D10: Impact of Contaminants - Hydromod

Integrated Water Resource Management for Important Deep European Lakes and their Catchment Areas
EUROLAKES
D10: Impact of Contaminants
FP5_Contract No.: EVK1-CT1999-00004
Version: 4.0
Date: 25/07/01
File: D10-vers.4.0.doc
Page 46 of 136
portant metals. The anthropogeneous zinc emissions (840000 t/a) exceed the natural
emissions about the 23fold . For humans the toxic effect of the metal is low,
apart from the inhalation of great zinc amounts. Quantities of 30 mg/l could cause
sickness and vomiting. Further more zinc interrupts the zinc-copper resorption which
can result in a copper scarcity [KÖCK 1996].
Description of Substances - Use and Mode of Action
Because of the multiplicity of substances, only a few are chosen and described in the
following paragraphs.
• Polychlorinated Biphenyles (PCB): PCBs are chemically inert and difficult inflammable.
Therefore they are multifaceted used as technical composites [FENT
1998]. For the new use PCBs are forbidden in Germany but it is still found in technically
outmoded plants (transformers, condensers, refrigerant and insulating material)
and come into the environment [LEISEWITZ 1996]. Today PCB is sorbed on organical
materials of soils and sediments and can be remobilised out of it. PCB is lipophilic
and stable in the environment.On the basis of biomagnification in fishes,
birds and marine mammals standing at the top of food chains maximum amounts of
PCB concentrations are found. This is relevant for higher chlorinated congeners,
because lower chlorinated congeners are metabolised.The chronical toxicity of
PCBs has a bigger human- and ecotoxicological relevance as the acute one. To
mammals and humans the chronical impacts of PCBs are carcinoma of the liver,
immunotoxicity and impairment of the reproduction [FENT 1998].
• DDT and other organo-chlorine compounds: DDT was the first synthetical produced
insecticide [SCHRENK-BERGT and STEINBERG 1998]. It belongs to the
heavy volatile chlorinated hydrocarbons and is still used in several developing countries
in spite of the ban in western Europe. DDT is heavy volatile, hydrophobic and
lipophilic. So a great accumulation in the food chain and sediments of water bodies
take place. In the depositions of rivers and lakes DDT is frequently about 10 000fold
higher concentrated as in the water [LEISEWITZ 1996]. DDT and its metabolite
DDE are especially accumulated in the fatty tissues, liver and the brain. It is active
as a nerve toxin with neurotoxical effects moreover it results in an increase of the
thyroid gland.
• Dioxines: Dioxine is a collective name for polychlorinated dibenzodioxines and furans
[LEISEWITZ 1996]. Polychlorinated dibenzo-1,4-dioxines and dibenzofuranes
(PCDD and PCDF) are unwelcome by-products of incineration and production processes.
On the basis of their chemically-physically and biologically persistence they
are staying a long time in the environment and accumulate and absorb themselves
in reservoirs. Further more they are resistant against chemical and biological decomposition
(cf. chapter 0). Their lipophility supports their bioaccumulation in the lever
and the fatty tissues of animals. The toxicity of different congeners must be differentiated.
Chlorinated dibenzo-1,4-dioxines are not only carcinogen but also have