Figure 4. Concentrations of polycyclic aromatic hydrocarbons (PAH's)
and DDT derivatives in surficial sediments of Geneva Lake, compared with
Canadian freshwater sediment quality guidelines: Interim Sediment Quality
Guidelines (ISQG) and Probable Effect Level (PEL) (Canadian Council of
Ministers of the Environment, 1999). Bars show ranges from minimum to
maximum concentrations reported (on log scale). If nondetectable, the
concentration used is approximately one-half of the detection limit.