Environmental Engineering Reference
In-Depth Information
Humic substances (humic and fuvic acids) are extensively applied as bio-
medicines to decrease the gastric damage induced by ethanol, to protect organ-
isms against cell-wall disruption, to maintain antibacterial and antiviral properties,
decrease viral respiratory illness, and to protect against cancer and related can-
cer-causing viruses (Brzozowski et al.
1994
; Klöcking et al.
2002
; Peña-Méndez
et al.
2005
). On the other hand, humic acid is a toxic factor for many mammalian
cells and can be involved in the so-called humic acid-induced cytotoxicity (Peña-
Méndez et al.
2005
; Ho et al.
2003
).
10 Scope of the Future Research
After the development of an effective method for TOC analysis in 1988, DOM
has been mostly determined in developed countries since 1990 to date, but fewer
studies have been carried out in developing countries. Considering the impor-
tance of DOM, it is important to determine its levels in natural water in develop-
ing countries, also considering that the DOC concentrations in many watersheds
have changed (either increased or decreased) over the last few decades. Moreover,
emerging contaminants and their transformation byproducts are extensively exam-
ined currently, but only limited information is available on their ecotoxicological
impacts on the aquatic environments.
Some important research demands for future challenges are the follow-
ing: (i) Determination of concentration levels of DOM in important rivers and
lakes in developing countries. (ii) Extraction of autochthonous fulvic acids from
algae or phytoplankton under both photorespiration by natural sunlight or arti-
ficial light, and microbial respiration or assimilation under dark incubation.
(iii) Characterization of the extracted autochthonous fulvic acids to examine the
presence of functional groups, elemental composition, and possible molecular
structure with reference to standard Suwannee River Fulvic Acid and Humic Acid.
(vi) Investigation on lakes having reduced DOC contents, using incorporation of ter-
restrial soils in lake surface waters. (v) Investigation on lakes having increased DOC
contents, trying to reduce photosynthesis and primary production in the lake surface
waters. (vi) Joint chemical and toxicological evaluation of emerging contaminants and
their transformation byproducts, for important end points and target organs and effects
such as mutagenicity, carcinogenicity, hepatotoxicity, nephrotoxicity, immunotoxicity,
neurotoxicity, developmental neurotoxicity and pharmacokinetics (Farré et al.
2008
).
Nomenclature
ABC
ATP binding cassette
ADAFs
Aircraft deicing/antiicing fluids
AEOs
Alkylphenol ethoxylates
BF
4
-
Tetrafluoroborate
CDOM
Colored and chromopheric dissolved organic matter
