MIL-HDBK-1005/9A
technical literature. If adequate data on treatability of these
wastewaters are not available, conduct pilot or bench scale
treatability tests.
2.4.7
Bioassay of Wastewaters. Effluent limitations are
based in part on limitations for individual chemicals or generic
pollutant parameters: chemical oxygen demand (COD), BOD, or
total organic carbon (TOC). Comprehensive physiochemical
characterization of an effluent does not directly indicate any
possible adverse effects on the ecosystem of the receiving
stream. The collective effects of physical, chemical, and
biological properties of the effluent are exhibited in the
observed toxicity as measured by the bioassay procedure.
Industrial process wastewater from naval installations may
contain toxic compounds that exhibit none of the generic
pollutant parameters or cannot be disclosed for security
reasons. The monitoring of these effluents by bioassay
techniques may be required by regulatory agencies.
2.4.7.1
Standard Bioassay Procedures. A bioassay measures the
concentration of pollutant at which a designated percentage of
selected test organisms exhibits an observable adverse effect.
The percentage is usually 50 percent, and the adverse effect is
usually death or immobility. Concentrations (percent by volume)
are expressed as LC5O for median lethal concentration and EC5O
for median effective concentration.
a) Test Organisms. Effluent tests should be
conducted with a sensitive species that is indigenous to the
receiving water. The test organisms do not have to be taken
from the receiving water. Refer to EPA 600/4-90-027F, Acute
Toxicity Freshwater and Marine Organisms, for a complete list
of acceptable test organisms and temperatures.
b) Methodology. Refer to EPA 600/4-90-027F, for a
complete description of required test equipment, laboratory and
test procedures, sampling and analytical procedures, procedures
for data gathering and reporting, and methods for data reduction
and analysis to determine LC50 or EC50.
Regulatory bioassay requirements and LC50 or EC50 are
usually based on 48- or 96-hour tests using fish or
invertebrates (for example minnows or Daphnia, respectively).
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