 0.03 - 58.38
DDE 0.0 - 1.47
Tampa Bay, Florida 2004 al-HCH 0.09 Grabe and Barro, 2004
b-HCH 0.16
g-HCH 0.19
d-HCH 0.23
DDT 0.31
DDD 0.49
DDE 0.81
Chlordane 1.76
Heptachlor 0.78
Heptachlor epoxide 0.04
Aldrin 0.23
Dieldrin 0.33
Endrin 0.18
Endrin aldehyde 0.1
Endosulfan 1 0.53
Endosulfan 2 0.12
Endosulfan sulfate 0.18
Methoxychlor 0.1
US Arctic lakes 1997 al-HCH 0.04 Allen-Gil et al., 1997
g-HCH 0.05
g-Chl ND

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India 522
Heptachlor epoxide ND
Endosulfan 2 ND
DDT 0.12
DDD 0.06
DDE 0.03
Uluabat lake, Turkey 2006 al-HCH 311 - 715 Barlas et al., 2006
b-HCH ND-559
g-HCH ND-405
HCB 158 - 556
Aldrin ND-446
Heptachlor epoxide 108 - 1533
Endosulfan 1 ND
DDE ND-1179
Endrin ND-580
Endosulfan 2 ND-248.4
DDT ND-1553
Pearl river estuary 2001 al-HCH ND-1.37 Li et al., 2001
b-HCH ND-1.14
g-HCH ND-0.72
d-HCH 0.43-3.71
DDT 1.27-6.65
DDD ND-10.8
DDE ND-4.09
Hep 0.47 - 1.62
Heptachlor epoxide 0.19 - 4.46
Aldrin ND-0.92
Dieldrin ND-0.19
Endrin ND-0.61
Endrin aldehyde ND-0.17
Endrin ketone 1.65 - 7.86
Endosulfan 1 ND-1.57
Endosulfan 2 ND-1.06
Endosulfan sulfate ND-41.8
Methoxychlor ND-1.49
the study are comparable to those by others in India as
well as other parts of the world, they are much higher at
some sites compared to the standards established for the
sediments. In the present study, at all the sampling sites,
the values of Endosulfan II and Methoxychlor were
found to be much higher than the standard (1.4 and 1.9
ng/g) [21]. As per CPCB, India [22] the environmental
standards for BHC and DDT are 10 μg/L each respec-
tively. The use of persistent OCPs have been banned or
severely restricted to use only in small number of coun-
tries with serious public health problems such as malaria
and other parasitic diseases. However, they are still used
in many developing countries including India in very
large quantities, mainly because of their low cost and
effectiveness. It is obvious, therefore, that the question is
still a matter of concern for the global society and a call
for worldwide attention through international bodies.
Thus, in order to have a comprehensive picture of OCP
distribution and their seasonal variation in Yamuna river
sediments, a detailed study is required.
5. Acknowledgements
The authors are grateful to University Grants Commis-
sion, New Delhi, for providing the funds in the form of
JRF (Junior Research Fellowship) to the corresponding
author. They would also like to thank Mrs. Irani Muk-
herjee for her valuable inputs during experimentation.
The corresponding author would also like to thank Dr.

Assessment of Organochlorine Pesticide Residues in the Surface Sediments of River Yamuna in Delhi, India523
Jamson Masih for his contribution in statistical analysis
and interpretation of the data.
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