Applications and statistical properties of minimum significant difference-based criterion testing in a toxicity testing program

As a follow up to the recommendations of the September 1995 SETAC Pellston Workshop on Whole Effluent Toxicity (WET) on test methods and appropriate e ndpoints, this paper will discuss the applications and statistical properti es of using a statistical criterion of minimum significant difference (MSD) . We examined the upper limits of acceptable MSDs as acceptance criterion i n the case of normally distributed data. The implications of this approach are examined in terms of false negative rate as well as false positive rate . Results indicated that the proposed approach has reasonable statistical p roperties. Reproductive data from short-term chronic WET test with Ceriodap hnia dubia tests were used to demonstrate the applications of the proposed approach. The data were collected by the North Carolina Department of Envir onment, Health, and Natural Resources (Raleigh, NC, USA) as part of their N ational Pollutant Discharge Elimination System program.