Environmental Engineering Reference
In-Depth Information
in biological organisms, and on the contrary, are toxic to some forms of life (Österlöf and
Österlund 2003; WHO 1996). Table 11.1 lists the functions and effects of some metals.
Some elements, as well as many compounds, can be toxic, despite the fact that they
are essential. For most essential metals, either a shortage or an excess of the metal in the
environment will lead to detrimental effects on organisms, populations and ecosystems.
For non-essential metals, only excess environmental concentrations will cause adverse
Some elements, as well as many
compounds, can be toxic, despite
the fact that they are essential.
TABLE 11.1
Functions and Effects of Some Metals on
Organisms (after Osterlof and Osterlund
2003; IPCS monographs WHO: 1988; 1989a,
b; 1990; 1991; 1992; 1995a,b; Janssen and
Muyssen 2001)
A
B
Deficient
Optimal
Toxic
Toxic
OCEE
Homeostatic
Regulation
Homeostatic
Regulation
Natural
Background
Range
Natural
Background
Range
[EE]
[NEE]
A. Biological activity as a function of the essential element concentration (EE). OCEE is the Optimal
Concentration range for Essential Elements for a species in a given enviroment (Van Assche et al . 1997).
B. Biological activity as a function of the non-essential element (NEE).
Metal
Shortage Defi ciency
Optimal Range Function
Excess Toxicity
Non-Essential Elements [NEE]
Arsenic (As)
No known useful function
No known useful function
Highly poisonous and possibly carcinogenic in humans.
Cadmium (Cd)
No known useful function
No known useful function
Cd may be linked to renal arterial hypertension and
violent nausea. Cd accumulates in liver and kidney tissue.
It depresses growth of some crops and is accumulated in
plant tissue.
Lead (Pb)
No known useful function
No known useful function
A cumulative body poison in humans and live stock.
Humans may suffer acute or chronic toxicity. Young chil-
dren are especially susceptible.
Mercury (Hg)
No known useful function
No known useful function
Hg and its compounds are highly toxic, esp. to the devel-
oping nervous system.
Essential Elements [EE]
Cobalt (Co)
Essential - Present in vitamin B12, required
for the formation of hemoglobin; Plays a role in
biological N2-fi xation
Copper (Cu)
Anaemia, disturbed forma-
tion of bone
Essential - Present in cytochrome and hemo-
cyanin, molecules; involved in (cellular) respira-
tion; Essential in oxidases; metabolism of iron
Large doses may induce vomiting, nausea, diarrhea,
cramps, or hepatic damage. Toxic to fi sh and aquatic life
at low levels.
(Continued)
 
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