    Sentence 1: 1 Lower and upper PMSD  bounds were determined from the 10th  and 90th percentile, respectively, of  PMSD- data from EPA's WET  Interlaboratory Variability Study  (USEPA, 2001a; USEPA, 2001b).    Sentence 2: The data obtained from the  EPA's WET Interlaboratory Variability  Study was consiffered the most reliabl  and therefore used to establish the                        upper and lower PMSD bounds.