Predicting Toxicity in Marine Sedimen'ts with Numerical Sediment Quality Guidelines

.Abstract-Mat~hing'syno~tically collected chemical and laboratory bioassay data (n = 1.068) were compiled from analyses of surficial sediment samples collecred during 1990 to 1993 to evaluate the predictive ability of sediment quality guidelines (SQGs). specifically, effects range-low (ERL). effects range-median (ERM). threshold effects level (TELL and probable eifects level (PEL) values. Dam were acquired from surveys of sediment quality periomed in estuaries along the Atlantic. Pacific. and Gulf of hlexico coasts. Samples were classified as either nontoxic ( p > 0.05 re!ative to controls). marginally toxic @ < 0.05 only). or highly toxic @ < 0.05 and response greater than minimum significant difference :elalive to controls). This analysis indic-red that. when nor exceeded. [he ERLs and TELs were highly predictive of nontoxicity. The percenrages of samples that were highly toxic generally increased with increasing numbers of guidelines (panicularly the EX.\.ls and PELS) that were exceeded. Also. the incidence of toxicity increased with increases in concentntions of mixtures of chemicals normalized to (divided by) the SQGs. The ERhls and PELs indicated high predictive ability in samples in which many substances exceeded these concentrations. Suggestions are provided on the uses of these estimates of the predictive ability o i sediment ~uidelines.