(i.e., hazard of a chemical described by ECx/LCx, NOEC, LOEC, or similar values)
may be used for the assessment of the potential risks, such as setting the environmental quality standards (EQS) for different matrices like water or soil.
In addition to individual chemicals, also “materials” containing mixtures of
known or unknown chemicals are prospectively tested for their ecotoxic properties.
An example can be wastes that should be tested before their further use (Moser and
Römbke 2009). Other examples include dredged sediments, which should be evaluated for ecotoxicity before their application on agricultural soils as fertilizers
(Vašíčková et al. 2013). Unfortunately, relevant legislations are country-specific
and not harmonized internationally.
27.5 Retrospective Assessment: Ecotoxicology
of Contaminated Samples
Retrospective ecotoxicity testing includes the assessment of contaminated environmental samples like water, sediments, or soil. Most commonly, risk assessment
of contaminated samples is based on chemical monitoring, i.e., targeted instrumental or bioanalytical analyses and quantification of known toxic components such as
toxic metals or various organic compounds. With respect to remediation and
removal of chemicals from contaminated environments, a number of methods
have been developed ranging from AAS or ICP-MS/MS for metals to diverse gas
and liquid chromatographic approaches (GC, LC) coupled with diverse detectors for
organic pollutants. However, the traditionally used chemical assessment has a
number of limitations and some efforts implement ecotoxicity and toxicity testing
into risk assessment schemes. One of the major advantages of ecotoxicity testing is
the response of the organism to all (potentially) toxic components in the sample
(including eventually also by-products formed during the sample treatment, etc.).
The bioassay or sets of bioassays (batteries) thus provide an integrative biological
response, which reflects the “overall toxic potential” of the sample.
The assessment of complex contaminated samples by bioassays has a number of
specificities, which further depend on the purpose. Namely, whether the bioassays
are intended (i) for the use in distributed monitoring of environmental quality,
i.e., assessment and comparison of multiple samples from different sites (effectbased environmental monitoring), or (ii) for the use during the site-specific
remediation.
As mentioned above, the bioassays have primarily been developed and used for
testing of individual chemicals where standard concentrations and conditions can be
assured. In complex samples, even the composition of matrix may vary considerably. This is important for both water (variable pH, salinity, hardness, OC content,
etc.), but even more for soils with enormous variability in parameters like texture,
granularity, content, and composition of the clay and the organic material, etc. All
these parameters affect bioavailability of present toxicants and consequently their
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L. Bláha and J. Hofman
may be used for the assessment of the potential risks, such as setting the environmental quality standards (EQS) for different matrices like water or soil.
In addition to individual chemicals, also “materials” containing mixtures of
known or unknown chemicals are prospectively tested for their ecotoxic properties.
An example can be wastes that should be tested before their further use (Moser and
Römbke 2009). Other examples include dredged sediments, which should be evaluated for ecotoxicity before their application on agricultural soils as fertilizers
(Vašíčková et al. 2013). Unfortunately, relevant legislations are country-specific
and not harmonized internationally.
27.5 Retrospective Assessment: Ecotoxicology
of Contaminated Samples
Retrospective ecotoxicity testing includes the assessment of contaminated environmental samples like water, sediments, or soil. Most commonly, risk assessment
of contaminated samples is based on chemical monitoring, i.e., targeted instrumental or bioanalytical analyses and quantification of known toxic components such as
toxic metals or various organic compounds. With respect to remediation and
removal of chemicals from contaminated environments, a number of methods
have been developed ranging from AAS or ICP-MS/MS for metals to diverse gas
and liquid chromatographic approaches (GC, LC) coupled with diverse detectors for
organic pollutants. However, the traditionally used chemical assessment has a
number of limitations and some efforts implement ecotoxicity and toxicity testing
into risk assessment schemes. One of the major advantages of ecotoxicity testing is
the response of the organism to all (potentially) toxic components in the sample
(including eventually also by-products formed during the sample treatment, etc.).
The bioassay or sets of bioassays (batteries) thus provide an integrative biological
response, which reflects the “overall toxic potential” of the sample.
The assessment of complex contaminated samples by bioassays has a number of
specificities, which further depend on the purpose. Namely, whether the bioassays
are intended (i) for the use in distributed monitoring of environmental quality,
i.e., assessment and comparison of multiple samples from different sites (effectbased environmental monitoring), or (ii) for the use during the site-specific
remediation.
As mentioned above, the bioassays have primarily been developed and used for
testing of individual chemicals where standard concentrations and conditions can be
assured. In complex samples, even the composition of matrix may vary considerably. This is important for both water (variable pH, salinity, hardness, OC content,
etc.), but even more for soils with enormous variability in parameters like texture,
granularity, content, and composition of the clay and the organic material, etc. All
these parameters affect bioavailability of present toxicants and consequently their
556
L. Bláha and J. Hofman