Environmental Engineering Reference
In-Depth Information
the environment). A biomonitor, on the other hand, is an organism (or part of an
organism or a community of organisms) that contains information on the quantita-
tive aspects of the quality of the environment. The clear differentiation between
bioindication and biomonitoring using the qualitative/quantitative approach makes
it comparable to instrumental measuring systems. Such effects (information bits) of
bioindicators (biomonitors) may include changes in their morphological, histologi-
cal or cellular structure, their metabolic-biochemical processes (including accumu-
lation rates), their behaviour or their population structure. Accumulation indicators/
monitors are organisms that accumulate one or more elements and/or compounds
from their environment. Effect or impact indicators/monitors are organisms that
demonstrate specific or unspecific effects in response to exposure to a certain ele-
ment or compound or a number of substances. According to the paths by which
organisms take up elements or compounds, various mechanisms contribute to over-
all accumulation (bioaccumulation), depending on the species-related interactions
between the indicators/monitors and their biotic and abiotic environment. Biomag-
nification is the term used for absorption of the substances from nutrients via the
epithelia of the intestines. It is therefore limited to heterotrophic organisms and is
the most significant contamination pathway for many land animals except in the
case of metals that form highly volatile compounds (e.g. Hg, As) and are taken
up through the respiratory organs (e.g. trachea, lungs). Bioconcentration means
the direct uptake of the substances concerned from the surrounding media, e.g. the
physical environment, through tissues or organs (including the respiratory organs).
Besides plants, that can only take up substances in this way (mainly through roots
or leaves), bioconcentration plays a major role in aquatic animals. The same may
also apply to soil invertebrates with a low degree of solarisation when they come
into contact with water in the soil.
Active
bioindication (biomonitoring) means when bioindicators (biomonitors)
bred in laboratories are exposed in a standardised form in the field for a defined
period of time. At the end of this exposure time, the reactions provoked are recorded
or the xenobiotics taken up by the organism are analyzed. In the case of
passive
bio-
indication (biomonitoring) organisms already occurring naturally in the ecosystem
are examined for their actions.
Various newer methods (biomarkers, biosensors, biotests in general) have been
introduced into the application field of bioindication, besides the classical floristic,
faunal and biocoenotic investigations that primarily record unspecific reactions to
pollutant exposure at higher organismical levels of bioindication.
Biomarkers
are measurable biological parameters at the suborganismic (genetic,
enzymatic, physiological. morphological) level in which structural or functional
changes indicate environmental influences in general and the action of particular
in qualitative and sometimes also in quantitative terms. Examples are enzyme or
substrate induction of cytochrome P-450 and other Phase I enzymes by various ha-
logenated hydrocarbons; the incidence of forms of industrial melanism as markers
for air pollution; tanning of the human skin caused by UV radiation; changes in the
morphological, histological or ultrastructure of organisms or monitor organs (e.g.
liver, thymus, testicles) following exposure to pollutants. A
biosensor
is a measuring
