Environmental Engineering Reference
In-Depth Information
Cause unknown—impaired biota
Cause unknown
Dioxins
Taste, color and odor
Flow alteration(s)
Ammonia
Temperature
Pesticides
Pathogens
Other cause
Habitat alterations
Salinity/total dissolved solids/chlorides/sulfates
Fish consumption advisory
Nuisance exotic species
Sediment
pH/acidity/caustic conditions
Algal growth
Metals (other than Mercury)
Turbidity
Organic enrichment/oxygen depletion
Polychlorinated biphenyls (PCBs)
Nutrients
Mercury
0
5
10
15
20
25
30
35
40
45
% of affected lake area
FIGURE 3.5
Percentage of lakes contaminated by various components. (Data from USEPA, National Summary of Impaired
Waters and TMDL Information , http://ofmpub.epa.gov/waters10/attains_index.control, 2014.)
3.3.2 Monitoring of Water Quality
In industrialized countries, concern over the quality of waters in rivers has resulted in
a considerable amount of public funds being invested in water quality monitoring dur-
ing the last decade. Accordingly, monitoring of chemical contaminants in the environ-
mental matrices has entered a new phase. Modiications in instrumentation, sampling,
and  sample  preparation techniques have become essential in keeping pace with the
requirements for (a) achieving low detection levels, (b) high speed analysis capability, and
(c) convenience and cost eficiency.
Environmental indicators such as water quality can be used as indicators of sustainabil-
ity. The term monitoring is used in many different ways. In the context of monitoring of a
particular site to determine whether the events expected to occur in the site have indeed
transpired, monitoring means the gathering of all pertinent pieces of information provid-
ing evidence that those events had occurred. We interpret from the deinition of monitor-
ing in the previous chapter to mean a program of sampling, testing, and evaluation of
status of the situation being monitored. In the situation being monitored, a management
zone needs to be established, as shown, for example, in Figure 3.6. To determine whether
attenuation of contaminants in a contaminated site has been effective, it is necessary to
obtain information pertaining to the nature, concentrations, toxicity, characteristics, and
properties of the contaminants in the attenuation zone. The contaminants have residence
in both the porewater (or groundwater) and on the surfaces of the soil solids, i.e., attached
to the soil solids' surfaces. Residence (of the contaminants) associated with the soil solids
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