Environmental Engineering Reference
In-Depth Information
250
(a)
Spring
Summer
Autumn
Winter
a
200
a
a
a
a
a
a
150
a
b
a
100
a
b
ab
a
a
ab
b
a
50
0
KR1+KR2
KR3+KR4
KR5+KR6
OR1+OR2
OR3+OR4
OR5+OR6
250
(b)
200
150
a
a
a
a
100
a
ab
a
b
ab
b
b
bc
a
b
b
b
b
50
c
0
KR1+KR2
KR3+KR4
KR5+KR6
OR1+OR2
OR3+OR4
OR5+OR6
Sampling
Fig. 9
Seasonal variations of the H
2
O
2
(
a
) and ROOH (
b
) concentrations in the waters of the
Kurose River and Ohta River in the Hiroshima prefecture, Japan. The error bar indicates the
standard deviation of seasonal average value of peroxides. Mean values labelled with different
letters are significantly different at
P
< 0.05 (Fisher's l.s.d. analysis).
Data source
Mostofa and
Sakugawa (
2009
)
et al.
2001
; Richard et al.
2007
), and the contribution of UV-B, UV-A and pho-
tosynthetically active radiation (PAR) is 40, 33 and 27 %, respectively (Richard
et al.
2007
). Production of H
2
O
2
at vertical depths depends on the penetration
of solar radiation, and decreases with an increase in depth of lakes or oceans
(Obernosterer et al.
2001
). A model study on a freshwater stream shows that the
H
2
O
2
concentrations over time significantly depend on photoinduced production
