108
Tecnología y Ciencias del Agua
, vol. VIII, núm. 2, marzo-abril de 2017, pp. 105-115
Wang
et al
.,
Research on the hydrologic cycle characteristics using stable isotopes of oxygen and hydrogen in the Jinxiuchuan Basin
•
ISSN 2007-2422
10-20 cm, 20-25 cm, 25-30 cm, 30-35 cm). The
collect private collector of soil was employed to
store it, to avoid isotope fractionation, the sam-
ples were sealed in a cool place. In the end, 67
samples of different water bodies were collected
for analyzing the composition of hydrogen and
oxygen stable isotopes.
Analysis method
Water samples were analyzed by using Liquid
Water Isotope Analyzer (LWIA-24d, Los Gatos
Research, USA) at the Key Laboratory for Yel-
low River Delta Ecological Environment of
Shandong Province. Based on the international
V-SMOW standard, isotope value was marked
by
δ
(‰).
δ
refers to thousand points of differ-
ence between the ratios of the two measured
stable isotopes and the standard (Craig, 1961),
as the following Eq. (1):
‰
=
R
sample
R
standard
R
standard
10
3
(1)
Where
R
is the isotope ratio (D/H or
18
O/
16
O), the positive and negative value of
δ
indicated that the sample is richer in the heavy
isotope and light isotope than the standard,
respectively. The precision of the D/H is within
± 0.6‰, and
18
O/
16
O within ± 0.2‰.
The calculation of weighted average is
showed in the following. As a starting point,
suppose that there are
X
samples, and they are
X
1
,
X
2
,…,
X
i
(
I
= 1, 2, 3…
n
). Every sample (
X
i
)
contains a certain amount of
Y
i
. The weighted
average of
Y
is called
Y
’, and the formula as
follow:
Y
=
X
i
*
Y
i
(
)
i
=
1
n
X
i
( )
i
=
1
n
i
=
1, 2, 3
…
n
(
)
(2)
Water retention and renewal time is an
important link in the transformation process
of water in the phreatic water aquifer. The two
end-member isotope mixing model is used to
part water sources. Given that mixed water
(sample) comprises well mixed M and N water
samples, the proportions of M and N in the
sample can be derived from a conventional two
end-member mass-balance equation in terms of
δ
values:
Q
sample sample
=
Q
M M
+
Q
N N
(3)
Q
sample
=
Q
M
+
Q
N
(4)
X
M
=
Q
M
Q
sample
(5)
Where
X
M
and
X
N
are the fractions of
M
and
N
in the sample, respectively.
The solution for
X
M
is:
X
M
=
sample
N
M N
(6)
Results and discussion
Variations of
δ
D and
δ
18
O of the Jinxiuchuan
Basin
From July 2011 to July 2012, the basic informa-
tion of precipitation, temperature and relative
humidity was measured and showed in fgure 2.
The results showed that: precipitation and tem-
perature have obvious seasonal variations. The
average monthly relative humidity gradually
decreases from February. The lowest value is
about 36% in April or May, the maximum value
of 89% in August. However, the value of relative
humidity in September decreases again, and the
difference between maximum and minimum
value is 53% in figure 2.
The data of stable isotopes in precipitation
was employed to research its change in the local
region. The characteristic values of isotopiciso-
topic included the weighted average value of
δ
D,
δ
18
O and deuterium excess in each sampling
