Environmental Engineering Reference
In-Depth Information
ek et al.
2004
; Lehmann et al.
2004
; Minero et al.
2007
).
Nutrients produced by DOM and OM can fuel new primary and second-
ary production in natural waters. Total contents of DOM in lake waters are
responsible for variation of the trophic level, due to eutrophication/oligotrop
hication processes. The latter are a major driver of change for chemical vari-
ables such as major ions, nutrients (phosphorus and nitrogen compounds, sil-
ica) and the chemical nature of DOM.
(5) DOM can control photosynthesis in natural waters. DOC can limit produc-
tivity (Jackson and Hecky
1980
; Carpenter et al.
1998
) and affect epilim-
netic (Hanson et al.
2003
) and hypolimnetic respiration (Houser et al.
2003
).
Photoinduced and microbial oxidation of DOM is responsible for the simul-
taneous generation of H
2
O
2
, CO
2
and DIC (Mostofa and Sakugawa
2009
;
Ma and Green
2004
; Johannessen et al.
2007
; Palenik and Morel
1988
;
Fujiwara et al.
1993
; Miller and Moran
1997
; Meriläinen et al.
2001
; Malkin
et al.
2008
). Such compounds could favor the occurrence of photosynthesis
in natural waters. Some studies show that H
2
O
2
could be involved as reac-
tant in photosynthesis (xCO
2
+
yH
2
O
2(H2O)
+
h
υ
→
C
x
(H
2
O)
y
+
O
2
+
ene
rgy; and 2H
2
O
2
+
h
υ
→
2H
2
O
+
O
2
) (Mostofa et al.
2009a
; Komissarov
1994
,
1995
,
2003
; Miller and Moran
1997
). Nutrients (PO
4
3
−
and NH
4
Green
2004
; Kopá
č
+
)
released by DOM and POM might also favor the occurrence of photosynthe-
sis and subsequently enhance the cyanobacterial or algal blooms in natural
waters (Zhang et al.
2008
,
2009
; Kim et al.
2006
; Li et al.
2008
; Lehmann
et al.
2004
; Huszar et al.
2006
; Nõges et al.
2008
; McCarthy et al.
2009
;
Mohlin and Wulff
2009
). High chlorophyll
a
concentrations are often detected
in waters with high contents of DOM, and the reverse happens in low-DOM
waters (Meriläinen et al.
2001
; Malkin et al.
2008
; Fu et al.
2010
; Guildford
and Hecky
2000
; Mostofa et al.
2005a
, Mostofa KMG et al., unpublished
data; Satoh et al.
2006
; Yacobi
2006
; Komatsu et al.
2007
).
(6) Chemical functions of OM (DOM and POM). DOM and POM are com-
posed of various functional groups in their molecular structures, which
can form complexes with trace metal ions (M) in aqueous solution via
strong
π
-electron bonding systems (Mostofa et al.
2009a
,
2011
; Lead et al.
1999
; Wang and Guo
2000
; Koukal et al.
2003
; Mylon et al.
2003
; Wu
et al.
2004
; Lamelas and Slaveykova
2007
; Lamelas et al.
2009
; Fletcher et
al.
2010
; Reiller and Brevet
2010
; Sachs et al.
2010
; Da Costa et al.
2011
).
These studies imply that the M-DOM complexation is important for specia-
tion, bioavailability, transport and ultimate fate of trace metal ions in the water
environment. The detailed functions of M-DOM complexes are discussed in
natural waters (McKnight et al.
1992
).
(7) Maintenance of the drinking water quality by DOM and POM in waters
(Mostofa et al.
2009a
). The production of POM is significantly dependent
on the DOM contents in natural waters, and POM can produce new autoch-
thonous DOM and nutrients under both irradiation and microbial respiration
