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Aquatic
Toxicology Services
Era's Aquatic Toxicology Laboratory is
dedicated to performing Whole Effluent Toxicity (WET) tests,
Toxicity Identification Evaluations (TIEs), Water Effect Ratios
(WERs) and Product Evaluations.
Product Evaluation
Wastewater Treatment Facilities (WWTFs)
use a variety of chemical additives to
help treat water. Improper or over usage of additives,
however, may contribute to causing Whole Effluent Toxicity
failure. Before using a new chemical additive, the WWTF
should ask the manufacturer if the substance has been tested for
environment effects.
Before new chemicals are exposed to the environment they must
have a PreManufacture Notice (PMN) submitted to the USEPA.
The PMN submittal is usually accompanied by results of studies
of the chemical to show the potential effects of disposal of the
substance. The studies include acute and or chronic
toxicity tests, biodegradation tests, and chemical property
tests of the substance. The tests follow USEPA, ASTM and
International methodologies.
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Whole Effluent Toxicity
Major Municipal and Industrial
NPDES permitees are required to monitor their discharge for
potential toxicological effects. The monitoring is
accomplished through Whole Effluent Toxicity (WET) tests.
The WET tests consist of exposing juvenile fish, invertebrates,
and algae to the effluent and observing the organisms for
effects. The tests are standardized to follow USEPA and
State specific guidelines. Both freshwater and marine
organisms are used for the tests, dependent upon the NPDES
permit.
Toxicity Identification Evaluations
If a Whole Effluent Toxicity
test indicates a harmful effect to the receiving water, Toxicity
Identification (TIE) procedures may be required by the USEPA or
a State regulatory agency to identify the causative agent.
TIE procedures consist of separating the potential toxicant from
the discharge and then identification.
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Water Effect
Ratios
Many NPDES permitee's are
required to monitor chemical specific parameters discharged
into their receiving water. The monitoring is conducted to
ensure that NPDES permit limitations are being met on an ongoing
basis. Many times, the required parameters include trace
metal concentrations such as copper, nickel, zinc, etc.
However, if the receiving water has the ability to absorb
additional inputs of the metal without adverse effects, the
USEPA and State regulatory agency will often raise the allowable
discharge concentration of the metal. Water Effect Ratio
(WER) tests are used to determine whether discharge of the
specific metal will adversely affect the receiving water and the
organisms inhabiting it.
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