The SQGs that were expressed on an organic carbon–normalized basis were converted to dry weight–normalized values at 1% organic carbon (MacDonald et al. 1994, 1996; US EPA 1997a). The dry
weight–normalized SQGs were utilized because the results of previous studies have shown that they predicted sediment toxicity as well or better than organic carbon–normalized SQGs in field-collected sediments (Barrick et al. 1988; Long et al. 1995; Ingersoll et al. 1996; US EPA 1996a; MacDonald 1997).