4.6.1.6 Laboratory techniques
Laboratory techniques selected for toxicity testing include USEPA methods using the short term chronic bioassay protocol. These methods are generally used to evaluate the toxicity of an effluent to receiving water. Specific methods for culturing and conducting toxicity tests using fathead minnows and Selenastrum may be found in (EPA 600/4-91-022). All tests have chronic end points, either growth or reproduction. In addition, fatheads and Daphnia are scored for survival (acute end point). All testing will be conducted at the screening level, comparing the control against 100 percent test water.
Culturing and testing protocols for Daphnia will follow those found in "Short Term Chronic Toxicity Test Using Daphnia magna' (EPA 600-D87-080). This test exposes ten-day-old females to the effluent for seven days. Three broods are expected during this period. Deviations from the method protocol for this Daphnia test will include the use of 35 mL low density polyethylene exposure cups with 30 mL of test solution instead of 100 mL glass beakers. Experience indicates that no over loading of animals will occur using the smaller test chambers.