Lakes and Watercourses

Environmental Quality
Criteria for Lakes and
Watercourses
Choice of parameters
Environmental Quality Criteria for Lakes and Watercourses should be
used to evaluate the results of environmental monitoring and other
studies. The parameters and methods to be used for this purpose are
largely determined using the Swedish EPA Environmental Monitoring
Handbook. Similarly, studies commenced before publication of the
handbook are governed by the Agency’s General Guidelines for
Coordinated Monitoring of Receiving Bodies.
The Swedish EPA method instructions contain a large number of
parameters. It is hardly feasible or even desirable to produce model
criteria for all of them. Instead, the parameters selected for this report are
those considered to be the most important indicators of water quality in a
wide sense. Hence, chemical parameters include those indicating threats
to the environment such as eutrophication, acidification and the
presence of metals. Among biological parameters are measures of the
state of different parts of food chains and which in some cases are
relevant to use of the water. The biological parameters do not usually
reflect specific threats; rather they provide an integrated measure of the
environmental situation as a whole and any impact to which an aquatic
area may be exposed. The environmental relevance of each parameter is
explained in detail in the individual chapters and in the reasons given for
each type of investigation in the EPA Environmental Monitoring Handbook.
For various reasons it has not been possible to include some parameters,
which do in fact represent important aspects of water quality.
These include measures of hydrological and substrate conditions. Nor
has it been possible to formulate instructions for assessing changes in
water quality over time.
An outline of the parameters included is given in Table 1 on pages 14
and 15.
Classification and class delimitation
Environmental Quality Criteria use two types of scale: one for assessing
current conditions and one for assessing deviation from reference values.
13