Environmental Engineering Reference
In-Depth Information
acid (Palmer et al.
1998
); bis (2,4,4-trimethylpentyl) dithiophosphinic acid
(Bhattacharyya et al.
2010
); 2-(aminomethyl)-benzimidazole (El-Sherif
2010
);
α
-isosaccharinic acid and
α
-isosaccharinate (Vercammen et al.
2001
; van Loon et
al.
2004
; Warwick et al.
2003
,
2004
); citrate (Fujii et al.
2008
); acetate (Saito et al.
2010
); phthalic and salicylic acids (Panak et al.
1995
); salicylate and thiosalicylate
(Vlassopoulos et al.
1990
); ethylenediaminetetraacetic acid (EDTA) (Fu et al.
2007
;
Fujii et al.
2008
); galacturonic acid (Harper et al.
2008
); gluconic acid (Warwick et
al.
2003
,
2004
); aminopolycarboxylic acids (Smith and Martell
1987
); and finally
O-bearing organic compounds such as carboxylic acids (acetic, adipic, succinic, malic,
malonic, maleic, lactic, oxalic, tartaric, citric and ortophosphoric acids) (Francis and
Dodge
2008
; Radalla
2010
; Filella and May
2005
; Tella and Pokrovski
2009
; Shoukry
2005
; Da Costa et al.
2011
; El-Sherif
2010
). Besides these organic ligands, the gill
membrane in fish can form complexes with metal ions such as Ag
+
, Ca
2
+
, Cu
2
+
,
Cd
2
+
, and Co
2
+
(Playle et al.
1993
; Janes and Playle
1995
; Richards and Playle
1998
;
Playle
1998
; Tao et al.
2002
). In addition, algae can complex or uptake trace metals
either directly or in the presence of humic acid that can enhance the metals uptake
substantially (Zhou and Wangersky
1985
,
1989
; Xue and Sigg
1990
; Koukal et al.
2003
; Mylon et al.
2003
; Lamelas and Slaveykova
2007
; Lamelas et al.
2009
).
The studied trace metal ions that form M-DOM complexes are the transi-
tion metals [Sc
3
+
, Y
3
+
, V
2
+
or VO
2
, Cr
2
+
or Cr
3
+
, Mn
2
+
, Fe (Fe
2
+
or Fe
3
+
),
Co
2
+
, Ni
2
+
, Cu
2
+
, Au
+
, Mo
2
+
, Zn
2
+
, Cd
2
+
, Hg
2
+
]; lanthanides [Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu, hereafter Ln
3
+
]; acti-
nides [Th
4
+
, U
4
+
, UO
2
2
+
, Np (Np
4
+
, Np
5
+
), NpO
2
+
, Pu
3
+
, Am
3
+
, Cm
3
+
];
metal/metalloid [Al
3
+
, Ga
3
+
, As
3
+
, Sb
3
+
, Sb
5
+
, Tl
3
+
, Sn
2
+
, Pb
2
+
], as well as
the alkali/alkaline earth elements [H
+
, Be
2
+
, Mg
2
+
, Ca
2
+
, Sr
2
+
, Ba
2
+
] (Nair and
Chander
1983
; Cabaniss and Shuman
1988
; Vlassopoulos et al.
1990
; Cabaniss
1992
; Panak et al.
1995
; Xia et al.
1996
; Bidoglio et al.
1997
; Takahashi et al.
1997
; Kaiser
1998
; Murphy et al.
1999
; Sekaly et al.
1999
; Wu et al.
2004a
,
b
;
Kautenburger et al.
2006
; Sonke and Salters
2006
; de Zarruk et al.
2007
; Fu et al.
2007
; Reszat and Hendry
2007
; Shcherbina et al.
2007
; Lippold and Lippmann-
Pipke
2009
; Pourret and Martinez
2009
; Schmeide and Bernhard
2009
; Vidali
et al.
2009
; Bhattacharyya et al.
2010
; Christoforidis et al.
2010
; Reiller and
Brevet
2010
; Saito et al.
2010
; Tserenpil and Liu
2011
). Any given metal ion in
the natural environment may potentially be found in many diverse forms, namely,
'free' (hydrated), complexed by 'simple' inorganic or organic ligands, complexed
by ligand atoms which are part of the structure of naturally occurring macromol-
ecules or colloids, and adsorbed on suspended organic or inorganic particles or liv-
ing organisms (Huber et al.
2002
; Filella et al.
2007
).
Heavy metals (e.g. Cd
2
+
, Pb
2
+
, and Sr
2
+
) show strong interaction with humic
acids (HA) in forming M-DOM complexes, leading to formation of covalent bonds
with the radicals of humic acids (Christoforidis et al.
2010
). Metal partitioning
between colloidal (1
μ
m-1 kDa) and truly dissolved (<1 kDa) fractions is detected
to match a decrease of metal toxicity (for Cd and Zn ions) in the presence of humic
acid, but not in the presence of Suwannee River Fulvic Acid (Koukal et al.
2003
).
This suggest that metal-HA complexes are of high molecular weight and relatively
+
