|
   
1. Source and Condition of
Test Organisms:
 | It is important that the test organisms be healthy, positively identified as to species,
of the same age, and from the same source |
2. Effluent Sampling and
Handling:
| The effluent should be sampled as specified in the NPDES permit. Some permits
specify a grab sample, but more often composite samples are required. Composite
samples are collected over an extended period of time (usually 24 hours) and they
represent an average of the quality of the effluent over that time period |
| Samples must be immediately chilled and held at 4 degrees C until immediately before use
when they are then warmed to the test temperature |
| Tests must be be started within 36 hours of collection of the effluent. No
effluent sample should be used in a test more than 72 hours after collection |
3. Dilution Water:
| Dilution water is required for controls and for making specified dilutions of the
effluent. If laboratory water is used for preparing dilutions, the water must meet EPA
specifications regarding parameters such hardness, pH, alkalinity and conductivity. |
| If the permit specifies that receiving water is to be used for dilutions and controls,
the water should be collected upstream from the effluent outfall |
| Receiving water for dilutions should be collected immediately prior to the test, and is
not to be held longer than 96 hours before beginning a test
|
4. Facilities and
Equipment:
| Instruments used for measurement of chemical and physical parameters (such as dissolved
oxygen, conductivity, temperature, etc.) must be calibrated and standardized daily |
| Temperature control equipment must be adequate to maintain a constant desired
temperature throughout the duration of biomonitoring tests |
| Recommended materials must be used in test equipment which comes in contact with the
effluent being tested |
| Test facilities must be clean, well-ventilated, and free of oil and toxic vapors which
could interfere with the test results |
5. Reference Toxicants:
| A "reference toxicant" is a substance of known toxicity to
the test organisms being used in biomonitoring tests. The test organisms can be
tested with the "reference toxicant" to ensure that they are in their normal
range of sensitivity to toxic substances. |
| A reference toxicant must be used to concurrently evaluate the sensitivity of each batch
of organisms being used in each chronic (7-day) test. |
| Laboratories conducting biomonitoring tests should also carry out monthly tests using a
reference toxicant to establish the precision and validity of their testing procedures. |
| Acceptable toxicants that can be used as reference toxicants include copper sulfate,
cadmium chloride, and sodium chloride. |
6. Record Keeping:
| Proper record keeping in bound notebooks is an important quality assurance aspect. |
| Detailed records of test organisms (such as species, source, age) should be maintained. |
| Instrument calibration should also be recorded on a daily basis. |
7. Data Evaluation and Test
Acceptability:
| Because the sensitivity of a test is dependent on the number of replicates, a sufficient
number of replicates must be used in the control and in the various dilutions of the
effluent. The minimum number of replicates that can be used varies according to the
particular test. In acute toxicity tests, typically at least 4 replicates of
10 organisms are tested at each dilution. |
| Survival of organisms in the controls must be at least 80% in Chronic tests and 90% in
acute tests for the test results to be valid. |
| In its biomonitoring Methods Manuals, the EPA has specified statistical procedures which
must be used to correctly evaluate test data and determine effluent concentrations at
which survival, growth, or reproduction differ significantly from the controls. |
|
